JP3096518U - Paper detection switch unit - Google Patents

Abstract

(57) [Problem] To provide a paper detection switch unit used for a printing device or the like by using an inexpensive general-purpose torsion coil spring as a return spring of a paper detection piece. The workability of assembling the torsion coil spring is improved.
The fluttering operation of the light blocking lever is suppressed to improve the operation reliability of the switch sensor. SOLUTION: A support shaft 2 at the base of a sheet detection piece 13 is rotatably attached to a bracket 12 of a housing 1. The switch sensor 3 is attached to the housing 1. The switch sensor 3 includes an optical switch 31 and a light blocking lever 35 extending from the support shaft 2. The wire diameter of the torsion coil spring 4 as a return spring of the sheet detecting piece 13 is increased, one end 42 of the torsion coil spring 4 is extended along the side surface of the light shielding lever 35, and its end is a rear end surface of the light shielding lever 35. 35a.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

  The present invention is directed to a paper detection switch unit used in a printing device or the like, particularly a paper feeding switch unit. After the paper moving in the feed path has passed over the paper detection piece by falling and swinging, the paper detection is detected. Paper that is designed to return to its initial position by the action of a torsion coil spring Regarding the detection switch unit.

[0002]

[Prior art]

  A conventional paper detection switch unit of this type is shown in FIG. Paper inspection of the figure The knowledge unit is attached to the shaft hole (not shown in the figure) of the bracket 12 of the housing 1, To rotatably fit and attach the support shaft portion 2 provided at the base of the paper detection piece 13. Thus, the leading edge of the sheet (not shown) that has moved in the direction of arrow F on the sheet transport path is detected as the sheet. After hitting the piece 13, the sheet detecting piece 13 is pushed down around the spindle 2. It is configured to ride on the sheet detecting piece 13 while swaying and swinging to the front side. And the laid-down posture of the paper detection piece 13 when the paper has climbed up is shown by imaginary lines. It

[0003]   A switch sensor 3 is attached to the housing 1, and the switch sensor 3 The sensor 3 causes the sheet detection piece 13 to oscillate and return after the oscillating swing. It is possible to detect motion and motion. That is, this switch sensor -3 is an optical switch including a light emitting portion and a light receiving portion which are integrally provided in the housing 1. 31 and a light-shielding lever 35, the light-shielding lever 35 detects the sheet from the support shaft portion 2. A space extending toward the opposite side (downward) of the piece 13 and facing the light emitting portion and the light receiving portion. Between the light-shielding position inside (shown by the solid line in the figure) and the non-light-shielding position behind the light-shielding position. In the meantime, the paper detection piece is rocked in conjunction with the fall return rocking movement. Na Note that the position of the light-shielding lever 35 when the sheet has climbed up on the sheet detection piece 13 is temporarily shown in the figure It is shown in a phantom line.

[0004]   Further, in this paper detection switch unit, the paper has passed over the paper detection piece 13. Immediately after that, the paper detection piece 13 is changed from the laid posture shown by a virtual line to the initial posture shown by a solid line. In addition, a torsion coil spring 4 for returning and swinging as shown by an arrow B is provided. this The torsion coil spring 4 belongs to a precision spring and has a very small wire diameter. Is adopted, and the coil portion 41 of the torsion coil spring 4 is fitted to the support shaft portion 2. Are held together, and the one end 42 thereof is a hole formed in the light-shielding lever 35. It is inserted and held in the part 36, and the other end 43 is fixed by the upper surface of the housing 1. It is mounted on and supported by the locking surface 14 formed as described above.

[0005]   By the way, in this type of paper detection switch unit, the recovery of the paper detection piece 13 The torsion coil spring 4 belonging to the precision spring as described above is used as the return spring. The paper detection piece 13 can perform a stable and accurate swaying motion even with weak paper. It depends on what you consider doing.

[0006]   On the other hand, in the conventional paper detection switch unit, the torsion coil spring 4 has Related to the use of torsion coil springs with a very small wire diameter belonging to precision springs I was forced to take the measures described below.

[0007]   That is, in the precision spring, since the wire diameter is extremely thin and flexible thin wire is used, The one end 42 of the torsion coil spring 4 is extended to extend the rear end surface 35 of the light-shielding lever 35. If it is locked to a, the rigidity of one end portion 42 thereof will be insufficient and the light-shielding lever 35 will The torsional elastic force of the ile portion 41 is less likely to be applied. Therefore, the one end 4 2 cannot be locked to the rear end surface 35a of the light blocking lever 35. Therefore, illustrated The coil spring 4 is twisted to the light-shielding lever 35 at a position as close to the support shaft portion 2 as possible. The hole 36 having an extremely small diameter corresponding to the wire diameter of the By inserting 42, the one end 42 is locked to the light blocking lever 35. I was taking measures.

[0008]   On the other hand, as a precedent example using a torsion coil spring, the telephone body is equipped with There is a switch device that can be applied to a hook switch that detects attachment / detachment of a container. this The switch device uses a torsion coil spring as the return spring for the hook switch. The torsion coil spring winding part (coil part) into the lever spring accommodating part. , The free end of the torsion coil spring on one side should be extended straight By locking it on the spring receiving surface and pressing the free end on the other side with the cover. It is described that the lever is biased in one direction (for example, Patent Document 1 or See Patent Document 2).

[0009]

[Patent Document 1]   JP-A-8-111140

[Patent Document 2]   JP, 9-7461, A

[0010]

[Problems to be solved by the device]

  However, in the conventional paper detection switch unit described with reference to FIG. The wire diameter of the one end portion 42 of the coil spring 4 is thin and easily bendable. Since the hole portion 36 of the bar 35 is a fine hole, the coil portion 41 is fitted to the support shaft portion 2. While assembling the torsion coil spring 4 in which the one end 42 is inserted into the hole 36 It is said that assembling work is extremely troublesome as it requires skill and great care. If there is a problem, the one end may hit the peripheral edge of the hole 36 There was also a situation where it was shaped.

[0011]   In addition, the one end 42 with respect to the center of the support shaft portion 2 and the light blocking lever 35 shown in FIG. The distance L1 to the locking part (hole 36) of is set as short as possible for the above reason. Since the sheet detection piece 13 is twisted, the imaginary line is collapsed by the urging force of the torsion coil spring 4. When the user swings from the prone position to the initial position indicated by the solid line, the shading lever 35 moves Light-blocking lever that bounces backward when it hits the contact surface 15 of the ging 1. There is a situation in which the action of suppressing the flapping motion of 35 is not sufficiently exerted. It was Therefore, the fluttering operation of the light-shielding lever 35 causes the apparent appearance of the optical switch 31. In the event that the operation becomes unstable and the operational reliability of the switch sensor 3 decreases, It could happen.

[0012]   In view of the above problems, the present invention does not use a precision spring as a return spring of the paper detection piece. While it is intended to use a torsion coil spring that is inexpensive and versatile, the paper detection switch Improve workability of assembling torsion coil springs as return springs for switch units Is intended.

[0013]   In addition, the present invention improves the workability of assembling the torsion coil spring, A paper detection switch unit that can easily suppress the flap action of the light blocking lever. The purpose is to provide

[0014]

[Means for Solving the Problems]

  The paper detection switch unit according to the present invention detects the paper detection on the bracket of the housing. The paper feed path can be attached by rotatably attaching the spindle provided on the base of the projecting piece. Do not allow the paper that has moved around to fall and swing the above-mentioned paper detection piece around the above-mentioned spindle. The housing is constructed so as to ride on the paper detection piece. A switch for detecting the fall swing of the sheet detection piece and the return swing after the fall swing. Sensors are installed and their switch sensors are An optical switch including a light section and a light receiving section, and the opposite side of the paper detection piece from the spindle section. To the light shielding position in the space where the light emitting portion and the light receiving portion of this optical switch face Swing in conjunction with the fall return swing of the paper detection piece between the light position and the non-light-shielded position. It is a light-shielding lever that is moved, and a torsion coil for returning and swinging the paper detection piece. The coil portion of the il spring is fitted to the support shaft portion, and the torsion coil spring The end on the side is inserted into the hole formed in the light-shielding lever at a location near the spindle. And the other end of the torsion coil spring is attached to the housing. In the paper detection switch unit mounted and supported on the locking surface, the twist Instead of increasing the wire diameter of the ill spring and inserting one end of the il spring into the hole, hold it. In addition, extend the length of the one side end along the side surface of the light shielding lever and Is locked to the rear end surface of the light-shielding lever in the vicinity of the free end.

[0015]   With this configuration, the torsion coil spring is increased in diameter to increase the torsion coil There is no need to use the il spring as a precision spring. And one side of the torsion coil spring Instead of inserting the end into the hole of the light blocking lever and holding it, the length of the one end Extend along the side of the light-blocking lever and place it near the free end of the light-blocking lever. By adopting a structure in which it is locked to the end surface, a torsion coil spring is assembled. When mounting, the work of locking the one side end to the rear end surface of the light blocking lever All you have to do is insert one end into the small hole of the light-shielding lever as in the past. Assembly of torsion coil springs as no need for skilled work The workability is greatly improved. Moreover, the length of the end on one side is set to It extends along and is locked to the rear end surface of the light shield lever near the free end. , The action of suppressing the flap action of the light-shielding lever is fully exerted, and the movement of the optical switch The operation is stable and the operational reliability of the switch sensor is improved.

[0016]   In the present invention, the free end of the light-shielding lever is up when the light-shielding lever is in the light-shielding position. The length of the light-shielding lever is set so that it is located in the space where the light emitting unit and the light receiving unit face each other. It is fixed and one end of the torsion coil spring and the light shielding lever When the light blocking lever is located at the light blocking position, A portion located in the space between the light emitting portion and the light receiving portion is selected, and the light shielding lever is The one side end portion extending along the side surface of the It is desirable that the light beam is escaped to a position where it does not intersect the light beam toward the light receiving portion. to this This prevents the light-shielding lever from protruding below the space where the light-emitting unit and the light-receiving unit face each other. The size of the switch sensor is suppressed, but the light-blocking lever flaps nevertheless. The action of suppressing the movement is enhanced.

[0017]   The paper detection switch unit according to the present invention has the following structure. It is embodied more. That is, at the base of the paper detection piece on the housing bracket You can move the paper feed path by rotatably attaching the provided spindle. While the paper is tilting and swinging the paper detection piece about the spindle, the paper It is configured to ride on the detection piece, and the paper detection A switch sensor that detects the falling rocking of the piece and the return rocking after the falling rocking is installed. The light emitting unit and the light receiving unit, which are mounted on the switch sensor, are arranged at intervals. And an optical switch equipped with and extending from the support shaft to the opposite side of the paper detection piece. Light shielding position in the space where the light emitting part and the light receiving part of the optical switch of Shading that is rocked in conjunction with the non-light-shielding position of the above-mentioned paper detecting piece It is composed of a lever and a coil of a torsion coil spring for returning and swinging the paper detection piece. And the torsion coil spring has one end on top. It is inserted and held in a hole formed in the light-shielding lever at a position near the support shaft, The other end of the torsion coil spring is mounted on the locking surface provided on the housing. In the supported paper detection switch unit, the light blocking lever is at the light blocking position. Its free end is positioned in the facing space between the light emitting part and the light receiving part when The length of the light-shielding lever is set so that Instead of increasing the wire diameter of the spring and inserting one end of the spring into the hole to hold it , The length of one end of the light shielding lever is extended along the side surface of the light shielding lever. Is locked to the rear end surface near the free end of the When the lever is in the light blocking position, it is positioned in the space where the light emitting unit and the light receiving unit face each other. The one to be placed is selected and extended along the side surface of the light shielding lever. Position where the side edge does not intersect with the light ray from the light emitting portion to the light receiving portion at the light shielding position Is formed by cutting off a part of the front end surface of the light-shielding lever. The forward-facing protruding piece that is abutted against the contact surface formed on the housing. Therefore, the light-shielding position of the light-shielding lever is regulated. It is made even more concrete by using. The operation of this invention will be described below. A detailed description will be given with reference to the form.

[0018]

[Embodiment of device]

  FIG. 1 is a front view of a paper detection switch unit according to the present invention, and FIG. 2 is a plan view of the same. 3 is a sectional view taken along the line III-III in FIG. 1, and FIG. 4 is an operation explanatory view.

[0019]   1 to 3, the housing 1 has a printer at the upper end of the front plate portion 16 thereof. And an attachment portion 17 for an attachment portion (not shown) provided in another printing device In addition, the upper plate portion 18 protruding rearward from the upper end of the front plate portion 16 is provided. A pair of brackets 12 that face the upper plate portion 18 in the left-right direction with a space therebetween are set up. Has been. These brackets 12 are provided in the shaft holes 19 at the base of the paper detection piece 13. A column-shaped lateral support shaft portion 2 is rotatably fitted and attached. And paper The front end of the sheet (not shown) that has moved in the direction of arrow F in FIG. After hitting 3, the paper detection piece 13 is pushed down around the support shaft 2 It is configured to ride on the sheet detection piece 13 while swaying and swinging to the side. . The fallen posture of the sheet detection piece 13 when the sheet has climbed up is shown in phantom lines in FIG. is there.

[0020]   An inner corner shape formed by the lower plate portion 23 of the housing 1 and the front plate portion 16 The switch sensor 3 is housed in the space of The above-described fall swing of the sheet detection piece 13 and the return swing after the fall swing are detected. Is able to. That is, this switch sensor 3 is The optical switch 31 and the light-shielding lever 35 attached to the optical switch 2 side While the lever 31 is attached to the lower plate portion 23, the light-shielding lever 35 is not attached to the support shaft portion 2. From the sheet detection piece 13 to the opposite side (downward). And the optical switch 31 One of the pair of elements 32 and 33 is formed as a light emitting portion and the other is formed as a light receiving portion. The light section and the light receiving section face each other with a relatively wide space. And the light blocking lever 3 Reference numeral 5 denotes a light shielding position in the facing space S between the light emitting portion and the light receiving portion (shown by a solid line in FIG. 3). And the non-light-shielding position behind the light-shielding position are linked to the fall return swing of the sheet detection piece 13. It is designed to move and rock. It should be noted that the sheet climbs on the sheet detection piece 13. The position of the light-shielding lever 35 when it is opened is shown by a virtual line in FIG.

[0021]   This paper detection switch unit is provided immediately after the paper has passed over the paper detection piece 13. The sheet detection piece 13 is changed from the laid posture shown by the phantom line in FIG. 3 to the initial posture shown by the solid line. In addition, a torsion coil spring 4 for returning and swinging as shown by an arrow B is provided. this The torsion coil spring 4 is the same as the torsion coil spring belonging to the precision spring described in FIG. A wire material having a thicker wire diameter is used, and the coil portion 4 of the torsion coil spring 4 is used. 1 is fitted and held by the support shaft portion 2, and one end portion 42 thereof is provided at the light-shielding lever 3 5, which extends straight along one side surface of the hook 5, and is bent at its end. Is locked to the rear end surface 35a of the light-shielding lever 35 near the free end thereof. this On the other hand, the other end 43 of the torsion coil spring 4 is provided on the upper plate portion 18 of the housing 1. It is mounted and supported on a locking surface 14 formed by the upper surface.

[0022]   Further, as shown in FIG. 3, the light-shielding lever 35 removes a part of the rear end surface 35a. In contrast to the forward projecting piece 37 formed by The surface of the front plate portion 16 of the housing 1 facing the portion 37 is formed as a contact surface 24. The front projection piece 37 hits the contact surface 24, and The light shielding position of No. 5 is regulated.

[0023]   Further, when the light blocking lever 35 is located at the light blocking position shown by the solid line in FIG. Has its free end located in the facing space S between the light emitting portion and the light receiving portion, and The length of the light-shielding lever 35 is determined so as not to project downward, and The one end 42 of the torsion coil spring 4 and the rear end surface 35a of the light blocking lever 35 are The locking position is near the free end of the light blocking lever 35, that is, the light blocking lever 35 blocks light. Select a position that is located in the space where the light emitting unit and the light receiving unit face each other when the position is set. In addition, the one end portion 42 extending along the side surface of the light blocking lever 35 has a light blocking When the bar 35 is located at the light-shielding position, it intersects with the light beam that goes from the light emitting unit to the light receiving unit. It has been escaped to a position where it does not exist.

[0024]   According to the paper detection switch unit configured as described above, the paper detection piece 13 Due to the return swing of the housing 1, the front projection 37 of the light-shielding lever 35 contacts the contact surface 2 of the housing 1. The light blocking lever 35 is restricted to the light blocking position by hitting the light blocking member 4. This shading In the position, as shown in FIG. 4, the light-shielding lever 35 forms the light emitting portion or the light receiving portion. Opposed to the light-projecting side slits 32 or 33 or the light-receiving side slits 32a and 33a. .

[0025]   Further, by cutting off a part of the rear end surface 35a of the light-shielding lever 35, the forward projection is performed. Since the piece portion 37 is formed, the light-shielding lever 35 is lightened accordingly. So Therefore, the paper passes over the paper detection piece 13 and is biased by the torsion coil spring 4. The sheet detection piece 13 changes from the fallen posture shown by the phantom line in FIG. 3 to the initial posture shown by the solid line. The operation of the sheet detection piece 13 when returning and swinging as shown by the mark B is performed by the torsion coil spring 4 Although the elastic force of the coil part 41 of FIG. The degree of influence is reduced. Therefore, the speed of return swing of the paper detection piece 13 and the timing It is possible to change the spring characteristics of the torsion coil spring 4.

[0026]   In this embodiment, the torsion coil spring 4 has the torsion coil described in FIG. A wire material with a larger wire diameter than that of the spring 4 is used, and it has low cost and versatility. It is a torsion coil spring. Therefore, the one end portion 42 thereof has the light-shielding lever 35. Is extended along the side surface of the light blocking lever 35 and is locked to the rear end surface 35a of the light blocking lever 35. Even if it is, ensure that the rigidity required for the one end 42 is sufficiently ensured. Therefore, the torsional elastic force of the coil portion 41 is efficiently applied to the light blocking lever 35. So Therefore, the elasticity of the coil portion 41 of the torsion coil spring 4 causes the paper detection piece 13 to move. The rocking motion from the lying posture to the initial posture is reliably performed. Moreover, as shown in FIG. When the light blocking lever 35 is in the light blocking position, The switch section is set to a length that does not protrude below the facing space S between the light section and the light receiving section. The size of the sensor 3 is suppressed. Further, as shown in FIG. 4, a torsion coil spring 4 the one end portion 42 and the rear end surface 35a of the light-shielding lever 35 are engaged with each other at the engaging position a. Since it is set at a position located in the space S, the center of the support shaft portion 2 and its locking position Of the coil portion 41 of the torsion coil spring 4 becomes sufficiently long. The elastic pressing force of the is efficiently transferred to the vicinity of the free end of the light-shielding lever 35 via the one end 42. Well transmitted, the fluttering movement of the light blocking lever is suppressed well, and the The operation of the switch 31 is stabilized, and the operational reliability of the switch sensor 3 is improved.

[0027]   Further, when the torsion coil spring 35 is assembled to the support shaft portion 2, the torsion coil The one end 42 of the spring 4 is simply locked to the rear end surface 35a of the light blocking lever 35. It is only necessary to perform the work that can be done purely and easily, as described in FIG. Skilled in inserting the one end 42 of the spring 35 into the hole 36 of the light-shielding lever 35 Since it is not necessary to perform the necessary troublesome work, the assembly work of the torsion coil spring 4 The workability is greatly improved.

[0028]   Further, as can be seen in FIG. 4, one side extended along the side surface of the light blocking lever 35. The end portion 42 changes from the light emitting portion to the light receiving portion when the light shielding lever 35 is located at the light shielding position. The light is directed to the position where it does not intersect with the light beam, A torsion coil spring when 5 swings between a light blocking position and a non-light blocking position behind it. It is unlikely that the one end 42 of No. 4 will emit a light beam, which is It is useful for improving the operational reliability of the touch sensor 3.

[0029]

[Effect of device]

  As described above, according to the paper detection switch unit of the present invention, the paper detection piece Uses a torsion coil spring, which is inexpensive and versatile, without using a precision spring as a return spring. And the workability of assembling the torsion coil spring is improved. The fruit is played. In addition, the workability of assembling the torsion coil spring is improved. At the same time, since the fluttering movement of the light-shielding lever is easily and reliably suppressed, There is also an advantage that the operation reliability of the switch sensor is improved.

[Brief description of drawings]

FIG. 1 is a front view of a paper detection switch unit according to the present invention.

FIG. 2 is a plan view of the paper detection switch unit of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an explanatory view of the action of a torsion coil spring.

FIG. 5 is a side view illustrating a conventional paper detection switch unit.

[Explanation of symbols]

1 housing 2 spindle 3 switch sensor 4 torsion coil spring 12 brackets 13 Paper detection piece 14 Locking surface 24 Contact surface 31 optical switch 35 Light-blocking lever 35a Rear end face of light-shielding lever 36 holes 37 Front protrusion 41 coil 42 one end S Opposing space between light emitting part and light receiving part B Lock location

Claims (3)

[Scope of utility model registration request] 1. A support shaft provided at the base of a paper detection piece is rotatably attached to a bracket of a housing, so that the paper moving in a paper feeding path is centered on the support shaft. A switch configured to ride on the sheet detecting piece while tilting and swinging the sheet detecting piece, and detecting the falling swing of the sheet detecting piece and the return swing after the falling swing in the housing. A sensor is attached, and the switch sensor has an optical switch provided with a light emitting portion and a light receiving portion which are arranged at a distance, and extends from the spindle portion to the opposite side of the sheet detecting piece to emit light from the optical switch. And a light-shielding lever which is oscillated in association with a fall-back return swing of the sheet detecting piece between a light-shielding position in a space facing the light-receiving unit and a non-light-shielding position behind the light-shielding position. Restore the paper detection piece The coil portion of the torsion coil spring for swinging back is fitted to the support shaft portion, and one end of the torsion coil spring is attached to the light shielding lever at a position near the support shaft portion. Inserted and held in the formed hole,
In a paper detection switch unit in which the other end of the torsion coil spring is mounted and supported on a locking surface provided on the housing, a free end of the light detection lever is located when the light blocking lever is located at the light blocking position. The length of the light-shielding lever is determined so as to be located in the space where the light emitting portion and the light receiving portion face each other, and the wire diameter of the torsion coil spring is increased so that one end portion thereof is increased. Instead of inserting it into the hole and holding it, the length of its one end is extended along the side surface of the light-shielding lever and its end is locked to the rear end face of the light-shielding lever near the free end. As the locking position, a position located in the facing space between the light emitting part and the light receiving part when the light blocking lever is located at the light blocking position is selected, and along the side surface of the light blocking lever. The above-mentioned one side end that has been extended At the light-shielding position, the light is emitted to a position that does not intersect with the light beam traveling from the light-emitting portion to the light-receiving portion, and the forward-facing protrusion formed by cutting off a part of the front end surface of the light-shielding lever is the housing. A sheet detection switch unit, wherein the light-shielding position of the light-shielding lever is regulated by hitting a contact surface formed on the sheet. 2. A support shaft provided at the base of the paper detection piece is rotatably attached to a bracket of the housing, so that the paper that has moved in the paper feeding path is centered on the support shaft. A switch configured to ride on the sheet detecting piece while tilting and swinging the sheet detecting piece, and detecting the falling swing of the sheet detecting piece and the return swing after the falling swing in the housing. A sensor is attached, and the switch sensor has an optical switch provided with a light emitting portion and a light receiving portion which are arranged at a distance, and extends from the spindle portion to the opposite side of the sheet detecting piece to emit light from the optical switch. And a light-shielding lever which is oscillated in association with a fall-back return swing of the sheet detecting piece between a light-shielding position in a space facing the light-receiving unit and a non-light-shielding position behind the light-shielding position. Restore the paper detection piece The coil portion of the torsion coil spring for swinging back is fitted to the support shaft portion, and one end of the torsion coil spring is attached to the light shielding lever at a position near the support shaft portion. Inserted and held in the formed hole,
In a paper detection switch unit in which the other end of the torsion coil spring is mounted and supported on a locking surface provided in the housing, the wire diameter of the torsion coil spring is increased, and one of Instead of inserting and holding the side end into the hole, the length of one end of the side end is extended along the side surface of the light-shielding lever so that its end is located at the rear end surface near the free end of the light-shielding lever. A paper detection switch unit characterized by being locked. 3. The length of the light-shielding lever is determined so that the free end of the light-shielding lever is located in the facing space between the light-emitting portion and the light-receiving portion when the light-shielding lever is in the light-shielding position. Along with the one end portion of the torsion coil spring and the rear end surface of the light-shielding lever, a space where the light-emitting portion and the light-receiving portion face each other when the light-shielding lever is in the light-shielding position. A portion located inside is selected, and the one end portion extended along the side surface of the light-shielding lever is escaped to a position where it does not intersect with the light beam traveling from the light-emitting unit to the light-receiving unit at the light-shielding position. The paper detection switch unit according to claim 2.