JP2001215638A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problem that a platen cover can not be fully closed owing to interference between components when a sensor unit provided on the side of a device main body is used in common and the closure angle of the platen cover detected by the sensor unit is set to the same angle in the case where platen covers having different specifications are used for devices of the same kind. SOLUTION: This reader has a sensor unit 9 on the device main body side and an operation unit 8 on the side of the platen cover 4 as a means for detecting the closure angle of the platen cover 4. The sensor unit 9 has a movable rod 10 which is arranged projecting from a top cover 3 on the device main body side. The operation unit 8 has a press member 30 which abuts against and presses in the movable rod 10 when the platen cover 4 is closed and support mechanism 19, 29 which while energizing the press member 30 away from the platen cover 4, support it movably in the opposite direction from the energizing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus capable of detecting a closing angle of a document pressing member for pressing a document placed on a document table.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine incorporates an image reading apparatus for forming a reflected light image from a document on an image sensor and reading the image. In this type of image reading apparatus, a platen glass (document table) is provided on an upper part of the apparatus main body, and an image recorded on the document is held down while a document placed on the platen glass is pressed by a platen cover (document pressing member). Is read optically.

In such an image reading apparatus,
An operator closes a platen cover provided at the top of the apparatus body so as to be openable and closable so that the original placed on the platen glass is pressed by the platen cover. At that time, an apparatus which detects the closing angle of the platen cover and automatically detects the document size based on the detection result is disclosed in, for example, Japanese Utility Model Laid-Open No. 63-94432.

As means for detecting the closing angle of the platen cover, there is known a means in which a sensor unit for detecting the closing angle is provided on the apparatus main body side and a projection for operating the sensor unit is provided on the platen cover side. ing. Further, as a sensor unit, there is known a sensor unit including a movable bar arranged in a protruding state at an upper portion of an apparatus main body and a sensor which is turned on / off by movement of the movable bar.

In the closing angle detecting means having the above structure,
When the operator closes the open platen cover, the protruding portion of the platen cover comes into contact with the movable rod during the closing. Thereafter, the movable bar is gradually pushed by the projection in conjunction with the closing operation of the platen cover. When the closing angle of the platen cover reaches a predetermined angle (when the amount of pushing of the movable rod by the protrusion reaches the predetermined amount), the on / off state of the sensor is switched. This makes it possible to detect from the output signal (ON / OFF signal) of the sensor that the platen cover has been closed to a predetermined angle.

By the way, when the platen cover is completely closed (fully closed state), a projection provided on the platen cover interferes with the top cover on the apparatus main body side (collision).
The length (projection dimension) of the protruding portion is set for each model so as not to prevent it.

On the other hand, when a platen cover with the same model but different specifications is used, for example, a platen cover serving only to hold down the document, and a function of editing the read image (for example, color When a platen cover having an input function such as designation, change, etc.) is used, it is necessary to change the position of the hinge serving as the opening / closing fulcrum of the platen cover according to the specifications of the platen cover due to design restrictions on the platen cover side. .

In such a case, in order to share a sensor unit provided on the apparatus main body side and set the closing angle of the platen cover detected by this sensor unit to the same angle, a projection is formed from the hinge position on the platen cover side. It is necessary to set the length of the protruding portion to be longer as the distance to is longer.

[0009]

However, if the length of the projection on the platen cover side is increased as described above,
When the platen cover is closed, the protrusion collides with the top cover on the apparatus main body side to cause mechanical damage, and the platen cover cannot be fully closed.

When the length of the projection is reduced to avoid such a problem, the closing angle of the platen cover detected by the sensor unit differs.
However, the closing angle of the platen cover to be detected by the sensor unit is determined by appropriately setting the document size detection timing as described above, or a so-called eye hazard that protects the operator's eyes from light emitted from a light source when detecting the document size. It is necessary to set the same angle even if the specifications of the platen cover are different for safety reasons. Therefore, the method of setting the length of the protruding portion to be short has a new disadvantage.

It is also conceivable to design a sensor unit in accordance with the specifications of the platen cover and handle the platen cover and the sensor unit in pairs. In such a case, however, the number of types of sensor units increases.
This leads to an increase in management man-hours and cost. In addition, a change in the specification of the platen cover in the market necessitates replacement of the sensor unit on the apparatus main body side, which increases the cost of parts and increases the number of man-hours for replacement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to detect the closing angle of the platen cover even when the same model and a different platen cover are used. The sensor unit can be shared, and the closing angle of the platen cover detected by the sensor unit can be set to the same angle,
In addition, an object of the present invention is to provide an image reading apparatus capable of fully closing the platen cover without mechanically damaging the apparatus body.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in order to achieve the above-mentioned object, and has a document holding member provided on the apparatus main body so as to be openable and closable, and a closing member for detecting a closing angle of the document holding member. In an image reading apparatus including an angle detection unit, a closing angle detection unit includes a sensor unit provided on the apparatus main body side and an operation unit provided on a document pressing member side and operating the sensor unit by opening and closing the document pressing member. The sensor unit has a movable member that is arranged to protrude above the apparatus main body when the document pressing member is opened, and the operating unit contacts the movable member when the document pressing member is closed. A pressing member that comes into contact with and presses the pressing member, and moves in a direction opposite to the pressing direction while pressing the pressing member in a direction away from the document pressing member. It has to have a support mechanism for supporting the ability.

In the image reading apparatus having the above configuration, when the document holding member in the open state is closed,
During the closing, the pressing member of the operating unit comes into contact with the movable member of the sensor unit, and when the document pressing member is closed from this state, the movable member is pushed by the pressing member in conjunction with the closing operation. As a result, the sensor unit operates to detect the closing angle of the document pressing member. Thereafter, when the document pressing member is closed to a state close to the fully closed state, the pressing member comes into contact with the upper surface of the apparatus main body depending on the length (projection dimension) of the operation unit on the document pressing member side. . However, when the document pressing member is closed from this state, the pressing member is pushed back to the document pressing member side against the urging force while being guided by the support mechanism due to the reaction force received from the apparatus main body side by the closing operation. It is. As a result, it is possible to close the document pressing member to a fully closed state while reducing the length of the operation unit including the pressing member.

According to the present invention, there is provided an image reading apparatus comprising: a document pressing member provided in the apparatus main body so as to be openable and closable; and a closing angle detecting means for detecting a closing angle of the document pressing member. A sensor unit having a movable member that is arranged to protrude above the apparatus main body when the document pressing member is opened, and a sensor unit that is provided on the document pressing member and contacts the movable member when the document pressing member is closed. The device body has a relief portion that allows the movable member to be freely inserted and removed on the device body and allows the end of the protrusion portion to advance into the device body.

In the image reading apparatus having the above structure, when the document holding member in the open state is closed,
During the closing, the projection of the document pressing member contacts the movable member of the sensor unit. When the document pressing member is closed from this state, the movable member is pushed by the projection in conjunction with the closing operation. As a result, the sensor unit operates to detect the closing angle of the document pressing member. After that, when the document pressing member is closed to the fully closed state, depending on the length (projection size) of the projecting portion on the document pressing member side, the end of the projecting portion is provided by the relief portion provided in the apparatus main body. To be deployed. Thus, even when the length of the protrusion is changed (longened) due to a change in the specification of the document pressing member, positional interference between the protrusion and the apparatus main body during closing of the document pressing member is avoided. Thus, the document pressing member can be closed to the fully closed state.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of an image reading apparatus according to the present invention. In FIG. 1, a platen glass 2 serving as a document table is attached to an upper portion of the apparatus main body 1. The apparatus main body 1 is formed in a substantially box shape by a metal frame or the like. The platen glass 2 is made of a transparent glass plate having a rectangular shape in a plan view, and a document to be read is placed on the upper surface thereof.

A top cover 3 and a platen cover 4 are attached to the upper part of the apparatus main body 1. The top cover 3 is made of, for example, an integrally molded product of resin, and is fixed to the upper portion of the apparatus main body 1 by screws or the like so as to surround the platen glass 2. The top cover 3 forms a part of the apparatus main body 1. The platen cover 4 is rotatably supported by a pair of hinge mechanisms (not shown) on the rear side of the apparatus main body 1 (on the rear side when viewed from the standing position of the operator).
Is the main body 1 around the pivot point of the hinge mechanism.
It is attached to the top of the car so that it can open and close.

The platen cover 4 includes a cover body 5
And a pressing sheet 7 attached to the lower surface of the cover body 5 via a cushion member 6 such as a sponge. Further, an operation unit 8 is mounted on the lower surface side of the platen cover 4, and a movable rod 10 constituting a sensor unit (9) described later is provided on the apparatus main body 1 correspondingly. The operation unit 8 and the movable bar 10 are arranged on the back side of the apparatus main body 1 avoiding the mounting positions of the holding sheet 7 and the platen glass 2 respectively.

FIG. 2 is a perspective view showing the structure of the sensor unit 9 provided on the apparatus main body side. In the illustrated sensor unit 9, the support bracket 11 is a sheet metal part obtained by processing a metal plate into a predetermined shape, and is fixed to the apparatus main body 1 by a screw or the like. A guide member 12 and a photo interrupter 13 are attached to the support bracket 11.

The guide member 12 is a block-shaped part made of resin. The movable bar 10 is guided and supported movably in the direction of the arrow (up and down) in the figure so as to penetrate (fit) the guide member 12. I have. In this support state, the rotating operation of the movable bar 10 is regulated by making the shape of the fitting between the movable bar 10 and the guide member 12 substantially rectangular in cross section. The photo interrupter 13 is for detecting the closing angle of the platen cover 4 and includes a light emitting unit and a light receiving unit facing each other.

The upper end of the support bracket 11 has a
One locking portion 14 is provided, and a second locking portion 15 is provided at the lower end of the movable rod 9 correspondingly. And
One end of the tension coil spring 16 is locked to the first locking portion 14, and the other end of the tension coil spring 16 is locked to the second locking portion 15. Further, a light-shielding plate 17 is provided at the lower end of the movable bar 10 so as to protrude in a direction different from that of the second locking portion 15.

The tension coil spring 16 always urges the movable rod 10 in one direction (upward in the figure) by the elastic force of the spring itself.
Is abutted against the lower end surface of the guide member 12. In this abutting state, the light-shielding plate 17 is arranged between the light-emitting portion and the light-receiving portion of the photo-interrupter 13 (on the optical path), whereby the output signal of the photo-interrupter 13 is kept in the off state.

FIG. 3 is a side view showing the structure of the operation unit 8 provided on the platen cover side, and FIG. 4 is an exploded perspective view of the operation unit viewed from below. In the illustrated operating unit 8, the support member 19 is made of a resin integrally molded product, and is formed in a substantially T-shape by left and right wing portions 20 and 21 and a sliding guide portion 22 hanging from an intermediate portion between them. I have.

The supporting member 19 is attached to the wing portions 20 and 21 of the supporting member 19 by the platen cover 4 (cover body 5).
The fixing holes 23A and 23B for fixing the holes 23A and 23B are formed. Among them, one fixing hole 23A is formed in a circular shape, and the other fixing hole 23B is formed in a long hole shape.
Then, using these fixing holes 23A and 23B, the support member 19 is fixed to the platen cover 4 by screws 24A and 24B.
It is configured to be fixed to.

The sliding guide portion 22 of the support member 19 has a columnar spring mounting portion 25 and a pair of guide pieces 26.
A, 26B and a stopper piece 27 are formed.
The pair of guide pieces 26A and 26B are formed on both sides of the spring mounting portion 25. The stopper piece 27 is attached to the spring mounting portion 2.
5 and formed in pairs in different directions from the pair of guide pieces 26A and 26B. This stopper piece 2
7, a claw portion 28 is formed integrally.

A compression coil spring 29 is mounted on the support member 19 so as to fit on the outer peripheral portion of the spring mounting portion 25. Further, outside the compression coil spring 29,
The pressing member 30 is mounted so as to accommodate this. The pressing member 30 has a substantially box-shaped structure with an upper part opened, and has a lower end surface 31 as a contact part with the movable rod 10 described above. On two opposing side walls of the pressing member 30,
A rectangular long hole 32 into which the claw portion 28 of the stopper piece 27 is fitted is provided.

The pressing member 30 has a sliding guide portion in a state where the inner surfaces of two opposing side walls (side walls without the elongated holes 32) are in contact with or close to the outer surfaces of the pair of guide pieces 26A and 26B. 22. In this mounted state, the lower end of the compression coil spring 29 is in contact with the bottom of the pressing member 30. In the same state, the claw portion 28 of the stopper piece 27 is fitted into the elongated hole 32 of the pressing member 30, and in the fitted state, the compression coil spring 29
Is brought into contact with the upper end of the elongated hole 32 by the urging force.

With the support member 19, the compression coil spring 29 and the pressing member 30 assembled in this manner, the pressing member 3
0 is slidably guided in the vertical direction in FIG. 3 by the sliding guide portion 22 of the support member 19, and is always in one direction (downward in FIG. 3) by the elastic force of the compression coil spring 29.
It is urged to.

In configuring the operating unit 8 and the sensor unit 9, the initial load required to move the pressing member 30 against the urging force of the compression coil spring 29 is Ta, and the urging force of the tension coil spring 16 is Ta. The initial load required to move the movable bar 19 against the tension is Tb, and the final load required to move the movable bar 19 against the urging force of the tension coil spring 16 with the platen cover 4 fully closed. That is, assuming that the final load that the pressing member 30 receives from the movable bar 10 is Tc, the magnitude relationship between these loads is Ta>
Tc> Tb is set.

The operating unit 8 and the sensor unit 9 having such a configuration are mounted on the platen cover 4 and the apparatus main body 1 in a state as shown in FIG. 5, respectively. That is, the operation unit 8 is attached in a state where the slide guide portion 22 of the support member 19 and the pressing member 30 attached thereto project from the lower surface of the platen cover 4 at a substantially right angle.
Thereby, the pressing member 30 is pressed by the compression coil spring 29.
Is biased away from the platen cover 4.

On the other hand, the sensor unit 9 is mounted so that the movable rod 10 stands substantially vertically from the upper surface of the top cover 3 mounted on the apparatus main body 1. That is, the top cover 3 is provided with a through hole 3A through which the movable bar 10 can be pulled out, and the distal end side of the movable bar 10 is arranged in a protruding state through the through hole 3A.

In this mounting state, when the platen cover 4 is closed in order to press the original placed on the platen glass 2 from above, the closing of the operating unit 8 during the closing as shown in FIG. The member 30 contacts the movable rod 10 of the sensor unit 9. At this time, the contact position of the pressing member 30 with respect to the movable bar 10 is P1.

Subsequently, when the platen cover 4 is further closed from the state shown in FIG. 5, the movable rod 10 is gradually pushed by the pressing member 30 in conjunction with the closing operation. Thereby, the light shielding plate 17 provided at the lower end of the movable bar 10 is displaced downward. When the platen cover 4 is closed to a predetermined angle, the light-shielding plate 17 displaced as described above is displaced from the optical path of the photo-interrupter 13, and the sensor output switches from the off state to the on state. This makes it possible to detect the closing angle of the platen cover 4 based on the sensor output from the photo interrupter 13.

Thereafter, when the platen cover 4 is almost fully closed, the pressing member 30 contacts the top cover 3 on the apparatus body 1 depending on the length (projection dimension) of the operating unit 8 on the platen cover 4 side. In contact with each other,
When the platen cover 4 is further closed from that state,
Due to the reaction force received from the top cover 3 by the closing operation, the pressing member 30 is pushed back to the platen cover 4 against the urging force of the compression coil spring 29. At this time, the pressing member 30 moves (slids) while being guided by the sliding guide portion 22 (a pair of guide pieces 26A and 26B) of the support member 19.

Thus, the entire length (projection size) of the operation unit 8 including the pressing member 30 on the platen cover 4 side
Therefore, even if the pressing member 30 comes into contact with the top cover 3 while the platen cover 4 is being closed, the platen cover 4 can be fully closed as shown in FIG. As a result, even when the length of the operation unit 8 is changed to set the closing angle of the platen cover detected by the sensor unit 9 to the same angle in accordance with the change in the specification of the platen cover, a mechanical The platen cover can be closed to the fully closed state without causing damage.

Incidentally, the movable dimension in which the pressing member 30 can be moved by being guided by the sliding guide portion 22 is set longer than the dimension in which the compression coil spring 29 is contracted when the platen cover 4 is fully closed. This is because when the platen cover 4 is fully closed, the movement of the pressing member 30 is restricted, and mechanical damage (such as impact) to the top cover 3 is not given.

Further, after the closing angle of the platen cover 4 is detected (after the sensor output of the photo-interrupter 13 is turned on) until the pressing member 30 comes into contact with the top cover 3, the movable member is movable by the pressing member 30. The pushing operation of the rod 10 is continuously maintained. This is because the initial load Ta required to move the pressing member 30 against the urging force of the compression coil spring 29 and the urging force of the tension coil spring 16 with the platen cover 4 fully closed as described above. Load Tc required to move the movable bar 19
Is set to Ta> Tc.

When the contact position of the pressing member 30 with respect to the movable bar 10 when the platen cover 4 is fully closed is P2 (see FIGS. 5 and 6), the movable bar is closed during the closing operation of the platen cover 4. Reference numeral 10 moves the lower surface of the pressing member 30 with a distance L between P1 and P2.
Therefore, in the present embodiment, the width W of the pressing member 30 is
Is set to be longer than the moving distance L of the movable rod 10, thereby preventing the movable rod 10 from being depressed due to the movement of the contact position (P1 → P2) and the erroneous detection of the cover closing angle due to this.

The structure of the sensor unit 9 is as follows.
A movable member that is pushed by contact with the pressing member 30 provided on the platen cover 4 side, an urging means for returning the pushed movable member to an initial state (projected state), and with the movement of the movable member Any configuration and component shape may be adopted as long as the configuration includes a sensor whose sensor output changes.

As for the structure of the operating unit 8, a pressing member 30 which comes into contact with and pushes the movable rod 10 provided on the apparatus main body 1 side, and biases the pressing member 30 in one direction as described above. Any structure and component shape may be adopted as long as the device has a support mechanism for supporting the movable member in a direction opposite to the urging direction.

Next, another embodiment of the image reading apparatus according to the present invention will be described with reference to FIGS.
In the present embodiment, the same components as those described in the above embodiment are denoted by the same reference numerals, and overlapping description will be omitted.

First, in FIG. 7, the platen cover 4
A projection 33 is provided on the side. The projection 33 is fixedly provided on the lower surface of the platen cover 4 as in the related art, and its length (projection dimension) is unchanged.

On the other hand, an escape hole 34 is formed in the top cover 3 on the apparatus body side so that the movable rod 10 of the sensor unit 9 can be freely inserted and removed. The diameter of the escape hole 34 is set to be larger than the cross-sectional dimension of the projection 33 in order to avoid positional interference with the projection 33 on the platen cover 4 side. Specifically, in addition to the cross-sectional dimensions of the projection 33, the hole diameter of the escape hole 34 is set in consideration of the movement trajectory when the projection 33 advances into the hole, the dimensional tolerance in manufacturing and assembling parts, and the like. Is done. As a result, the escape hole 34 of the top cover 3 is formed in such a size that both the movable bar 10 and the protrusion 33 can be inserted and removed.

In such a configuration, the projection 33 comes into contact with the movable bar 10 while the platen cover 4 is being closed, and the movable bar 10 is pushed in as it is, so that the sensor output of the photointerrupter 13 is changed as in the previous embodiment. Switches from the off state to the on state. When the platen cover 4 is fully closed as shown in FIG. 7, the tip of the projection 33 is inserted into the escape hole 34, that is, the tip of the projection 33 advances toward the apparatus body. Positional interference between the projection 33 and the top cover 3 is avoided. Accordingly, even when the length of the protrusion 33 is changed in order to set the closing angle of the platen cover detected by the sensor unit 9 to the same angle in accordance with the specification change of the platen cover, the protrusion toward the apparatus body side The platen cover can be closed to a fully closed state by allowing the advance of the platen 33.

On the other hand, in FIG.
A recess 35 having a substantially concave cross section is formed on the top cover 3 on the apparatus body side with respect to the protrusion 33 provided on the side.
The inner diameter of the recess 35 is the same as the diameter of the escape hole 34, that is, in addition to the cross-sectional dimension of the protrusion 33,
Are set in consideration of the movement trajectory of when the S moves into the concave portion 35, the dimensional tolerances in manufacturing and assembling parts, and the like.
A through hole 36 is formed at the bottom of the recess 35 so that the movable bar 10 can be freely inserted and removed.

In such a configuration, the projection 33 comes into contact with the movable bar 10 while the platen cover 4 is being closed, and the movable bar 10 is pushed in as it is, so that the sensor output of the photo interrupter 13 is changed as in the previous embodiment. Switches from the off state to the on state. When the platen cover 4 is fully closed as shown in FIG. 8, the position of the projection 33 and the top cover 3 is changed such that the tip of the projection 33 advances into the recess 35, that is, toward the apparatus body. Interference is avoided.
Accordingly, even when the length of the projection 33 is changed in order to set the closing angle of the platen cover detected by the sensor unit 9 to the same angle in accordance with the specification change of the platen cover in the same manner as described above, the apparatus body side Is allowed to close, and the platen cover can be closed to the fully closed state.

[0049]

As described above, according to the present invention, even when using the same type of original pressing member with different specifications, the sensor unit provided on the apparatus main body side is shared and the sensor unit is used. It is possible to set the detected closing angle of the document pressing member to the same angle, and to close the document pressing member to the fully closed state while avoiding mechanical damage due to interference between components during the closing operation of the document pressing member. It becomes possible. Accordingly, when changing the specifications of the document pressing member, it is possible to reduce the cost of the replacement part and the replacement work associated therewith, and it is possible to avoid an increase in man-hours for managing the sensor unit.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image reading apparatus according to the present invention.

FIG. 2 is a perspective view illustrating a configuration of a sensor unit.

FIG. 3 is a side view showing a configuration of an operation unit including a partially broken surface.

FIG. 4 is an exploded perspective view showing a configuration of an operation unit.

FIG. 5 is a diagram showing an arrangement state of an operation unit of the sensor unit while the platen cover is being closed.

FIG. 6 is a diagram showing an arrangement state of a sensor unit and an operation unit in a fully closed state of a platen cover.

FIG. 7 is a diagram illustrating another embodiment of the present invention.

FIG. 8 is a diagram illustrating still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device main body, 2 ... Platen glass, 3 ... Top cover, 4 ... Platen cover, 8 ... Operating unit, 9 ... Sensor unit, 10 ... Movable rod, 13 ... Photo interrupter, 16 ... Tension coil spring, 17 ... Light shielding plate, 19 ...
Supporting member, 22: sliding guide portion, 26A, 26B: guide piece, 27: stopper piece, 29: compression coil spring, 3
0: pressing member, 33: protrusion, 34: escape hole, 35: recess, 36: through hole

Claims (4)

[Claims] 1. An image reading apparatus comprising: a document pressing member provided on an apparatus main body so as to be openable and closable; and a closing angle detecting means for detecting a closing angle of the document pressing member. A sensor unit provided on the main body side; and an operating unit provided on the document pressing member side and operating the sensor unit by opening and closing the document pressing member. The sensor unit includes the document pressing member. A movable member disposed in a protruding state above the apparatus main body in an open state, wherein the operating unit abuts against the movable member and presses the movable member when closing the document pressing member;
An image reading apparatus comprising: a support mechanism that urges the pressing member in a direction away from the document pressing member and movably supports the pressing member in a direction opposite to the urging direction. 2. An initial load required to move the pressing member in a direction opposite to the urging direction is larger than a final load received by the pressing member from the movable member in a state where the document pressing member is fully closed. 2. The image reading device according to claim 1, wherein the image reading device is set. 3. An image reading apparatus comprising: a document pressing member provided in the apparatus main body so as to be openable and closable; and a closing angle detecting means for detecting a closing angle of the document pressing member. A sensor unit having a movable member arranged in a protruding state above the apparatus main body when the pressing member is opened, and a sensor unit provided on the document pressing member side and abutting on the movable member when closing the document pressing member. A projection portion for pushing the same, wherein the device main body has a relief portion that allows the movable member to be freely inserted and removed on the device main body, and that allows an end of the projection portion to advance into the device main body. Characteristic image reading device. 4. An image reading apparatus according to claim 3, wherein said relief portion is constituted by a relief hole having a predetermined size or a concave portion having a substantially concave cross section.