JP2003040488A - Carried sheet detecting device, and image forming device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sheet detection accuracy for detecting presence of a sheet. SOLUTION: This carried sheet detecting device 81 includes a light emitting element 11 for irradiating light to a sheet carrying path 1 for guiding the sheet S, a light receiving element 2 for receiving light emitted for the light emitting element, and slits 13, 23 provide by respectively facing to the light emitting element and the light receiving element, and crossing with respect to a sheet carrying direction. The light emitting element and the light receiving element include a plurality of lead wires 14, 15, 24, 25 mounted on printed circuit boards 12, 22, and the lead wires are arranged in the sheet carrying direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveyed sheet detection device for detecting a conveyed sheet, and an image forming apparatus for forming an image on a sheet by equipping the apparatus body with the conveyed sheet detection device.

[0002]

2. Description of the Related Art Conventionally, a conveyed sheet detecting apparatus may be incorporated in the apparatus body of a sheet handling apparatus that handles a sheet and constitutes a part of the sheet handling apparatus. The conveyed sheet detection device is incorporated in the main body of an image forming apparatus, which is a type of sheet handling apparatus, for example, and is useful for measuring the timing of forming an image on a sheet.

In the conveyed sheet detection device, the fact that the sheet comes into contact with one end of the tiltable lever arranged in the sheet conveying path and the tiltable lever falls down makes use of the light arranged at the other end of the tiltable lever. 2. Description of the Related Art There is a contact type sensor that detects that a folding lever is tilted by a transmissive sensor to detect a sheet passing through a sheet conveyance path.

However, in recent years, the sheet handling speed of the sheet handling apparatus has been increased, so that the sheet conveying speed is increased. In the conventional contact type conveyed sheet detecting apparatus, the sheet collides with the retractable lever at a high speed, so that the sheet tip end is moved. It could be damaged. For this reason, a non-contact optical conveyance sheet detection device which optically detects the conveyance of a sheet has come to be widely used.

The optical conveying sheet detecting device will be described.

The conveyed sheet detecting device shown in FIG. 8 includes a reflection type photo sensor 110 disposed on one side of the sheet conveying path 111. A light emitting element 113 and a light receiving element 114 are built in the photo sensor 110. Through holes 118, 118 are formed in the pair of guide walls 117, 117 forming the sheet conveying path 111.

As shown in FIG. 8A, when the sheet S does not pass through the sheet conveying path 111, the light emitting element 11
The light L emitted from the light source 3 has a slit 115 and a through hole 11.
It does not reach the light receiving element 114 through 8, 118.
However, as shown in FIG. 8B, when the sheet S passes through the sheet conveyance path 111 in the front and back directions in the drawing, the light L from the light emitting element 113 passes through the slit 115 and is reflected by the sheet S. Then, the light passes through the slit 116 and reaches the light receiving element 114. As a result, the conveyed sheet detection device can detect that the sheet is passing through the sheet conveyance path 111.

Therefore, the conveying sheet detecting apparatus shown in FIG. 8 determines that there is a sheet when the light receiving element 114 detects light, and determines that there is no sheet when it does not detect light.

The conveyed sheet detecting device shown in FIG. 9 also includes a reflection type photo sensor 120 disposed on one side of the sheet conveying path 111. A light emitting element 122 and a light receiving element 123 are built in the photo sensor 120. Through holes 128, 128 are formed in the pair of guide walls 127, 127 forming the sheet conveying path 121. On the other side of the sheet conveying path 121, the through hole 1
A reflecting member 126 that covers 28 is provided.

As shown in FIG. 9A, when the sheet S does not pass through the sheet conveying path 121, the light emitting element 12
The light L emitted from the light source 2 has a slit 124 and a through hole 12.
The light is reflected by the reflecting member 126 through 8 and 128 and reaches the light receiving element 123 through the through holes 128 and 128 and the slit 125. However, as shown in FIG.
When the sheet S passes through the sheet conveyance path 121 in the front-back direction of the drawing, the light L from the light emitting element 122 passes through the slit 124, is blocked by the sheet S, and does not reach the light receiving element 123. As a result, the conveyed sheet detection device can detect that the sheet is passing through the sheet conveyance path 121.

Therefore, the conveying sheet detecting device shown in FIG. 9 determines that there is a sheet if the light receiving element 123 does not detect light, and determines that there is no sheet if it detects light.

The conveyed sheet detecting device shown in FIG. 10 has a light emitting element 1 arranged on both sides of a sheet conveying path 131 so as to face each other.
A transmissive photosensor 1 including 32 and a light receiving element 133.
Equipped with 30. Through-holes 138, 1 are formed in the pair of guide walls 137, 137 forming the sheet conveying path 131.
38 is formed.

As shown in FIG. 10A, when the sheet S does not pass through the sheet conveying path 131, the light emitting element 1
The light L emitted from 32 is reflected by the slits 134, 138,
It reaches the light receiving element 133 through 138 and 135. However, as shown in FIG. 10B, when the sheet S passes through the sheet conveyance path 131 in the front-back direction of the drawing, the light L emitted from the light emitting element 132 is blocked by the sheet S and is received by the light receiving element. It does not reach 133. As a result, the conveyed sheet detection device can detect that the sheet is passing through the sheet conveyance path 131.

Therefore, in the conveyed sheet detecting device shown in FIG. 10, if the light receiving element 133 detects light, there is no sheet,
If it does not detect light, it will determine that there is a seat.

In any of the above-mentioned conveyed sheet detecting devices, the slits 124, 125, 134, 135, 115, 116 are provided.
Has a tendency to narrow the width of the sheet in the conveyance direction in order to improve the sheet detection accuracy for detecting the presence or absence of the sheet. In this case, when the slit width is narrowed, unless the light emitting element and the light receiving element are accurately opposed to the slit, the amount of light passing through the slit is reduced and the sheet detection accuracy is reduced. For this reason, the light emitting element and the light receiving element must be correctly aligned in the slit.

[0016]

However, the electrode lines (113a, 1a) of the light-emitting elements 113, 122, 132 and the light-receiving elements 114, 123, 133 of the conventional conveying sheet detection device are used.
13b) (122a, 122b) (132a, 132
b) (114a, 114b) (123a, 123b)
(133a, 133b) are arranged in a direction intersecting with the sheet conveying direction. For this reason, the light emitting element and the light receiving element tend to fall on the downstream side and the upstream side in the sheet conveying direction, and it is difficult to accurately align the positions with the slits. Even if the correct position is set, it was easy to get confused by long-term use.

Therefore, in the conventional conveying sheet detecting device, the width of the slit has to be widened, and the sheet detecting accuracy for detecting the presence or absence of the sheet is reduced accordingly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conveyed sheet detecting device with improved sheet detecting accuracy for detecting the presence or absence of a sheet, and an image forming apparatus provided with the conveyed sheet detecting device in the apparatus main body.

[0019]

In order to achieve the above object, a conveyed sheet detecting device of the present invention provides a light emitting element for irradiating a sheet conveying path for guiding a sheet with light and a light emitted from the light emitting element. A light-receiving element capable of receiving light; and a slit that is provided to face the light-emitting element and the light-receiving element and that intersects with the sheet conveying direction. The light-emitting element and the light-receiving element are attached to each other. It has a plurality of lead wires attached to the member, and the lead wires are arranged in the sheet conveying direction.

In the conveyed sheet detecting device of the present invention, the light emitting element and the light receiving element are arranged on opposite sides of the sheet conveying path so that the light emitted from the light emitting element to the light receiving element is the sheet. The conveyance of the sheet is detected when the sheet is blocked by the sheet passing through the conveyance path.

In the conveyed sheet detecting device of the present invention, the light emitting element and the light receiving element are arranged on one side of the sheet conveying path toward the sheet conveying path, and the other side of the sheet conveying path is arranged. A sheet is provided with a reflection member that reflects the light of the light emitting element to the light receiving element, and when the light emitted from the light emitting element to the sheet conveying path is blocked by the sheet passing through the sheet conveying path, the sheet Is detected.

In the conveyed sheet detecting device of the present invention, the light emitting element and the light receiving element are arranged on one side of the sheet conveying path toward the sheet conveying path, and the sheet emitting path is irradiated from the light emitting element. When light is reflected by the sheet passing through the sheet conveyance path and received by the light receiving element, conveyance of the sheet is detected.

The conveyed sheet detecting device of the present invention further comprises:
The light emitting element and the light receiving element are each provided with a fall prevention member for preventing the light emitting element and the light receiving element from falling in a direction intersecting with the sheet conveying direction.

In order to achieve the above object, the image forming apparatus of the present invention detects any one of the above-mentioned sheets to be conveyed.
It is provided with one conveyance sheet detection device and an image forming means for forming an image on the sheet.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION A conveying sheet detecting device according to an embodiment of the present invention and a copying machine which is an image forming apparatus having the conveying sheet detecting device in an apparatus body will be described below with reference to the drawings.

The conveyed sheet detecting device is incorporated in the main body of the sheet handling device that handles sheets,
It is designed to form a part of the sheet handling device. The sheet handling device includes an image forming device that forms an image on a sheet, an image reading device that reads an image of a document, a punching device that punches holes in a sheet, a sheet binding device that binds sheets, a sheet folding device that bends sheets, and the like. . The image forming apparatus includes a copying machine, a printer, a facsimile, and a composite machine of these.

The conveyed sheet detecting device detects a sheet passing through a certain position in these sheet handling devices,
This is useful for, for example, timing the handling process of the sheet handling apparatus.

Therefore, the conveying sheet detecting device is not provided only in the copying machine.

The sheets include plain paper, thin resin substitutes for plain paper, thick paper, and paper for overhead projectors.

(Copier) A copier 80, which is an image forming apparatus shown in FIG. 1, supplies a sheet to a portion where an image is formed on a sheet, and forms an image on the sheet.
Further, it can be divided into an image forming and discharging portion for discharging the sheet on which the image is formed.

The sheet supply portion is a half-moon roller which is unlatched by a stepping motor (not shown) which drives a portion related to sheet conveyance at a predetermined speed in accordance with an instruction from the controller 90 and which is unlatched by a solenoid (not shown). 20
1, a cassette 214 on which sheets are stacked, a transport roller 202 disposed on the downstream side of the half-moon roller 201,
A registration roller 204 that can be switched between stop and rotation by an electromagnetic clutch, a contact-type pre-registration sensor 203 that is arranged immediately before the registration roller 204 to detect the presence or absence of a sheet, and an optical system that is arranged downstream of the registration roller 204. And a leading edge sensor 205 that detects the presence or absence of a sheet.

In the image forming and discharging portion, a photosensitive drum 211 on which a toner image is formed by a developing device 209, a scanner 210 and the like, and a transfer drum 207 on which an image is transferred from a plurality of rotating photosensitive drums 211 to a wound sheet.
A gripper 208 provided on the transfer drum 207 for sandwiching the leading edge of the sheet; a gripper position sensor 206 for detecting that the gripper 208 has arrived at a position equivalent to the sheet feeding position of the leading edge sensor 205; and a separation claw 212.
And a fixing device 213 that thermally fixes the transferred toner image on the sheet separated from the photosensitive drum 211. Developing unit 209, scanner 210, photosensitive drum 2
11 and the like form an image forming unit (image forming means) 216.

In the above structure, when a print signal is generated by the operator, the control unit 90 rotates the half-moon roller 201 once to supply one sheet at a predetermined speed and rotate the transfer drum 207. . The pre-registration sensor 203 detects a sheet. Registration roller 2
04 has stopped rotation. After a lapse of a fixed time after the pre-registration sensor 203 detects the sheet, the registration roller 20
Rotate 4. While the registration roller 204 stops rotating, the conveyance roller 202 and the registration roller 204
A certain amount of loops are formed in the sheet between and, and the skew feeding of the sheet is performed.

The control unit 90 again controls the registration roller 20.
Rotate 4. The registration roller 204 conveys the sheet. When the leading edge sensor 205 detects the leading edge of the sheet, the control unit 90 stops the driving of the stepping motor to stop the registration rollers 204 and the conveyance rollers 202, and puts the sheet on standby. When the gripper position sensor 206 detects the arrival of the gripper 208 on the transfer drum 207, the control unit 90 restarts the stepping motor to rotate the registration roller 204 and the conveyance roller 202. Under the control of the control unit 90, the registration roller 204 and the conveyance roller 202 convey the sheet at a sheet supply speed relatively higher than that of the transfer drum 207 for a certain period of time, and thereafter,
The speed is returned to the same as that of the transfer drum 207, and a predetermined amount of the leading edge of the sheet is abutted against the gripper 208 which is developed at about 30 degrees.

The gripper 208 is closed to hold the leading edge of the sheet. In this case, the control unit 90 synchronizes the rotation of the transfer drum 207 and the feeding of the sheet so that the sheet can be stably supplied to the position of the gripper 208 which is the leading end position of the sheet during transfer.

Next, the operation when the sheet is an overhead projector sheet (hereinafter referred to as "OHP sheet") will be described.

Conveying roller 202, registration roller 204
However, when the OHP sheet is supplied, the leading edge sensor 205
When a light-shielding portion printed with a width of about 5 mm is detected downstream from the front end of the HP sheet, the stepping motor detects that the OHP
The transport roller 202 and the registration roller 204 that are transporting the sheet for use are stopped. As a result, the OHP sheet is once put on standby. Gripper position sensor 206
When the gripper 208 is detected, the stepping motor is restarted, and the transport roller 202 and the registration roller 204 are
Then, the OHP sheet is sent to the transfer drum 207. Then, when the leading edge sensor 205 detects a transmissive portion of about 20 mm downstream from the leading edge of the OHP sheet, the control unit 90 determines that the sheet is an OHP sheet. Then, the controller 90 transfers the toner image onto the sheet and then separates the OHP sheet from the transfer drum 207 and discharges it. At this time, the sheet conveying speed of the fixing device 213 is reduced to about (1/3) of the plain paper by the control unit 90. Finally, the discharge roller pair 215 discharges the OHP sheet to the outside.

In the above description, the leading edge sensor 205 includes the conveyed sheet detecting device 8 of each embodiment described below.
1, 82, 83 are used.

(Conveyed Sheet Detection Apparatus of First Embodiment) Based on FIG. 2, the conveyed sheet detection apparatus 81 of the first embodiment is shown.
Will be explained.

FIG. 2A is a sectional view of the conveyed sheet detecting device 81 in a direction intersecting the sheet conveying direction.
FIG. 2B is a cross-sectional view of the conveyed sheet detection device 81 in a direction intersecting the sheet conveying direction, and is a state in which the sheet is detected. FIG. 2C is a cross-sectional view of the conveyed sheet detecting device 81 taken along the sheet conveying direction, showing a state in which the sheet is detected.

The conveyed sheet detecting device 81 includes a light emitting unit 10 and a light receiving unit 20, which are arranged so as to face each other on both sides of the sheet conveying path (sheet conveying path) 1. The sheet conveyance path 1 is formed by parallel sheet guides 2 and 3 for guiding the sheet conveyed by the registration rollers 204 and the conveyance rollers 202. The sheet guides 2 and 3 are formed with through holes 17 and 27 through which light L of the light emitting element 11 described later passes.

2A and 2B, the sheet is conveyed from the front side to the back side of the drawing, and in FIG. 2C, the sheet is conveyed from right to left of the drawing.

The light emitting unit 10 includes a light emitting element 11 that emits light, a printed board (attached member) 12 on which the light emitting element 11 is mounted, and a case member (tilt prevention member) 16.
It consists of and. As the light emitting element 11, for example, an infrared light emitting diode is used. The infrared light emitting diode does not emit perfectly parallel light as shown in FIG. 6A, but emits light having a certain spread.

The case member 16 has a slit 13 and a guide hole 16a into which the light emitting element 11 is inserted. The slit 13 is formed in order to narrow the light emitted from the light emitting element 11 and give the light directivity.

The light receiving unit 20 is composed of a light receiving element 21, a printed circuit board (attached member) 22 on which the light receiving element 21 is mounted, and a case member (falling prevention member) 26. For the light receiving element 21, for example, a phototransistor is used. The phototransistor is shown in Figure 6.
As shown in (b), it reacts not only to parallel light, but also to light from the side to some extent, and photoelectrically converts the received light into photocurrent.

The case member 26 has a slit 23 and a guide hole 26a into which the light receiving element 21 is inserted. The slit 23 is formed in order to narrow down the light received by the light receiving element 21 so that the light has directivity.

The light emitting element 11 has two electrode lines 14 and 15 extending on the side opposite to the direction of emitting light that spreads in a conical shape around the central axis of the light emitting element 11. Further, the light receiving element 21 also includes two electrode wires 2 extending on the side opposite to the light receiving surface in the light receiving direction that spreads in a conical shape around the central axis of the light receiving element 21.
4 and 25.

The light emitting element 11 is attached to the printed circuit board 12 by inserting two electrode wires 14 and 15 into the holes 14a and 15a arranged in the sheet conveying direction of the printed circuit board 12. Therefore, the two electrode wires 14 and 15 are arranged in the sheet conveying direction.

The light receiving element 21 is attached to the printed circuit board 22 by inserting two electrode wires 24 and 25 into holes 24a and 25a arranged in the printed circuit board 22 in the sheet conveying direction. Therefore, the two electrode wires 24 and 25 are arranged in the sheet conveying direction.

The light emitting element 11, when mounted on the printed circuit board 12, is unlikely to tilt in the direction in which the electrode lines 14 and 15 can be seen to overlap (the direction of arrow A in FIG. 2C). That is,
The light emitting element 11 is unlikely to tilt on the upstream side and the downstream side in the sheet conveying direction. However, there is a possibility that the electrode lines 14 and 15 may be tilted in a direction intersecting with the direction in which they are seen to overlap (the direction of arrow B in FIGS. 2A and 2B). Therefore, the guide hole 16a of the case member 16 prevents the light emitting element 11 from collapsing. If the guide hole 16a of the guide member 16 is not provided and the light emitting element 11 is forcibly tilted in the direction of arrow B intersecting with the direction in which the electrode wires 14 and 15 are seen to overlap with each other, the printed circuit board may be forced. There is a risk that the 12 patterns will come off.

When the light receiving element 21 is mounted on the printed board 22, the light receiving element 21 is unlikely to tilt in the direction in which the electrode lines 24 and 25 are seen to overlap (the direction of arrow A in FIG. 2C). That is,
The light receiving element 21 is unlikely to tilt on the upstream side and the downstream side in the sheet conveying direction. However, there is a possibility that the electrode lines 24 and 25 may be tilted in a direction intersecting a direction in which the electrode lines 24 and 25 are seen to overlap with each other (the direction of arrow B in FIGS. Therefore, the guide hole 26a of the case member 26 prevents the light receiving element 21 from collapsing. If the guide hole 26a of the case member 26 is not provided and the light receiving element 21 is forcibly tilted in the direction of arrow B intersecting with the direction in which the electrode lines 24 and 25 are seen to overlap with each other, the printed circuit board may be forced. There is a risk that the pattern of 22 will come off.

As shown in FIGS. 2A, 2B and 2C, the sheet conveying direction and the electrode wire 1 of the light emitting element 11 are arranged.
The arrangement direction of 4, 15 and the electrode lines 24, 2 of the light receiving element 21
The arrangement directions of 5 are the same, and the longitudinal directions of the slits 13 and 23 are orthogonal to this direction. That is, the slits 13 and 23 are formed in the case members 16 and 26 in a direction orthogonal to the sheet conveying direction.

The slits 13 and 23 are formed in the shape shown in FIG. Printed circuit board 1 on which light emitting element 11 is mounted
2, the slit width Sb in the direction of the straight line connecting the two holes 14a and 15a (sheet conveyance direction) and the light receiving element 21
Two holes 24a provided in the printed circuit board 22 for mounting the
The slit width Sb in the direction of the straight line connecting 25a (sheet conveying direction) is the slit width (length) Sa in the direction crossing the straight line connecting the two holes 14a, 15a (direction of arrow B), and the two holes 24a, It is smaller (shorter) than the slit width (length) Sa in the direction (arrow B direction) intersecting the straight line connecting 25a. That is, the slits 13 and 23 are formed in the case members 16 and 26 at right angles to the sheet conveying direction.

The shapes of the slits 13 and 23 are to increase the sheet detection accuracy of the sheet S, so that the slit width Sb along the conveying direction of the sheet S is narrowed and the amount of light is reduced. Although the slit width (length) Sa in the direction orthogonal to the transport direction of (1) is wide (long), the slit in the direction in which the positional accuracy is difficult to be obtained due to the mounting positional accuracy of the light emitting unit 10 and the light receiving unit 20. It is preferable that the width is wide.

Next, the electric circuit of the controller 90 will be described with reference to FIG.

An analog signal converted into an electric signal according to the light received by the light receiving element 21 is input to the analog input section AN0 of the CPU 91 which is an arithmetic processing unit. The input analog signal is A / D converted inside the CPU 91 and becomes a digital value of 256 steps. The signal amplification section 93 and the analog input section are provided for each of the sheet detection sensors in the conveyance path. CPU
The output parts OUT0, OUT1 and OUT2 of 91 are D / A
It is connected to the converter 94. This D / A converter 94
When the clock (CLK), the load signal (LD) and the digital data (DATA) of the serial code are input, the serial output (A0) of several channels is sequentially output.

The amount of light of the light emitting element 11 can be changed by causing a current based on the analog signal to flow through the light emitting element 11 of the light emitting unit 10 in the transport path.

The CPU 91 determines that the reflected light is returned when the signal level input from the analog input section exceeds a certain threshold value. Therefore, the CPU
Reference numeral 91 controls to gradually increase the output of the D / A converter 94 until the signal level input from the analog input section exceeds a certain threshold value, and when the threshold value is exceeded, the output data is fixed. The minimum amount of light emitted by the light receiving element is set by the above method.

Next, the operation of the conveyed sheet detection device 81 of the first embodiment will be described.

As shown in FIG. 2A, when the sheet S is not fed, the light L emitted from the light emitting element 11 is emitted.
Reaches the light receiving element 21 through the slit 13, the through holes 17, 27, and the slit 23. Then, as shown in FIG.
As shown in FIG. 2C, when the sheet S is sent, the light L emitted from the light emitting element 11 is blocked by the sheet S and does not reach the light receiving element 21.

Therefore, the conveying sheet detecting device 81 of the first embodiment is configured to judge that there is no sheet when the light receiving element 21 detects light, and to judge that there is a sheet when not detecting light.

The conveyed sheet detecting device 81 of this embodiment is
As shown in FIG. 2C, the light emitting element 11 and the light receiving element 2
Since the one electrode line is arranged in the sheet conveying direction, the light emitting element 11 and the light receiving element 21 are unlikely to fall in the same direction. Therefore, even if the width of the slit in the sheet conveying direction is narrowed, the light emitting element 11 and the light receiving element 21 can be accurately arranged in accordance with the slit, and the light of the light emitting element surely passes through the slit to receive light. By increasing the dynamic range of the element, it is possible to improve the sheet detection accuracy of the conveyed sheet detection device 81 for detecting the presence or absence of a sheet.

Further, even when the sheet is used for a long period of time, the facing positions of the light emitting element 11 and the light receiving element 21 with respect to the slit are not deviated, and the sheet detection accuracy can be kept constant for a long period of time.

Further, the light of the light emitting element surely passes through the slit to increase the dynamic range of the light receiving element. However, the narrowed slit reduces the amount of light passing through the slit. The reduced amount is compensated by widening the slit width (Sa) in the direction intersecting the sheet conveying direction (making the slit length longer) to further increase the dynamic range and reliably detecting the sheet. can do.

Further, the light emitting element 11 and the light receiving element 21 are prevented from being tilted by the guide holes 16a and 26a of the case members 16 and 26 even if they are tilted in the lateral direction in a state where the electrode wire looks like one line in the projection.

Further, such a conveyance sheet detecting device 8
The copying machine 80 having the apparatus main body 1 can accurately form an image on a conveyed sheet.

(Conveyed Sheet Detecting Device of Second Embodiment) A conveyed sheet detecting device 82 of the second embodiment will be described with reference to FIG.

FIG. 4A is a sectional view of the conveyed sheet detecting device 82 in a direction intersecting the sheet conveying direction.
FIG. 4B is a cross-sectional view of the conveyed sheet detection device 82 in a direction intersecting with the sheet conveying direction, and is a state in which the sheet is detected. FIG. 4C is a cross-sectional view of the conveyed sheet detection device 82 along the sheet conveying direction, showing a state in which the sheet is detected. In the conveyed sheet detection device 82 of the second embodiment, the same parts as those of the conveyed sheet detection device 81 of the first embodiment are designated by the same reference numerals, and the description thereof will be partially omitted.

FIGS. 4A, 4B, and 4C are shown in FIG.
These correspond to (a), (b), and (c), respectively. In the conveyed sheet detection device 81 of the first embodiment, the light emitting unit 10 and the light receiving unit 20, which are opposed to each other with the sheet conveying path 1 interposed therebetween, are integrated into a light emitting and receiving unit 30, and one side of the sheet conveying path 1 is provided. It is provided in. A reflecting member 40 is provided on the other side of the sheet conveying path 1. Therefore, the conveyance sheet detection device 82 according to the second embodiment includes the light emitting / receiving unit 30 and the reflecting member 40. The sheet is conveyed from the front side to the back side of the drawings in FIGS. 4A and 4B, and from the right side to the left side of the drawings in FIG. 4C.

The light emitting / receiving unit 30 includes the light emitting element 11,
The light receiving element 21, the light emitting element 11, and a printed board (attached member) 32 on which the light receiving element 21 is mounted, and a case member (tilt prevention member) 44 are included. In the case member 44, the slit 13 for giving directivity by narrowing the light emitted from the light emitting element 11, the slit 23 for giving directivity by narrowing the light received by the light receiving element 21, and the light emitting element 11 The shield wall 37 that prevents light other than the light reflected by the reflecting member 40 from being detected by the light receiving element 21, the guide hole 16a into which the light emitting element 11 is inserted, and the light receiving element 21.
And a guide hole 26a into which is inserted.

The guide hole 16a is shown in FIG.
(A) and FIG. 4 (b) are prevented from falling in the direction of arrow B. The guide hole 26a prevents the light receiving element 21 from falling in the direction of arrow B in FIGS. 4 (a) and 4 (b).

The reflecting member 40 has nine reflecting surfaces 42 and 43.
It uses a glass or acrylic prism that forms a 0 degree angle. The reflection member 40 is inserted into the through hole 27 of the sheet guide 3. The reflecting member 40 is the light emitting element 1
The incident light emitted from 1 and transmitted through the surface 41 in an orthogonal state is
The inner surface is reflected by the critical angles of the reflecting surfaces 42 and 43 so that the surface 41 is transmitted in the orthogonal state again.
That is, the incident light and the reflected light are parallel to each other. The reflecting member 40 is not limited to a prism, and has a higher reflectance than the sheet S (it is easy to reflect light).
Any member may be used.

Next, the operation of the conveyed sheet detecting device 82 of the second embodiment will be described.

As shown in FIG. 4A, when the sheet S is not fed, the light L emitted from the light emitting element 11 is
Reflecting member 4 passes through slit 13 and through holes 17 and 27.
It is reflected by 0 and reaches the light receiving element 21 through the through holes 27, 17 and the slit 23. Then, as shown in FIG.
As shown in FIG. 4C, when the sheet S is sent, the light L emitted from the light emitting element 11 is blocked by the sheet S and does not reach the light receiving element 21.

Therefore, the conveyed sheet detecting device 82 of the second embodiment is configured to judge that there is no sheet when the light receiving element 11 detects light and that there is a sheet when it does not detect light.

The conveyed sheet detecting device 82 of this embodiment is
As shown in FIG. 4C, the light emitting element 11 and the light receiving element 2
Since the one electrode wire 14, 15, 24, 25 is arranged in the sheet conveying direction, the light emitting element 11 and the light receiving element 21 are less likely to fall in the arrow A direction.

Therefore, the conveyed sheet detecting device 82 of the present embodiment can also improve the sheet detecting accuracy as in the conveyed sheet detecting device 81 of the first embodiment.

Further, the light emitting element 11 and the light receiving element 21 are laterally (in the direction of arrow B) in a state where the electrode lines can be seen as one line in the projection.
The guide holes 16a, 2 of the case member 44
The inclination is prevented by 6a.

Further, since the slits 13 and 23 are formed in the common case member 44, the relative positional relationship between the slits 13 and 23 can be made accurate, and the light emitting element 11 can be made.
Light can be sent to the light receiving element 21 without waste.

Further, such a conveyance sheet detecting device 82
The copying machine 80 having the apparatus main body can accurately form an image on a conveyed sheet.

(Conveyed Sheet Detection Apparatus of Third Embodiment) Based on FIG. 5, the conveyed sheet detection apparatus 83 of the third embodiment is shown.
Will be explained.

FIG. 5A is a sectional view of the conveyed sheet detecting device 83 in a direction intersecting the sheet conveying direction.
FIG. 5B is a cross-sectional view of the conveyed sheet detection device 83 in a direction intersecting the sheet conveyance direction, and is a state in which a sheet is detected. FIG. 5C is a cross-sectional view of the conveyed sheet detection device 83 along the sheet conveyance direction, showing a state in which the sheet is detected.

Incidentally, in the conveyed sheet detecting device 83 of the third embodiment, the conveyed sheet detecting device 81 of the first embodiment is used.
The same parts as those of the above are given the same reference numerals, and the description thereof will be partially omitted.

FIGS. 5A, 5B, and 5C are shown in FIG.
These correspond to (a), (b), and (c), respectively. The conveyed sheet detection device 83 of the third embodiment has a configuration in which the reflection member 40 is omitted from the conveyed sheet detection device 82 of the second embodiment.

Conveying sheet detecting device 83 of the third embodiment
Includes a light emitting / receiving unit 50 provided on one side of the sheet conveying path 1. 5A and 5B, the sheet is shown in FIG.
In (c), the sheet is conveyed from right to left in the drawing.

The light emitting / receiving unit 50 includes the light emitting element 11,
Light receiving element 21, light emitting element 11, printed board 52 on which light receiving element 21 is mounted, case member (tilt prevention member) 64
It consists of and. The case member 64 includes the light emitting element 1
Other than the light reflected by the sheet S from the light emitting element 11, the slit 53 that gives the directivity by narrowing the light emitted from 1 and the slit 63 that gives the directivity by narrowing the light received by the light receiving element 21. Of light to prevent the light from being detected by the light receiving element 21, a guide hole 56a into which the light emitting element 11 is inserted, and a guide hole 66 into which the light receiving element 21 is inserted.
a are formed.

The guide hole 56a is shown in FIG.
(A) and FIG. 5 (b) are prevented from falling in the direction of arrow B. The guide hole 66a prevents the light receiving element 21 from falling in the direction of arrow B in FIGS. 5 (a) and 5 (b). In addition,
The guide hole 56a and the guide hole 66a are inclined toward each other so that the light L emitted from the light emitting element 11 is reflected by the sheet S and can be received by the light receiving element 21.

Next, the operation of the conveyed sheet detection device 83 of the third embodiment will be described.

As shown in FIG. 5A, when the sheet S is not fed, the light L emitted from the light emitting element 11 is
The light passes through the slit 53 and the through holes 17 and 27 and reaches the light receiving element 21. Then, as shown in FIG.
As shown in FIG. 5C, when the sheet S is sent, the light L emitted from the light emitting element 11 is reflected by the sheet S and reaches the light receiving element 21.

Therefore, the conveyed sheet detection device 83 of the third embodiment determines that there is no sheet when the light receiving element 21 does not detect light and that there is a sheet when it detects light.

The conveyed sheet detecting device 83 of this embodiment is
As shown in FIG. 5C, the light emitting element 11 and the light receiving element 2
Since the one electrode wire 14, 15, 24, 25 is arranged in the sheet conveying direction, the light emitting element 11 and the light receiving element 21 are less likely to fall in the arrow A direction.

Therefore, the conveyed sheet detection device 83 of the present embodiment can also improve the sheet detection accuracy as in the conveyed sheet detection device 81 of the first embodiment.

Further, the light emitting element 11 and the light receiving element 21 are laterally (in the direction of arrow B) in a state where the electrode lines can be seen as one projected line.
The guide holes 56a, 6 of the case member 64
The inclination is prevented by 6a.

Further, since the slits 53 and 63 are formed in the common case member 64, the relative positional relationship between the slits 53 and 63 can be made accurate, and the light emitting element 11
Light can be sent to the light receiving element 21 without waste.

Further, such a conveyed sheet detecting device 83
The copying machine 80 having the apparatus main body can accurately form an image on a conveyed sheet.

[0096]

The conveyed sheet detecting device of the present invention can improve the detection position accuracy of a conveyed sheet and can perform stable detection regardless of the mounting position accuracy of the detection means.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a copying machine which is an image forming apparatus including a conveyance sheet detection device according to an embodiment of the present invention in an apparatus body.

FIG. 2 is a diagram for explaining the operation of the conveyed sheet detection device according to the first embodiment. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected. (C) It is a cross-sectional view taken along the sheet conveyance direction, and is a diagram showing a state in which a sheet is being detected.

FIG. 3 is a view of a slit.

FIG. 4 is a diagram for explaining the operation of the conveyed sheet detection device according to the second embodiment. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected. (C) It is a cross-sectional view taken along the sheet conveyance direction, and is a diagram showing a state in which a sheet is being detected.

FIG. 5 is a diagram for explaining the operation of the conveyed sheet detection device according to the third embodiment. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected. (C) It is a cross-sectional view taken along the sheet conveyance direction, and is a diagram showing a state in which a sheet is being detected.

FIG. 6 is a characteristic diagram of a light emitting element and a light receiving element. (A) It is a figure which shows the directivity of a light emitting element. (B) It is a figure which shows the directivity characteristic of a light receiving element.

FIG. 7 is an electric circuit diagram of a control unit.

FIG. 8 is a diagram for explaining the operation of a conventional conveyed sheet detection device. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected.

FIG. 9 is a diagram for explaining the operation of another conventional conveyed sheet detection device. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected.

FIG. 10 is a diagram for explaining the operation of the conventional conveyed sheet detection device. (A) It is sectional drawing of the direction crossing a sheet conveyance direction. (B) It is a cross-sectional view in a direction intersecting with the sheet conveying direction, and is a diagram of a state in which a sheet is detected.

[Explanation of symbols]

S sheet 1 sheet transport path (sheet transport path) 11 Light emitting element 12 Printed circuit board (attached member) 14 electrode wire 15 electrode wire 16 Case member (Collapse prevention member) 21 Light receiving element 22 Printed circuit board (attached member) 24 electrode wires 25 electrode wires 26 Case member (Collapse prevention member) 32 Printed circuit board (attached member) 40 Reflective member 44 Case member (falling prevention member) 64 Case member (Collapse prevention member) 80 Copier (image forming device) 216 Image forming unit (image forming means)

Claims (6)

[Claims] 1. A light emitting element for irradiating light onto a sheet conveying path for guiding a sheet, a light receiving element capable of receiving light emitted from the light emitting element, and a light receiving element facing the light emitting element and the light receiving element, respectively. A slit provided and intersecting with the sheet conveying direction,
And a light-receiving element having a plurality of lead wires attached to a member to be attached, wherein the lead wires are arranged in a sheet conveying direction. 2. The sheet, wherein the light emitting element and the light receiving element are arranged on both sides of the sheet conveying path so as to face each other, and light emitted from the light emitting element to the light receiving element passes through the sheet conveying path. The conveyed sheet detection device according to claim 1, wherein the conveyance of the sheet is detected when the sheet is blocked by. 3. The light emitting element and the light receiving element are arranged on one side of the sheet conveying path toward the sheet conveying path, and the light of the light emitting element is arranged on the other side of the sheet conveying path. A reflecting member that reflects the light-receiving element is disposed, and when the light emitted from the light-emitting element to the sheet conveyance path is blocked by the sheet passing through the sheet conveyance path, the conveyance of the sheet is detected. The conveyed sheet detection device according to claim 1. 4. The light emitting element and the light receiving element are arranged on one side of the sheet conveying path toward the sheet conveying path,
2. The conveyance of the sheet is detected when the light emitted from the light emitting element to the sheet conveyance path is reflected by the sheet passing through the sheet conveyance path and received by the light receiving element. The conveyance sheet detection device according to item 1. 5. A tilt prevention member for preventing the light emitting element and the light receiving element from falling in a direction intersecting with the sheet conveying direction, respectively.
The conveyed sheet detection device according to any one of 4 to 4. 6. The conveyed sheet detection device according to claim 1, which detects a conveyed sheet, and an image forming unit that forms an image on the sheet. A characteristic image forming apparatus.