JP3949497B2 - Sheet transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet conveying apparatus used in an image forming apparatus including a facsimile, a copying machine, and a scanner, and more particularly to a sheet conveying apparatus that calculates a sheet size based on a detection result from a movable sheet detecting unit.
[0002]
[Prior art]
As a conventional sheet feeding apparatus, Japanese Patent No. 2780292 discloses an apparatus that includes a number of sensors corresponding to the type of sheet size and discriminates the sheet size based on data from these sensors.
[0003]
[Problems to be solved by the invention]
However, in the conventional sheet feeding apparatus, a plurality of sensors for detecting a sheet are separately provided, and it is necessary to separately provide a number of sensors corresponding to the type of sheet size. There was a problem of high costs.
[0004]
Accordingly, an object of the present invention is to provide a sheet feeding apparatus that can determine the size of each sheet without separately providing a number of sensors corresponding to the type of sheet size.
[0005]
[Means for Solving the Problems]
  In order to solve the above problems, a sheet conveying apparatus according to the present invention detects sheet presence / absence of a sheet, and drive control for moving the sheet detecting means in a vertical direction perpendicular to a conveying direction in which the sheet is conveyed. And sheet size calculating means for calculating the size of the sheet in the vertical direction based on the result of detecting the presence or absence of the sheet while the sheet detecting means moves in the vertical direction,The drive control unit moves the sheet detection unit in the vertical direction when the sheet detection unit detects the presence of the sheet in the transport direction, and when the sheet detection unit no longer detects the presence of the sheet in the vertical direction. The sheet detecting means is moved back to the side where the sheet detecting means detects the presence of the sheet in the transport direction, and the sheet detecting means returns to the side where the presence of the sheet in the transport direction is detected and returns to the transport direction. The sheet size calculating means calculates the size of the sheet in the transport direction based on the result of the sheet detection means detecting the presence or absence of the sheet in the transport direction.It is characterized by this.
[0006]
  With this configuration, the sheet detection unit itself detects the presence or absence of a sheet while moving in the vertical direction, and the sheet size calculation unit calculates the vertical size of the sheet based on the detection result of the sheet detection unit. Therefore, it is not necessary to separately provide the number of sensors corresponding to the type of size in the vertical direction of the sheet, and the cost corresponding to the number of sensors that are no longer necessary can be reduced.
  Also, with this configuration, the sheet detecting means detects the other end in the sheet conveying direction after detecting one end in the sheet conveying direction, and the sheet size calculating means detects the other end in the sheet conveying direction. Since the size in the sheet conveyance direction is calculated based on the detection result of the detection means, it is necessary to provide a sensor for obtaining the size in the sheet conveyance direction and a sensor for obtaining the size in the vertical direction of the sheet separately. Thus, the cost corresponding to the number of sensors that are no longer required can be reduced.
[0007]
In the sheet conveying apparatus according to the present invention, the sheet conveying apparatus includes a conveying guide unit that guides the sheet in the conveying direction, the sheet size calculating unit includes a distance relationship between the conveying guide unit and the drive control unit, and the sheet detecting unit The vertical size of the sheet is calculated based on the result of detecting the presence or absence of the sheet while moving in the vertical direction.
[0008]
With this configuration, even if the sheet detection means does not move from one end portion to the other end portion of the sheet in the vertical direction, the sheet size calculation means calculates the size of the sheet in the vertical direction. The occupied space can be reduced, and the sheet conveying apparatus can be reduced in size.
[0009]
In the sheet conveying apparatus according to the present invention, the sheet size calculating means includes a distance relationship between a center line of the sheet parallel to the conveying direction and the drive control means, and the sheet detecting means moves in the vertical direction while moving the sheet. Based on the result of detecting the presence or absence, the size of the sheet in the vertical direction is calculated.
[0010]
With this configuration, even if the sheet detection means does not move from one end portion to the other end portion of the sheet in the vertical direction, the sheet size calculation means calculates the size of the sheet in the vertical direction. The occupied space can be reduced, and the sheet conveying apparatus can be reduced in size.
[0013]
In the sheet conveying apparatus according to the present invention, the sheet detecting means is arranged in parallel with the detection signal generating means for generating a sheet detection signal and receiving the sheet detection signal while being arranged in parallel with the detection signal generating means. Means. When the sheet detection unit detects the presence / absence of a sheet in the transport direction, the drive control unit is configured such that the detection signal generation unit and the detection signal reception unit are parallel to the vertical direction. When the detection unit detects the presence or absence of the sheet in the vertical direction, the sheet detection unit is rotated so that the detection signal generation unit and the detection signal reception unit are aligned in parallel with the conveyance direction.
[0014]
With this configuration, since only one of the detection signal generation unit and the detection signal reception unit does not deviate from the region where the sheet exists, the sheet detection signal generated by the detection signal generation unit enters the detection signal reception unit. This increases the probability of the sheet detection, and the detection accuracy of the sheet detection means can be increased.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that “SH” in the drawings refers to a sheet.
[0016]
(First embodiment)
As shown in FIGS. 1 and 2, the sheet conveying apparatus 100 according to the first embodiment of the present invention opposes a conveying roller 110 that conveys a sheet and a surface that has a large area among the surfaces of the sheet. The sheet is formed by a sheet conveying plate having a surface downstream in the conveying direction of the conveying roller 110 (hereinafter referred to as a sheet length direction, meaning the X direction in FIG. 2) and a surface perpendicular to the opposing surface of the sheet conveying plate. A conveyance guide plate 130 that constitutes a conveyance guide unit that guides in a direction, and a sheet detection unit 140 that detects the presence or absence of a sheet are provided.
[0017]
Here, the sheet conveying plate has a sheet length detection hole 121 and a sheet width detection hole 122 for the sheet detection unit 140 to detect the presence or absence of a sheet. The sheet width detection hole 122 is a minimum width sheet SH in which the sheet detection unit 140 has the smallest width._minAnd the maximum width sheet SH having the largest width_max3 is formed on the sheet conveying plate so as to be able to detect the end portion in the sheet width direction, specifically as shown in FIG. Further, as shown in FIG. 4, the sheet detection unit 140 is arranged alongside the detection signal generation unit 141 that generates the sheet detection signal and the detection signal generation unit 141, and the detection signal reception unit that receives the sheet detection signal. 142, the sheet detection signal generated from the detection signal generation unit 141 is reflected on the sheet, and the reflected sheet detection signal is received by the detection signal reception unit 142, thereby detecting the presence or absence of the sheet. . Although it is desirable to use an optical signal, an electrical signal, or the like as the sheet detection signal, it does not prevent detection using other signals.
[0018]
As shown in FIGS. 2 and 5, the sheet conveying apparatus 100 calculates the sheet length based on the drive control unit 150 that moves the sheet detection unit 140 and the result of detecting the presence or absence of the sheet in the sheet length direction, The distance between the conveyance guide plate 130 and the drive control unit 150 and the sheet detection unit 140 move in the vertical direction perpendicular to the sheet length direction (hereinafter referred to as the sheet width direction, meaning the Y direction in FIG. 2). Sheet size calculating means 160 for calculating the sheet width based on the result of detecting whether or not the image is present.
[0019]
Here, the drive control means 150 includes two pulleys 151a and 151b driven by a motor (not shown), and a belt provided around the two pulleys 151a and 151b so as to be interlocked with the rotation of the two pulleys 151a and 151b. 152, a program for controlling the rotation of the pulleys 151a and 151b, and pulley control means 153 comprising the CPU 170. The pulley 151a and 151b are linked with the CPU 170 and the program for controlling the rotation of the pulleys 151a and 151b. , And the sheet detecting means 140 fixed to the belt 152 is driven. The CPU 170 is linked not only to the pulley control unit 153 but also to the sheet detection unit 140, the sheet size calculation unit 160, the memory 183, the image reading unit 181, the conveyance roller driving unit 182 that drives the conveyance roller 110, and the like. ing.
[0020]
Next, the operation of the sheet conveying apparatus 100 according to the present embodiment will be described with reference to the flowchart shown in FIG. The conveyance roller 110 moves the sheet at a constant speed V in the sheet length direction.₀(S101). At this time, as shown in FIG. 7, the sheet detection unit 140 waits to detect the presence of the sheet from below the sheet length detection hole 121 of the sheet conveying plate 120.
[0021]
When the sheet detection unit 140 detects the presence of the sheet from the sheet length detection hole 121, that is, detects the leading edge of the sheet (S102), the pulleys 151a and 151b are rotated at the rotational speed N.₁The sheet detecting means 140 fixed to the belt 152 also rotates 90 degrees clockwise around the pulleys 151a and 151b (S103). At this time, the sheet detection unit 140 is positioned so as to detect the presence / absence of a sheet from the sheet width detection hole 122 of the sheet conveying plate 120. Here, the clockwise direction means the direction of the arrow described in the drawings showing the pulleys 151a and 151b in FIGS. As shown in FIG. 8, when the sheet detection unit 140 detects the presence / absence of a sheet from the sheet length detection hole 121, the arrangement of the detection signal generation unit 141 and the detection signal reception unit 142 is parallel to the sheet width direction. It becomes. On the other hand, when the sheet detection unit 140 detects the presence / absence of a sheet from the sheet width detection hole 122, the arrangement of the detection signal generation unit 141 and the detection signal reception unit 142 is parallel to the sheet length direction.
[0022]
The sheet detection unit 140 is rotated 90 degrees around the pulleys 151a and 151b, and then moves at a constant speed in the sheet width direction while detecting the presence or absence of the sheet from the sheet width detection hole 122. After the sheet detection unit 140 no longer detects the presence of the sheet from the sheet width detection hole 122 (S104), the sheet size calculation unit 160 detects the presence of the sheet from the sheet length detection hole 121. The time until no sheet presence is detected from the sheet width detection hole 122 is calculated (S105). At this time, the sheet size calculation unit 160 may calculate the sheet width based on the data from the sheet detection unit 140. Sheet width L in sheet size calculation means 160_SThe calculation formula of (mm) is as follows.
[0023]
L_S= L₁+ 2 × π × d (1/60) × N₁× (T₁-15 / N₁) ... (Formula 1)
[0024]
Where L₁(Mm) is the distance from the conveyance guide plate 130 to the rotation center of the pulley 151a. π is the circumference ratio. d (mm) is the radius of the pulleys 151a and 151b. N₁(Rpm) is the rotational speed of the pulleys 151a and 151b. T₁(S) is the time from when the sheet detection unit 140 detects the presence of the sheet through the sheet length detection hole 121 until it stops detecting the presence of the sheet through the sheet width detection hole 122. 15 / N₁(S) is the time required for the pulleys 151a and 151b to rotate 90 degrees.
[0025]
The sheet detection means 140 detects the presence of the sheet from the sheet length detection hole 121 and then₀After a lapse of seconds (S106), as shown in FIG. 9, the temporarily stopped pulleys 151a and 151b₀Seconds are driven counterclockwise by a motor (not shown) (S107).
[0026]
After the pulleys 151a and 151b are driven counterclockwise, the sheet detection unit 140 detects the presence of the sheet again from the sheet width detection hole 122 (S108). At this time, the time from when the sheet detecting unit 140 is stopped until the presence of the sheet is detected again from the sheet width detecting hole 122 is expressed as T.₂If (s), then in (Equation 1), T₁(S) is defined as in the following (Expression 2) (S109).
[0027]
T₁= T₀-T₂                          ... (Formula 2)
[0028]
T after pulleys 151a and 151b are driven counterclockwise₀When a second elapses (S110), the pulleys 151a and 151b are stopped, and the sheet detecting means 140 detects the presence / absence of a sheet from the sheet length detection hole 121 as shown in FIG. 10 (S111).
[0029]
As shown in FIG. 11, after the sheet detection unit 140 does not detect the presence of the sheet at the position where the presence / absence of the sheet is detected from the sheet length detection hole 121 (S112), that is, the sheet trailing edge is detected. After the completion, the sheet size calculation means 160 reads the sheet length L_L(Mm) is calculated according to the following (Equation 3) (S113).
[0030]
L_L= V₀× T₃                          ... (Formula 3)
[0031]
Where V₀(Mm / s) is the speed at which the sheet is conveyed as described above. T₃(S) is the time from when the sheet detection unit 140 detects the presence of the sheet through the sheet length detection hole 121 in step S102 until it stops detecting the presence of the sheet from the sheet length detection hole 121 in step S113.
[0032]
When the sheet size calculating unit 160 finishes calculating the sheet length, the conveying roller 110 stops conveying the sheet (S114).
[0033]
As described above, in the present embodiment, the sheet detection unit 140 detects the presence and absence of a sheet from the sheet length detection hole 121 and the sheet width detection hole 122, and the sheet size calculation unit 160 is based on the detection result. The sheet length and sheet width are calculated. In this embodiment, when the sheet size calculation unit 160 holds the data from the sheet detection unit 140 in a memory 183 (not shown) or the like and all the data for calculating the sheet length and the sheet width are collected, the sheet length and Does not interfere with the calculation of the sheet width.
[0034]
According to the present embodiment, the sheet detection unit 140 itself detects the presence or absence of a sheet while moving in the sheet width direction, and the sheet size calculation unit 160 calculates the sheet width based on the detection result of the sheet detection unit 140. Therefore, the number of sensors corresponding to the type of sheet width need not be separately provided, and the cost corresponding to the number of sensors that are no longer required can be reduced.
[0035]
According to the present embodiment, the sheet detecting unit 140 does not move from one end of the sheet to the other end in the sheet width direction, and the sheet size calculating unit 160 calculates the sheet width. Therefore, the two pulleys 151a and 151b The space occupied by the drive control means 150 including can be reduced, and the sheet conveying apparatus 100 can be reduced in size. The present embodiment does not hinder the configuration in which the sheet detection unit 140 moves from one end portion to the other end portion of the sheet in the sheet width direction.
[0036]
According to the present embodiment, the sheet detecting unit 140 detects one end of the conveyed sheet in the sheet length direction, that is, the other end in the sheet length direction after moving in the sheet width direction after detecting the leading end of the sheet. The sheet size calculating unit 160 calculates the sheet length based on the detection result of the sheet detecting unit 140, and the sensor for obtaining the sheet length and the sheet width are obtained. It is not necessary to provide the sensors separately and independently, and the cost corresponding to the number of sensors that need not be provided can be reduced.
[0037]
According to the present embodiment, since only one of the detection signal generation unit 141 and the detection signal reception unit 142 does not deviate from the region where the sheet exists, the sheet detection signal generated by the detection signal generation unit 141 receives the detection signal. The probability of entering the means 142 is increased, and the detection accuracy of the sheet detecting means 140 can be increased.
[0038]
According to the present embodiment, since the sheet detection unit 140 is driven by the belt 152, a drive mechanism that moves the sheet detection unit 140 in the sheet width direction and a drive mechanism that rotates the sheet detection unit 140 by 90 degrees are separately provided. Since there is no need to provide this, it is possible to reduce the cost of providing a drive mechanism that rotates the sheet detecting means 140 by 90 degrees. Note that this embodiment does not interfere with a configuration in which a drive mechanism that moves the sheet detection unit 140 in the sheet width direction and a drive mechanism that rotates the sheet detection unit 140 by 90 degrees are provided separately.
[0039]
(Second Embodiment)
Unlike the sheet conveying apparatus 100 according to the first embodiment, the sheet conveying apparatus 200 according to the second embodiment of the present invention does not include a conveyance guide plate. Therefore, the sheet size calculating unit 260 calculates the sheet length based on the result of detecting the presence or absence of the sheet in the sheet length direction, and the distance between the sheet center line C parallel to the sheet length direction and the rotation center of the pulley 251a. The sheet width is calculated based on the relationship and the result of the sheet detection unit 240 detecting the presence or absence of the sheet while moving in the sheet width direction. In addition, about the description which overlaps with the description of the sheet conveying apparatus 100 which concerns on 1st Embodiment, this is abbreviate | omitted.
[0040]
Next, the operation of the sheet conveying apparatus 200 according to the present embodiment will be described with reference to the flowchart shown in FIG. The conveyance roller 210 moves the sheet at a constant speed V in the sheet length direction.₀(S101). At this time, as shown in FIG. 12, the sheet detection unit 240 waits to detect the presence of the sheet from below the sheet length detection hole 221 of the sheet conveying plate 220.
[0041]
When the sheet detection means 240 detects the presence of the sheet from the sheet length detection hole 221, that is, detects the leading edge of the sheet (S 102), the pulleys 251 a and 251 b rotate at the rotational speed N.₁And the sheet detecting means 240 fixed to the belt 252 is also rotated 90 degrees clockwise around the pulleys 251a and 251b (S103). At this time, the sheet detection unit 240 is positioned so as to detect the presence / absence of a sheet from the sheet width detection hole 222 of the sheet conveying plate. As shown in FIG. 13, when the sheet detection unit 240 detects the presence / absence of a sheet from the sheet length detection hole 221, the arrangement of the detection signal generation unit 241 and the detection signal reception unit 242 is parallel to the sheet width direction. It becomes. On the other hand, when the sheet detection unit 240 detects the presence / absence of a sheet from the sheet width detection hole 222, the arrangement of the detection signal generation unit 241 and the detection signal reception unit 242 is parallel to the sheet length direction.
[0042]
The sheet detection unit 240 is rotated 90 degrees around the pulleys 251a and 251b, and then moves at a constant speed in the sheet width direction while detecting the presence / absence of the sheet from the sheet width detection hole 222. After the sheet detection unit 240 no longer detects the presence of the sheet from the sheet width detection hole 222 (S104), the sheet size calculation unit 260 detects the presence of the sheet from the sheet length detection hole 221. The time until the presence of the sheet is not detected from the sheet width detection hole 222 is calculated (S105). At this time, the sheet size calculation unit 260 may calculate the sheet width based on the data from the sheet detection unit 240. Sheet width L in sheet size calculation means 260_SThe calculation formula of (mm) is as follows.
[0043]
L_S= 2 × {2 × π × d (1/60) × N₁× (T₁-15 / N₁-L₂} (Formula 4)
[0044]
Where L₂(Mm) is the distance from the center line C to the rotation center of the pulley 251a. π is the circumference ratio. d (mm) is the radius of the pulleys 251a and 251b. N₁(Rpm) is the rotational speed of the pulleys 251a and 251b. T₁(S) is the time from when the sheet detection unit 240 detects the presence of the sheet through the sheet length detection hole 221 until it stops detecting the presence of the sheet from the sheet width detection hole 222. 15 / N₁(S) is the time required for the pulleys 251a and 251b to rotate 90 degrees.
[0045]
The sheet detection means 240 detects the presence of the sheet from the sheet length detection hole 221 and then₀After a lapse of seconds (S106), the temporarily stopped pulleys 251a and 251b are turned on again as shown in FIG.₀Seconds are driven counterclockwise by a motor (not shown) (S107).
[0046]
After the pulleys 251a and 251b are driven counterclockwise, the sheet detection unit 240 detects the presence of the sheet again from the sheet width detection hole 222 (S108). At this time, the time from when the sheet detection unit 240 stops until the presence of the sheet is detected again from the sheet width detection hole 222 is expressed as T.₂If (s), then in (Expression 4), T₁(S) is defined as in the following (Formula 5) (S109).
[0047]
T₁= T₀-T₂                          ... (Formula 5)
[0048]
T after pulleys 251a and 251b are driven counterclockwise₀When the second has elapsed (S110), the pulleys 251a and 251b are stopped, and the sheet detection unit 240 detects the presence / absence of a sheet from the sheet length detection hole 221 as shown in FIG. 15 (S111).
[0049]
As shown in FIG. 16, after the sheet detection unit 240 does not detect the presence of the sheet at the position where the presence / absence of the sheet is detected from the sheet length detection hole 221 (S <b> 112), i. After the completion, the sheet size calculation means 260_L(Mm) is calculated according to the following (Equation 3) (S113).
[0050]
L_L= V₀× T₃                          ... (Formula 3)
[0051]
Where V₀(Mm / s) is the speed at which the sheet is conveyed as described above. T₃(S) is the time from when the sheet detection unit 240 detects the presence of the sheet through the sheet length detection hole 221 in step S102 until it stops detecting the presence of the sheet from the sheet length detection hole 221 in step S113.
[0052]
When the sheet size calculating unit 260 finishes calculating the sheet length, the conveying roller 210 stops conveying the sheet (S114).
[0053]
As described above, in the present embodiment, the sheet detection unit 240 detects the presence and absence of a sheet from the sheet length detection hole 221 and the sheet width detection hole 222, and the sheet size calculation unit 260 is based on the detection result. The sheet length and sheet width are calculated. In the present embodiment, when the sheet size calculation unit 260 holds the data from the sheet detection unit 240 in a memory 283 (not shown) or the like and all the data for calculating the sheet length and the sheet width are obtained, the sheet length and Does not interfere with the calculation of the sheet width.
[0054]
According to the present embodiment, even if the conveyance guide plate is not provided, the sheet size calculation unit 260 does not move from one end portion to the other end portion of the sheet in the sheet width direction. Since the sheet width is calculated, the space occupied by the drive control means 250 including the two pulleys 251a and 251b can be reduced, and the sheet conveying apparatus 200 can be reduced in size. The present embodiment does not hinder the configuration in which the sheet detection unit 240 moves from one end portion of the sheet to the other end portion in the sheet width direction.
[0055]
【The invention's effect】
According to the present invention, it is not necessary to separately provide the number of sensors corresponding to the type of size in the vertical direction of the sheet, and the cost corresponding to the reduced number of sensors can be reduced.
[Brief description of the drawings]
FIG. 1 is a side view showing a sheet conveying apparatus according to each embodiment of the present invention.
FIG. 2 is a top view showing the sheet conveying apparatus according to the first embodiment of the present invention.
3 is a side cross-sectional view in the direction of AA in FIG. 2 showing the positional relationship between the sheet conveying plate and the sheet detecting means in the first embodiment of the present invention.
4A is a side view and FIG. 4B is a top view showing a positional relationship between an end portion of a sheet and a sheet detection unit according to the first embodiment of the present invention.
FIG. 5 is a block diagram illustrating a sheet conveying apparatus according to each embodiment of the invention.
FIG. 6 is a flowchart showing the operation of the sheet conveying apparatus according to each embodiment of the invention.
FIG. 7 is a top view of the sheet conveying apparatus showing a state in which the sheet detecting unit detects the leading end of the sheet in the sheet length direction in the first embodiment of the present invention.
FIG. 8 is a top view of the sheet conveying apparatus showing a state in which the sheet detecting unit detects the end of the sheet in the sheet width direction in the first embodiment of the present invention.
FIG. 9 is a top view of the sheet conveying apparatus showing a state in which the pulley is driven counterclockwise in the first embodiment of the present invention.
FIG. 10 is a top view of the sheet conveying apparatus showing a state in which the sheet detection unit waits to detect the trailing edge of the sheet in the sheet length direction in the first embodiment of the present invention.
FIG. 11 is a top view of the sheet conveying apparatus illustrating a state in which the sheet detection unit detects the trailing edge of the sheet in the sheet length direction according to the first exemplary embodiment of the present invention.
FIG. 12 is a top view of the sheet conveying apparatus showing a state in which the sheet detecting unit detects the leading end of the sheet in the sheet length direction in the second embodiment of the present invention.
FIG. 13 is a top view of the sheet conveying apparatus showing a state in which the sheet detecting unit detects the end of the sheet in the sheet width direction in the second embodiment of the present invention.
FIG. 14 is a top view of the sheet conveying apparatus showing a state in which the pulley is driven counterclockwise in the second embodiment of the present invention.
FIG. 15 is a top view of the sheet conveying apparatus illustrating a state in which the sheet detection unit waits to detect the trailing edge of the sheet in the sheet length direction in the second embodiment of the present invention.
FIG. 16 is a top view of the sheet conveying apparatus showing a state in which the sheet detecting unit detects the trailing edge of the sheet in the sheet length direction in the second embodiment of the present invention.
[Explanation of symbols]
130 Transport guide plate (transport guide means)
140, 240 Sheet detection means
141, 241 Detection signal generating means
142, 242 Detection signal receiving means
150, 250 Drive control means
160, 260 Sheet size calculation means

Claims (4)

Sheet detection means for detecting the presence or absence of a sheet;
Drive control means for moving the sheet detecting means in a vertical direction perpendicular to the conveying direction in which the sheet is conveyed;
Sheet size calculating means for calculating the size of the sheet in the vertical direction based on the result of detecting the presence or absence of the sheet while the sheet detecting means moves in the vertical direction;
The drive control unit moves the sheet detection unit in the vertical direction when the sheet detection unit detects the presence of the sheet in the transport direction, and when the sheet detection unit no longer detects the presence of the sheet in the vertical direction. Moving the sheet detection means back to the side where the sheet detection means has detected the presence of the sheet in the transport direction;
The sheet detecting means detects the absence of the sheet in the transport direction by returning to the side where the presence of the sheet in the transport direction is detected,
The sheet conveying apparatus, wherein the sheet size calculating unit calculates a size of the sheet in the conveying direction based on a result of detecting whether or not the sheet is detected in the conveying direction . The sheet detection unit includes a detection signal generation unit that generates a sheet detection signal, and a detection signal reception unit that is arranged side by side with the detection signal generation unit and receives the sheet detection signal,
When the sheet detection unit detects the presence or absence of a sheet in the transport direction, the drive control unit is configured such that an arrangement of the detection signal generation unit and the detection signal reception unit is parallel to the vertical direction, and the sheet detection unit When detecting the presence / absence of a sheet in the vertical direction, the sheet detection unit is rotated so that the arrangement of the detection signal generation unit and the detection signal reception unit is parallel to the conveyance direction. The sheet conveying apparatus according to claim 1. A conveyance guide means for guiding the sheet in the conveyance direction;
The sheet size calculating unit is configured to determine a size of the sheet in the vertical direction based on a distance relationship between the conveyance guide unit and the drive control unit and a result of detecting whether or not a sheet exists while the sheet detecting unit moves in the vertical direction. sheet conveying device according to claim 1 or claim 2, characterized in that computing the. The sheet size calculating unit is configured to detect the presence of the sheet based on a distance relationship between a center line of the sheet parallel to the conveyance direction and the drive control unit, and a result of detecting the presence or absence of the sheet while the sheet detecting unit moves in the vertical direction. sheet conveying device according to claim 1 or claim 2, characterized in that for calculating the size of the vertical direction.

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