JP4451417B2 - Image recording apparatus provided with double feed detection device and image recording method provided with double feed detection method - Google Patents

Description

The present invention relates to an image recording method comprising a multi-feed method out image recording apparatus and double feed comprises a double feed detector you detected by the ultrasonic sensor of the transport object, such as a recording sheet or document.

  2. Description of the Related Art In recent years, an image recording apparatus such as a digital multi-function peripheral having a scanner function, a printer function, a facsimile function, and the like has an automatic document reading device, and reads images one by one on a document stacked on a document tray of the automatic document reading device. A large number of originals are processed at high speed by reading the image recorded on the original, reading the image recorded on the original, and performing processing such as printing on a recording sheet based on the read image. .

  However, when the recording paper is transported for printing by such an image recording apparatus, the recording paper is not separated and transported one by one due to the influence of humidity or static electricity, and two or more recording papers overlap. There may be a case where a multi-feed is carried. Similarly, when an original is transported by the automatic document reader, double feeding of the original may occur.

  Examples of such double feed detection means include an optical sensor and an ultrasonic sensor (see, for example, Patent Document 1). Conventionally, optical sensors were often used, but ultrasonic sensors are not easily affected by the thickness of recording paper or originals, and accurate double feed detection is possible even when recording papers and originals with different thicknesses are mixed. There is an advantage that it can be performed, and recently, examples of use are increasing.

  However, since an ultrasonic sensor performs multifeed detection with a considerably large sound pressure, a temperature rise becomes a problem when it is used continuously for a long time. Such an ultrasonic sensor is usually arranged along a conveyance path for recording paper or a document. However, particularly in an image recording apparatus, the conveyance path for the recording paper does not like dust or dust from the outside of the apparatus. In many cases, the structure is cut off, and heat tends to stay inside. Even if an attempt is made to install a heat sink or the like together with the ultrasonic sensor, there are many restrictions on the arrangement space and the like, and countermeasures for temperature rise of the ultrasonic sensor are not easy.

Therefore, paying attention to the fact that the transmitting element and receiving element of the ultrasonic sensor are composed of the same piezoelectric element, the role of the transmitting element and the receiving element is periodically exchanged using a selector or the like, so that the influence of the temperature rise is affected. An image forming apparatus capable of being suppressed has been proposed (see, for example, Patent Document 2).
JP 2004-26349 A (page 3-5, FIG. 1) JP 2005-15124 A

  However, the conventional technique disclosed in Patent Document 2 described above not only requires a selector in addition to the ultrasonic sensor, but is not necessarily applicable to all ultrasonic sensors. In addition, if the transmitting and receiving elements are placed in a small space with the recording paper conveyance path in between, there is no change in the continuous generation of heat in that space. It can be said that it does not lead to.

In view of such problems of the prior art, an object of the present invention, an image with a detection equipment double feeding that can significantly suppress an increase in the temperature with a simple configuration, such as an ultrasonic sensor used for multifeed detection it is to provide an image recording method comprising a recording equipment Contact and multifeed detection method.

The image recording apparatus of the present invention is an image recording apparatus including a multifeed detection device, and the multifeed detection device includes a plurality of conveyance paths that can be selectively used for conveyance of a conveyance object, and the plurality of conveyances. And a double feed detection unit that is arranged in the vicinity of the downstream of the merging unit of the path, detects a double feed of the transport object, and selects which of the plurality of transport paths is used for transport of the transport object, and When the transport object is transported from a plurality of transport paths other than the specific transport path, control is performed so that normal power feeding to the multifeed detection unit is performed, and the transport target object is transported from the specific transport path. A control unit that controls power supply to the multi-feed detection unit to be stopped or less than normal power supply when transported, and the image recording apparatus is detachable from the image recording apparatus main body. And all of the plurality of transport paths The control unit further includes a plurality of units each including different parts, and when the multifeed of the transport object is detected by the multifeed detection unit, the transport object being transported is detected. When it is determined that the image recording apparatus main body and only one of the plurality of units are present, the conveyance is stopped, and the control unit detects the conveyance object in the double feed detection unit. When it is determined that the object to be transported exists over any two or more of the image recording apparatus main body and the plurality of units when the double feed is detected. the transport object is characterized that you stops feeding was continued for transport to move to a position that will exist within only.

  Here, examples of the conveyance object include, but are not limited to, a recording sheet and a document. Examples of the double feed detection unit include, but are not limited to, an ultrasonic sensor based on a transmission type detection method. For example, other sensors that are used for detecting double feed and generate a large amount of heat during operation can be considered.

According to the image recording apparatus having such a configuration, the necessity of double feed detection is determined, and when this is not necessary, power supply to the double feed detection unit is stopped or less power is supplied than usual. To control. That is, when it is known in advance that double feed will not occur when the transport object is transported from a specific transport path among the plurality of transport paths, it is determined that double feed detection is unnecessary, and the Control is performed to stop power feeding to the feed detection unit. Alternatively, control may be performed so that less power is supplied than usual. As a result, a temperature increase due to heat generation of the double feed detector is suppressed, and a stable operation is possible. Further, when the conveyance is stopped after the double feed is detected, a conveyance object such as a recording sheet exists in only one of the image recording apparatus main body and the plurality of units. Thereby, the removal operation | work of the conveyance target object can be performed easily and reliably.

In the image record detection device of the present invention, the conveyance object that has already been subjected to double feed detection by the double feed detection unit may be conveyed from the specific conveyance path. . Alternatively, the specific conveyance path is a part of a circulation-type conveyance path, and the conveyance object for which double-feed detection has already been performed by the double-feed detection unit is again made via the circulation-type conveyance path. You may be comprised so that conveyance is possible.

According to the image recording apparatus having such a configuration, when the transport object is transported from a specific transport path among the plurality of transport paths, a double feed does not occur and a double feed detection is unnecessary. Since it can be determined, control is performed so as to stop the power supply to the double feed detection unit, or control is performed so that less power is supplied than usual. As a result, a temperature increase due to heat generation of the double feed detector is suppressed, and a stable operation is possible.

Alternatively, the image recording method of the present invention can be inserted into and removed from the main body of the image recording apparatus, and is used for an image recording apparatus including a plurality of units including different portions inside the plurality of conveying paths. An image recording method comprising a detection method, wherein the double feed detection method includes a conveyance path selection step for selecting which of a plurality of selectively usable conveyance paths to be used for conveyance of a conveyance object; and When the conveyance path selection step selects a conveyance path other than a specific conveyance path from among the plurality of conveyance paths, normal power feeding is performed to the double feed detection unit disposed in the vicinity of the junction of the plurality of conveyance paths. In addition, when the specific transport path is selected from the plurality of transport paths, the power supply to the multifeed detection unit is stopped or the power supply is controlled to be less than usual. And a multi-feed detection step for performing multi-feed detection of the object to be conveyed by the multi-feed detection unit when the control step is controlled so that normal power feeding to the multi-feed detection unit is performed. Furthermore, when the double feed of the transport object is detected in the double feed detection step, the transport target being transported is only one of the image recording apparatus main body and the plurality of units. When the multi-feed of the transport object is detected in the first transport stop step for stopping the transport and the multi-feed detection step, the transport during transport is determined. When it is determined that the object is present over any two or more of the image recording apparatus main body and the plurality of units, the carrying is performed up to a position where only one of the objects is to be present. Characterized in that it comprises a second conveyance stop step that stops the conveyance after the object is continued transport to move.

According to the image recording method having such a configuration, the necessity of double feed detection is determined, and when this is not necessary, power supply to the double feed detection unit is stopped or less power is supplied than usual. To control. As a result, a temperature increase due to heat generation of the double feed detector is suppressed, and a stable operation is possible. Further, when the conveyance is stopped after the double feed is detected, a conveyance object such as a recording sheet exists in only one of the image recording apparatus main body and the plurality of units. Thereby, the removal operation | work of the conveyance target object can be performed easily and reliably.

According to the image recording apparatus provided with the double feed detection device and the image recording method provided with the double feed detection method of the present invention, the necessity of double feed detection is determined, and if it is not necessary, to the double feed detection unit. The power supply is controlled to be stopped or less than usual. As a result, a temperature increase due to heat generation of the double feed detector is suppressed, and a stable operation is possible. Further, when the conveyance is stopped after the double feed is detected, a conveyance object such as a recording sheet exists in only one of the image recording apparatus main body and the plurality of units. Thereby, the removal operation | work of the conveyance target object can be performed easily and reliably.

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

<Configuration of Image Recording Apparatus 100>
FIG. 1 is a schematic front sectional view showing the configuration of an image recording apparatus 100 according to an embodiment of the present invention. The image recording apparatus 100 includes an image reading unit 200, an image forming unit 300, a paper feed unit 400, and a large capacity paper feed tray 410.

  The image reading unit 200 includes an automatic document feeder (ADF) 201, a first document table 202, a second document table 203, a first mirror base 204, a second mirror base 205, a lens 206, and a solid-state imaging device ( A CCD (Charge Coupled Device) 207 is provided.

  The ADF 201 conveys documents one by one from the document tray 211 to the discharge tray 212 via the second document table 203. The ADF 201 is rotatable about the back side so that the top surface of the first document table 202 can be opened and closed. By rotating the ADF 201 so that the front side moves upward, the upper surface of the first document table 202 is exposed, so that the document can be placed on the first document table 202 by manual operation.

  Both the first platen 202 and the second platen 203 are made of hard glass plates.

  The first mirror base 204 and the second mirror base 205 are movable in the horizontal direction below the first document table 202 and the second document table 203. The moving speed of the second mirror base 205 is ½ of the moving speed of the first mirror base 204. The first mirror base 204 is equipped with a light source and a first mirror. The second mirror base 205 is equipped with a second mirror and a third mirror.

  When reading an image of a document conveyed by the ADF 201, the first mirror base 204 is stopped below the second document table 203. The light from the light source is emitted toward the image surface of the document passing over the second document table 203, and the reflected light on the image surface of the document is reflected toward the second mirror base 205 by the first mirror.

  When reading an image of a document placed on the first document table 202, the first mirror base 204 and the second mirror base 205 move horizontally below the first document table 202. The light from the light source is emitted toward the image surface of the document placed on the first document table 202, and the reflected light on the image surface of the document is reflected toward the second mirror base 205 by the first mirror.

  Regardless of whether or not the ADF 201 is used, the reflected light on the image surface of the document is incident on the CCD 207 via the lens 206 by the second mirror and the third mirror with a constant optical path length.

  The CCD 207 outputs an electrical signal corresponding to the amount of reflected light on the image surface of the document. This electrical signal is input to the image forming unit 300 as image data.

  The image forming unit 300 includes a photosensitive drum 31, a charger 32, an exposure device 33, a developing device 34, a transfer belt 35, a cleaner 36, and a fixing device 37 that constitute the image recording unit 30.

  The photosensitive drum 31 has a photosensitive layer formed on the surface thereof, and rotates in the direction of the arrow. The charger 32 uniformly charges the surface of the photosensitive drum 31 to a predetermined potential. The charger 32 may use either a non-contact method using a charger or a contact method using a roller or a brush.

  The exposure device 33 irradiates the surface of the photosensitive drum 31 with light based on the image data. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 31 by the photoconductive action in the photosensitive layer. The exposure device 33 scans the laser beam modulated based on the image data in the axial direction of the photosensitive drum 31 through a polygon mirror. Alternatively, an exposure apparatus in which light emitting elements such as EL and LEDs are arranged in an array can be used.

  The developing device 34 supplies toner to the surface of the photosensitive drum 31 and visualizes the electrostatic latent image into a toner image.

The transfer belt 35 is looped between a plurality of rollers below the photosensitive drum 31, and has a resistance value of about 1 × 10 ⁹ to 1 × 10 ¹³ Ω · cm. A transfer roller 35A that presses against the photosensitive drum 31 with the transfer belt 35 interposed therebetween is provided inside the loop-shaped movement path of the transfer belt 35. A predetermined transfer voltage is applied to the transfer roller 35 </ b> A, and the toner image carried by the photosensitive drum 31 is transferred onto a recording sheet that passes between the transfer belt 35 and the photosensitive drum 31. The transfer belt 35 and the transfer roller 35A constitute a part of the fixing device of the present invention.

  The cleaner 36 removes residual toner from the surface of the photosensitive drum 31 after the transfer of the toner image to the recording paper.

  The fixing device 37 includes a heating roller 37A and a pressure roller 37B. The heating roller 37A is heated by an internal heater to a temperature at which the toner can be melted. The pressure roller 37B is in pressure contact with the heating roller 37A with a predetermined pressure. The fixing device 37 firmly fixes the toner image on the recording paper by heating and pressing the recording paper passing between the heating roller 37A and the pressure roller 37B. The recording paper that has passed through the fixing device 37 is discharged to a paper discharge tray 38 mounted on one side surface of the image recording device 100. The paper discharge tray 38 corresponds to the paper discharge unit of the present invention.

  The paper feed unit 400 includes paper feed cassettes 401, 402, 403, 404 and a manual feed tray 405. Each of the paper feed cassettes 401, 402, 403, and 404 stores a plurality of recording sheets of the same size. On the manual feed tray 405, recording paper of a size or quality that is not frequently used is placed.

  The paper feed unit 400 feeds the recording paper one by one from one of the paper feed cassettes 401, 402, 403, 404 or the manual feed tray 405. The recording sheet fed from the sheet feeding unit 400 is conveyed to the image recording unit 30 via a sheet conveying path 10 described later.

  The paper feed unit 400 is equipped with a large capacity paper feed tray 410 that can accommodate a large capacity recording paper.

<Regarding the paper conveyance path 10 of the image recording apparatus 100>
FIG. 2 is a diagram illustrating a configuration of the sheet conveyance path 10 in the image recording apparatus 100. Inside the image forming unit 300, a paper transport path 10 is configured. The paper transport path 10 includes a first transport path 11, a second transport path 12, a third transport path 13, a fourth transport path 14, and a fifth transport path 15.

  The first transport path 11 reaches the paper discharge tray 38 via the first unit 21, the image recording unit 30, the first branch unit 24, and the second unit 22 in this order from the paper feed unit 400. In the first conveyance path 11, conveyance rollers 61, 62, and 63, a registration roller 51, and a paper discharge roller 52 are arranged. The conveyance rollers 61, 62, 63, the registration roller 51, and the paper discharge roller 52 are supplied with rotation from a first motor (not shown).

  A portion passing through the image recording unit 30 in the first transport path 11 is a recording sheet on which the toner image is stably transferred from the photosensitive drum 31 to the surface of the recording sheet, and the toner image before fixing is electrostatically adsorbed The transfer belt 35 is disposed in order to stably convey the image and is substantially horizontal.

  The second transport path 12 passes the second branch section 25 and the third branch section 26 below the first branch section 24 disposed between the image recording section 30 and the paper discharge tray 38 in the first transport path 11. The switchback unit 12A is reached in order. The switchback unit 12A is substantially parallel to a range passing through the image recording unit 30 in the first conveyance path 11, and conveys the recording paper in the reciprocating direction. Reversing rollers 53 and 58 are disposed in the second transport path 12. Rotation is selectively supplied to the reverse rollers 53 and 58 from a second motor (not shown) via a first clutch (not shown) in the forward direction or the reverse direction.

  The third conveyance path 13 passes from the third branching section 26 via the third merging section 23 to the first merging section 21 disposed between the paper feeding unit 400 and the image recording section 30 in the first conveyance path 11. It reaches. Reversing rollers 54, 55, 56, and 57 are disposed in the third conveyance path 13. The reversing rollers 54, 55, 56, and 57 are selectively supplied in a forward rotation direction or a reverse rotation direction from a third motor (not shown) via a second clutch (not shown).

  The fourth conveyance path 14 connects the second branch portion 25 and the third junction portion 23.

  The fifth conveyance path 15 connects between the second branch portion 25 and the second junction portion 22.

  The switchback portion 12A of the second conveyance path 12 is arranged vertically so as to be substantially parallel to a range passing through the image recording unit 30 arranged in the substantially horizontal direction in the first conveyance path 11. A third conveyance path 13 is disposed between the range passing through the image recording unit 30 in the first conveyance path 11 and the switchback portion 12A of the second conveyance path 12.

  As can also be seen with reference to FIG. 1, after the conveyance path from the manual feed tray 405 and the conveyance path from the large-capacity paper feed tray 410 merge, an intermediate between the registration roller 51 and the conveyance roller 61 is further obtained. The fourth merging section 20 in the vicinity merges with the first conveyance path 11. In other words, all of the plurality of transport paths through which the recording paper is transported are merged before reaching the fourth merge section 20.

  An ultrasonic sensor 82B for detecting the double feed of the recording paper is located in the vicinity of the downstream side of the fourth junction 20 and immediately upstream of the registration roller 51 (details will be described later with reference to FIGS. 9 to 12). The transmitter 82Ba and the receiver 82Bb are arranged so as to face each other with the first transport path 11 in between. By disposing on the downstream side of the fourth merging unit 20, it is possible to detect double feed accurately even if the recording paper is conveyed from any of a plurality of conveying paths by using only one set of the transmitting unit 82Ba and the receiving unit 82Bb. It becomes possible.

  Note that a part of the first transport path 11 (from the first junction 21 to the first branching section 24), the second transport path 12 including the switchback portion 12A, and the third transport path 13 circulate the transport path. Is formed. The recording paper on which image recording has already been performed once in the image recording unit 30 can be transported again to the image recording unit 30 via the circulation transport path.

  In addition, as will be described later with reference to FIG. 15, the front and back of the recording sheet is reversed in the course of passing through the circulation type conveyance path. Thereby, it is possible to record images on both sides of the recording paper.

  FIG. 3 is a diagram illustrating the configuration of the first branching section 24, the second branching section 25, and the third branching section 26 in the paper conveyance path 10 of the image recording apparatus 100. A branch claw 41 is disposed in the first branch portion 24. The branching claw 41 swings between a position indicated by a solid line in FIG. 3 and a position indicated by a two-dot chain line in FIG. 3 by the operation of a first solenoid (not shown). Switching between the transport path 11 and the second transport path 12 is performed.

  A branch claw 42 and a branch claw 43 are arranged in the second branch portion 25. The branching claw 42 is in a position indicated by a solid line in FIG. 3 in a state where no external force is applied, and guides the recording sheet conveyed upward from the second conveyance path 12 or the fourth conveyance path 14 to the fifth conveyance path 15. . The recording paper conveyed upward from the second conveyance path 12 or the third conveyance path 13 is restricted from entering the second conveyance path 12 by the branching claw 42.

  The branching claw 43 swings between a position indicated by a solid line and a position indicated by a two-dot chain line in FIG. 3 by the operation of a second solenoid (not shown). Either the conveyance path 15 or the second conveyance path 12 and the fifth conveyance path 15 is opened.

  Note that the branching claw 42 swings to the position indicated by the broken line in FIG. 3 by contact with the recording paper conveyed downward in the second conveyance path 12 from the first branching portion 24.

  A branch claw 44 is disposed in the third branch portion 26. The recording paper whose front and rear ends are reversed in the switchback portion 12A is not discharged from the second transport path 12 to the paper discharge tray 38 via the fifth transport path 15. The branch claw 44 is urged to a position indicated by a solid line in FIG. 3 by an elastic member. This elastic member has such an elasticity that the branching claw 44 easily swings to the position indicated by the broken line in FIG. 3 by the recording paper from the first conveying path 11 through the second conveying path 12 to the switchback portion 12A. A force is applied to the branch claw 44. Thereby, the branching claw 44 selectively opens the second conveyance path 12 between the second conveyance path 12 and the third conveyance path in the third branch portion 26.

<Regarding First Unit 1 and Second Unit 2 of Image Recording Apparatus 100>
FIG. 4 is an enlarged view showing a part of the configuration of the image recording apparatus 100, and shows the positions of the first unit 1 and the second unit 2. FIG. 5 is an external view when the first unit 1 and the second unit 2 are pulled out from the inside of the image recording apparatus 100 to the front side. FIG. 6 is an external view when the second unit 2 is pulled out from the first unit 1. FIG. 7 is an explanatory diagram for explaining the configuration of the second unit 2.

  As shown in FIG. 4, the image recording apparatus 100 includes a first unit 1 and a second unit 2. The first unit 1 includes a transfer belt 35, a transfer roller 35A, and a fixing device 37, and can be pulled out (inserted / removed) from the inside of the image recording apparatus 100 in the arrow Y direction on the front side (external) by slide rails 3A and 3B. ) Is supported.

  As shown in FIG. 4, the first unit 1 includes a portion of the first transport path 11 that passes through the image recording unit 30 and a part of the third transport path 13. When the first unit 1 is pulled out from the inside of the image recording apparatus 100 to the front side, a portion passing through the image recording unit in the first transport path 11 is exposed as shown in FIG. Thus, the recording paper staying in the first conveyance path 11 in the image recording unit 30 can be easily removed by simply pulling out the first unit 1 when a conveyance jam occurs. In addition, it is possible to easily confirm the presence or absence of the recording paper staying on the first conveyance path 11.

  As shown in FIG. 4, the second unit 2 includes a part of the first transport path 11, a second transport path 12, a part of the third transport path 13, a fourth transport path 14, and a fifth transport path 15. In the state shown in FIG. 5 where the first unit 1 is pulled out from the inside of the image recording apparatus 100, it can be pulled out in the direction of the arrow Z, which is a direction perpendicular to the direction of the arrow Y, by the slide rails 4A and 4B as shown in FIG. It is supported (insertable / removable).

  Further, as shown in FIG. 7, the second unit 2 is rotated from the position indicated by the solid line from the position indicated by the solid line to the position indicated by the dotted line while being pulled out (detached) from the first unit 1. A part of the second transport path 12 and a part of the third transport path 13 can be exposed by rotation.

  In particular, the opening of the opening / closing plate 6 makes it relatively easy to cause a conveyance failure (conveyance jam) of the recording paper arranged in the vertical direction along a part of the second conveyance path 12 in the paper conveyance path 10. All of the branching portion 24, the second branching portion 25, and the third branching portion 26 are exposed to the outside, and the removal work of the staying recording paper can be simplified.

  This makes it possible to easily remove the recording paper staying in the second conveyance path 12 and the third conveyance path 13 when a conveyance jam occurs, so that the user's user in the sheet conveyance path where the conveyance jam is likely to occur. Workability can be improved and the burden can be reduced.

  Further, when the first unit 1 is detached from the first unit 1, the upper and side surfaces of the second unit 2 can be freely opened and closed, so that the upper and side surfaces of the first unit 1 and the second unit 2 can be opened more than the integrated structure. Since the amount can be increased, it is possible to increase the exposure amount of the second transport path 12 by opening one upper surface or the like as compared with the conventional case.

  As a result, the workability of removing the recording paper on the paper transport path 10 can be improved, and a location where the upper surface of the second unit 2 is opened in order to check whether there is any recording paper staying on the paper transport path 10 is provided. This can be reduced compared to the conventional case, and the burden on the user can be reduced.

  Moreover, since the second unit 2 can be pulled out from the first unit 1 in the arrow Z direction instead of the arrow Y direction, there is no need for a space for pulling out the second unit 2 in addition to the space for pulling out the first unit in the arrow Z direction. . The space for pulling out the second unit 2 from the first unit 1 in the direction of arrow Y is reserved only for pulling out the second unit 2 because the user uses the space for taking out the recording paper on which the image has been recorded. Therefore, it is possible to suppress an increase in space necessary for the arrangement of the image recording apparatus 100 with a simple configuration.

<Electrical Configuration of Image Recording Apparatus 100>
FIG. 8 is a diagram showing an electrical configuration of a part mainly related to the conveyance of the recording paper in the image recording apparatus 100. The image recording apparatus 100 includes a control unit 70 having a CPU 71, a ROM 72, and a RAM 73. The control unit 70 includes motor drivers 74, 75, 76, solenoid drivers 77, 78, clutch drivers 80, 81, and recording paper. Are connected to an ultrasonic sensor 82B for detecting double feed (details will be described later with reference to FIGS. 9 to 12) and a sensor unit 82A including sensors other than double feed detection.

  The sensor unit 82A includes a plurality of sensors arranged in the paper conveyance path 10. Each of the plurality of sensors detects a recording sheet at a different position in the sheet conveyance path 10 and inputs a detection signal to the CPU 71.

  The CPU 71 refers to the detection signal input from the sensor unit 82A and the signal output from the ultrasonic sensor 82B according to a program written in advance in the ROM 72, and motor drivers 74, 75, 76, solenoid drivers 77, 78, Drive data is output to the clutch drivers 80 and 81. Note that the CPU 71 can output a signal for controlling power feeding to the ultrasonic sensor 82B, and the ultrasonic sensor 82B is normally fed only when it is necessary to detect double feed. The temperature rise of 82B is suppressed.

  A first motor 83, a second motor 84, and a third motor 85 are connected to the motor drivers 74, 75, and 76, respectively. The motor drivers 74, 75, 76 drive the first motor 83, the second motor 84, and the third motor 85 based on the drive data output from the CPU 71.

  A first solenoid 86 and a second solenoid 87 are connected to the solenoid drivers 77 and 78, respectively. Solenoid drivers 77 and 78 drive the first solenoid 86 and the second solenoid 87 based on the drive data output from the CPU 71.

  The first solenoid 86 positions the branching claw 41 in a state indicated by a solid line in FIG. 3 when not driven, and positions the branching claw 41 in a state indicated by a two-dot chain line in FIG. 3 when driven. The branching claw 41 guides the recording sheet from the first branch part 24 to the first transport path 11 when the first solenoid 86 is not driven, and the recording sheet is guided to the first branch part 24 when the first solenoid 86 is driven. To the second conveyance path 12.

  Note that the branching claw 41 may arbitrarily select a position indicated by a solid line in FIG. 3 or a position indicated by a broken line in FIG. 3 as a position in an initial state where the energization of the solenoid is turned off. it can. Accordingly, the position of the branching claw 41 in the initial state is set to a position suitable for face-up discharge or face-down discharge depending on whether the user frequently uses face-up discharge or face-down discharge. be able to.

  The second solenoid 87 positions the branching claw 43 in a state indicated by a solid line in FIG. 3 when not driven, and positions the branching claw 43 in a state indicated by a two-dot chain line in FIG. 3 when driven. The branching claw 43 guides the recording sheet from the second branching section 25 to the third transport path 13 and from the fourth transport path 14 to the fifth transport path 15 when the second solenoid 87 is not driven, and the second solenoid 87. Is driven from the second branching section 25 to the second transport path 12 and from the second transport path 12 to the fifth transport path 15.

  A first clutch 89 and a second clutch 90 are connected to the clutch drivers 80 and 81, respectively. The clutch drivers 80 and 81 drive the first clutch 89 and the second clutch 90 based on the drive data output from the CPU 71.

  The first clutch 89 transmits the rotation of the second motor 84 as it is to the reversing rollers 53 and 58 when not driven, and reverses the rotation of the second motor 84 and transmits it to the reversing rollers 53 and 58 during driving. The reverse rollers 53 and 58 rotate forward when the first clutch 89 is not driven to guide the recording paper into the switchback portion 12A, and reversely rotate when the first clutch 89 is driven to switch back the recording paper. The portion 12A leads to the second branch portion 25.

  The second clutch 90 transmits the rotation of the third motor 85 to the reversing rollers 54, 55, 56, 57 as it is when it is not driven, and reverses the rotation of the third motor 85 during driving to reverse the reversing rollers 54, 55, 57. 56, 57. The reverse rollers 54, 55, 56, 57 rotate forward when the second clutch 90 is not driven to guide the recording sheet from the second branch portion 25 into the third transport path 13, and the second clutch 90 is driven. At this time, the recording paper is reversed to guide the recording paper from the third conveyance path 13 to the second branch portion 25.

  In the image recording apparatus 100, a face-up conveying operation in which a recording sheet on which an image is recorded on one side is discharged to the discharge tray 38 with the image recording side facing up, and a recording sheet on which an image is recorded on one side is directed downward Then, either the face-down conveying operation for discharging to the paper discharge tray 38 or the reverse conveying operation for recording an image on both sides of the recording paper is selectively performed.

  The CPU 71 has motor drivers 74, 75, 76 and a solenoid driver 77 so that the recording paper is conveyed in the paper conveyance path 10 through conveyance paths corresponding to the face-up conveyance operation, the face-down conveyance operation, and the reverse conveyance operation. 78, the drive data is output to the clutch drivers 80, 81, and the first motor 83, the second motor 84, the third motor 85, the first solenoid 86, the second solenoid 87, the first clutch 89, and the second clutch 90 are output. To work.

  When the image recording operator is in the vicinity of the image recording apparatus 100 and wants to quickly check the recording state of the image on the recording sheet, as in the case of copying and recording the image of the document on the recording sheet, the image recording surface is directed upward. Thus, a face-up transport operation for discharging the recording paper to the paper discharge tray 38 is performed.

  During the face-up transport operation, the CPU 71 rotates the first motor 83 via the motor driver 74. The recording paper fed from the paper feed unit 400 is transported in the first transport path 11 by the rotation of the first transport path 11 transport rollers 61, 62, 63, the registration roller 51 and the paper discharge roller 52. While the recording paper passes through the image recording unit 30, the toner image is transferred and fixed on the upper surface of the recording paper in the image recording unit 30. The recording paper is discharged to the paper discharge tray 38 with the image recording surface facing upward.

  The CPU 71 starts transmitting the rotation of the first motor 83 to the registration roller 51 at a predetermined timing via a clutch (not shown). As a result, the front end of the recording paper faces the front end of the toner image formed on the surface of the photosensitive drum 31 at a position where the transfer roller 35A is in pressure contact with the photosensitive drum 31.

<Ultrasonic sensor 82B for double feed detection>
FIG. 9 is a block diagram showing a configuration of an ultrasonic sensor 82B that performs double feed detection by a transmission type detection method. The ultrasonic sensor 82B includes an oscillation circuit 82Bc that generates a drive waveform (for example, an oscillation frequency of about 220 kHz), an amplification circuit 82Bd that amplifies the drive waveform generated by the oscillation circuit 82Bc, and a transmitter 82Ba that transmits the drive waveform. A receiving unit 82Bb that receives a signal transmitted by the transmitting unit 82Ba, a resonance circuit 82Be that detects a signal received by the receiving unit 82Bb over a wide band (for example, 220 kHz ± 20 kHz), an amplification circuit 82Bf that amplifies the received signal, and An A / D conversion circuit 82Bg that converts the amplified signal into a digital signal, a power supply circuit 82bh that supplies power to these, and the like are provided.

  The ultrasonic sensor 82B transmits a signal from the transmitter 82Ba to the recording paper P being conveyed, receives the transmitted signal at the receiver 82Bb, and receives the detection signal from the A / D conversion circuit 82Bg. Output to 70. Based on the magnitude of the energy of the detection signal output in this way, the control unit 70 detects the number of recording sheets P being conveyed, and determines that double feeding has occurred if the detected number is two or more.

  In addition, the power supply circuit 82bh switches between a state in which normal power supply to each part of the ultrasonic sensor 82B is performed and a state in which power supply is stopped based on a control signal from the control unit 70.

  For example, when a part of the ultrasonic sensor 82B has a circuit that consumes less current but takes a relatively long time from the start of power supply until the operation is stabilized, the circuit is relatively long. You may make it always supply electric power. In this case, based on a control signal from the control unit 70, a state in which normal power feeding is performed and a state in which less power feeding is performed than normal are switched.

  FIGS. 10A to 10D are explanatory diagrams illustrating an example of double feeding of the recording paper P. FIG. The arrows in the figure indicate the conveyance direction of the recording paper P. FIG. 10A shows a case where the recording paper P is normally conveyed one by one with a predetermined separation dimension. FIG. 10B shows a case where the second recording sheet P2 is overlaid on the first recording sheet P1 with the leading ends thereof being shifted. FIG. 10C shows a case where the second recording sheet P2 is overlapped under the first recording sheet P1 with the leading ends thereof being shifted. FIG. 10D shows a case where the first recording sheet P1 and the second recording sheet P2 are overlapped with their leading ends being coincident with each other.

  FIG. 11 is a time chart showing the level of the double feed detection signal when the multi-feed is performed with the leading ends of the recording paper P being shifted. The energy (for example, transmitted energy) of the signal received by the receiving unit 82Bb of the ultrasonic sensor 82B changes according to the number of recording papers P through which the signal is transmitted. For example, when there is no recording paper P, the received signal energy is E0, when there is one recording paper P, the received signal energy is E1 (E0> E1), and when the recording paper P is two, it is received. The energy of the signal is E2 (E1> E2). At time t1, it is possible to detect that the next recording sheet P has been conveyed by changing the signal energy from E0 to E1. When double feeding of the recording paper P occurs, for example, the energy of the signal changes from E1 to E2 at time t2. As described above, it is possible to detect that the two recording sheets P are double-fed in a state where the leading ends thereof are deviated from each other due to the energy level difference of the received signals. At time t3, the signal energy changes again from E2 to E1.

  Note that it is also possible to calculate how much the recording paper P is shifted and double-fed based on the conveyance speed of the recording paper P and the time difference between the times t2 and t1.

  FIG. 12 is a time chart showing the relationship of the double feed detection signal when the leading ends of the recording paper P are coincident with each other. At time t4, the signal energy changes from E0 to E2. Based on the difference in energy level of the received signal, it can be detected that the two recording sheets P are double-fed while the leading ends of the next recording sheet P overlap each other. At time t5, the signal energy changes again from E2 to E0.

<About various transport operations>
Hereinafter, various conveyance operations will be described. In any transport operation, first, the CPU 71 switches the control signal for the power feeding circuit 82bh of the ultrasonic sensor 82B to a state where normal power feeding is performed. During the subsequent transport operation, the CPU 71 constantly monitors the signal output from the A / D conversion circuit 82Bg of the ultrasonic sensor 82B, and promptly detects the occurrence of double feeding of recording paper. This is stored in the double feed detection flag.

  However, it is not always preferable to immediately stop the recording sheet conveying operation when the occurrence of double feeding is detected. For example, although the front portion of the recording paper conveyed from the paper supply unit 400 is already in the first unit 1, the remaining portion of the recording paper is still present in the main body of the image recording apparatus 100. In this case, it is assumed that a double feed is detected and the recording paper transport operation is immediately stopped. If an attempt is made to pull out the first unit 1 in order to remove the recording sheet, the recording sheet existing in the first unit 1 and the image recording apparatus 100 main body is torn, and in this case, debris is removed. This is because it can be considered to be scattered.

  Therefore, taking into account the subsequent restoration work and the like, if necessary, the conveyance operation is continued until the recording sheet moves to an appropriate position. In the above example, the conveyance operation is stopped after the recording paper has completely entered the first unit 1. As a result, when the first unit 1 is subsequently pulled out, the recording paper is not torn, and the recording paper can be removed easily and reliably.

≪Face-down transfer operation (1) ≫
FIG. 13 is a diagram for explaining a first paper transport path during the face-down transport operation in the image recording apparatus 100. As in the case of recording an image on recording paper based on image data transmitted from an external device, the image recording operator is not in the vicinity of the image recording device 100, and the image recorded on the recording paper can be easily confirmed. When it is desired not to do so, a face-down conveyance operation is performed in which the recording sheet is discharged to the discharge tray 38 with the image recording surface facing downward. Also, when recording a plurality of images with continuous pages on a recording sheet, a face-down conveyance operation is performed in order to eliminate a collating operation after discharging the plurality of recording sheets.

  During the face-down conveyance operation, the CPU 71 rotates the first motor 83 via the motor driver 74 and conveys the recording sheet fed from the sheet feeding unit 400 to the image recording unit 30. The CPU 71 drives the first solenoid 86 and the second solenoid 87 via the solenoid drivers 77 and 78 before the front end of the recording paper reaches the first branch portion 24. Accordingly, the branching claws 41, 43, and 44 are positioned in a state indicated by a two-dot chain line in FIG. 3, and the recording sheet that has passed through the image recording unit 30 is guided from the first branching unit 24 into the second conveyance path 12. .

  However, if it is stored in the double feed detection flag that the double feed has been detected before the front edge of the recording paper reaches the first branch portion 24, the double fed recording paper remains in the first unit 1. The conveying operation is stopped at such timing. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  The CPU 71 drives the second motor 84 via the motor driver 75 until the front end of the recording paper passes through the second branch portion 25. At this time, the first clutch 89 is not driven. As a result, the reverse rollers 53 and 58 are rotated forward.

  As a result, the recording sheet guided from the first branching section 24 into the second transport path 12 is transported through the second transport path 12 into the switchback section 12A. The branch claw 42 swings in a state indicated by a two-dot chain line in FIG. 3 by abutting the front end of the recording paper passing downward through the second branch portion 25 and opens the second transport path 12. To do.

  The CPU 71 detects whether or not double feed has been detected so far when the trailing edge of the recording sheet passes through the third branching portion 26 downward and is sandwiched between the reversing rollers 53. Check by flag. If double feeding is detected, the transport operation is immediately stopped. This is because the recording sheet exists only in the second unit 2 at this time. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  Next, the CPU 71 drives the first clutch 89 via the clutch driver 80. As a result, the reverse rollers 53 and 58 are reversed. The recording paper in the switchback portion 12A is transported upward in the second transport path 12 in a state where the front and rear in the transport direction are reversed, and after entering the fifth transport path 15 in the second branch section 25, The ink is guided into the first conveyance path 11 at the second junction 22 and discharged onto the paper discharge tray 38 by the paper discharge roller 52 with the image recording surface facing downward.

≪Face-down transfer operation (2) ≫
FIG. 14 is a diagram for explaining a second paper conveyance path during the face-down conveyance operation in the image recording apparatus 100.

  The CPU 71 rotates the first motor 83 via the motor driver 74 and conveys the recording paper fed from the paper feeding unit 400 to the image recording unit 30. The CPU 71 drives the first solenoid 86 via the solenoid driver 77 before the front end of the recording paper reaches the first branching section 24. Accordingly, the branching claw 41 is positioned in a state indicated by a two-dot chain line in FIG. 3, and the recording sheet that has passed through the image recording unit 30 is guided from the first branching unit 24 into the second conveyance path 12. The branch claw 42 swings in a state indicated by a two-dot chain line in FIG. 3 by abutting the front end of the recording paper passing downward through the second branch portion 25 and opens the second transport path 12. To do.

  However, if it is stored in the double feed detection flag that the double feed has been detected before the front edge of the recording paper reaches the first branch portion 24, the double fed recording paper remains in the first unit 1. The conveying operation is stopped at such timing. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  At this time, the second solenoid 87 is not driven. As a result, the branch claws 43 and 44 are positioned in the state indicated by the solid line in FIG. 3, and the recording paper guided from the first branch part 24 into the second transport path 12 is transported in the second branch part 25 by the fourth transport. Guided to path 14.

  The CPU 71 drives the third motor 85 via the motor driver 76 until the front end of the recording paper passes through the second branch portion 25. At this time, the first clutch 89 is not driven. As a result, the reversing rollers 54, 55, 56, and 57 rotate forward, and the recording sheet guided to the fourth conveyance path 14 is conveyed into the third conveyance path 13.

  The CPU 71 detects whether or not double feed has been detected so far in a state where the rear end portion of the recording sheet passes through the fourth conveyance path 14 downward and is sandwiched between the reverse rollers 54. Check by flag. If double feeding is detected, the transport operation is immediately stopped. This is because the recording sheet exists only in the second unit 2 at this time. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  Next, the CPU 71 drives the second clutch 90 via the clutch driver 81. As a result, the reverse rollers 54, 55, 56, and 57 are reversed. After the recording paper in the third transport path 13 is transported upward in the fourth transport path 14 with the front and rear in the transport direction reversed, and after entering the fifth transport path 15 at the second branch portion 25 Then, the ink is guided into the first conveyance path 11 at the second junction 22 and discharged to the paper discharge tray 38 by the paper discharge roller 52 with the image recording surface facing downward.

≪Reverse transfer operation≫
FIG. 15 is a diagram for explaining a sheet conveyance path during a reverse conveyance operation in the image recording apparatus 100. When images are recorded on both sides of the recording paper, the recording paper on which the image is recorded on the first surface by the image recording unit 30 is reversed and conveyed to the image recording unit 30 again on the second surface. Also, a reverse conveying operation for discharging the image onto the paper discharge tray 38 after the image is recorded is performed.

  During the reverse conveyance operation, the CPU 71 rotates the first motor 83 via the motor driver 74 and conveys the recording paper fed from the paper feeding unit 400 to the image recording unit 30. The CPU 71 drives the first solenoid 86 and the second solenoid 87 via the solenoid drivers 77 and 78 before the front end of the recording paper reaches the first branch portion 24. Accordingly, the branching claws 41, 43, and 44 are positioned in a state indicated by a two-dot chain line in FIG. 3, and the recording paper on which the image is formed on the first surface by the image recording unit 30 is transferred from the first branching unit 24 to the second. Guided into the transport path 12.

  However, if it is stored in the double feed detection flag that the double feed has been detected before the front edge of the recording paper reaches the first branch portion 24, the double fed recording paper remains in the first unit 1. The conveying operation is stopped at such timing. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  The CPU 71 drives the second motor 84 via the motor driver 75 until the front end of the recording paper passes through the second branch portion 25. At this time, the first clutch 89 is not driven. As a result, the reverse rollers 53 and 58 are rotated forward.

  As a result, the recording sheet guided from the first branching section 24 into the second transport path 12 is transported through the second transport path 12 into the switchback section 12A. The branch claw 42 swings in a state indicated by a two-dot chain line in FIG. 3 by abutting the front end of the recording paper passing downward through the second branch portion 25 and opens the second transport path 12. To do.

  The CPU 71 detects whether or not double feed has been detected so far when the trailing edge of the recording sheet passes through the third branching portion 26 downward and is sandwiched between the reversing rollers 53. Check by flag. If double feeding is detected, the transport operation is immediately stopped. This is because the recording sheet exists only in the second unit 2 at this time. In addition, if continuous printing is performed, the start of the transport operation to the next recording sheet is also stopped. If double feeding is not detected, the conveying operation is continued.

  Here, the fact that the double feed has not been detected until this time indicates that only one recording sheet exists in the switchback unit 12A. Therefore, when the recording sheet is made the image recording unit 30 again via the third conveyance path 13 as will be described below, the double feed detection by the ultrasonic sensor 82B is unnecessary. Therefore, the CPU 71 switches the control signal for the power supply circuit 82bh of the ultrasonic sensor 82B to a state where power supply is stopped. Thereby, generation | occurrence | production of a heat | fever stops in the ultrasonic sensor 82B, and the temperature rise of the ultrasonic sensor 82B can be suppressed.

  Next, the CPU 71 drives the first clutch 89 via the clutch driver 80 and stops driving the second solenoid 87. Further, the CPU 71 drives the third motor 85 via the motor driver 76. At this time, the second clutch 90 is not driven. As a result, the reversing rollers 53 and 58 are reversed, and the branching claw 44 is positioned in the state indicated by the solid line in FIG. 3, and the reversing rollers 54, 55, 56, and 57 are rotated forward.

  The recording paper in the switchback unit 12A is conveyed upward in the second conveyance path 12 in a state where the front and rear in the conveyance direction are reversed, and after entering the third conveyance path 13 in the third branching unit 26, The inside of the 3rd conveyance path 13 is conveyed toward the 1st junction part 21. FIG. Thereafter, the recording sheet is guided into the first conveyance path 11 at the first junction 21 and is directed toward the image recording section 30 in the first conveyance path 11 so that the second surface faces the photosensitive drum 31. Are transported.

  The CPU 71 stops driving the first solenoid 86 until the front end of the recording sheet with the second surface facing upward passes through the image recording unit 30. Thereby, the branch claw 41 is located in the state shown by the solid line in FIG. The image recording unit 30 finishes recording the image on the second side, the image is recorded on both sides, and the recording sheet passes through the first branching unit 24 and is discharged to the discharge tray 38 by the discharge roller 52.

<Other embodiments>
FIG. 16 is a schematic diagram showing a configuration of a document reading apparatus 500 according to another embodiment of the present invention. The document reading device 500 includes a double-sided automatic document feeder (RADF), an image reading unit 520, and the like.

  When only one side of the original is read, the originals placed on the original original tray 502 are pulled out one by one by the up and down movement and rotation of the attracting roller 508 and conveyed to the main conveyance path 505. Then, after the image reading unit 520 reads the image of the document, the document is discharged onto the paper discharge tray 504.

  When reading both sides of a document, first, the swinging plate 510 positioned between the front end of the main transport path 505 and the paper discharge tray 504 is lowered (a state indicated by a two-dot chain line in the drawing). In this state, the image reading unit 520 reads the image on the surface of the document, and then the document is discharged onto the intermediate tray 503. At this time, the conveyance is stopped in a state where the end of the document is sandwiched between the conveyance rollers 511. Then, after the swinging plate 510 is raised to the original position, the transport roller 511 is rotated in the reverse direction, so that the original is transported again to the main transport path 505 through the sub transport path 506. At this time, since the front side and the reverse side of the document are reversed, the image reading unit 520 can read the image on the back side of the document. Thereafter, the document is discharged onto a discharge tray 504.

  Similarly to the image recording apparatus 100 described above, the original reading apparatus 500 includes an ultrasonic sensor for detecting double feeding of originals. The transmitter 530a and the receiver 530b of the ultrasonic sensor are disposed in the vicinity of the downstream of the junction 507 between the main transport path 505 and the sub transport path 506 with the main transport path 505 interposed therebetween.

  When reading both sides of a document, it is considered unnecessary to detect double feed when reading the back side. Therefore, the temperature increase of the ultrasonic sensor is suppressed by stopping the power supply to the ultrasonic sensor.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-mentioned embodiment is only a mere illustration in all points, and should not be interpreted limitedly. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

1 is a schematic front sectional view showing a configuration of an image recording apparatus 100 according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a sheet conveyance path 10 in the image recording apparatus 100. FIG. 3 is a diagram illustrating a configuration of a first branching unit 24, a second branching unit 25, and a third branching unit 26 in the sheet conveyance path 10 of the image recording apparatus 100. 2 is an enlarged view showing a partial configuration of the image recording apparatus 100. FIG. FIG. 3 is an external view when the first unit 1 and the second unit 2 are pulled out from the inside of the image recording apparatus 100 to the front side. FIG. 3 is an external view when the second unit 2 is pulled out from the first unit 1. FIG. 3 is an explanatory diagram illustrating a configuration of a second unit 2. FIG. 2 is a diagram illustrating an electrical configuration of a part mainly related to conveyance of a recording sheet in the image recording apparatus. It is a block diagram which shows the structure of the ultrasonic sensor 82B which performs double feed detection by a transmissive | pervious detection system. 5 is an explanatory diagram illustrating an example of double feeding of recording paper P. FIG. 6 is a time chart showing the level of a double feed detection signal when the multi-feed is performed in a state where the leading ends of the recording paper P are shifted from each other. 6 is a time chart showing the relationship of double feed detection signals when double feed is performed in a state where leading ends of the recording paper P are coincident with each other. 3 is a diagram illustrating a first paper conveyance path during a face-down conveyance operation in the image recording apparatus 100. FIG. 6 is a diagram illustrating a second paper conveyance path during a face-down conveyance operation in the image recording apparatus 100. FIG. 3 is a diagram illustrating a paper conveyance path during a reverse conveyance operation in the image recording apparatus 100. FIG. FIG. 6 is a schematic diagram showing a configuration of a document reading apparatus 500 according to another embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 1st unit 2 2nd unit 10 Paper conveyance path 11 1st conveyance path 12 2nd conveyance path 12A 1st switchback part 13 3rd conveyance path 14 4th conveyance path 15 5th conveyance path 20 4th junction part 21 1st DESCRIPTION OF SYMBOLS 1 Junction part 22 2nd junction part 23 3rd junction part 24 1st branch part 25 2nd branch part 26 3rd branch part 30 Image recording part 31 Photoconductor drum 35 Transfer belt 35A Transfer roller 37 Fixing device 70 Control part 82A Sensor Unit 82B Ultrasonic sensor 100 Image recording apparatus 200 Image reading unit 300 Image forming unit 400 Paper feed unit 500 Document reading apparatus 505 Main conveyance path 506 Sub conveyance path 507 Junction section 530a Ultrasonic sensor transmission section 530b Ultrasonic sensor reception section

Claims (5)

An image recording apparatus comprising a double feed detection device,
The multifeed detection device is:
A plurality of transport paths that can be selectively used for transporting a transport object;
A multifeed detection unit that is arranged in the vicinity of the downstream of the merging unit of the plurality of transport paths, and detects a multifeed of the transport object;
While selecting which of the plurality of transport paths is used for transporting the transport target object, the multi-feed detection is performed when the transport target object is transported from other than the specific transport path among the plurality of transport paths. Control so that normal power supply to the unit is performed, and when the object to be transported is transported from the specific transport path, power supply to the multifeed detection unit is stopped or power supply less than normal is performed. A control unit for controlling ,
The image recording apparatus further includes a plurality of units that are detachable from the main body of the image recording apparatus and include different portions inside the plurality of conveying paths.
When the multi-feed of the conveyance object is detected by the multi-feed detection unit, the control unit is configured such that the conveyance object being conveyed is only one of the image recording apparatus main body and the plurality of units. When it is determined that it is present inside, stop the transportation,
When the multi-feed of the conveyance target is detected by the multi-feed detection unit, the control unit is configured such that the conveyance target being conveyed covers any two or more of the image recording apparatus main body and the plurality of units. when it is determined as being present, characterized that you stops feeding was continued for conveying to the conveying object is moved to only one will be present in the interior of the location Image recording device. The image recording apparatus according to claim 1,
An image recording apparatus, wherein the conveyance object that has already been subjected to double feed detection by the double feed detection unit is conveyed from the specific conveyance path. The image recording apparatus according to claim 1,
The specific conveyance path is a part of a circulation type conveyance path, and the object to be conveyed for which double feed detection has already been performed by the double feed detection unit can be conveyed again via the circulation type conveyance path. It is comprised so that it may become. The image recording device characterized by the above-mentioned. The image recording apparatus according to any one of claims 1 to 3,
The image recording apparatus, wherein the double feed detection unit is an ultrasonic sensor using a transmission type detection method. An image recording method comprising a double feed detection method that is detachable from an image recording apparatus main body and is used in an image recording apparatus that includes a plurality of units including different portions of the entire plurality of conveyance paths. ,
The double feed detection method is:
A transport path selection step for selecting which of the plurality of transport paths that can be selectively used to transport the transport target; and
When the transport path selection step selects a transport path other than a specific transport path from among the transport paths, normal power feeding is performed to the multifeed detection unit disposed in the vicinity of the junction of the transport paths. And when the specific conveyance path is selected from among the plurality of conveyance paths, power supply to the multifeed detection unit is stopped or less than normal power supply is performed. Control steps to control;
A double feed detection step for performing double feed detection of the object to be conveyed by the double feed detector when the control step is controlled to perform normal power feeding to the double feed detector ;
further,
When the multi-feed of the conveyance object is detected in the multi-feed detection step, the conveyance object being conveyed exists in only one of the image recording apparatus main body and the plurality of units. A first conveyance stop step for stopping conveyance,
When the double feed of the transport object is detected in the double feed detection step, the transport target being transported exists over any two or more of the image recording apparatus main body and the plurality of units. when the determination is that it comprises a second conveyance stop step that stops the conveyance after continued conveying to the conveying object is moved to a position that would exist within only one A characteristic image recording method.

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