JP4848816B2 - Recording medium transport device - Google Patents

Description

  The present invention relates to a recording medium transport apparatus capable of transporting a tabbed recording medium with a tab on the edge, and in particular, with a tab by reversely controlling the rotation direction after a tabbed recording medium is carried. The present invention relates to a recording medium conveyance device for an image forming apparatus that carries out the recording medium with its front and back reversed.

  In an image forming apparatus such as a copying machine or a printer, an image carrier such as a photoconductor is charged, and an electrostatic latent image is formed on the surface of the image carrier by irradiating a laser beam. To form a toner image made of powder toner or the like. Then, a recording medium such as paper is conveyed to a position in contact with the image carrier, the toner image is transferred to the surface of the recording medium, and then the toner image on the surface of the recording medium is fixed by a fixing device to form an image. .

  Further, when the recording medium is reversed and discharged, the recording medium is conveyed to a reversing unit provided with a pair of reversing rollers, and is rotated forward with the rear end of the recording medium held between the reversing rollers. The reversing roller is rotated in the reverse direction so that the recording medium is reversed and conveyed. Further, as a recording medium, a so-called tabbed paper having a tab from which a part of the edge of the paper protrudes is used. After an image is formed on the tabbed paper, the front and back of the tabbed paper may be reversed.

  As described above, when the front and back sides of the sheet are reversed in the reversing unit, usually, the trailing edge of the sheet is detected, and control at the time of reversal is performed based on the detection result. When transporting tabbed paper, the tab side is generally transported upstream in the transport direction. However, the sensor that detects the rear end depending on the position of the tab detects the part with the tab. Since there is a case where a part without a mark is detected, it is recognized in advance that the sheet is tabbed paper, and the stop timing at the time of reversal is shifted by the length of the tab.

  In this case, depending on whether a portion with a tab is detected or a portion without a tab is detected, if the reverse roller is rotated backward after a certain period of time has elapsed after the trailing edge of the tabbed paper has been detected, the tabbed paper will remain constant. Since the sheet is transported by the distance, the trailing edge stop position of the sheet at the time of reversing is different, and the maximum is longer by “tab length + shift amount”. Therefore, the length from the reversal branch to the reversing roller is required to be long, which hinders the space saving of the apparatus.

  In order to solve this problem, a method has been proposed in which position information of a tab is input or detected in advance, and reversal control is performed based on the detection result of the sensor that detects the information and the rear end (for example, see Patent Document 1). .

In addition, a method (for example, see Patent Document 2) in which the length is detected in the entire width direction of the paper and the paper is controlled based on the detection result has been proposed.
JP 2003-267588 A JP-A-11-109687

  However, the method disclosed in Patent Document 1 has a problem in that it takes time to perform an input operation, and a number of sensors are required for the conveyance path in order to detect an input error and detect it. Further, the method of Patent Document 2 has problems in terms of detection space and cost.

  The present invention has been made to solve the above-described problems. When the tabbed recording medium is reversed and transported, the tab position input operation and the tab position detection by a large number of sensors are performed. An object of the present invention is to provide a recording medium transporting apparatus that can control the reversal of a tabbed recording medium without performing it, and can configure the distance from the branch position of the reversing unit to the reversing roller with a minimum length. .

In order to solve the above-mentioned object, the recording medium conveying apparatus according to claim 1 is configured such that the rotation direction is reversed and controlled with the first sensor arranged to measure the length of the recording medium in the conveying direction. A reversing roller for reversing the conveyance direction of the recording medium, reversing means for reversing and carrying out the front and back of the loaded recording medium, conveying the recording medium carried from the carry-in path toward the reversing means, and reversing the recording medium. A conveying means for conveying the recording medium unloaded from the means in the direction of the unloading path, and an end portion of the portion where the length of the recording medium is measured is located at a position where it can be detected, and is conveyed in the direction of the reversing means. When a tab-attached recording medium is transported with a second sensor that detects the end of the recording medium that is present, the tab portion has passed based on the length of the recording medium in the transport direction or other than the tab portion has passed. To determine whether Results and based on the detection timing of the passage of an end portion of the second of said recording medium by the sensor, wherein the control means for controlling the inversion timing of the rotation direction of the reverse roller, the first sensor The position at which the length of the recording medium in the conveyance direction is measured and the position at which the end of the recording medium of the second sensor is detected are relative to the central position in the direction perpendicular to the conveyance direction of the recording medium. It is characterized by being shifted by 3 mm to 20 mm .

  According to the first aspect of the present invention, since the second sensor is disposed at a position where the end of the part where the length of the recording medium is measured by the first sensor can be detected, the same portion of the recording medium is disposed. Can be detected. Therefore, when the recording medium to be transported is provided with a tab, it can be recognized whether the tab portion has passed the detection position of the first sensor and the second sensor or a portion other than the tab portion has passed. Inversion control can be performed at timing.

According to the first aspect of the present invention, the detection positions of the first sensor and the second sensor are slightly shifted with respect to the center position in the direction orthogonal to the conveyance direction of the recording medium. Can be detected.

In order to achieve the above object, a recording medium transporting apparatus according to claim 2 is configured such that the rotation direction is reversed and controlled with a first sensor arranged to measure the length of the recording medium in the transporting direction. A reversing roller for reversing the conveyance direction of the recording medium, reversing means for reversing and carrying out the front and back of the loaded recording medium, conveying the recording medium carried from the carry-in path toward the reversing means, and reversing the recording medium. A conveying means for conveying the recording medium unloaded from the means in the direction of the unloading path, and an end portion of the portion where the length of the recording medium is measured is located at a position where it can be detected, and is conveyed in the direction of the reversing means. When a tab-attached recording medium is transported with a second sensor that detects the end of the recording medium that is present, the tab portion has passed based on the length of the recording medium in the transport direction or other than the tab portion has passed. Whether or not Based on the detection timing of the passage of the ends of the different results and the second of said recording medium by a sensor, and control means for controlling the inversion timing of the rotation direction of the reverse roller, the tab for conveying the tabbed recording medium Selecting means for selecting an attachment mode, and the control means, when the tab attachment mode is selected, whether the tab portion has passed based on the length in the transport direction of the recording medium or other than the tab portion And the reversing timing in the rotation direction of the reversing roller is controlled based on the determination result and the detection timing of the end of the recording medium by the second sensor. The position of the sensor for measuring the length of the recording medium in the conveyance direction and the position of the second sensor for detecting the end of the recording medium are center positions in a direction perpendicular to the conveyance direction of the recording medium Wherein the shifted 3 millimeters to 20 millimeters for.

According to the second aspect of the present invention, the tabbed mode can be selected when the recording medium is tabbed. Therefore, when the tabbed recording medium is conveyed, the reversal control is surely performed at an appropriate timing. be able to.

According to the second aspect of the present invention, since the detection positions of the first sensor and the second sensor are slightly shifted from the center position in the direction orthogonal to the conveyance direction of the recording medium, Can be detected.

  According to the present invention, when the recording medium with tabs is turned upside down and conveyed, the end of the recording medium with tabs can be detected because it can be determined whether the tab part has passed the detection position of the sensor or the part other than the tab part has passed. Since the reverse rotation of the reversing roller can be controlled at a predetermined timing from this detection timing, it is not necessary to input the tab position, and it is not necessary to detect the tab position by a large number of sensors. Further, it is possible to prevent the distance from the branch position of the carry-in path and the carry-out path to the reversing roller from being increased, and the space can be saved.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an image forming apparatus 10 including a recording medium conveying apparatus according to the present embodiment.

  In the image forming apparatus 10, paper feed cassettes 12 </ b> A to 12 </ b> D that store sheets of different sizes are disposed in a lower portion of a housing 11. Any one of the sheet feeding cassettes 12A to 12D accommodates a tabbed sheet having a tab provided on the edge of the sheet.

  A paper feed unit 14 is disposed on the downstream side in the feed direction of the paper feed cassettes 12A to 12D. A pickup roll 15 and a feed roll 16 and a retard roll 17 are disposed in the paper feeding unit 14 for each of the paper feeding cassettes 12 </ b> A to 12 </ b> D, and paper is fed from the paper feeding cassettes 12 </ b> A to 12 </ b> D by the pickup roll 15. Are fed out and fed in a state where the sheets are sandwiched one by one by the feed roll 16 and the retard roll 17.

  A paper transport unit 18 is disposed on the downstream side of the paper feed unit 14, and a plurality of transport rollers 19 are provided along the paper transport path 20 in the paper transport unit 18. Then, the sheets fed one by one from the sheet feeding unit 14 are transported along the sheet transport path 20 by the transport roller 19.

  On the downstream side of the sheet conveyance path 20 in the conveyance direction, an intermediate transfer bald 24 is provided in the vicinity of the upper portion of the central portion of the housing 11. The intermediate transfer belt 24 is stretched by a large-diameter drive roller 21 and a support roller 22 and a plurality of small-diameter support rollers 23 arranged therebetween. The support roller 22 and the support roller 23 are driven to rotate by the rotation of the drive roller 21, and the intermediate transfer belt 24 is configured to rotate in a fixed direction (the arrow direction in FIG. 1). The tension of the intermediate transfer belt 24 can be adjusted by a tension roller 25 that presses the surface side thereof.

  On the upper part of the intermediate transfer belt 24, four photosensitive drums 26 are arranged side by side in the moving direction of the intermediate transfer belt 24. Around each photosensitive drum 26, an electrostatic latent image is formed by irradiating the surface of the photosensitive drum 26 with laser light and a charging roller 27 for charging the photosensitive drum 26 in order from the upstream side in the rotation direction. There are disposed an exposure device 28 for developing, and a developing device 29 for developing the electrostatic latent image formed on the photosensitive drum 26 with toner. Further, on the downstream side of the developing device 29, a primary transfer roller 30 for transferring the toner image on the photosensitive drum 26 to the intermediate transfer belt 24 is disposed at a position opposed to the intermediate transfer belt 24, and this primary transfer roller. A cleaning device 31 for removing residual toner on the photosensitive drum 26 after transfer is disposed on the downstream side of 30. Four developing devices 29 arranged at positions facing the respective photosensitive drums 26 respectively store toners of different colors of yellow (Y), magenta (M), cyan (C), and black (K). .

  At the time of image formation, the photosensitive drum 26 rotates in a certain direction, and the surface of the photosensitive drum 26 is charged to a predetermined potential by the charging roller 27, and then laser light is irradiated by the exposure device 28, depending on the image information. An electrostatic latent image is formed. This electrostatic latent image is developed with different color toners by the developing device 29, and yellow (Y), magenta (M), cyan (C), and black (K) toner images are respectively formed on the surfaces of the photosensitive drums 26. It is formed. These toner images are superimposed and transferred onto the surface of the intermediate transfer belt 24 that circulates in the direction of the arrow by the action of the primary transfer roller 30 at a predetermined timing.

  On the downstream side of the primary transfer roller 30 in the circumferential direction of the intermediate transfer belt 24, a secondary transfer roller 32 for transferring the four color toner images transferred on the intermediate transfer belt 24 is disposed. Further, a backup roller 33 that stabilizes the contact between the secondary transfer roller 32 and the intermediate transfer belt 24 is disposed at a position where the secondary transfer roller 32 and the intermediate transfer belt 24 are in contact with each other. The paper transported along the paper transport path 20 is transported between the intermediate transfer belt 24 and the secondary transfer roller 32 at a predetermined timing. Then, the yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred onto the intermediate transfer belt 24 are collectively transferred onto the sheet by the action of the secondary transfer roller 32. Is transcribed. A registration unit 34 is disposed upstream of the secondary transfer roller 32 in the sheet conveyance path 20. The pair of registration rollers disposed in the registration unit 34 allows the sheet to be transferred to the toner on the intermediate transfer belt 24. In synchronization with the image, the image is conveyed between the intermediate transfer belt 24 and the secondary transfer roller 32.

  A conveyance belt 36 is disposed on the downstream side of the secondary transfer roller 32, and a fixing unit 38 is disposed on the sheet conveyance path 40 on the downstream side of the conveyance belt 36. In the fixing unit 38, the toner image on the paper is fixed on the paper by heating and pressing.

  As shown in FIG. 2, the sheet conveyance path 40 on the downstream side of the fixing unit 38 conveys the sheet to the sheet conveyance path 46 that conveys the sheet to the sheet discharge unit 42 and the reversing unit 44 that reverses the front and back of the sheet. Branching into the reversing path 48. When the front and back sides of the sheet are not reversed, the sheet on which the toner image is fixed is conveyed along the sheet conveyance path 46, and is ejected on the side of the housing 11 by the ejection roll 43 provided on the sheet ejection unit 42. The paper is discharged as it is onto a paper tray 80 (see FIG. 1).

  The reversing path 48 is provided with a carry-in path 49 </ b> A for carrying the paper into the reversing unit 44 and a carry-out path 49 </ b> B for carrying out the paper from the reversing part 44. A transport roller 57 that transports the paper to the reversing unit 44 is disposed in the carry-in path 49A. Further, a conveyance roller 58 sharing one roll of the conveyance roller 57 is disposed in the carry-out path 49B. The carry-out path 49B is joined to the paper conveyance path 46 by the paper discharge unit 42, and the paper carried out to the carry-out path 49B is discharged to the paper discharge tray 80 (see FIG. 1) with the formed image facing down. The Further, a gate (not shown) for switching the paper transport direction is provided at a branching portion between the carry-in path 49A and the carry-out path 49B.

  As shown in FIG. 2, a pair of reversing rollers 50 are arranged in the reversing unit 44, and the reversing rollers 50 are rotated in the paper drawing direction (forward rotation) or rotated in the reversing direction (reverse rotation) by the motor 52. ) Is configured to. The drive of the motor 52 is controlled by the control unit 64. Then, the paper is carried in from the carry-in path 49A and pulled into the reversing unit 44, and the reverse roller 50 is rotated in the reverse direction with the reverse roller 50 sandwiching the rear end of the paper, thereby reversing the front and back of the paper and carrying-out path 49B. Can be carried out to

  Further, as shown in FIG. 2, the carry-in path 49A is a lower part on the opposite side to the carry-out path 49B, and is branched into a paper transport path 54 through which the paper is transported with the image facing back during duplex printing. At a branch portion between the carry-in path 49 </ b> A and the sheet conveyance path 54, a gate (not shown) for switching sheet conveyance is provided. At the time of duplex printing, the sheet on which the toner image is fixed is conveyed to the carry-in path 49A, and the reversing unit 44 reverses the front and back of the sheet and conveys it to the sheet conveyance path 54.

  As shown in FIG. 1, a plurality of transport rollers 56 are arranged in the paper transport path 54, and the paper is transported along the paper transport path 54 by the transport rollers 56, and again with the image backside. The paper is guided to the paper conveyance path 20 and conveyed between the intermediate transfer belt 24 and the secondary transfer roller 32. The toner image formed on the intermediate transfer belt 24 is transferred to the back surface of the sheet by the action of the secondary transfer roller 32, and the toner image is fixed by the fixing unit 38. Then, the paper is discharged to the paper discharge tray 80 by the paper discharge unit 42 through the paper conveyance path 46.

  In addition, a manual feed tray 82 on which a sheet of an arbitrary size and type is placed is disposed on a side portion of the housing 11. In the feeding direction of the manual feed tray 82, a pickup roll 83 and a feed roll 84 and a retard roll 85 are arranged on the downstream side of the pickup roll 83. 20 is conveyed and conveyed between the intermediate transfer belt 24 and the secondary transfer roller 32. As a result, an image can be formed on any size and type of paper.

  Here, the installation position of each sensor in the paper conveyance path will be described. FIG. 3 is an enlarged view of the periphery of the resist unit 34 of the image forming apparatus 10. The first sensor 61 is upstream of the registration unit 34, that is, immediately before the sheet is conveyed along the sheet conveyance path 20 by the conveyance roller 19 and conveyed by a pair of registration rollers installed in the registration unit 34. It is arranged at the position. The reason for this arrangement is that the conveyance speed is stable and the length of the sheet in the conveyance direction can be measured reliably. However, it can also be measured by a second sensor 62 described later disposed in the reversing unit 44.

  As shown in FIG. 2, the second sensor 62 that detects the passage of the trailing edge of the sheet is disposed on the upstream side of the transport roller 41 disposed on the downstream side in the transport direction of the fixing unit 38. . Then, the second sensor 62 detects passage of the trailing edge of the sheet. In the present embodiment, the second sensor 62 is disposed on the upstream side of the transport roller 41, but may be disposed on the downstream side of the transport roller 41 (shown by a broken line in FIG. 2).

  Here, FIG. 6 shows the position of each sensor from above. As shown in the figure, the first sensor 61 and the second sensor 62 are disposed at positions separated by distances L1 and L2 in a direction orthogonal to the reference line from the reference line along the paper conveyance direction. . The distances L1 and L2 are set to the same or substantially the same distance. As described above, by arranging the sensors on substantially the same line along the sheet conveyance direction, the second sensor is a part where the length of the sheet is measured by the first sensor in the sheet to be conveyed. Will be detected. Therefore, when one of the first sensor and the second sensor detects the tab portion of the tabbed paper, the other also detects the tab portion, and one of the first sensor and the second sensor detects a portion other than the tab portion. Then, the other part also detects a part other than the tab part.

  Further, as shown in FIG. 4, in the control unit 64, based on the detection timing of the trailing edge of the paper detected by the second sensor 62 and the length in the paper conveyance direction, The inversion timing is controlled.

  Next, the operation of the image forming apparatus 10 including the recording medium conveying apparatus according to the present invention will be described. In this embodiment, when an image is formed on a tabbed sheet, the operator inputs in advance that the tabbed sheet mode is selected by the input unit (not shown) of the image forming apparatus 10. Accordingly, the control unit 64 recognizes that the tabbed paper is fed.

  As shown in FIG. 1, the tabbed paper is fed from a paper feed cassette 12 (any one of 12 </ b> A to 12 </ b> D) and is transported along a paper transport path 20 by a transport roller 19. Then, the tabbed paper is conveyed by the registration unit 34 between the intermediate transfer belt 24 and the secondary transfer roller 32 at a predetermined timing, and the toner image formed on the intermediate transfer belt 24 is transferred onto the tabbed paper. Is done. At that time, the length of the sheet in the conveyance direction is measured by the first sensor 61 arranged on the upstream side of the registration unit 34. Based on the measured length, the control unit 64 determines whether the portion detected by the first sensor is a tab portion or a portion other than the tab portion. Thereafter, the tabbed paper is transported to the fixing unit of the paper transport path 40 via the transport belt 36, and the toner image is fixed on the tabbed paper.

  As shown in FIG. 2, when the front and back of the tabbed paper is reversed and discharged, the tabbed paper is guided from the paper transport path 40 to a gate (not shown) and carried into the carry-in path 49A. Further, it is guided by a gate (not shown) and conveyed to the reversing unit 44 by the conveying roller 57. At that time, the passage of the rear end portion of the tabbed paper is detected by the second sensor 62 disposed on the upstream side of the conveying roller 41.

  Here, the paper reversal control by the control unit 64, that is, the reversal timing of the reversing roller 50 will be described.

  As shown in FIG. 5, when the image forming operation starts, in step 500, the first sensor 61 measures the length in the transport direction of the transported paper. In step 510, based on the measured paper length, it is determined whether the portion detected by the first sensor 61 is a tab portion of the tabbed paper or a portion other than the tab portion. If a tab portion is detected, the process proceeds to step 520. In step S530, the sheet reversal control is set so as to be suitable for the presence of tabs, and if a portion other than the tab portion is detected, the process proceeds to step 530.

  Inversion control corresponding to the presence or absence of tabs in step 520 and step 530 is performed as follows.

  When the first sensor 61 detects the tab portion of the sheet, as shown in FIG. 7A, the second passage of the rear end portion (of the tab portion) of the tabbed sheet conveyed in the arrow direction is second. The time from when the sensor 62 is detected until the reversing roller 50 is stopped is T1, and when the first sensor 61 detects a portion other than the tab portion at the rear end of the sheet, it is shown in FIG. Thus, T2 is the time from when the second sensor detects the trailing edge (other than the tab) of the tabbed paper conveyed in the direction of the arrow until the reversing roller 50 is stopped.

  Here, T1 is the same as that in the case of a sheet without a normal tab, and T2 is the length of the tab of the sheet (length in the transport direction: usually 1/2 inch or 12 to 13 mm as a standard) than T1. Is set longer by the time of conveyance, and the timing of stopping the reversing roller 50 is delayed.

  In the present embodiment, the first sensor 61 and the second sensor 62 are set to have substantially the same installation position in the direction orthogonal to the sheet conveyance direction, so that the second sensor is detected from the detection result of the first sensor 61. Since it is known in advance whether the tab portion of the paper or the portion other than the tab portion passes through the detection position 62, the time (T1 or T2) corresponding to each case has elapsed since the end of the paper was detected. The paper can be reversed by stopping the reversing roller 50 and rotating (reversely rotating) it in the reversing direction.

  Therefore, since it is not known whether the portion where the edge of the sheet is detected is a tab portion or a portion other than the tab portion, considering the case where it is a portion other than the tab portion, the reversing roller 50 is extra by the length of the tab portion in the conveyance direction. No need to insert into For this reason, it is not necessary to arrange the reversing roller 50 with a margin from the branch position of the reversing unit 44 in the length of the tab in the conveyance direction, and space saving can be realized.

  In this embodiment, paper having a tab portion at the center of the paper is used, but there are various types of tabbed paper (difference in the number of tabs). When the number n is an odd number, the (n + 1) / 2th tab is at the center of the sheet, but when the number n is an even number, no tab is arranged at the center of the sheet. Therefore, if a sensor is arranged at the center of the sheet, the tab portion cannot be detected on a tabbed sheet having an even number of tabs n, or an obliquely cut portion of the tab is detected, resulting in an error in the measured length. In order to avoid this, if the sensor is arranged at a position several millimeters (3 mm to 20 mm) away from the paper transport direction reference line (the central portion of the paper), the tab portion can be reliably detected.

  Also, in this embodiment, it is necessary for the operator to select the tabbed paper mode in advance so that it can be understood that an image is formed on the tabbed paper. No need to enter.

  In this embodiment, the trailing edge of the sheet is detected, but the leading edge may be detected.

1 is a schematic configuration diagram illustrating an image forming apparatus according to the present invention. FIG. 2 is a configuration diagram illustrating a configuration near a reversing unit of the image forming apparatus illustrated in FIG. 1. It is a figure which shows the arrangement | positioning position of a 1st sensor. FIG. 3 is a block diagram illustrating signal transmission in a motor that rotates a second sensor, a control unit, and a reverse roller for detecting passage of paper in the image forming apparatus illustrated in FIG. 1. 3 is a flowchart showing a flow of control for reversing tabbed paper by a reversing roller of the image forming apparatus shown in FIG. 1. It is a figure which shows the arrangement | positioning position in the direction orthogonal to the conveyance direction of a 1st sensor and a 2nd sensor. (A) is a diagram showing a state in which a tab portion of a sheet is detected by the first sensor and the second sensor, and a timing diagram of detection by the second sensor and reverse rotation of the reverse roller, and (B) is a first sensor. FIG. 5 is a diagram illustrating a state in which a portion other than the tab portion of the sheet is detected by the second sensor, and a timing diagram of detection by the second sensor and reverse rotation of the reverse roller. It is a figure which shows the number of tabs, and the detail of the arrangement position of a sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Paper feed cassette 14 Paper feed part 40 Paper conveyance path 42 Paper discharge part 44 Inversion part 46 Paper conveyance path 48 Inversion path 49A Carry-in path 49B Unloading path 50 Reverse roller 52 Motor 54 Paper conveyance path 56 Conveyance roller 61 1st 1 sensor 62 2nd sensor 64 Control unit (control means)

Claims (2)

A first sensor arranged to measure the length of the recording medium in the transport direction;
A reversing means comprising a reversing roller for reversing the conveying direction of the recording medium by reversing the rotation direction, reversing the front and back of the loaded recording medium;
A conveying means for conveying the recording medium carried in from the carry-in path in the direction of the reversing means, and for conveying the recording medium carried out of the reversing means in the direction of the carry-out path;
A second sensor that is disposed at a position where the end of the part where the length of the recording medium is measured can be detected, and that detects the end of the recording medium conveyed in the direction of the reversing unit;
When transporting a tabbed recording medium, it is determined whether a tab portion has passed or a portion other than the tab portion has passed based on the length of the recording medium in the transport direction, and the result of the determination and the second sensor Control means for controlling the reversal timing of the rotation direction of the reversing roller based on the detection timing of the end of the recording medium by
It includes,
The position of the first sensor for measuring the length of the recording medium in the conveyance direction and the position of the second sensor for detecting the end of the recording medium are directions orthogonal to the conveyance direction of the recording medium. A recording medium conveying apparatus characterized by being shifted by 3 mm to 20 mm with respect to the center position. A first sensor arranged to measure the length of the recording medium in the transport direction;
A reversing means comprising a reversing roller for reversing the conveying direction of the recording medium by reversing the rotation direction, reversing the front and back of the loaded recording medium;
A conveying means for conveying the recording medium carried in from the carry-in path in the direction of the reversing means, and for conveying the recording medium carried out of the reversing means in the direction of the carry-out path;
A second sensor that is disposed at a position where the end of the part where the length of the recording medium is measured can be detected, and that detects the end of the recording medium conveyed in the direction of the reversing unit;
When transporting a tabbed recording medium, it is determined whether a tab portion has passed or a portion other than the tab portion has passed based on the length of the recording medium in the transport direction, and the result of the determination and the second sensor Control means for controlling the reversal timing of the rotation direction of the reversing roller based on the detection timing of the end of the recording medium by
Selecting means for selecting a tabbed mode for conveying a tabbed recording medium;
It includes,
The control means, when the tabbed mode is selected, determines whether the tab portion has passed or other than the tab portion has passed based on the length of the recording medium in the transport direction, and the result of the determination And the reversal timing in the rotational direction of the reversing roller based on the detection timing of the passage of the end of the recording medium by the second sensor,
The position of the first sensor for measuring the length of the recording medium in the conveyance direction and the position of the second sensor for detecting the end of the recording medium are directions orthogonal to the conveyance direction of the recording medium. A recording medium conveying apparatus characterized by being shifted by 3 mm to 20 mm with respect to the center position.

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