Sheet transport device, image forming apparatus

Abstract

When multiple correction mechanisms correct the orientation of a sheet in multiple preceding transport paths, the sheet is transported in an appropriate orientation regardless of the sheet's transport path. [Solution] Multiple pre-transport paths 302 merge into a main transport path 303. Transport mechanisms 32-34 transport the sheet along the multiple pre-transport paths 302 and the main transport path 303. Multiple straightening mechanisms 7 are each positioned in the multiple pre-transport paths 302 and correct the sheet posture, which is one or both of the inclination angle and widthwise offset of the sheet being transported. A posture detection device 6 detects the sheet posture of the sheet being transported along the main transport path 303. A control device 8 identifies the target straightening mechanism that the target sheet passes through among the multiple straightening mechanisms 7 and corrects the straightening parameters of the target straightening mechanism according to the detection result of the sheet posture for the target sheet.

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device and an image forming apparatus that include a plurality of correcting mechanisms for correcting the posture of sheets in a plurality of conveying paths. [Background Art]

[0002] An image forming apparatus includes a sheet conveying device and a printing device. The printing device forms an image on a sheet conveyed by the sheet conveying device.

[0003] It is known that the sheet conveying device includes a posture correcting mechanism that corrects the posture of a sheet, such as the inclination of the sheet conveyed toward the printing device.

[0004] For example, it is known that the inclination of a sheet is corrected when the sheet is conveyed to a nipping portion of a pair of registration rollers where the sheet is temporarily stopped (see Patent Document 1). [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2008-30412 [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] Incidentally, there are cases where the sheet conveying device includes a main conveying path on which image formation is performed by the printing device, and a plurality of upstream conveying paths that merge with the main conveying path.

[0007] Furthermore, there are cases where the sheet conveying device includes a plurality of correcting mechanisms each configured to correct the sheet posture in the plurality of upstream conveying paths.

[0008] In order to improve the output image quality of the image forming apparatus, it is desirable that the sheet be transported in an appropriate orientation on the main transport path, regardless of which of the plurality of preceding transport paths the sheet passes through.

[0009] The object of the present invention is to provide a sheet conveying device and an image forming apparatus that can convey a sheet in an appropriate posture on the main conveying path, regardless of the sheet's conveying path, when multiple correction mechanisms correct the sheet's posture in multiple preceding conveying paths. [Means for solving the problem]

[0010] A sheet conveying device according to one aspect of the present invention comprises a main conveying path, a plurality of pre-conveying paths, a conveying mechanism, a plurality of straightening mechanisms, a posture detection device, and a control device. The main conveying path is a passage for the sheet. The plurality of pre-conveying paths are each passages for the sheet and merge with the main conveying path. The conveying mechanism conveys the sheet along the plurality of pre-conveying paths and the main conveying path. The plurality of straightening mechanisms are each arranged in the plurality of pre-conveying paths and correct the sheet posture, which is one or both of the inclination angle and widthwise offset of the sheet being conveyed. The posture detection device detects the sheet posture of the sheet being conveyed along the main conveying path. The control device identifies the target straightening mechanism that the target sheet being conveyed along the main conveying path passes through among the plurality of straightening mechanisms and corrects the straightening parameters of the target straightening mechanism according to the detection result of the sheet posture for the target sheet.

[0011] An image forming apparatus according to another aspect of the present invention comprises a sheet transport device and a printing device that forms an image on a sheet transported by the sheet transport device. [Effects of the Invention]

[0012] According to the present invention, when multiple correction mechanisms correct the orientation of the sheet in multiple preceding transport paths, it becomes possible to provide a sheet transport device and an image forming device that can transport the sheet in an appropriate orientation in the main transport path regardless of the sheet transport path. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a configuration diagram of an image forming apparatus according to an embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the control device in the image forming apparatus according to the embodiment. [Figure 3] Figure 3 is a plan view showing the configuration of the conveyor belt and line sensor in the image forming apparatus according to the embodiment. [Figure 4] Figure 4 is a diagram showing the configuration of the orthodontic mechanism in an image forming apparatus according to an embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the procedure for posture correction control in an image forming apparatus according to an embodiment. [Figure 6] Figure 6 shows an example of a sheet outline image extracted from a read image by posture detection processing in an image forming apparatus according to an embodiment of the present invention. [Figure 7] Figure 7 is a flowchart showing an example of the procedure for posture correction control in an image forming apparatus according to a modified example. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0015] [Configuration of the image forming apparatus 10] The image forming apparatus 10 according to this embodiment includes a sheet storage unit 2, a sheet transport device 3, a printing device 4, and a control device 8. Furthermore, the image forming apparatus 10 also includes a drying device 5, an operating device 801, and a display device 802.

[0016] The sheet accommodating portion 2 accommodates a sheet 9. The sheet conveying device 3 feeds the sheet 9 out from the sheet accommodating portion 2, and further conveys the sheet 9.

[0017] The sheet conveying device 3 includes a main conveying path 303 which is a conveying path for the sheet 9. The sheet conveying device 3 conveys the sheet 9 along the main conveying path 303.

[0018] The printing device 4 forms an image on the sheet 9 conveyed along the main conveying path 303 by the sheet conveying device 3.

[0019] In the example shown in FIG. 1, the printing device 4 executes the printing process by an inkjet method.

[0020] The printing device 4 includes a plurality of ink heads 41 and a plurality of ink supply portions 42 respectively corresponding to inks of different colors. Specifically, the printing device 4 includes four ink heads 41 and four ink supply portions 42 respectively corresponding to yellow, magenta, cyan and black.

[0021] The plurality of ink heads 41 each eject ink onto the sheet 9. The plurality of ink supply portions 42 each store ink of a different color, and supply ink to the plurality of ink heads 41.

[0022] In the present embodiment, the image forming apparatus 10 also includes a drying device 5. The drying device 5 dries the ink image on the sheet 9 by blowing warm air to the sheet 9 on which an image has been formed.

[0023] The operating device 801 detects a human operation. For example, the operating device 801 includes a plurality of operation buttons and a touch panel. The display device 802 can display various types of information. For example, the display device 802 is a panel display device such as a liquid crystal display panel.

[0024] The control device 8 controls the sheet transport device 3, the printing device 4, and the drying device 5.

[0025] As shown in Figure 2, the control device 8 includes a CPU (Central Processing Unit) 80, RAM (Random Access Memory) 81, secondary storage device 82, signal interface 83, and communication device 84, among others.

[0026] The CPU 80 performs various control and data processing by executing computer programs. The RAM 81 temporarily stores the computer programs executed by the CPU 80 and various data.

[0027] The secondary storage device 82 is a computer-readable, non-volatile storage device. The secondary storage device 82 stores the computer program executed by the CPU 80 and various data. For example, flash memory, a hard disk drive, or both may be used as the secondary storage device 82.

[0028] The signal interface 83 converts detection signals from various sensors into digital detection data and transmits the detection data to the CPU 80. Furthermore, the signal interface 83 converts control commands output from the CPU 80 into control signals and transmits the control signals to the controlled device.

[0029] The communication device 84 performs communication with other devices such as the host device 100 via the network 1000. The CPU 80 performs communication with other devices via the communication device 84. The host device 100 is an information processing device that requests the image forming apparatus 10 to perform the print processing.

[0030] The CPU 80 includes a plurality of processing modules that are realized by executing the computer program. These plurality of processing modules include a transport control unit 8a and a print control unit 8b, etc. (see Figure 2).

[0031] The transport control unit 8a controls the transport of the sheet 9 by controlling multiple devices in the sheet transport device 3. In this embodiment, the transport control unit 8a constitutes a part of the sheet transport device 3. The transport control unit 8a of the CPU 80 is an example of a control device that controls the transport of the sheet 9.

[0032] The print control unit 8b causes the printing device 4 to perform the printing process in synchronization with the transport of the sheet 9. Furthermore, the print control unit 8b operates the drying device 5 when the printing process is being performed.

[0033] Furthermore, some or all of the processing performed by the CPU 80 may be performed by a DSP (Digital Signal Processor) or SoC (System on a Chip), etc. The CPU 80, the DSP, and the SoC are each examples of processors.

[0034] Incidentally, the sheet conveying device 3 is equipped with multiple pre-conveyor paths 302 that merge with the main conveying path 303 (see Figure 1). In the example shown in Figure 1, the sheet conveying device 3 is equipped with two pre-conveyor paths 302. The sheet conveying device 3 may be equipped with three or more pre-conveyor paths 302.

[0035] In the following explanation, the direction in which the sheet 9 is transported in each transport path will be referred to as the transport direction D1, and the direction perpendicular to the transport direction D1 will be referred to as the width direction D2.

[0036] Furthermore, the sheet conveying device 3 is equipped with multiple straightening mechanisms 7, each positioned in a plurality of preceding conveying paths 302, to correct the sheet orientation of the conveyed sheet 9 (see Figure 1). In the example shown in Figure 1, the sheet conveying device 3 is equipped with two straightening mechanisms 7. The sheet conveying device 3 may be equipped with three or more straightening mechanisms 7.

[0037] The aforementioned sheet orientation is determined by either or both the inclination angle θ1 and the offset amount X1 in the width direction D2 of the sheet 9 as it is transported along each of the preceding transport paths 302 (see Figure 6). For example, the inclination angle θ1 is the inclination angle of the sheet 9 with respect to the transport direction D1.

[0038] In order to improve the output image quality of the image forming apparatus 10, it is desirable that the sheet 9 be transported in an appropriate orientation on the main transport path 303, regardless of which of the multiple pre-transport paths 302 the sheet 9 passes through.

[0039] The sheet transport device 3 is configured to transport the sheet 9 in an appropriate posture along the main transport path 303, regardless of the transport path of the sheet 9.

[0040] [Configuration of Sheet Transport Device 3] The sheet conveying device 3 includes a supply path 301, which is a conveying path for the sheet 9, a plurality of pre-conveying paths 302, a main conveying path 303, and a sub-conveying path 304 (see Figure 1).

[0041] The supply and transport path 301 has a base end that communicates with the sheet storage section 2 and an end that branches off to a plurality of preceding transport paths 302. The supply and transport path 301 is the source of the branching to the plurality of preceding transport paths 302.

[0042] Multiple pre-transport paths 302 merge into the main transport path 303. A secondary transport path 304 branches off from the downstream portion of the transport direction D1 relative to the image formation position in the main transport path 303 and merges into a specific pre-transport path 302a. The specific pre-transport path 302a is one of the multiple pre-transport paths 302.

[0043] In the following explanation, one of the multiple orthodontic mechanisms 7 located in the specific pre-transport path 302a will be referred to as the specific orthodontic mechanism 7a.

[0044] When single-sided printing is performed, the sheet transport device 3 transports the sheet 9 along the supply path 301, one of the multiple pre-transport paths 302, and the main transport path 303, and then discharges the sheet 9 from the main transport path 303. Single-sided printing is a process in which an image is formed on only one side of the sheet 9.

[0045] When double-sided printing is performed, the sheet transport device 3 transports the sheet 9 along the supply path 301, one of the multiple pre-transport paths 302, and the main transport path 303. Furthermore, the sheet transport device 3 transports the sheet 9 from the main transport path 303 back to the main transport path 303 via the sub-transport path 304, and then discharges the sheet 9 from the main transport path 303. The double-sided printing is a process in which an image is formed on both sides of the sheet 9.

[0046] The sheet conveying device 3 includes a feeding mechanism 30, multiple pairs of feeding rollers 31, multiple pairs of pre-conveying rollers 32, a first belt conveying device 33, a second belt conveying device 34, a discharge roller pair 35, and multiple pairs of sub-conveying rollers 36 (see Figure 1).

[0047] Furthermore, the sheet transport device 3 includes a first route switching mechanism 3a, a second route switching mechanism 3b, and a third route switching mechanism 3c (see Figure 1).

[0048] The feeding mechanism 30 sends the sheets 9 in the sheet storage section 2 to the feeding path 301. Multiple pairs of feeding rollers 31 transport the sheets 9 along the feeding path 301 and then transport the sheets 9 to one of the multiple upstream transport paths 302.

[0049] The first path switching mechanism 3a selectively guides the sheet 9 to one of the multiple preceding transport paths 302.

[0050] Multiple pairs of front-stage conveying rollers 32 convey the sheet 9 along each of the front-stage conveying paths 302. The first belt conveying device 33 and the second belt conveying device 34 convey the sheet 9 along the main conveying path 303.

[0051] The first belt conveyor 33 takes over the conveying of the sheet 9 from multiple sets of front conveyor rollers 32 and further conveys the sheet 9 to the second belt conveyor 34. The second belt conveyor 34 takes over the conveying of the sheet 9 from the first belt conveyor 33 and further conveys the sheet 9 to the discharge rollers 35 or the auxiliary conveyor path 304.

[0052] The first belt conveying device 33 comprises an endless conveying belt 330 and a plurality of support rollers 331 that rotatably support the conveying belt 330. Furthermore, the first belt conveying device 33 also comprises a suction device 332 that attracts the sheet 9 to the upper surface of the conveying belt 330. The first belt conveying device 33 conveys the sheet 9 attracted to the upper surface of the rotating conveying belt 340.

[0053] The second belt conveying device 34 comprises an endless conveying belt 340 and a plurality of support rollers 341 that rotatably support the conveying belt 340. The second belt conveying device 34 conveys a sheet 9 that is placed on the upper surface of the rotating conveying belt 340.

[0054] The sheet conveying device 3 also includes a belt-driven motor (not shown) that rotates one of the multiple support rollers 331 and one of the multiple support rollers 341.

[0055] Multiple pairs of front-stage conveying rollers 32, a first belt conveying device 33, and a second belt conveying device 34 constitute an example of a conveying mechanism that conveys sheets 9 along multiple front-stage conveying paths 302 and a main conveying path 303.

[0056] The discharge roller pair 35 transports the sheet 9 from the main transport path 303 to the downstream section. The downstream section is a post-processing device that performs post-processing on the sheet tray or the sheet 9. The post-processing includes punching holes in the sheet 9, stapling the sheet 9 together, or folding the sheet 9.

[0057] The second path switching mechanism 3b selectively guides the sheet 9 that has passed through the second belt conveyor 34 towards either the discharge roller pair 35 or the secondary conveyor path 304.

[0058] Multiple pairs of auxiliary conveyor rollers 36 transport the sheet 9 along the auxiliary conveyor path 304, and then transport the sheet 9 from the auxiliary conveyor path 304 to the main conveyor path 303.

[0059] The auxiliary transport path 304 includes a first auxiliary transport path 304a and a second auxiliary transport path 304b. The first auxiliary transport path 304a branches off from the main transport path 303. The second auxiliary transport path 304b branches off from the first auxiliary transport path 304a and merges with the specific upstream transport path 302a. The second auxiliary transport path 304b merges with the specific straightening mechanism 7a in the specific upstream transport path 302a in the transport direction D1.

[0060] In this embodiment, the supply path 301 and the sub-conveyor path 304 are examples of multiple pre-pre-conveyor paths that supply sheets 9 to the specific pre-conveyor path 302a. The sheet conveying device 3 may have three or more pre-pre-conveyor paths. For example, the multiple pre-pre-conveyor paths may include a manual sheet conveying path from a manual feed tray (not shown) to the specific pre-conveyor path 302a.

[0061] The multiple pairs of auxiliary conveyor rollers 36 include pairs of reversing rollers 36a positioned near the branching point from the first auxiliary conveyor path 304a to the second auxiliary conveyor path 304b.

[0062] The reversing roller pair 36a rotates in the first rotational direction, transporting the sheet 9 toward the end of the first sub-transport path 304a. Furthermore, the reversing roller pair 36a rotates in the second rotational direction, reversing and transporting the sheet 9 from the first sub-transport path 304a to the second sub-transport path 304b. As a result, the sheet 9 is transported to the second sub-transport path 304b with its front and back sides and front and back reversed.

[0063] The third path switching mechanism 3c guides the sheet 9 toward the end of the first sub-conveyor path 304a when the reversing roller pair 36a rotates in the first rotation direction. Furthermore, when the reversing roller pair 36a rotates in the second rotation direction, the third path switching mechanism 3c guides the sheet 9 from the first sub-conveyor path 304a to the second sub-conveyor path 304b.

[0064] The sheet conveying device 3 is further equipped with a line sensor 6 (see Figures 1 and 3). The line sensor 6 is positioned opposite the detection position P1 on the upper surface of the conveying belt 320 in the first belt conveying device 33 (see Figure 1). The line sensor 6 is positioned along the width direction D2 (see Figure 3).

[0065] The detection position P1 is located upstream of the image formation position in the main transport path 302 in the transport direction D1. The line sensor 6 is an image sensor that reads the image of the region along the width direction D2 at the detection position P1.

[0066] The line sensor 6 comprises a light-emitting unit 6a and a plurality of photoelectric conversion elements 6b (see Figure 3). The plurality of photoelectric conversion elements 6b are arranged along the width direction D2. The light-emitting unit 6a irradiates light onto the detection position P1 on the surface of the conveyor belt 320.

[0067] Each of the multiple photoelectric conversion elements 6b detects the amount of diffusely reflected light on the surface of the conveyor belt 320 and outputs multiple pixel signals representing the detected light amount. The signal interface 83 includes an AFE (Analog Front End) 83a that converts the multiple pixel signals sequentially output by the line sensor 6 into multiple pixel data (see Figure 2).

[0068] The multiple pixel data for multiple lines output from AFE83a are transmitted to CPU80 as read image data RD1 (see Figure 2). The read image data RD1 is obtained when the line sensor 6 operates as sheet 9 passes through detection position P1.

[0069] The multiple processing modules in the CPU 80 include an image processing unit 8c that processes the read image data RD1 (see Figure 2). The image processing unit 8c performs posture detection processing to detect the seat posture.

[0070] For example, in the posture detection process, the image processing unit 8c extracts the sheet outline image G1 from the image of the read image data RD1 by performing edge detection processing on the read image data RD1 (see Figure 6). The sheet outline image G1 represents the outline of the sheet 9. In the read image data RD1, the X coordinate represents the position in the width direction D2, and the Y coordinate represents the position in the transport direction D1.

[0071] Furthermore, in the posture detection process, the image processing unit 8c detects the tilt angle θ1 and the offset amount X1 in the width direction D2 of the sheet 9 based on the sheet outline image G1 (see Figure 6).

[0072] For example, the image processing unit 8c identifies the coordinates of the first side endpoint Px1 and the second side endpoint Px2, which are one of the endpoints in the X-axis direction of the sheet outline image G1 in the first Y coordinate and second Y coordinate (see Figure 6).

[0073] Furthermore, in the attitude detection process, the image processing unit 8c derives the angle formed by the straight line passing through the first side endpoint Px1 and the second side endpoint Px2 with respect to the Y-axis direction as the inclination angle θ1.

[0074] Furthermore, in the posture detection process, the image processing unit 8c identifies the coordinates of the first side endpoint Px1 and the third side endpoint Px3, which are the two endpoints in the X-axis direction of the sheet outline image G1 in the first Y coordinate (see Figure 6).

[0075] Furthermore, in the attitude detection process, the image processing unit 8c derives the difference between the X coordinates of the midpoint Px4 of the first side endpoint Px1 and the third side endpoint Px3 and a predetermined reference coordinate as the offset amount X1.

[0076] The image processing unit 8c may also identify the coordinates of the first and second tip points, which are the Y-axis endpoints of the sheet outline image G1 at two locations separated in the X-axis direction. In this case, the image processing unit 8c derives the angle formed by the line passing through the first and second tip points with respect to the X-axis direction as the inclination angle θ1.

[0077] In this embodiment, the line sensor 6, AFE 83a, and image processing unit 8c are an example of an attitude detection device that detects the attitude of a sheet 9 being transported along the main transport path 303. The attitude detection device detects the attitude of a sheet 9 as it passes through a detection position P1 in the main transport path 303.

[0078] As described later, one of the correction parameters of the multiple correction mechanisms 7 is corrected according to the detection results of the inclination angle θ1 and offset amount X1.

[0079] In the example shown in Figure 1, the image forming apparatus 10 is divided into a main unit 1a, a pre-stage unit 1b, and a post-stage unit 1c. The pre-stage unit 1b and the post-stage unit 1c are each connected to the main unit 1a.

[0080] The sheet storage section 2, the feeding path 301, multiple pre-stage transport paths 302, multiple pairs of feeding rollers 31, multiple pairs of pre-stage transport rollers 32, and multiple straightening mechanisms 7 are arranged within the pre-stage unit 1b.

[0081] The first belt conveyor 33 and the printing device 4 are located within the main unit 1a. The drying device 5, the second belt conveyor 34, and the discharge roller pair 35 are located within the downstream unit 1c.

[0082] The auxiliary transport path 304 and multiple pairs of auxiliary transport rollers 36 are arranged across the downstream unit 1c, the main unit 1a, and the preceding unit 1b.

[0083] [Correcting mechanism 7] In this embodiment, each of the straightening mechanisms 7 corrects the inclination angle θ1 and offset amount X1 of the sheet 9 being transported along each of the preceding transport paths 302.

[0084] Each of the straightening mechanisms 7 comprises a diagonal transport mechanism 70, a straightening member 71, a tilt adjustment mechanism 72, a support member 73, and an offset adjustment mechanism 74 (see Figure 4).

[0085] The straightening member 71 has a contact surface 71a that contacts the side edge 9a of the sheet 9 at one end in the width direction D2 of each of the preceding transport paths 302. The contact surface 71a is a surface that guides the side edge 9a of the sheet 9 along the transport direction D1.

[0086] The diagonal conveying mechanism 70 conveys the material toward the contact surface 71a along a third direction D3 that is diagonal to the conveying direction D1.

[0087] In the example shown in Figure 4, the oblique conveying mechanism 70 includes a pair of rotating shafts 70a arranged obliquely to the width direction D2, and a pair of rollers 70b supported by the pair of rotating shafts 70a.

[0088] The straightening member 71 is rotatably supported around the shaft portion 71x (see Figure 4). As the straightening member 71 rotates, the angle of the contact surface 71a with respect to the transport direction D1 changes.

[0089] The tilt adjustment mechanism 72 operates when a first drive signal is input, and changes the angle of the contact surface 71a with respect to the transport direction D1. In this embodiment, the tilt adjustment mechanism 72 is a mechanism that rotates the straightening member 71 around the shaft portion 71x. The first drive signal is output from the control device 8 to the tilt adjustment mechanism 72.

[0090] In the example shown in Figure 4, the tilt adjustment mechanism 72 comprises a first control motor 721, a cam 722, and a spring 723. Furthermore, the tilt adjustment mechanism 72 also includes a first base point detection sensor 724.

[0091] The first control motor 721 rotates in a first or second rotation direction when the first drive signal is input. For example, the first control motor 721 is a stepping motor or a servo motor. The first control motor 721 operates according to the first drive signal and rotates the cam 722 around the rotation axis 722x.

[0092] The cam 722 rotates while in contact with the contacted portion 71b of the straightening member 71, thereby causing the straightening member 71 to oscillate around the shaft portion 71x. As the straightening member 71 oscillates, the angle of the contact surface 71a with respect to the conveying direction D1 changes.

[0093] The spring 723 biases the straightening member 71 toward the cam 722, thereby maintaining the state in which the cam 722 is in contact with the contacted portion 71b of the straightening member 71.

[0094] The first base point detection sensor 724 is supported by the support member 73 and detects the first detectable portion 71c formed on the straightening member 71. The first base point detection sensor 724 detects that the contact surface 71a of the straightening member 71 is at a predetermined reference angle with respect to the transport direction D1.

[0095] For example, the first base point detection sensor 75 is a transmissive photosensor or a reflective photosensor. The angle of the contact surface 71a is adjusted by the amount of rotation of the cam 722 from the point in time when the first detected part 71c is detected by the first base point detection sensor 724.

[0096] The tilt adjustment mechanism 72 may be any other mechanism that converts the rotational motion of the output shaft of the first control motor 721 into the oscillating motion of the straightening member 71.

[0097] The support member 73 supports the straightening member 71 and the tilt adjustment mechanism 72. The support member 73 is supported so as to be movable along the width direction D2 (see Figure 4).

[0098] The offset adjustment mechanism 74 operates when a second drive signal is input, and changes the position of the contact surface 71a in the width direction D2. In this embodiment, the offset adjustment mechanism 74 is a mechanism that moves the support member 73 in the width direction D2.

[0099] In the example shown in Figure 4, the offset adjustment mechanism 74 comprises a plurality of rotatably supported rotating bodies 741, a second control motor 742, and an endless drive belt 743. Each rotating body 741 has a screw shaft 741a and a pulley 741b. The offset adjustment mechanism 74 also includes a second base point detection sensor 744.

[0100] The drive belt 743 is stretched between the pulleys 741b of the multiple rotating bodies 741 and the output shaft of the second control motor 742. The support member 73 has multiple screw holes 73a that engage with the screw shafts 741a of the multiple rotating bodies 741.

[0101] The second control motor 742 rotates in the first or second rotation direction when the second drive signal is input. For example, the second control motor 742 is a stepping motor or a servo motor. The second control motor 742 operates according to the second drive signal and rotates the multiple rotating bodies 741 via the drive belt 743.

[0102] When the second control motor 742 operates, the multiple rotating bodies 741 rotate and the support member 73 moves along the width direction D2.

[0103] The second base point detection sensor 744 detects the second detectable portion 73b formed on the support member 73. The second base point detection sensor 744 detects that the support member 73 is positioned at a predetermined reference position.

[0104] For example, the second base point detection sensor 744 is a transmissive photosensor or a reflective photosensor. The position D2 in the width direction of the contact surface 71a is adjusted by the amount of rotation of the second control motor 742 from the time the second detected part 73b is detected by the second base point detection sensor 744.

[0105] The offset adjustment mechanism 74 may be any other mechanism that converts the rotational motion of the output shaft of the second control motor 742 into the linear motion of the support member 73.

[0106] As the position of the support member 73 changes, the position in which the contact surface 71a restricts the sheet 9 in the width direction D2 changes.

[0107] Each of the straightening mechanisms 7 adjusts the degree of correction of the inclination angle θ1 of the sheet 9 by adjusting the angle of the contact surface 71a of the straightening member 71. Furthermore, each of the straightening mechanisms 7 adjusts the degree of correction of the offset amount X1 of the sheet 9 by adjusting the position D2 in the width direction of the support member 73.

[0108] In the following description, the adjustment value of the angle of the contact surface 71a in the tilt adjustment mechanism 72 will be referred to as the tilt adjustment value. Also, the adjustment value of the position of the support member 73 in the offset adjustment mechanism 74 will be referred to as the offset adjustment value.

[0109] In this embodiment, multiple correction parameters are set corresponding to multiple correction mechanisms 7. Each of the multiple correction parameters includes the tilt adjustment value and the offset adjustment value. The multiple correction parameters are stored in a secondary storage device 82.

[0110] In each of the aforementioned multiple correction parameters, the standard values ​​for the inclination adjustment value and the offset adjustment value are set in advance as initial values.

[0111] Each of the correction mechanisms 7 may be implemented with a configuration different from that shown in Figure 4. For example, each of the correction mechanisms 7 may include a turntable mechanism for correcting the tilt of the sheet 9 and a sliding mechanism for correcting the offset of the sheet 9.

[0112] The turntable mechanism holds the sheet 9 and rotates the held sheet 9. The slide mechanism slides the turntable mechanism in the width direction D2. In this case, the turntable mechanism temporarily stops transporting the sheet 9, and resumes transporting the sheet 9 after the slide mechanism has operated.

[0113] [Posture Correction Treatment] The transport control unit 8a causes the sheet transport device 3 to transport the sheet 9 in response to a print request. The transport control unit 8a and the image processing unit 8c perform posture correction processing while the sheet 9 is being transported by the sheet transport device 3.

[0114] For example, the transport control unit 8a and the image processing unit 8c execute the orientation correction process in parallel with the printing process when the print request occurs. For example, the transport control unit 8a and the image processing unit 8c execute the orientation correction process each time one or more sheets 9 are transported.

[0115] Below, an example of the procedure for the posture correction process will be described with reference to the flowchart shown in Figure 5.

[0116] In the following description, S1, S2, ... represent identification codes for multiple steps in the posture correction process. In the posture correction process, the process of step S1 is executed first.

[0117] Furthermore, the sheet 9 being transported along the main transport path 303 is referred to as the target sheet. The target sheet is the sheet 9 that is subject to detection of the sheet posture.

[0118] <Process S1> In process S1, the transport control unit 8a identifies the target path and target straightening mechanism corresponding to the target sheet. The target straightening mechanism is one of a plurality of straightening mechanisms 7 that the target sheet passes through.

[0119] The aforementioned target path is the path that the target sheet traveled before reaching the main transport path 303. The aforementioned target path includes information that identifies which of at least one of the preceding transport paths 302 it traveled through.

[0120] Here, the two combinations of the specific pre-transport path 302a and the supply path 301 and sub-transport path 304 are referred to as two combined paths. In this embodiment, when the target sheet passes through the specific pre-transport path 302a, the target path includes information that identifies which of the two combined paths it passed through.

[0121] That is, when the target orthodontic mechanism is a specific orthodontic mechanism 7a, the transport control unit 8a determines which of the plurality of combination paths the target sheet will pass through.

[0122] Furthermore, if the sheet transport device 3 has three or more pre-pre-transport paths, the target path is information that identifies which of the three or more pre-pre-transport paths the sheet traveled through.

[0123] After executing the process in step S1, the transport control unit 8a moves the process to step S2.

[0124] <Process S2> In step S2, the transport control unit 8a selects a target parameter corresponding to the target orthodontic mechanism from among a plurality of pre-set orthodontic parameters.

[0125] As described above, each of the plurality of orthodontic parameters includes the inclination adjustment value and the offset adjustment value. In this embodiment, the parameter corresponding to the specific orthodontic mechanism 7a among the plurality of orthodontic parameters includes two specific orthodontic parameters corresponding to the two combined paths.

[0126] Therefore, if the specific orthodontic mechanism 7a is the target orthodontic mechanism, the transport control unit 8a selects one of the two specific orthodontic parameters that corresponds to the target path as the target parameter.

[0127] After executing the process in step S2, the transport control unit 8a moves the process to step S3.

[0128] <Process S3> In step S3, the transport control unit 8a selects the following process depending on whether the target parameter is the same as or different from the current adjustment state in the target orthodontic mechanism.

[0129] If the target parameter differs from the current adjustment state of the target orthodontic mechanism, the transport control unit 8a moves the process to step S4. On the other hand, if the target parameter is the same as the current adjustment state of the target orthodontic mechanism, the transport control unit 8a moves the process to step S5.

[0130] <Process S4> In step S4, the transport control unit 8a operates the target correction mechanism to bring it into an adjusted state according to the target parameter.

[0131] Specifically, the transport control unit 8a outputs one or both of the first drive signal and the second drive signal corresponding to the target parameter to the target correction mechanism. As a result, the target correction mechanism is adjusted according to the target parameter.

[0132] After executing the process in step S4, the transport control unit 8a moves the process to step S5.

[0133] <Process S5> In step S5, the image processing unit 8c acquires read image data RD1 when the target sheet passes the detection position P1. This read image data RD1 is image data obtained for the target sheet by the line sensor 6.

[0134] After executing the process in step S5, the image processing unit 8c moves the process to step S6.

[0135] <Process S6> In step S6, the image processing unit 8c performs the posture detection process on the read image data RD1 obtained in step S5. This derives the detected sheet posture value for the target sheet.

[0136] In this embodiment, the detected seat posture includes the tilt angle θ1 and the offset amount X1 (see Figure 6). After executing the process in step S6, the image processing unit 8c moves the process to step S7.

[0137] <Process S7> In step S7, the transport control unit 8a selects the following process depending on whether the detected sheet posture value is within a preset tolerance range.

[0138] If the detected sheet posture value is within the allowable range, the transport control unit 8a proceeds to process S1. As a result, the processes from process S1 onward are executed for the new target sheet.

[0139] On the other hand, if the detected value of the seat posture falls outside the acceptable range, the transport control unit 8a moves the process to step S8.

[0140] <Process S8> In step S8, the transport control unit 8a corrects the target parameter according to the detected value of the sheet posture that falls outside the allowable range.

[0141] In other words, if the detected value of the inclination angle θ1 falls outside the allowable angle range, the transport control unit 8a corrects the inclination adjustment value of the target parameter according to the detected value of the inclination angle θ1.

[0142] Similarly, if the detected value of offset amount X1 falls outside the acceptable offset range, the transport control unit 8a corrects the offset adjustment value of the target parameter according to the detected value of offset X1.

[0143] The processing in step S8 updates the target parameter stored in the secondary storage device 82.

[0144] After executing the process in step S8, the transport control unit 8a moves the process to step S9.

[0145] <Process S9> In step S9, the transport control unit 8a selects the following process depending on whether the target sheet is the last sheet 9 to be transported in the printing process.

[0146] If the target sheet is not the last sheet 9, the transport control unit 8a moves the process to step S1. As a result, the processes from step S1 onward are executed for the new target sheet.

[0147] On the other hand, if the target sheet is the last sheet 9, the transport control unit 8a terminates the posture correction control.

[0148] As shown above, the transport control unit 8a identifies the target straightening mechanism 7 that the target sheet, which is transported along the main transport path 303, passes through (see step S1).

[0149] Furthermore, the transport control unit 8a corrects the target parameters corresponding to the target correction mechanism according to the detection result of the seat posture for the target seat (see step S8).

[0150] The tendency of the sheet's posture differs depending on the transport path of the sheet 9. By performing the posture correction control, it is possible to transport the sheet 9 in an appropriate posture along the main transport path 303, regardless of the transport path of the sheet 9.

[0151] Furthermore, if the target orthodontic mechanism is a specific orthodontic mechanism 7a, the transport control unit 8a determines which of the two combined paths the target sheet will pass through (see step S1).

[0152] Furthermore, the transport control unit 8a individually performs correction of the two specific correction parameters corresponding to the specific correction mechanism 7a for each of the two combined paths (see steps S2 and S8).

[0153] Therefore, the two specific correction parameters are appropriately set according to the tendency of the seat posture in each of the two combined paths.

[0154] [Differentiation] Next, the procedure for posture correction control in a modified image forming apparatus 10 will be described with reference to the flowchart shown in Figure 7. In the following description, the posture correction control in this modified example will be referred to as the control modification.

[0155] The deformation control example described above is performed in a procedure in which step S1a is added to the posture correction control shown in Figure 5. The differences between the deformation control example and the posture correction control shown in Figure 5 will be explained below.

[0156] In the deformation control example described above, the process of step S1a is executed first.

[0157] <Process S1a> In step S1a, the transport control unit 8a acquires target sheet data, which includes information about the type of target sheet. The target sheet data is included in the print request.

[0158] For example, the information on the type of target sheet includes one or more of the thickness, size, and weight of each sheet 9 transported in the print process corresponding to the print request.

[0159] After executing the process in step S1a, the transport control unit 8a moves the process to step S1.

[0160] <Process S1> The process of step S1 in this modified example is the same as the process of step S1 shown in Figure 5. After executing the process of step S1, the transport control unit 8a moves the process to step S2.

[0161] <Process S2> In step S2 of this modified example, the transport control unit 8a selects the target parameter corresponding to the target orthodontic mechanism from among the plurality of orthodontic parameters.

[0162] In this modified example, the multiple orthodontic parameters are set for each combination of multiple orthodontic mechanisms 7 and sheet types 9. As mentioned above, the sheet type 9 includes one or more of thickness, size, and weight.

[0163] In this modified example, the transport control unit 8a selects the target parameter from among the plurality of straightening parameters that corresponds to the combination of the target straightening mechanism and the type of target sheet.

[0164] After executing the process in step S2, the transport control unit 8a moves the process to step S3.

[0165] <Process S3~S9> The processes S3 to S9 in this modified example are the same as the processes S3 to S9 shown in Figure 5.

[0166] However, if the detected sheet posture value in step S7 is within the allowable range, the transport control unit 8a moves the process to step S1a. As a result, the processes from step S1a onward are executed for the new target sheet.

[0167] Similarly, in process S9, if the target sheet is not the last sheet 9, the transport control unit 8a moves the process to process S1a. As a result, the processing from process S1a onward is executed for the new target sheet.

[0168] As shown above, in this modified example, the transport control unit 8a acquires information on the type of target sheet (see step S1a).

[0169] Furthermore, in this modified example, the transport control unit 8a sets the correction value of the correction parameter of the target correction mechanism for each type of target sheet.

[0170] When this modified version is adopted, the same effects as when the image forming apparatus 10 is adopted can be obtained.

[0171] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0172] <Note 1> The main transport path is the passage for the sheets, Each of these is a passage for the aforementioned sheet, and there are multiple preceding transport paths that merge with the main transport path, A conveying mechanism that conveys the sheet along the plurality of preceding conveying paths and the main conveying path, Each of the above-mentioned multiple pre-transport paths is arranged to correct the sheet posture, which is one or both of the inclination angle and widthwise offset of the sheet being transported, A posture detection device for detecting the posture of the sheet being transported along the main transport path, A sheet transport device comprising: a control device that identifies a target corrective mechanism from among the plurality of corrective mechanisms that a target sheet transported along the main transport path passes through, and corrects the corrective parameters of the target corrective mechanism according to the detection result of the sheet posture for the target sheet.

[0173] <Note 2> The system includes a plurality of pre-pre-conveyor paths that are supply paths for the sheet to a specific pre-conveyor path, which is one of the plurality of pre-conveyor paths, The plurality of straightening mechanisms include specific straightening mechanisms arranged in the specific preceding transport path, The control device, when the target correction mechanism is the specific correction mechanism, determines which of the multiple combination paths, each being a combination of the specific pre-transport path and the multiple pre-pre-transport paths, the target sheet will pass through. Furthermore, the control device performs the correction of the correction parameters of the specific correction mechanism individually for each of the plurality of combination paths, as described in Appendix 1 of the sheet transport device.

[0174] <Note 3> The aforementioned multiple pre-pre-transport paths are The supply path which is the source of the branching to the aforementioned multiple upstream transport paths, The sheet conveying device according to Appendix 2, further comprising a secondary conveying path that branches off from the main conveying path and merges with the specified preceding conveying path.

[0175] <Note 4> The sheet transport device according to any one of the appendices 1 to 3, wherein the control device acquires information on the type of sheet and sets correction values ​​for the orthodontic parameters of the target orthodontic mechanism for each type of target sheet.

[0176] <Note 5> A sheet transport device described in any one of the above appendices 1 to 4, An image forming apparatus comprising: a printing device that forms an image on a sheet conveyed by the aforementioned sheet conveying device. [Explanation of Symbols]

[0177] 4: Printing device 5:Drying device 6: Line sensor 7: Correction mechanism 7a: Specific correction mechanism 8: Control device 10: Image forming apparatus 30: Feeding mechanism 31: Feed roller pair 32: Front-stage conveyor rollers 33: First belt conveying device 34: Second belt conveying device 35: Discharge roller vs. 36: Sub-conveyor roller pair 70: Diagonal conveying mechanism 71: Orthodontic member 72: Tilt adjustment mechanism 74: Offset adjustment mechanism 301: Feeding route 302: Pre-transport path 302a: Specific pre-transport route 303: Main transport route 304: Secondary transport route

Claims

1. The main transport path is the passage for the sheets, Each of these is a passage for the aforementioned sheet, and there are multiple preceding transport paths that merge with the main transport path, A conveying mechanism that conveys the sheet along the plurality of preceding conveying paths and the main conveying path, Each of the above-mentioned multiple pre-transport paths is arranged to correct the sheet posture, which is one or both of the inclination angle and widthwise offset of the sheet being transported, A posture detection device for detecting the posture of the sheet being transported along the main transport path, A sheet transport device comprising: a control device that identifies a target corrective mechanism from among the plurality of corrective mechanisms that a target sheet transported along the main transport path passes through, and corrects the corrective parameters of the target corrective mechanism according to the detection result of the sheet posture for the target sheet.

2. The system includes a plurality of pre-pre-conveyor paths that are supply paths for the sheet to a specific pre-conveyor path, which is one of the plurality of pre-conveyor paths, The plurality of straightening mechanisms include specific straightening mechanisms arranged in the specific preceding transport path, The control device, when the target correction mechanism is the specific correction mechanism, determines which of the multiple combination paths, each being a combination of the specific pre-transport path and the multiple pre-pre-transport paths, the target sheet will pass through. Furthermore, the control device performs correction of the correction parameters of the specific correction mechanism individually for each of the plurality of combination paths, as described in claim 1.

3. The aforementioned multiple pre-pre-transport paths are The supply path which is the source of the branching to the aforementioned multiple upstream transport paths, The sheet conveying device according to claim 2, further comprising a secondary conveying path that branches off from the main conveying path and merges with the specified preceding conveying path.

4. The sheet transport device according to claim 1 or 2, wherein the control device acquires information on the type of sheet and sets correction values ​​for the orthodontic parameters of the target orthodontic mechanism for each type of target sheet.

5. A sheet conveying device according to claim 1 or claim 2, An image forming apparatus comprising: a printing device that forms an image on a sheet conveyed by the aforementioned sheet conveying device.

Images