Reading device and image forming device

Abstract

To provide a reading device that appropriately detects an edge position of a medium and appropriately corrects the attitude (registration amount and skew amount) of the medium, and an image forming apparatus.SOLUTION: An image forming apparatus comprises: a sheet conveying unit 210 of a main control unit 301 that conveys a medium; one or more reading units that read a sheet conveyed by the sheet conveying unit; and a reading parameter calculation unit included in a sheet attitude detection unit 220 that adjusts and updates setting values of the one or more reading units based on a result of comparison between read values of a background area of the sheet read by the one or more reading units and a preset read value of a background area of a sheet of the same type. The one or more reading units perform reading of the medium conveyed by the sheet conveying unit again based on the adjusted and updated setting values.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a reading device and an image forming device. [Background technology]

[0002] In image forming devices (sheet-fed machines), a technology is already known that detects the edge position of a medium from the reading results obtained by reading the medium while it is being transported using a contact image sensor (CIS) or the like, and then detects and corrects the medium's posture (resist amount and skew amount).

[0003] Conventionally, the CIS of an image forming device adjusts the light intensity and gain according to the medium to prevent white saturation when reading the background of the medium. Conventionally, the CIS of an image forming device sets parameters (setting values) for the light intensity and gain according to the medium type set by the user before starting a print job. Therefore, in an environment where parameters according to the medium are set, the edge position of the medium can be detected without any problems.

[0004] Patent Document 1 discloses a configuration in which an edge sensor is positioned at a predetermined distance from the imaging unit located on the most upstream side so that light adjustment of the imaging unit located on the most upstream side is completed when the edge sensor detects the leading edge of the transported medium. This solves the problem in Patent Document 1 that light adjustment is not completed in time when the imaging target switches between the medium and the transport belt, making it impossible to capture an image with an appropriate amount of light. Summary of the Invention [Problem to be solved by the invention]

[0005] However, if there are differences or fluctuations in the environment when reading is actually performed (for example, a decrease in the LED light intensity due to aging or temperature fluctuations during continuous printing) compared to the environment when the parameters for the media were determined (for example, at the time of factory shipment), there is a problem in that a discrepancy occurs in the reading results of the CIS, making it impossible to properly detect the edge position of the media and to properly correct the media's posture (resist amount and skew amount).

[0006] The present invention has been made in view of the above, and has an object to appropriately detect the edge position of a medium and appropriately correct the attitude (resist amount and skew amount) of the medium. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present invention provides a medium transport unit that transports a medium; a plurality of the medium conveying units are provided along the conveying direction of the medium conveyed by the medium conveying unit, The medium transported by the medium transport unit is read. Complex Number reading section and , complex Based on the result of comparing the read values ​​of the background area of ​​the medium read by the number of reading units with the read values ​​of the background area of ​​a predetermined medium of the same type, , complex a setting value calculation unit that adjusts and updates the setting values ​​of the number of reading units, The setting value calculation unit adjusts and updates the setting values ​​of the first reading unit and the setting values ​​of the other reading units located downstream of the first reading unit based on a comparison result between a read value of a background area of ​​the medium read by a first reading unit located upstream in the transport direction among the plurality of reading units and a read value of a background area of ​​a medium of the same type that has been previously set. The reading unit may read the medium transported by the medium transport unit again based on the adjusted and updated setting values. [Effects of the Invention]

[0008] According to the present invention, it is possible to appropriately detect the edge position of the medium and appropriately correct the attitude of the medium (resist amount and skew amount). [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 illustrates an example of a configuration of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of the registration imaging unit. [Figure 3] FIG. 3 is a block diagram showing an example of the hardware configuration of the registration imaging unit. [Figure 4] FIG. 4 is a diagram for explaining an example of a process for detecting the registration amount and skew amount of a sheet by a registration / imaging unit. [Figure 5] FIG. 5 is a functional block diagram showing the functional configuration of the paper transport control unit and the image formation control unit. [Figure 6] FIG. 6 is a functional block diagram showing the functional configuration of the paper orientation detection unit. [Figure 7] FIG. 7 is a flowchart showing the outline of the flow of the reading control process. [Figure 8] FIG. 8 is a flowchart showing the outline of the flow of the read parameter readjustment process. [Figure 9] FIG. 9 is a flowchart showing an outline of the flow of the paper setting error detection process according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a reading device and an image forming device will be described in detail with reference to the accompanying drawings.

[0011] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of an image forming apparatus 10 according to a first embodiment. The image forming apparatus 10 according to this embodiment is a line-head type sheet-fed perfecting press or the like. The image forming apparatus 10 according to this embodiment also functions as a media reading device. In this embodiment, as shown in FIG. 1, the image forming apparatus 10 includes a registration / imaging unit 1, a pre-coating unit 2, a paper feed unit 3, a drying / cooling unit 4, an inversion unit 5, and a paper discharge unit 6.

[0012] The paper feed unit 3 transports paper, which is an example of a medium, one sheet at a time from right to left in Fig. 1 into the image forming apparatus 10 and feeds it to the registration / imaging unit 1. The pre-coating unit 2 applies an undercoat liquid to the paper fed into the image forming apparatus 10 by the paper feed unit 3, making it easier for the ink to adhere to the paper.

[0013] The registration and imaging unit 1 prints an image on the paper using a line head while adsorbing the paper to the drum. The registration and imaging unit 1 also detects and corrects the paper's posture (amount of registration and amount of skew). The registration and imaging unit 1 uses a gripper (paper transport claw) to transfer the paper from the cylinder 103 (see Figure 2) to the drum 102 (see Figure 2).

[0014] The drying and cooling unit 4 dries the ink adhering to the paper. The drying and cooling unit 4 also cools the paper that has become hot due to the drying of the ink. When an image is to be printed on the back side of the paper, the reversing unit 5 performs a switchback reversal of the paper and transports it to the registration and imaging unit 1. The paper discharge unit 6 discharges the paper with the image printed on it from the image forming device 10 and stacks it.

[0015] 2 is a diagram showing an example of the configuration of the registration / imaging unit 1. Next, an example of the configuration of the registration / imaging unit 1 will be described with reference to FIG.

[0016] The registration / imaging unit 1 includes an image forming section 101, a drum 102, cylinders 103 and 104, a transport roller 105, a registration / skew correction roller 106, CIS (Contact Image Sensors) 107-1 to 107-3 as a reading section, paper leading edge detection sensors 108-1 and 108-2, and a scanner 109.

[0017] The registration / imaging unit 1 generates a reference trigger when the leading edge of a sheet of paper (an example of a print medium) is detected by the paper leading edge detection sensor 108-1, and detects and corrects the paper posture (registration amount and skew amount) using the CISs 107-1 to 107-3 and the registration / skew correction roller 106. In this embodiment, the CISs 107-1 to 107-3 are arranged below the paper transport path, but the present invention is not limited to this and they may be arranged above the paper transport path.

[0018] The drum 102 and cylinders 103 and 104 are connected and driven by gears. The drum 102 and cylinders 103 and 104 are each equipped with a gripper that opens and closes mechanically, and the gripper holds the leading edge of the paper while transporting it. The registration and imaging unit 1 controls the transport roller 105 based on the relationship between the timing at which the leading edge of the paper is detected by the paper leading edge detection sensor 108-2 and the signal output from the encoder of the drum 102, and adjusts the timing at which the paper is transported to the gripper of cylinder 103, which is installed upstream in the paper transport direction.

[0019] The registration and imaging unit 1 also detects the rotation speed, rotation angle, and rotation position of the surface of the drum 102 based on a signal output from the encoder of the drum 102. For example, the registration and imaging unit 1 detects the rotation speed, rotation angle, and rotation position of the surface of the drum 102 using an encoder disk provided on the rotation shaft of the drum 102 or an encoder linear scale provided on the surface of the drum 102. The registration and imaging unit 1 then controls the suction timing and suction amount of the pump based on the detection results of the rotation speed, rotation angle, and rotation position of the surface of the drum 102, thereby adsorbing the paper onto the surface of the drum 102 through holes provided in the surface of the drum 102 and transporting the paper.

[0020] Image forming unit 101 is an example of an image printing unit that forms an image on paper, and has multiple print heads (recording heads). In this embodiment, image forming unit 101 has print heads for each of CMYK, and forms an image on paper by ejecting ink from the print heads onto the paper. Also, in this embodiment, image forming unit 101 performs blank ejection of ink from each of the print heads for CMYK onto blank ejection receiving member 102a (e.g., a sponge) provided on drum 102.

[0021] The scanner 109 is provided on the drum 102 and reads the object to be read, such as paper, an image formed on paper, or the surface of the drum 102. Since the scanner 109 is disposed at a distance from the object to be read, it is preferable that the scanner 109 be a reduction optical system. If the width of the scanner 109 in the main scanning direction (pixels in the main scanning direction) is insufficient compared to the width of the drum 102 in the main scanning direction, the registration / imaging unit 1 reads all of the object to be read that exists in the main scanning direction of the drum 102 by arranging multiple scanners 109 in a staggered pattern in the main scanning direction of the drum 102.

[0022] Fig. 3 is a block diagram showing an example of the hardware configuration of the registration / imaging unit 1. Next, an example of the hardware configuration of the registration / imaging unit 1 included in the image forming apparatus according to the present embodiment will be described with reference to Fig. 3.

[0023] In this embodiment, the registration / imaging unit 1 (an example of a reading device) has a main control unit 301, a drum rotation encoder 302, paper leading edge detection sensors 108-1 and 108-2, a print timing sensor 304, a reading timing sensor 305, a drum drive motor 306, a print head 307, CISs 107-1 to 107-3, a scanner 109, and drive circuits 310 to 313, as shown in FIG.

[0024] The main control unit 301 controls the entire image forming apparatus 10. In this embodiment, the main control unit 301 includes a paper transport control unit 200, an image formation control unit 300, and a scanner control unit 400.

[0025] The paper transport control unit 200, the details of which will be described later, executes a process for detecting the attitude of the paper (the amount of registration and the amount of skew).

[0026] The image forming control unit 300, details of which will be described later, corrects the image printing position and prints the image data based on the correction error (correction residual), which is the paper attitude (resistance amount and skew amount) calculated after correcting the paper attitude based on the paper attitude (resistance amount and skew amount) detected by the paper conveying control unit 200.

[0027] 4 is a diagram for explaining an example of the detection process of the attitude of the paper (the amount of registration and the amount of skew) by the registration / imaging unit 1. Next, an example of the detection process of the attitude of the paper (the amount of registration and the amount of skew) by the registration / imaging unit 1 will be described with reference to FIG.

[0028] Paper transport control unit 200 reads the outside of the paper range and the paper using CIS 107-1 to 107-3 arranged on the paper transport path, and detects the edge position of paper X based on the difference between the CIS read values ​​(density or reflectance) of the outside of the paper range and the paper. In this case, paper transport control unit 200 may detect edge positions E1 and E2 based on the CIS read values ​​of all RGB channels of CIS 107-1 to 107-3, or may detect the edge positions based on the CIS read value of any one channel.

[0029] 4, the paper transport control unit 200 reads the outside of the paper range and paper X using CIS 107-1 and 107-2, and detects edge positions E1 and E2 of paper X based on the difference between the CIS read values ​​of the outside of the paper range and paper X. Then, the paper transport control unit 200 detects the attitude of paper X (resistance amount and skew amount) based on the edge positions E1 and E2 of paper X, and calculates the correction amount for the attitude of paper X (resistance amount and skew amount). Next, the paper transport control unit 200 corrects the attitude of paper X (resistance amount and skew amount) using the registration / skew correction roller 106 based on the calculated correction amount.

[0030] 4, after performing the correction operation (after correction), the paper transport control unit 200 reads the outside of the paper range and paper X using CIS 107-2 and 107-3, and detects edge positions E3 and E2' of paper X based on the difference between the CIS read values ​​of the outside of the paper range and paper X. Then, based on the edge positions E3 and E2' of paper X, the paper transport control unit 200 again detects the correction error (correction residual), which is the attitude of paper X (resist amount and skew amount).

[0031] Next, the image formation control unit 300 controls the drive circuit 311 of the print head 307 based on the amount of correction error (amount of correction residual error) to move the position on the paper X where the image is to be formed.

[0032] 3, paper transport control unit 200 controls CIS 107-1 to 107-3 to read the paper and transfers the CIS read values ​​of the background area of ​​the paper to scanner control unit 400. Therefore, in this embodiment, CIS 107-1 to 107-3 function as an example of a second reading unit that reads the background area of ​​the paper.

[0033] The scanner control unit 400 calculates a correction amount for writing an image by the image forming unit 101 based on the difference between the read value of the gradation chart read by the scanner 109 (hereinafter referred to as the scanner read value, an example of the first read value) and the density or reflectance of the image instructed by the write control unit. Here, the scanner read value is the read value (for example, at least one of the density and reflectance of the gradation chart) by the scanner 109 of the gradation chart (an example of an image for gradation adjustment) formed on paper by the print head 307.

[0034] The drum rotation encoder 302 is an encoder used to detect the rotation speed, rotation angle, rotation position, etc. of the drum 102. It is preferable to install the drum rotation encoder 302 in multiple locations to eliminate eccentricity unevenness of the drum 102. For example, the main control unit 301 detects the rotation speed, rotation angle, rotation position, etc. of the drum 102 using the drum rotation encoder 302, which detects an encoder disk attached to the rotation shaft of the drum 102 and an encoder linear scale attached to the surface of the drum 102. Furthermore, the drum rotation encoder 302 is preferably an encoder that can output a Z-phase signal in addition to an A-phase or B-phase signal to detect the home position HP, which is the reference position for the rotation of the drum 102. Alternatively, the home position HP may be detected using a sensor (home position sensor) separate from the drum rotation encoder 302.

[0035] The paper leading edge detection sensors 108-1 and 108-2 are reflective sensors or the like, and detect the leading edge of the paper in the paper transport direction.

[0036] Print timing sensor 304 is used to control the timing of ink ejection from print head 307. Main control unit 301 ejects ink from print head 307 based on the pulse signal output from drum rotation encoder 302, using as a reference the timing when paper is detected by print timing sensor 304 (for example, the timing when paper passes directly below print timing sensor 304). Alternatively, main control unit 301 may eject ink from print head 307 based on the timing when the leading edge of the paper is detected by paper leading edge detection sensors 108-1 and 108-2, without using print timing sensor 304. However, it is preferable that the sensor used to control the timing of ink ejection from print head 307 be installed near print head 307.

[0037] The read timing sensor 305 is used to control the timing of reading an image by the scanner 109. The scanner control unit 400 starts reading an image by the scanner 109 based on the pulse signal output from the drum rotation encoder 302, using as a reference the timing when the paper is detected by the read timing sensor 305 (for example, the timing when the paper passes directly below the read timing sensor 305). Alternatively, the scanner control unit 400 may read an image by the scanner 109 based on the timing when the leading edge of the paper is detected by the paper leading edge detection sensors 108-1 and 108-2, without using the read timing sensor 305. However, it is preferable that the sensor used to control the timing of reading an image by the scanner 109 is set near the scanner 109.

[0038] The drum drive motor 306 is an AC servo motor or the like, and is the drive source for the drum 102. The main control unit 301 outputs a drive signal to a drive circuit 310 based on a pulse signal output from the drum rotation encoder 302. The drum drive motor 306 rotates the drum 102 based on the drive signal input from the drive circuit 310.

[0039] The print head 307 is an inkjet print head or the like, and forms an image on paper by ejecting droplets of ink or the like onto the paper. The print head 307 is a line head for each of the colors CMYK. The main control unit 301 determines the timing for ejecting ink from the print head 307 based on signals input from the print timing sensor 304 and the drum rotation encoder 302, and outputs a drive signal corresponding to the drive waveform of the print head 307 to the drive circuit 311 based on image data of the image to be formed. The print head 307 ejects ink onto the paper based on the drive signal input from the drive circuit 311.

[0040] CIS 107-1 to 107-3 are sensors used to detect the edge position (conveyance position) of the paper. Main control unit 301 determines the timing for CIS 107-1 to 107-3 to read the paper based on the timing at which paper leading edge detection sensors 108-1 and 108-2 detect the leading edge of the paper. Next, main control unit 301 determines paper reading conditions for CIS 107-1 to 107-3 based on the determined timing, and outputs drive signals according to the reading conditions to drive circuit 312. CIS 107-1 to 107-3 read the paper based on the drive signals output from drive circuit 312.

[0041] Scanner 109 reads a gradation chart or the like formed on paper. Main control unit 301 determines the timing at which scanner 109 reads a gradation chart or the like based on signals input from read timing sensor 305 and drum rotation encoder 302. Main control unit 301 also determines reading conditions for scanner 109 based on the reading target, such as a gradation chart, and outputs a drive signal according to the reading conditions to drive circuit 313. Scanner 109 reads the reading target, such as a gradation chart, based on the drive signal output from drive circuit 313.

[0042] Next, the functional configuration of the paper transport control unit 200 and the image formation control unit 300 in the main control unit 301 that controls the image forming apparatus 10 will be described.

[0043] FIG. 5 is a functional block diagram showing the functional configuration of the paper transport control unit 200 and the image formation control unit 300. As shown in FIG.

[0044] First, the functional configuration of the paper transport control unit 200 will be described.

[0045] The paper transport control unit 200 includes a paper transport unit 210 , a paper orientation detection unit 220 , a paper orientation correction amount determination unit 230 , a paper orientation correction unit 240 , and a correction residual storage unit 250 .

[0046] The paper transport unit 210 is a medium transport unit that controls the transport rollers 105 and the like to transport the paper sheets one by one.

[0047] The paper attitude detection unit 220 is a medium attitude calculation unit that detects the attitude of the paper (the amount of registration and the amount of skew) relative to the paper transport reference axis. More specifically, the paper attitude detection unit 220 detects the edge position of the paper based on the difference between the read values ​​(hereinafter referred to as CIS read values; an example of second read values, such as density or reflectance) of the outside of the paper range and the paper using CISs 107-1 and 107-2 arranged on the paper transport path. Then, the paper attitude detection unit 220 detects the paper attitude (the amount of registration and the amount of skew) based on the edge position of the paper.

[0048] The paper attitude correction amount determination unit 230 is a medium attitude correction amount determination unit, and determines the amount of correction for the paper attitude based on the paper attitude (resist amount and skew amount) detected by the paper attitude detection unit 220.

[0049] The paper attitude correction unit 240 is a medium attitude correction unit that performs paper attitude correction by correcting the paper attitude (resist amount and skew amount) using the resist / skew correction roller 106 based on the correction amount determined by the paper attitude correction amount determination unit 230.

[0050] In addition, after the correction operation (after correction), the paper attitude detection unit 220 detects the attitude of the paper (the amount of registration and the amount of skew) relative to the paper transport reference axis. More specifically, after the correction operation (after correction), the paper attitude detection unit 220 reads the outside of the paper range and the paper using CIS 107-2, 107-3 arranged on the paper transport path, and detects the edge position of the paper based on the difference between the read values ​​of the outside of the paper range and the paper (hereinafter referred to as CIS read values; an example of second read values; for example, density or reflectance). Then, the paper attitude detection unit 220 again detects the paper attitude (the amount of registration and the amount of skew) (hereinafter referred to as correction residual) based on the edge position of the paper.

[0051] The correction residual storage unit 250 stores the correction residual detected by the paper orientation detection unit 220 .

[0052] Next, the functional configuration of the image formation control unit 300 will be described.

[0053] The image formation control unit 300 includes an image printing control unit 340 and an image printing position correction unit 320.

[0054] Image printing control unit 340 controls image forming unit 101 in accordance with a print timing instruction sent from paper transport unit 210 of paper transport control unit 200 , and prints image data 330 .

[0055] Image printing position correction unit 320 acquires the correction residual stored in correction residual storage unit 250 of paper transport control unit 200. Then, image printing position correction unit 320 corrects the image printing position in image printing control unit 340 based on the correction residual. More specifically, image printing position correction unit 320 controls drive circuit 311 of print head 307 based on the correction residual to move the position where the image is formed on the paper.

[0056] Next, the paper orientation detection unit 220 will be described in detail.

[0057] Fig. 6 is a functional block diagram showing the functional configuration of paper orientation detection unit 220. As shown in Fig. 6, paper orientation detection unit 220 includes a reading timing detection unit 221, a first reading control unit 222, a second reading control unit 223, a third reading control unit 224, a reading parameter calculation unit 225, a reading parameter storage unit 226, a paper orientation calculation unit 227, and a paper orientation storage unit 228.

[0058] The reading timing detection unit 221 controls the paper leading edge detection sensors 108-1 and 108-2 and the like to detect the reading timing.

[0059] The first reading control unit 222 controls the CIS 107-1 to read the image.

[0060] The second reading control unit 223 controls the CIS 107-2 disposed downstream of the CIS 107-1 in the paper transport direction to read the image.

[0061] The third reading control unit 224 controls the CIS 107-3 disposed downstream of the CIS 107-2 in the paper transport direction to read the image.

[0062] The reading parameter calculation unit 225 is a setting value calculation unit that calculates reading parameters (light intensity, gain, exposure time, shading correction coefficient, etc.) that are setting values ​​according to the reading result of CIS 107-1. The reading parameter (light intensity) is the light intensity when CIS 107-1 reads. The reading parameter (gain) is the gain amount of the color component when CIS 107-1 reads. The reading parameter (exposure time) is the exposure time when CIS 107-1 reads. The reading parameter (shading correction coefficient) is the shading correction coefficient when CIS 107-1 reads.

[0063] The reading parameter storage unit 226 is a reading parameter storage unit that stores past or standard (for example, factory default) reading parameters for each paper type.

[0064] The paper attitude calculation unit 227 calculates the attitude of the paper (the amount of registration and the amount of skew) according to the results of reading by the CIS 107-1 to CIS 107-3.

[0065] The paper orientation storage unit 228 stores the orientation of the paper (the amount of registration and the amount of skew).

[0066] Next, the flow of the reading control process by the paper transport control unit 200 will be described.

[0067] 7 is a flowchart showing the flow of the reading control process. As shown in Fig. 7, reading parameter calculation unit 225 of paper transport control unit 200 acquires reading parameters (light intensity, gain, exposure time, shading correction coefficient, etc.) corresponding to the paper of CIS 107-1 to CIS 107-3 from a storage unit, and sets them in an adjustment unit such as a register (step S1).

[0068] When reading paper that has not been set by the user, the paper transport control unit 200 sets, in the adjustment unit, reading parameters that do not cause white saturation, assuming that the paper is colored paper, for example.

[0069] Furthermore, in the subsequent flow, the reading parameters can be automatically adjusted online (while the paper is being transported), so the user does not need to input paper information in advance.

[0070] Next, first reading control section 222 of paper transport control section 200 executes a pre-scan to read the paper using CIS 107-1 in accordance with the reading timing notified by reading timing detection section 221 (step S2).

[0071] Next, the reading parameter calculation unit 225 of the paper conveyance control unit 200 readjusts the reading parameters of the CISs 107-1 to 107-3 based on the reading result of the CIS 107-1 (step S3). The readjustment process of the reading parameters in step S3 will be described in detail later.

[0072] Next, when the (same) paper is transported and straddles CIS107-1 and CIS107-2, the first reading control unit 222 and the second reading control unit 223 of the paper transport control unit 200 read the (same) paper using CIS107-1 and CIS107-2 using the reading parameters readjusted in step S3 (step S4).

[0073] Next, the paper attitude correction unit 240 of the paper conveying control unit 200 performs paper attitude correction by correcting the paper attitude (resist amount and skew amount) using the resist / skew correction roller 106 based on the correction amount determined by the paper attitude correction amount determination unit 230 (step S5).

[0074] Next, when the (same) paper is transported and straddles CIS107-2 and CIS107-3, the second reading control unit 223 and the third reading control unit 224 of the paper transport control unit 200 read the (same) paper using CIS107-2 and CIS107-3 using the reading parameters readjusted in step S3 (step S6).

[0075] Next, the read parameter readjustment process in step S3 will be described in detail.

[0076] Here, FIG. 8 is a flowchart showing the outline of the flow of the read parameter readjustment process.

[0077] 8, the reading parameter calculation unit 225 of the paper conveyance control unit 200 calculates the reading value of the paper background area from the reading result of the CIS 107-1 (step S11). Note that it is desirable to calculate the reading value of the paper background area by averaging it over a predetermined main scanning range and sub-scanning range.

[0078] Next, the reading parameter calculation unit 225 of the paper conveyance control unit 200 checks whether the reading value of CIS 107-1 calculated in step S11 is included in the range X1 to X2 [digit] (step S12). The range X1 to X2 [digit] is, for example, the reading value of the background area of ​​the same type of paper obtained in the environment when the reading parameters set in CIS 107-1 in step S1 were determined (for example, at the time of shipping from the factory).

[0079] When the reading parameter calculation unit 225 of the paper transport control unit 200 determines that the read value of the CIS 107-1 is within the range X1 to X2 [digits] (Yes in step S12), the process ends.

[0080] On the other hand, if the reading parameter calculation unit 225 of the paper transport control unit 200 determines that the read value of the CIS 107-1 is not within the range X1 to X2 [digits] (No in step S12), the process proceeds to step S13.

[0081] In step S13, the reading parameter calculation unit 225 of the paper transport control unit 200 recalculates the reading parameters of the CIS 107-1 in accordance with the reading value of the CIS 107-1.

[0082] For example, if the read value of CIS 107-1 falls below the range X1 to X2 [digits], the read parameter calculation unit 225 increases one or more of the read parameters (light intensity, gain, exposure time, shading correction coefficient, etc.) to a value greater than the value set for CIS 107-1 in step S1, depending on the degree of the fall. Specifically, if the read value of CIS 107-1 is 50% of the range X1 to X2 [digits], the read parameter calculation unit 225 doubles the light intensity per unit time, for example.

[0083] The reading parameter storage unit 226 stores the reading parameters recalculated by the reading parameter calculation unit 225. The storage unit preferably has an area capable of storing the reading parameters of CIS107-1 to CIS107-3 for at least the past several times and standard (for example, factory default) reading parameters for each paper type.

[0084] The reading parameter calculation unit 225 of the paper conveyance control unit 200 sets the recalculated reading parameters in the control register of CIS 107-1. Note that the control registers of CIS 107-2 and CIS 107-3 may be set with the same values ​​as the reading parameters recalculated in accordance with the read values ​​of CIS 107-1 (the recalculated reading parameters of CIS 107-1), or may be set with different values ​​that take into account the recalculated reading parameters of CIS 107-1, rather than the values ​​set by CIS 107-2 and CIS 107-3 in step S1.

[0085] The reading parameters recalculated in step S13 may be set as the pre-scan reading parameters for the next and subsequent print jobs that read the same type of paper. This eliminates the need to adjust and update the reading parameters, reducing processing time and enabling high-speed reading.

[0086] Thus, according to this embodiment, even if there are differences or variations in the environment when reading is actually performed (for example, a decrease in the LED light intensity due to aging or temperature fluctuations during continuous printing) compared to the environment when the parameters for the medium were determined (for example, at the time of factory shipment), the CIS reading results can be stabilized, the edge position of the medium can be properly detected, and the attitude of the medium (resist amount and skew amount) can be properly corrected.

[0087] Furthermore, according to this embodiment, in a configuration in which multiple CISs are used to detect the paper posture (resistance amount and skew amount), a first CIS located upstream in the paper transport direction detects the color and brightness of the paper, and based on the results, readjusts the light intensity and gain of the first CIS and a second CIS located downstream of the first CIS. This makes it possible to stabilize the CIS reading results, properly detect the paper edge position, and properly correct the paper posture (resistance amount and skew amount), even if there are differences or fluctuations in the environment when the actual reading is performed compared to the environment when the parameters for the paper were determined (e.g., at the time of factory shipment).

[0088] Furthermore, according to this embodiment, even when reading paper that has not been set by the user, parameters can be automatically adjusted online (while the paper is being transported), so the user does not need to input paper information in advance, and no paper waste occurs due to parameter adjustment.

[0089] The program executed by image forming apparatus 10 of this embodiment is provided by being pre-installed in a ROM (Read Only Memory) or the like. The program executed by image forming apparatus 10 of this embodiment may be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk).

[0090] Furthermore, the program executed by image forming apparatus 10 of the present embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Also, the program executed by image forming apparatus 10 of the present embodiment may be provided or distributed via a network such as the Internet.

[0091] The program executed by the image forming apparatus 10 of this embodiment has a modular structure including each of the above-mentioned parts (main control unit 301), and in terms of actual hardware, a CPU (Central Processing Unit), which functions as an example of a processor, reads and executes the program from the ROM, thereby loading each of the above-mentioned parts onto the main memory device and generating the main control unit 301 on the main memory device.

[0092] (Second embodiment) Next, a second embodiment will be described.

[0093] The second embodiment differs from the first embodiment in that it detects and notifies users of incorrect paper loading. In the following description of the second embodiment, the same parts as those in the first embodiment will be omitted, and only the differences from the first embodiment will be described.

[0094] Fig. 9 is a flowchart showing the outline of the flow of the paper setting error detection process according to the second embodiment. Note that the paper setting error detection process shown in Fig. 9 is preferably performed before the readjustment process of the reading parameters described with reference to Fig. 8.

[0095] 9, the reading parameter calculation unit 225 of the paper conveyance control unit 200 calculates the reading value of the paper background area from the reading result of the CIS 107-1 (step S21). Note that it is desirable to calculate the reading value of the paper background area by averaging it over a predetermined main scanning range and sub-scanning range.

[0096] Next, the reading parameter calculation unit 225 of the paper conveyance control unit 200 checks whether the read value of CIS 107-1 calculated in step S21 is included in the range X3 to X4 [digits] (step S22). The range X3 to X4 [digits] is wider than the range X1 to X2 [digits] shown in step S12, for example, and is the range that the read value of CIS 107-1 can take when the paper settings are correctly implemented.

[0097] When the reading parameter calculation unit 225 of the paper transport control unit 200 determines that the read value of the CIS 107-1 is within the range X3 to X4 [digits] (Yes in step S22), the process ends.

[0098] On the other hand, if the reading parameter calculation unit 225 of the paper transport control unit 200 determines that the read value of the CIS 107-1 is not within the range X3 to X4 [digits] (No in step S22), the process proceeds to step S23.

[0099] In step S23, the reading parameter calculation unit 225 of the paper transport control unit 200 notifies the user via an operation panel or buzzer (not shown) that the paper or paper settings may be different from what the user intended, i.e., that the paper settings are incorrect.

[0100] The user may be able to set in advance whether or not to receive a notification of improper paper settings, which allows the user to choose not to be notified even when improper paper settings occur.

[0101] As described above, according to this embodiment, the CIS 107-1 determines whether the paper is different from the paper settings based on the read value of the background area of ​​the paper, and if the paper is different, notifies the user that the paper is set incorrectly. By notifying the user of the possibility of an operational error, damage to the device and resources can be minimized.

[0102] In the above embodiment, the image forming apparatus of the present invention is described as being applied to a multifunction peripheral having at least two of the functions of a copy function, a printer function, a scanner function, and a facsimile function, but the present invention can be applied to any image forming apparatus such as a copier, printer, scanner device, or facsimile device. [Explanation of symbols]

[0103] 10 Media reading device, image forming device 101 Image printing unit 107-1~107-3 Reading unit 210 Media transport unit 220 Media attitude calculation unit 225 Setting value calculation unit 226 Setting value memory section 230 Media attitude correction amount determination unit 240 Media posture correction section [Prior art documents] [Patent documents]

[0104] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-216033

Claims

1. a medium transport unit that transports the medium; a plurality of reading units provided along a transport direction of the medium transported by the medium transport unit, the reading units reading the medium transported by the medium transport unit; a setting value calculation unit that adjusts and updates setting values ​​of the plurality of reading units based on a comparison result between read values ​​of the background area of ​​the medium read by the plurality of reading units and read values ​​of the background area of ​​a predetermined medium of the same type; Equipped with the setting value calculation unit adjusts and updates the setting value of a first reading unit and the setting values ​​of other reading units located downstream of the first reading unit based on a comparison result between a read value of a background area of ​​the medium read by a first reading unit located upstream in the transport direction among the plurality of reading units and a read value of a background area of ​​a predetermined medium of the same type; the plurality of reading units re-reading the medium transported by the medium transport unit based on the adjusted and updated setting values; A reading device characterized by:

2. The setting values ​​of the plurality of reading units are light intensities, the set value calculation unit adjusts and updates the light intensities of the plurality of reading units; 2. The reading device according to claim 1, wherein:

3. The setting values ​​of the plurality of reading units are gains, the setting value calculation unit adjusts and updates gains of the plurality of reading units; 2. The reading device according to claim 1, wherein:

4. The setting values ​​of the plurality of reading units are exposure times, the setting value calculation unit adjusts and updates the exposure times of the plurality of reading units; 2. The reading device according to claim 1, wherein:

5. The setting values ​​of the plurality of reading units are shading correction coefficients, the setting value calculation unit adjusts and updates shading correction coefficients of the plurality of reading units; 2. The reading device according to claim 1, wherein:

6. a medium orientation calculation unit that calculates the orientation of the medium being transported by the medium transport unit based on the results of detection of the edge positions of the medium by the multiple reading units; a medium attitude correction amount determination unit that determines a correction amount for the attitude of the medium based on the attitude of the medium calculated by the medium attitude calculation unit; a medium attitude correction unit that corrects the attitude of the medium based on the correction amount determined by the medium attitude correction amount determination unit; 2. The reading device according to claim 1, further comprising:

7. a setting value storage unit that stores the setting values ​​of the plurality of reading units adjusted and updated by the setting value calculation unit; the plurality of reading units re-reading the medium transported by the medium transport unit based on the setting values ​​stored in the setting value storage unit; 7. The reading device according to claim 1, wherein the reading device is a reading device for reading a document.

8. When the setting value calculation unit determines that the medium is different from the user setting based on a comparison result between the read values ​​of the background area of ​​the medium read by the plurality of reading units and the read values ​​of the background area of ​​a medium of the same type that is set in advance, the setting value calculation unit notifies the user that the medium is different from the user setting.

8. The reading device according to claim 1, wherein the reading device is a reading device for reading a document.

9. A reading device according to any one of claims 1 to 8; an image printing unit that prints image data on a medium conveyed by the reading device; An image forming apparatus comprising:

Images