Recording device and control method for recording device

Abstract

To determine the detailed type of recording paper.SOLUTION: A recording device of the present invention includes: a light source that emits light onto recording paper; a sensor that detects the light reflected from the recording paper; a reflecting member located opposite the sensor and in contact with the opposite surface of the surface of the recording paper that receives the light when the recording paper receives the light; a conveyance mechanism for conveying the recording paper; and control means for determining the type of the recording paper based on a feature amount obtained by the sensor detecting the light from a plurality of positions of the recording paper being conveyed. The reflecting member includes a first region and a second region with lower reflectivity than the first region, and the multiple positions include a position corresponding to the first region and a position corresponding to the second region.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology disclosed herein relates to a recording device and a control method for the recording device. [Background technology]

[0002] Some recording devices, such as copiers and printers, are equipped with sensors for determining the type of recording paper. These recording devices use the sensors to determine the type of recording paper, and then perform control appropriate to the type of recording paper, such as setting fixing conditions or controlling printing, based on the results of that determination.

[0003] Patent document 1 discloses an image forming apparatus that has a transmission optical sensor on a manual feed tray and acquires the amount of transmitted light at multiple positions on the recording paper, thereby determining the type of recording paper before the recording paper is fed through. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-85589 Summary of the Invention [Problem to be solved by the invention]

[0005] There are many different types of recording paper used in recording devices, and the optical characteristics of each type of recording paper vary. Patent Document 1 measures the amount of light transmitted through the recording paper to identify its type, but it can be difficult to identify the type of recording paper based solely on the amount of transmitted light. For example, the method described in Patent Document 1 makes it difficult to distinguish between multiple plain papers that have the same basis weight but different surface properties.

[0006] An object of the technique of the present disclosure is to provide a recording device that can determine the detailed type of recording paper. [Means for solving the problem]

[0007] The recording device of the present disclosure includes a light source that emits light onto recording paper; By the light source From the recording sheet of a recording device comprising: a sensor that detects light; a reflective member that is positioned opposite the sensor and that contacts the surface of the recording paper opposite the surface that receives the light when the recording paper receives the light; a transport mechanism that transports the recording paper; and a control means that determines the type of the recording paper based on feature amounts obtained by the sensor detecting the light from multiple positions on the recording paper being transported, wherein the reflective member includes a first region and a second region that has a lower reflectivity than the first region, and the multiple positions include a position corresponding to the first region and a position corresponding to the second region; The control means calculates, as the characteristic amount, a first value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the first area, and a second value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the second area, and determines the type of the recording paper based on the first value and the second value. It is characterized by: [Effects of the Invention]

[0008] According to the technology of the present disclosure, it is possible to determine the detailed type of recording paper. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing the internal configuration of a recording apparatus. [Figure 2] FIG. 2 is a diagram showing the configuration of a control system of the printing apparatus. [Figure 3] FIG. 4 is a diagram showing a transport path of recording paper fed from a first cassette. [Figure 4] FIG. 10 is a diagram showing a transport path of recording paper fed from a second cassette. [Figure 5] FIG. 3 is a diagram illustrating the internal configuration of a media discrimination sensor. [Figure 6] FIG. 4 is a diagram for explaining the functional configuration of a media discrimination sensor control unit. [Figure 7] 10 is a flowchart of a paper type determination process. [Figure 8] FIG. 10 is a diagram for explaining the relationship between the combination of the white background average value and the white background standard deviation and the paper type. [Figure 9]10A and 10B are diagrams for explaining the relationship between the average white background value / average black background value and basis weight for plain paper. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the technology of the present disclosure will be described with reference to the accompanying drawings. Note that the following embodiments do not limit the technology of the present disclosure, and not all combinations of features described in the following embodiments are necessarily essential to the solutions of the technology of the present disclosure. Furthermore, in the following embodiments, as an example, the recording apparatus (printing apparatus) will be described as an inkjet recording apparatus.

[0011] <Embodiment 1> [Overall configuration of inkjet recording device] Figure 1 is a diagram showing the internal configuration of an inkjet recording apparatus 1 (hereinafter referred to as recording apparatus 1). In Figure 1, the x direction is the horizontal direction, the y direction (perpendicular to the paper surface) is the direction in which ejection ports are arranged in a recording head 8 (described later), and the z direction, which intersects with the x and y directions, is the vertical direction.

[0012] Recording device 1 is a multifunction device equipped with a printing unit 2 and a scanner unit 3, and various processes related to recording and reading operations can be performed by the printing unit 2 and the scanner unit 3 individually or in conjunction with each other. The scanner unit 3 is equipped with an ADF (automatic document feeder) and an FBS (flatbed scanner), and can read documents automatically fed by the ADF and read (scan) documents placed on the platen of the FBS by the user. Note that while this embodiment shows a recording device equipped with both the printing unit 2 and the scanner unit 3, a recording device without the scanner unit 3 may also be used. FIG. 1 shows recording device 1 in a standby state in which neither recording nor reading operations are being performed.

[0013] In the printing unit 2, a first cassette 5A and a second cassette 5B are removably installed at the bottom vertically below the housing 4 for storing recording paper (cut sheets) S as recording media. The first cassette 5A stores relatively small recording paper up to A4 size, while the second cassette 5B stores relatively large recording paper up to A3 size, stacked flat. A first feeding unit 6A is provided near the first cassette 5A for separating and feeding the stored recording paper one sheet at a time. Similarly, a second feeding unit 6B is provided near the second cassette 5B. When a recording operation is performed, recording paper S is selectively fed from one of the cassettes.

[0014] The transport rollers 7, discharge rollers 12, pinch rollers 7a, spurs 7b, guide 18, inner guide 19, and flapper 11 constitute a transport mechanism for guiding the recording paper S in a predetermined direction. The transport rollers 7 are disposed upstream and downstream of the recording head 8 in the transport direction, and are drive rollers driven by a DC motor 651 (see FIG. 6). The pinch rollers 7a are driven rollers that nip the recording paper S together with the transport rollers 7 and rotate. The discharge rollers 12 are disposed downstream of the transport rollers 7 and are drive rollers driven by a transport motor. The spurs 7b, together with the transport rollers 7 and discharge rollers 12 disposed downstream of the recording head 8, pinch and transport the recording paper S.

[0015] The media discrimination sensor 21 is a sensor for discriminating the type (paper type) of the recording paper S, and is disposed upstream in the conveying direction from the recording head 8 on the conveying path formed by the conveying mechanism. The paper type discriminated based on the detection results of the media discrimination sensor 21 includes not only paper types such as plain paper, glossy paper, and art paper, but also more specific paper types included in plain paper, such as plain paper with different basis weights (such as thin plain paper).

[0016] Regardless of whether the recording paper S is transported from the first cassette 5A or the second cassette 5B, the media discrimination sensor 21 is positioned at a position where it can read the transported recording paper S. The media discrimination sensor roller 22 is positioned opposite the media discrimination sensor 21, and the recording paper S is transported while being pressed toward the media discrimination sensor roller 22 by a pressing roller 505 (see FIG. 5) provided on the media discrimination sensor 21 side. This allows the recording paper S to be transported at a focal length suitable for the media discrimination sensor 21 to discriminate the paper type.

[0017] Guide 18 is provided on the transport path of recording paper S and guides recording paper S in a predetermined direction. Inner guide 19 is a member extending in the y direction and has curved sides, guiding recording paper S along these sides. Flapper 11 is a member for switching the direction in which recording paper S is transported during double-sided recording. Discharge tray 13 is a tray for holding and stacking recording paper S that has been discharged by discharge rollers 12 after the recording operation is completed.

[0018] The recording head 8 is a full-line type color inkjet recording head, and has a plurality of ejection ports arranged in the y direction in FIG. 1, which eject ink in accordance with recording data, and which correspond to the width of the recording paper S. When the recording head 8 is in the standby position, the ejection port surface 8a of the recording head 8 faces vertically downward as shown in FIG. 1 and is capped by a cap unit 10. When performing a recording operation, a print controller 201 (see FIG. 2), which will be described later, controls the recording head 8 to change its orientation so that the ejection port surface 8a faces a platen 9. The platen 9 is made up of a flat plate extending in the y direction, and supports the rear surface of the recording paper S, on which the recording operation is performed by the recording head 8.

[0019] The ink tank unit 14 stores each of the four colors of ink to be supplied to the recording head 8. Here, the four colors of ink refer to cyan (C), magenta (M), yellow (Y), and black (K) ink. The ink supply unit 15 is provided in the middle of the flow path connecting the ink tank unit 14 and the recording head 8, and adjusts the pressure and flow rate of the ink inside the recording head 8 to an appropriate range. The recording device 1 has a circulation-type ink supply system, and the ink supply unit 15 adjusts the pressure of the ink supplied to the recording head 8 and the flow rate of the ink collected from the recording head 8 to an appropriate range.

[0020] The maintenance unit 16 includes a cap unit 10 and a wiping unit 17, and operates these at a predetermined timing to perform maintenance operations on the recording head 8.

[0021] In addition, a manual feed tray may be included that allows the user to replenish recording paper S without pulling out the cassette. The type of recording paper S stored in the manual feed tray can also be determined by the media determination sensor 21.

[0022] [Control configuration] 2 is a block diagram showing part of the control configuration of the recording apparatus 1. The control section of the recording apparatus 1 is made up of a controller unit 100 that controls the entire recording apparatus 1, and a print engine unit 200 that mainly controls the print section 2. The control configuration will be described in detail below.

[0023] The main controller 101 in the controller unit 100 is composed of a CPU. The main controller 101 controls the entire printing apparatus 1 using the RAM 105 as a work area in accordance with programs and various parameters stored in the ROM 106. For example, a printing job is input from the host device 300 via the host I / F 102 or the wireless I / F 103. Thereafter, in accordance with instructions from the main controller 101, the image processing unit 107 acquires image data to be printed from the printing job and performs predetermined image processing on the acquired image data. The main controller 101 then transmits the processed image data to the print engine unit 200 via the print engine I / F 105.

[0024] The recording device 1 may obtain image data to be recorded from the host device 300 via wireless or wired communication, or may obtain image data to be recorded from an external storage device (such as a USB memory) connected to the recording device 1. There are no limitations on the communication method used for wireless or wired communication. For example, Wi-Fi (Wireless Fidelity) (registered trademark) and Bluetooth (registered trademark) can be used as communication methods for wireless communication. Furthermore, USB (Universal Serial Bus) or the like can be used as a communication method for wired communication.

[0025] The operation panel 104 is a mechanism for receiving input (instructions) from the user to the recording device 1 and outputting predetermined notifications to the user. The user can instruct operations such as copying or scanning and set the recording mode via the operation panel 104. The user can also view information about the recording device 1 via the operation panel 104.

[0026] The print controller 201 in the print engine unit 200 is composed of a CPU. The print controller 201 controls various mechanisms of the print section 2 according to programs and various parameters stored in a ROM 203, using a RAM 202 as a work area. During a recording operation, the print controller 201 drives the first feeding unit 6A, the second feeding unit 6B, the conveyance rollers 7, the discharge rollers 12, and the flapper 11 shown in FIG. 1 via a conveyance control section 205 to convey the recording paper S.

[0027] The media detection sensor control unit 206 controls the media detection sensor, and will be described later.

[0028] The image processing unit 107, the media discrimination sensor control unit 206, the transport control unit 205, etc. may be realized by the main controller 101 or the print controller 201 executing a predetermined program. Alternatively, they may be realized by a combination of software and hardware such as a dedicated IC, or some or all of the functions may be realized solely by hardware.

[0029] [Regarding recording paper transport] 3(a) to 3(c) are diagrams showing the conveyance path when A4 size recording paper S stored in the first cassette 5A is fed. In Fig. 3(a) to 3(c), the recording paper S is represented by a dotted line.

[0030] 3A shows the conveyance state of the recording paper S just before its leading edge reaches the recording area P. The topmost recording paper S in the first cassette 5A is separated from the second and subsequent sheets of recording paper by the first feeding unit 6A. Then, while being nipped between the conveyance roller 7 and the pinch roller 7a, the recording paper S is conveyed toward the area (called the recording area P) facing the ejection opening surface 8a between the platen 9 and the recording head 8. The traveling direction of the recording paper S is changed from the horizontal direction (x direction) to a direction tilted at approximately 45 degrees relative to the horizontal direction while being fed by the first feeding unit 6A and reaching the recording area P.

[0031] While the recording paper S is reaching the recording area P, the media discrimination sensor 21 reads the recording paper S, and the paper type of the recording paper S is discriminated based on the image data obtained as a result. Depending on the discriminated paper type, subsequent transport conditions or image processing conditions for the image data to be recorded, which indicates the image to be recorded on the recording paper S, are determined. Details of the paper type discrimination process will be described later.

[0032] FIG. 3(b) shows the state in which the leading edge of the recording paper S passes through the recording area P and is transported vertically upward. In the recording area P, ink is ejected toward the recording paper S from multiple ejection ports provided in the recording head 8. The back surface of the recording paper S in the area where ink is applied is supported by a platen 9, and the distance between the ejection port surface 8a and the recording paper S is maintained constant. After ink is applied, the recording paper S is guided by the transport roller 7 and spur 7b, passes to the left of the flapper 11, whose leading edge is tilted to the right, and is transported vertically upward in the recording device 1 along the guide 18. In other words, the traveling direction of the recording paper S is changed from its position in the recording area P, where it is tilted approximately 45 degrees from the horizontal, to a vertically upward direction by the transport roller 7 and spur 7b.

[0033] 3(c) shows the state in which the leading edge of the recording paper S passes through the discharge roller 12 and is discharged onto the discharge tray 13. The recording paper S is transported vertically upward, and then discharged onto the discharge tray 13 by the discharge roller 12 and the spur 7b. The discharged recording paper S is held on the discharge tray 13 with the side on which the image has been recorded by the recording head 8 facing downward.

[0034] 4(a) to 4(c) are diagrams showing the transport path when the A3 size recording paper S stored in the second cassette 5B is fed.

[0035] 4(a) is a diagram showing the conveyance state of the recording paper S just before its leading edge reaches the recording area P. The topmost recording paper S in the second cassette 5B is separated from the second and subsequent sheets of recording paper by the second feeding unit 6B, and is conveyed toward the recording area P between the platen 9 and the recording head 8 while being nipped by the conveyance roller 7 and the pinch roller 7a. A plurality of conveyance rollers 7, pinch rollers 7a, and an inner guide 19 are arranged along the conveyance path from when the recording paper S is fed by the second feeding unit 6B to when it reaches the recording area P, so that the recording paper S is conveyed to the platen 9 in an S-shaped curve.

[0036] As with the A4 size recording paper S, the media discrimination sensor 21 also reads the A3 size recording paper S as it reaches the recording area P, and the paper type of the recording paper S is determined based on the image data obtained as a result. Depending on the determined paper type, subsequent transport conditions or image processing conditions for the image data to be recorded, which indicates the image to be recorded on the recording paper S, are determined.

[0037] Fig. 4(b) is a diagram showing the state where the leading edge of the recording paper S passes through the recording area P and is transported vertically upward. Fig. 4(c) is a diagram showing the state where the leading edge of the recording paper S passes through the discharge rollers 12 and is discharged onto the discharge tray 13. The transport path of the A3-sized recording paper S after the leading edge of the recording paper S has passed through the recording area P is the same as that of the A4-sized recording paper S shown in Figs. 3(b) and (c).

[0038] [Configuration of the media detection sensor] 5(a) is a diagram showing the internal configuration of the media discrimination sensor 21. In this embodiment, an example will be described in which a contact image sensor (CIS), which is a reflective sensor, is used as the media discrimination sensor 21.

[0039] The media discrimination sensor 21, which is a CIS, has a linear image sensor 611 and a light guide 504. The image sensor 611 includes a photodiode (light receiving element) 502 and a rod lens array 503. In addition, a media discrimination sensor roller 22 and a pressing roller 505 are provided as a mechanism for transporting the recording paper S to be read by the media discrimination sensor 21.

[0040] Light emitted by the LED 612 (see FIG. 6), which serves as a light source, passes through the light guide 504 and is reflected by the media discrimination sensor roller 22 or the recording paper S. That is, when the recording paper S is sandwiched between the media discrimination sensor roller 22 and the pressure roller 505 as shown in FIG. 5(a), the light emitted by the LED 612 is reflected by the recording paper S, and the light that has passed through the recording paper S is reflected by the media discrimination sensor roller 22. When the recording paper is not sandwiched between the media discrimination sensor roller 22 and the pressure roller 505, the light emitted by the LED 612 is reflected by the media discrimination sensor roller 22.

[0041] Light reflected by the media discrimination sensor roller 22 or the recording paper S passes through the rod lens array 503 and enters the photodiode 502. As the recording paper S is conveyed between the media discrimination sensor roller 22 and the pressing roller 505, the media discrimination sensor 21 can read the light reflected by the recording paper S at a focal length suitable for the lens.

[0042] FIG. 5(b) is a diagram showing a schematic diagram of the media discrimination sensor 21 as seen from the paper transport direction.

[0043] The media discrimination sensor roller 22 includes at least two reflective members (reflective regions): a white member (white region) 511 and a black member (black region) 512 with a lower reflectivity than the white member. A boundary 513 between the white region 511 and the black region 512 is located near the center in the y direction. The media discrimination sensor roller 22, which is a reflective member, is located opposite the image sensor 611 and, when the recording paper S receives light from the LED 612, is in contact with the side of the recording paper S opposite the side that receives light.

[0044] The media discrimination sensor 21 also includes an image sensor 611 in which multiple photodiodes 502 are arranged in a line in the y direction. Therefore, the media discrimination sensor 21 can read light reflected from each position on one line extending in the y direction of the recording paper S in a single reading.

[0045] As shown in Figure 5(b), the white area 511, the black area 512, and the image sensor 611 extend in the Y direction. Therefore, each photodiode 502 of the image sensor 611 facing the white area 511 reads reflected light from each position on the back side of the area in the recording paper S that was in contact with the white area 511. Image data representing the reading results is then obtained. The image data obtained by reading reflected light from the back side of the area in the recording paper S that was in contact with the white area 511 is sometimes called white background image data.

[0046] 5(b), each photodiode 502 of the image sensor 611 facing the black area 512 reads reflected light from each position on the back side of the area in the recording paper S that was in contact with the black area 512. Then, image data representing the reading results is obtained. The image data obtained by reading reflected light from the back side of the area in the recording paper S that was in contact with the black area 512 is sometimes called black background image data.

[0047] By predetermining the photodiode 502 that receives light corresponding to the black region 512 and the photodiode 502 that receives light corresponding to the white region 511, it is possible to obtain image data of a white background and image data of a black background.

[0048] When light emitted from the light source passes through the recording paper S, the light incident on the image sensor 611 includes light reflected by the white areas 511, but includes almost no light reflected by the black areas 512. On the other hand, when the recording paper S does not easily transmit light, the light incident on the image sensor 611 includes almost no influence of light reflected by the white members 511 and the black members 512. Therefore, by comparing image data of a black background with image data of a white background, it is possible to measure the opacity of the recording paper S without providing an additional sensor that measures the amount of transmitted light. Details will be described later.

[0049] 5(b) as long as it is possible to acquire image data of the recording paper S with a black background and image data of the recording paper S with a white background. For example, the media discrimination sensor roller 22 may be configured with multiple rollers, such as a white roller corresponding to the white region 511 and a black roller corresponding to the black region 512, rather than a single roller.

[0050] 5(c), the media discrimination sensor roller 22 may be configured so that the area of ​​the media discrimination sensor roller 22 that comes into contact with the recording paper S switches between a white area and a black area as the media discrimination sensor roller 22 rotates. In this case, image data with a white background can be obtained by the media discrimination sensor 21 reading one line when the recording paper S comes into contact with the white area 511 of the media discrimination sensor roller 22. Also, image data with a black background can be obtained by the media discrimination sensor 21 reading one line when the recording paper S comes into contact with the black area 512 of the media discrimination sensor roller 22.

[0051] Furthermore, although the media discrimination sensor roller 22 is described as having two regions, a white region 511 and a black region 512, the media discrimination sensor roller 22 may also include a third region having a different reflectivity, for example, a reflectivity lower than that of white and higher than that of black.

[0052] FIG. 6 is a diagram for explaining the electrical configuration of the media discrimination sensor control unit 206 and the media discrimination sensor 21. As shown in FIG.

[0053] The media discrimination sensor 21 has a CIS module 600. The CIS module 600 includes an image sensor 611 arranged in a line, an LED 612 that is a light source for irradiating the recording paper S with light, and the like.

[0054] The LED 612 is configured to include an R (Red) LED, a G (Green) LED, and a B (Blue) LED, corresponding to the three primary colors of light. The LED 612 irradiates the recording paper S with light during a reading operation of the recording paper S. The image sensor 611 has multiple photodiodes 502 arranged in a line. The image sensor 611 accumulates the electric charge obtained by photoelectrically converting light reflected from the surface of the recording paper S with the photodiodes 502 for a predetermined period of time, converts the electric charge into a voltage, and then outputs the image data as an image signal.

[0055] The image signal output from the CIS module 600 is input to an AFE (Analog Front End) 603. The AFE 603 ​​samples the input image signal, adjusts gain and offset, and then performs analog-to-digital (A / D) conversion. The image signal is then output from the AFE 603 ​​to a read signal processor 606 included in the media discrimination sensor controller 206.

[0056] The read signal processing unit 606 performs image processing such as packing of the input image signal, shading correction of the image signal, and color correction. Shading correction is performed to correct uneven distribution due to lens characteristics or uneven sensitivity of the image sensor.

[0057] The drive unit 650 includes a DC motor 651 and an encoder 652. The DC motor 651 is a transport motor for driving the transport roller 7. The encoder 652 is, for example, an optical rotary encoder. When the DC motor 651 rotates a predetermined number of times (i.e., when the recording paper S is transported a predetermined transport amount), an encoder pulse is output from the encoder 652. The encoder pulse is output in accordance with the number of rotations of the DC motor 651, and is used to detect the drive amount of the DC motor 651, i.e., the transport amount of the recording paper S. The encoder pulse is input to the encoder processing unit 632.

[0058] The encoder processing unit 632 counts the encoder pulses and generates a line start pulse when the count reaches a number corresponding to one line. The interval between these line start pulses corresponds to the reading time (line time) of one line. The line start pulse is input from the encoder processing unit 632 to the SH generating unit 604. The line start pulse input to the SH generating unit 604 is multiplied by a predetermined number in the SH generating unit 604 as a horizontal synchronization signal (SH). In this embodiment, the image sensor 611 is described as being a monochrome line sensor. For this reason, when reading in color, the LEDs 612 are turned on in line sequence from G color (Green) to B color (Blue) to R color (Red) to accumulate charge in the image sensor 611, so the multiplication factor is set to three. Note that the multiplication factor is not limited to this. The multiplication factor can be set using a register or the like.

[0059] When a horizontal synchronization signal (SH) is input, the sensor control unit 605 generates a trigger signal that serves as an accumulation control trigger for the image sensor 611. Upon receiving the trigger signal, the image sensor 611 accumulates charges in the light-receiving pixels in synchronization with the trigger signal and outputs an image signal to the AFE 603.

[0060] The print controller 201 also applies feedback control to the motor control unit 633 so that the paper can be conveyed at a target speed, using conveyance distance information (encoder pulse count number) and speed information (pulse interval) obtained by the encoder processing unit 632. The motor control unit 633 performs PWM (Pulse Width Modulation) control of the current supplied from the motor driver 653 to the DC motor 651.

[0061] In this way, the LED 612 is turned on in response to the rotation of the DC motor 651, and the image sensor 611 begins to receive the reflected light, generating image data indicating the reading result of the reflected light. However, to determine the paper type of the recording paper S, the image data obtained from the reading result of the image sensor 611 when the recording paper is in a paper type determination position, which will be described later, is used.

[0062] [About paper type identification process] 7 is a flowchart of the paper type discrimination (determination) process. The paper type discrimination process starts after the recording paper S is fed and is executed until the leading edge of the recording paper S reaches the recording area P.

[0063] In S701, in response to the start of the paper type discrimination process, a shading data acquisition process is executed for the media discrimination sensor 21. The shading data is data for offsetting individual differences among the multiple image sensors 611. The shading data acquisition process is executed before the recording paper S reaches the media discrimination sensor roller 22.

[0064] In the shading data acquisition process, the main controller 101 causes the LED 612 to emit light via the LED control unit 601, and causes the image sensor 611 to receive the light reflected from the media discrimination sensor roller 22. The main controller 101 then compares the measured value indicating the actual amount of received light with the ideal amount of received light, and causes the LED control unit 601 to adjust the light emission amount of the light source LED 113 so that the measured value approaches the ideal value. With the light emission amount adjusted, the read signal processing unit 606 acquires shading data.

[0065] In S702, the main controller 101 transports the recording paper S to the paper type determination position via the transport control unit 205. Whether the position of the recording paper S is at the paper type determination position is determined from the count number of encoder pulses. The paper type determination position is a position where the recording paper S can be sandwiched between the media determination sensor roller 22 and the pressing roller 505, and where the recording paper S and the media determination sensor 21 are close to each other.

[0066] In S703, the main controller 101 is at the paper type determination position and causes the LED 612 to emit light toward the recording paper S being transported. The main controller 101 then acquires one line of image data obtained by the image sensor 611 receiving light reflected from the recording paper S. Two-dimensional image data is acquired by repeatedly transporting the recording paper S while the linear image sensor 611 reads one line of reflected light. For example, image data representing the results of reading the center of the leading edge of the recording paper S on the downstream side in the transport direction within an area about 1 cm wide is acquired.

[0067] It is also possible to acquire image data corresponding to multiple lines corresponding to multiple locations on the recording paper S. Alternatively, it is also possible to acquire image data for one line on the recording paper S. In this way, image data is acquired as data representing the amount of received light (amount of reflected light) at each position on the recording paper S.

[0068] The image data acquired in S703 is the image data of the white background and the image data of the black background described above. The image data of the white background and the image data of the black background may be acquired as separate image data, or image data in which the image data of the white background and the image data of the black background are combined and expressed as a single image may be acquired. In the case of image data expressed as a single image, the image (pixels) corresponding to the white area 511 in the acquired image are referred to as the image data of the white background, and the image (pixels) corresponding to the black area 512 are referred to as the image data of the black background.

[0069] In S704, the read signal processing unit 606 performs shading correction on the acquired image data using shading data. Specifically, in the read image data, the value obtained by a certain image sensor is corrected using the shading data acquired for that image sensor.

[0070] In S705, the main controller 101 calculates feature amounts from the corrected image data of the white background. In this embodiment, the main controller 101 calculates the average value of the amount of light received read by each photodiode of the image sensor 611 arranged at a position facing the white region 511 (hereinafter referred to as the white background average value). For example, the average value of the pixel values ​​of all pixels in the image data of the white background is calculated as the white background average value. The pixel value is, for example, a luminance value.

[0071] Furthermore, the main controller 101 calculates, from the corrected white background image data, the standard deviation of the amount of received light read by each photodiode of the image sensor 611 arranged at a position opposite the white area 511 (hereinafter referred to as the white background standard deviation). For example, the standard deviation of the pixel values ​​of all pixels in the white background image data is calculated as the white background standard deviation.

[0072] In S706, the main controller 101 calculates feature amounts from the corrected black background image data. In this embodiment, the main controller 101 calculates the average value of the amount of received light read by each photodiode of the image sensor 611 arranged at a position opposite the black area 512 (hereinafter referred to as the black background average value). For example, the average value of the pixel values ​​of all pixels in the black background image data is calculated as the black background average value.

[0073] In S707, the main controller 101 compares the calculated white background average value, black background average value, and white background standard deviation with paper type setting information previously stored in ROM 106 to determine the paper type of the recording paper S. The paper type setting information is information that is set so that multiple paper types are associated with the characteristics of each paper type. By determining the transport conditions and image processing conditions according to the determined paper type, it is possible to execute print control appropriate for the paper type.

[0074] FIG. 8 is a diagram illustrating an example of paper type setting information. FIG. 8 shows the distribution of combinations of white background average values ​​and white background standard deviations for each type of recording paper. Generally, paper with a high degree of whiteness has a high white background average value. Furthermore, paper with a high degree of surface smoothness has a low white background standard deviation. For this reason, in this embodiment, by measuring reflected light, it is possible to determine paper types with different surface properties (whiteness and unevenness).

[0075] As shown in Figure 8, for glossy paper, the whiteness is high and the surface smoothness is high, so the calculated values ​​are distributed in a region where the white background average value is high and the standard deviation is low. For matte paper, the whiteness is high and the surface smoothness is low, so the calculated values ​​are distributed in a region where the average value is high and the standard deviation is high. For plain paper, the characteristics vary considerably depending on the recording paper, but many recording papers have low whiteness and low surface smoothness, so the calculated values ​​are distributed in a region where the white background average value is low and the white background standard deviation is high. Therefore, the surface properties of the recording paper can be measured by combining the white background average value and white background standard deviation calculated in S705, and the paper type can be determined based on the surface properties.

[0076] However, when attempting to determine a more specific paper type, it may be difficult to determine the paper type from the combination of the white background average value and the white background standard deviation. For example, as shown in Fig. 8, for plain paper, points representing combinations of the white background average value and the white background standard deviation, such as points 801 and 802, may be close to each other. In this case, if points 801 and 802 each represent different paper types included in plain paper (for example, plain paper 1 and plain paper 2), it is difficult to determine whether the paper is plain paper 1 or plain paper 2 from the combination of the white background average value and the white background standard deviation.

[0077] FIG. 9 is a distribution diagram showing the relationship between the ratio of the average black background value to the average white background value of plain paper calculated from image data acquired by the media discrimination sensor 21 and the basis weight (opacity) of the recording paper.

[0078] When light emitted from the light source passes through the recording paper, the light is reflected by the white region 511 and enters the image sensor 611. For this reason, the white background average value includes the influence of light that passes through the recording paper S and is reflected by the white region 511. On the other hand, even if light emitted from the light source passes through the recording paper S, the light is hardly reflected by the black region 512, so even if the light passes through the recording paper S, the black background average value includes almost no influence of light reflected by the black region 512. If the recording paper has low transparency, such as when the recording paper has a high basis weight, light does not pass through easily, so the difference between the white background average value and the black background average value becomes smaller, and the ratio of the black background average value to the white background average value approaches 1.

[0079] In this way, the ratio of the white background average value to the black background average value is considered to represent the opacity of the recording paper S. The media discrimination sensor 21 of this embodiment is a reflective sensor that detects light reflected from the recording paper S, but in this embodiment, the opacity of the recording paper S can be measured using a sensor that detects reflected light without the need for an additional sensor that detects light transmitted through the recording paper S. As a result, this embodiment makes it possible to determine the paper type in more detail than would be possible based solely on characteristics such as the amount of specularly reflected light or the amount of diffusely reflected light. Furthermore, although it is difficult to measure the surface properties of recording paper based solely on the amount of transmitted light, this embodiment makes it possible to determine the paper type by taking the surface properties of the recording paper into consideration.

[0080] As shown in Figure 9, for plain paper, the ratio of the white background average value to the black background average value decreases as the basis weight increases. Therefore, it is possible to determine more specific paper types with different basis weights from the ratio of the white background average value to the black background average value (opacity). For example, for recording paper S determined to be plain paper using Figure 8, the ratio of the white background average value to the black background average value (opacity) can be compared with the paper type setting information for plain paper stored in advance in ROM 106, as shown in Table 1, to determine more specific paper types included in plain paper.

[0081] [Table 1]

[0082] Plain paper 1 in Table 1 is thin plain paper. In this way, in S707, the main controller 101 can determine that recording paper with a low white background average value, a high white background standard deviation, and a small ratio between the white background average value and the black background average value is thin plain paper (plain paper 1).

[0083] As described above, in this embodiment, the surface properties of the recording paper S can be measured from image data acquired by the image sensor. Furthermore, the opacity of the recording paper S can be measured by comparing the amount of received light detected by the image sensor positioned opposite the white area 511 with the amount of received light detected by the image sensor positioned opposite the black area 512. In this way, according to this embodiment, the surface properties and opacity of the recording paper can be measured with a single image sensor. Therefore, the paper type can be determined in more detail from the surface properties and opacity of the recording paper. Therefore, by determining transport conditions or image processing conditions, etc., that are suited to the paper type, printing control that is suited to the paper type can be performed.

[0084] In the present embodiment, only the black background average value is calculated from the image data of the black background. The main controller 101 may calculate the standard deviation of the amount of received light detected by each photodiode of the image sensor 611 arranged at a position facing the black area (hereinafter referred to as the black background standard deviation) from the corrected image data of the black background. Then, the paper type may be determined using the black background average value instead of the white background average value in FIG. 8, and the black background standard deviation instead of the white background standard deviation in FIG. 8.

[0085] In the above description, the white background standard deviation or the black background standard deviation is calculated, but the calculation is not limited to the standard deviation as long as a value representing the variation in the amount of received light is calculated. For example, a variance may be calculated instead of the standard deviation.

[0086] 5(b) has a boundary 513 in the y direction. In this case, it is conceivable that the photodiode 502 facing the boundary 513 will detect both the light reflected from the white region 511 and the light reflected from the black region 512. For this reason, the results read by the photodiode 502 facing the vicinity of the boundary 513 of the media discrimination sensor roller 22 may not be used. In other words, the white background average value, black background average value, white background standard deviation, or black background standard deviation may be calculated without using the pixel values ​​of pixels in the image data that indicate the detection results of the photodiode 502 corresponding to the vicinity of the boundary 513.

[0087] Alternatively, the paper type may be determined based only on the white background average value and the black background average value without using the standard deviation. For example, the whiteness of the recording paper S may be calculated from the white background average value, and the opacity of the recording paper S may be calculated from the ratio between the white background average value and the black background average value, and the paper type of the recording paper S may be determined based on the combination of the whiteness and the opacity.

[0088] <Other embodiments> The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0089] 1. Inkjet recording device 101 Main Controller 21 Media detection sensor 22 Media detection sensor roller

Claims

1. a light source that emits light onto the recording paper; a sensor that detects light from the recording paper by the light source; a reflecting member that is positioned opposite the sensor and that comes into contact with a surface of the recording paper opposite to a surface that receives the light when the recording paper receives the light; a conveying mechanism for conveying the recording paper; a control means for determining the type of the recording paper based on the characteristic amount obtained by the sensor detecting the light from a plurality of positions on the recording paper being conveyed; A recording device having: the reflective member includes a first region and a second region having a reflectivity lower than that of the first region, and the plurality of positions include a position corresponding to the first region and a position corresponding to the second region; The control means As the feature amount, a first value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the first area, and a second value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the second area are calculated, and the type of the recording paper is determined based on the first value and the second value. A recording device characterized by:

2. The control means The type of recording paper is determined by using at least a result of comparing a value based on the first value and the second value with information associated with each of a plurality of types of recording paper.

2. The recording apparatus according to claim 1, wherein the recording apparatus is a recording medium.

3. The control means A third value representing the variation of the values ​​obtained by the detection by the sensor from each position on the recording paper corresponding to the first region is further calculated as the feature amount.

3. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

4. The type of recording paper is determined by using at least a result of comparing the combination of the first value and the third value with information associated with each of a plurality of types of recording paper.

4. The recording apparatus according to claim 3.

5. The control means Acquire information on the characteristics of each type of recording paper, The type of recording paper is determined by comparing the feature amount obtained by the sensor detecting the light with the feature included in the information.

5. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

6. The control means As the feature amounts, at least a feature amount representing the surface properties of the recording paper and a feature amount representing the opacity of the recording paper are calculated, and the type of the recording paper is determined.

6. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

7. The feature amount representing the surface properties of the recording paper includes a feature amount representing the smoothness of the recording paper and a feature amount representing the whiteness of the recording paper.

7. The recording apparatus according to claim 6.

8. The recording device further includes a recording means for recording an image on the recording paper being conveyed, The sensor and the reflecting member are The recording device is disposed upstream of the recording means in the recording paper transport path in the transport direction.

8. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

9. The control means The sensor detects the light from a plurality of positions on the recording paper, thereby obtaining image data, and calculating the feature amount from pixel values ​​included in the image data.

9. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

10. The boundary between the first area and the second area exists in a direction intersecting the conveying direction of the recording paper on the reflecting member.

10. The recording apparatus according to claim 1, wherein the recording medium is a recording medium.

11. The sensor is a reflective line sensor.

11. The recording apparatus according to claim 1, wherein the recording apparatus is a recording medium.

12. The control means calculates the feature amount from image data obtained by the sensor detecting the light from a plurality of lines on the recording paper.

12. The recording apparatus according to claim 11.

13. The first value and the second value are average values ​​of pixel values ​​of all pixels of each image data.

2. The recording apparatus according to claim 1, wherein the recording apparatus is a recording medium.

14. a light source that emits light onto the recording paper; a sensor that detects light from the recording paper by the light source; a reflecting member that is positioned opposite the sensor and that comes into contact with a surface of the recording paper opposite to a surface that receives the light when the recording paper receives the light; a conveying mechanism for conveying the recording paper, A method for controlling a recording device, wherein the reflective member includes a first region and a second region having a lower reflectivity than the first region, determining the type of the recording paper based on the feature amount obtained by the sensor detecting the light from a plurality of positions on the recording paper, the plurality of positions include a position corresponding to the first region and a position corresponding to the second region; In the process, As the feature amount, a first value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the first area, and a second value which is an average value of values ​​detected by the sensor from each position on the recording paper corresponding to the second area are calculated, and the type of the recording paper is determined based on the first value and the second value. A control method comprising:

Images