Identification device and image forming device

Abstract

To provide an identification device capable of improving accuracy in measuring a surface property of a sheet.SOLUTION: An identification device includes: a scanning part that scans a sheet inserted into a guide path; a first detection part that is arranged in the upstream of an insertion direction with respect to the scanning part and detects the sheet; and a second detection part that is arranged in the downstream in the insertion direction with respect to the scanning part and detects the sheet. The identification device starts measurement of a surface property of the sheet by the scanning part (S6) in accordance with a change in a detection result of one of the first detection part and the second detection part (Yes in S5), and completes the measurement in accordance with a change in a detection result of the other of the first detection part and the second detection part (Yes in S10).SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a discrimination device for measuring the surface properties of a sheet and an image forming apparatus.

Background Art

[0002] In recent years, in image forming apparatuses such as copiers, printers, facsimiles, and multifunction devices thereof, various types of sheets are used as the recording material in accordance with user demands. For example, in an electrophotographic image forming apparatus, optimal conditions in each process such as charging, exposure, development, transfer, and fixing differ depending on the type of sheet. Therefore, it is desirable to appropriately set in advance the type of sheet for image formation. However, for example, a user may not know the type of sheet, and there is also a risk that the type of sheet cannot be correctly set in the image forming apparatus. Thus, a device has been proposed that discriminates the type of sheet by measuring the surface properties of the sheet with an optical sensor when the user inserts the sheet (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in recent years, due to demands for diversification in on-demand printing, for example, the types of sheets used have become even more diverse, and as mentioned above, there is a need to improve the measurement accuracy of identification devices that identify the type of sheet. However, in identification devices where the user inserts the sheet for measurement, the user may not insert the sheet correctly. In such cases, for example, if the sheet does not move and the position of the sheet scanned by the optical sensor remains the same, the measurement data will be insufficient, and the measurement accuracy may not be good.

[0005] Therefore, the present invention aims to provide an identification device and an image forming device that can improve the accuracy of measuring the surface properties of a sheet. [Means for solving the problem]

[0006] One aspect of the present invention is an identification device comprising: a guide member that forms a guide path for guiding an inserted sheet; a scanning unit that scans a sheet inserted into the guide path; a first detection unit positioned upstream of the scanning unit in the insertion direction of the sheet in the guide path and detecting the presence or absence of a sheet; and a second detection unit positioned downstream of the scanning unit in the insertion direction of the guide path and detecting the presence or absence of a sheet, wherein the scanning unit starts measuring the surface properties of the sheet when the detection result of one of the first detection unit and the second detection unit changes, and the measurement is completed when the detection result of the other of the first detection unit and the second detection unit changes.

[0007] One aspect of the present invention is an identification device comprising: a guide member that forms a guide path for guiding an inserted sheet; a scanning unit that scans the sheet inserted in the guide path; and a movement detection unit that detects whether the inserted sheet is moving, wherein the scanning unit completes the measurement of the surface properties of the sheet when the movement detection unit detects that the inserted sheet is moving to the scanning position of the scanning unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to improve the accuracy of measuring the surface properties of a sheet. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an image forming apparatus equipped with a paper type identification device according to this embodiment. [Figure 2] This is a block diagram showing the control system according to this embodiment. [Figure 3] (a) is a diagram showing the state in which the sheet is separated from the heating roller of the fixing unit, and (b) is a diagram showing the state in which the sheet is wrapped around the heating roller of the fixing unit. [Figure 4] (a) is a cross-sectional view showing the paper type identification device according to this embodiment before the sheet is inserted, and (b) is a schematic diagram showing the paper type identification device according to this embodiment viewed from above before the sheet is inserted. [Figure 5] (a) is a cross-sectional view showing the paper type identification device with the sheet according to this embodiment inserted, and (b) is a schematic diagram showing the paper type identification device with the sheet according to this embodiment inserted, viewed from above. [Figure 6] This is a schematic diagram showing the paper type identification device according to this embodiment with a sheet inserted, viewed from the insertion direction. [Figure 7] This is a flowchart showing the measurement process of the paper type identification device according to this embodiment. [Figure 8] This figure shows the start screen for paper settings according to this embodiment. [Figure 9] This diagram shows the relationship between the transmission coefficient of ultrasound and basis weight. [Figure 10] This figure shows the measurement error screen according to this embodiment. [Figure 11] This is a flowchart showing the paper type identification process according to this embodiment. [Figure 12] This figure shows the relationship between the adjacent pixel difference integration value, brightness, and sheet type. [Figure 13] This figure shows the paper selection screen for paper settings according to this embodiment. [Figure 14] It is a diagram showing a brand discrimination screen among the paper selection screens for paper settings according to this embodiment. [Figure 15] It is a diagram showing paper type data according to this embodiment. [Figure 16] It is a diagram showing paper reference data in which the relationship between the paper brand according to this embodiment and the reference values of measurement items is recorded.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an image forming apparatus 201 provided with a paper type identification apparatus 100 as an identification apparatus according to the present invention will be described using FIG. 1. FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment.

[0011] [Schematic Configuration of Image Forming Apparatus] As shown in FIG. 1, 201 is an image forming apparatus, 201A is an image forming apparatus main body, and 201B is an image forming unit that forms an image on a sheet. 202 is an image reading apparatus installed substantially horizontally above the image forming apparatus main body 201A, and a discharge space V for sheet discharge is formed between the image reading apparatus 202 and the image forming apparatus main body 201A. Note that above the image forming apparatus main body 201A, that is, at the upper part of the image forming apparatus 201, there are arranged an operation unit 502 as an operation display unit configured by a touch panel or the like and capable of operation input and screen display, and specifically, a paper type identification apparatus 100 that will be described later.

[0012] The image forming unit 201B, which is an image forming means, is of a four-drum full-color type. The image forming unit 201B includes a laser scanner 210 and four process cartridges 211Y, 211M, 211C, 211K for forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). Here, each process cartridge 211 includes a photosensitive drum 212, a charger 213 which is a charging means, and a developing device 214 which is a developing means. Further, the image forming unit 201B includes an intermediate transfer unit 201C disposed above the process cartridge 211 and a fixing unit 201E. Note that 215 is a toner cartridge for supplying toner to the developing device 214.

[0013] The intermediate transfer unit 201C includes an intermediate transfer belt 216 wound around a driving roller 216a and a tension roller 216b. Note that an primary transfer roller 219 which abuts against the intermediate transfer belt 216 at a position facing the photosensitive drum 212 is provided inside the intermediate transfer belt 216. Here, the intermediate transfer belt 216 is rotated in the direction of the arrow by a driving roller 216a driven by a driving unit (not shown).

[0014] Then, the toner images of each color having a negative polarity on the photosensitive drum are sequentially multi-transferred onto the intermediate transfer belt 216 by the primary transfer roller 219. A secondary transfer roller 217 for transferring the color image formed on the intermediate transfer belt onto the sheet S is provided at a position facing the driving roller 216a of the intermediate transfer unit 201C. A secondary transfer portion 201D is constituted by between the intermediate transfer belt 216 and the secondary transfer roller 217. Further, a fixing unit 201E having a pressure roller 220a and a heating roller 220b is disposed above the secondary transfer roller 217. Also, a first discharge roller pair 225a, a second discharge roller pair 225b, and a duplex reversing unit 201F are disposed at the upper left portion of the fixing unit 201E. The duplex reversing unit 201F is provided with a reversing roller pair 222 capable of forward and reverse rotation and a re-transfer passage R for re-transferring the sheet having an image formed on one side to the image forming unit 201B again.

[0015] A sheet feeding unit 230 is provided at the bottom of the main body 201A of the image forming apparatus for feeding the set sheet S to the image forming section 201B. The sheet feeding unit 230 comprises a feeding cassette 1, which serves as a sheet support section for storing and supporting the sheet, and a sheet feeding section 5, which feeds the sheet S stored in the feeding cassette 1. The sheet feeding section 5 comprises a pickup roller 2 and a feed roller 3 and a retard roller 4, which serve as separation means for separating the sheet S that have been fed out from the pickup roller 2.

[0016] Furthermore, a manual feed unit 235 for feeding the set sheet S to the image forming unit 201B is provided on the right side of the main body 201A of the image forming apparatus in Figure 1. The manual feed unit 235 is equipped with a manual feed tray 6 as a sheet support unit for supporting the sheet S, and is equipped with sheet feeding means and separation means, similar to the sheet feeding unit 230.

[0017] Next, the image forming operation of the image forming apparatus 201 will be described. First, when the image information of the original is read by the image reading device 202, this image information is processed and then converted into an electrical signal and transmitted to the laser scanner 210 of the image forming unit 201B. In the image forming unit 201B, the surface of the photoreceptor drum 212, whose surface is uniformly charged to a predetermined polarity and potential by the charger 213, is sequentially exposed by laser light. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photoreceptor drum of each process cartridge 211, respectively.

[0018] Next, this electrostatic latent image is developed and visualized using each color toner, and the primary transfer bias applied to the primary transfer roller 219 sequentially superimposes and transfers the toner images of each color on each photoreceptor drum onto the intermediate transfer belt 216. As a result, a toner image is formed on the intermediate transfer belt 216.

[0019] Meanwhile, the sheet S fed by the feed roller 3 of the sheet feeding unit 230 is transported to a registration roller pair (hereinafter referred to as the registration roller pair) 240, which consists of a drive roller and a driven roller. At this time, the registration roller pair 240 is stopped from driving, and the leading edge of the sheet S comes into contact with the registration roller pair 240. This causes the leading edge of the sheet S to conform to the registration roller pair 240. Subsequently, as the sheet S is transported by the feed roller 3, a flex (loop) is formed in the sheet S, and when a predetermined loop amount is reached, the registration roller pair 240 is driven. As a result, the skew of the sheet S is corrected by the registration roller pair 240, and the skew-corrected sheet S is transported by the registration roller pair 240 to the secondary transfer section 201D. Subsequently, in the secondary transfer section 201D, the toner image is transferred onto the sheet S all at once by the secondary transfer bias applied to the secondary transfer roller 217. The sheet S onto which the toner image has been transferred is then transported to the fuser unit 201E, where it is subjected to heat and pressure, causing the toners of each color to melt and mix, and then fixed to the sheet S as a color image.

[0020] After this, the sheet S on which the image has been fixed is discharged into the discharge space V by the first discharge roller pair 225a and the second discharge roller pair 225b located downstream of the fixing unit 201E, and is loaded onto the loading section 223 formed on the bottom surface of the discharge space V. When forming images on both sides of the sheet S, after the image has been fixed, the sheet S is transported to the re-transport passage R by the reversing roller pair 222, and then transported again to the image forming unit 201B.

[0021] [Control systems for image forming apparatus and paper type identification apparatus] Next, the control systems of the image forming apparatus 201 and the paper type identification device 100 will be described using Figure 2. Figure 2 is a block diagram showing the control system according to this embodiment.

[0022] As shown in Figure 2, the image forming apparatus 201 is equipped with a main control unit 400, which comprehensively controls the operation of the image forming apparatus 201 and the operation of the paper type identification device 100 electrically connected to the image forming apparatus 201. The image forming apparatus 201 is also equipped with a memory 401 composed of RAM or the like, a paper type database 402 composed of ROM or the like, and the operation unit 502, all of which are electrically connected to the main control unit 400.

[0023] On the other hand, the paper type identification device 100 is equipped with a control unit 160 connected to the main control unit 400 of the image forming apparatus 201. The paper type identification device 100 is also equipped with an upstream paper sensor 104, a downstream paper sensor 105, an optical sensor 130, an ultrasonic sensor 135, and a paper thickness sensor 140, which are connected to this control unit 160 and will be described in more detail later.

[0024] [Necessity of setting the sheet type in an image forming apparatus] Here, the necessity of setting the type of sheet when performing the image forming operation in the image forming apparatus 201 will be explained using Figure 3. Figure 3(a) shows the state in which the sheet is separated from the heating roller of the fixing unit, and Figure 3(b) shows the state in which the sheet is wrapped around the heating roller of the fixing unit.

[0025] The conditions in the image formation process (printing), such as transport speed and temperature during fixing and transfer voltage during secondary transfer, vary depending on the type of sheet used to form the image (physical properties such as basis weight, stiffness, surface texture, and material). Therefore, it is necessary to pre-set the type of sheet to be used during the image formation process.

[0026] First, some sheets have restrictions when being loaded into the feed cassette 1 or manual feed tray 6. For example, some thick, rigid paper can only be fed through the manual feed tray 6, where the curvature of the transport path is smaller. Coated paper, which has a smooth surface and strong adhesion between sheets, must be fed one sheet at a time from the manual feed tray 6. Furthermore, especially with pulp-based paper, the bending rigidity generally differs between the longitudinal and transverse directions due to the bias in the orientation direction (grain direction) of the pulp fibers that occurs due to the manufacturing process. Therefore, some sheets have recommended longitudinal and transverse directions when loaded into the feed cassette 1 or manual feed tray 6 to minimize bending rigidity in the transport path. In addition, some single-sided coated paper, which is coated on only one side compared to plain paper, has a specified up-and-down orientation when loaded into the feed cassette 1 or manual feed tray 6 in order to print on the coated side.

[0027] Furthermore, there are types of sheets that cannot be used with the image forming apparatus 201. For example, thick cardboard with excessive stiffness may stop being transported due to the resistance when transporting it along the curved transport path. Alternatively, thin paper with excessive stiffness is strongly affected by the adhesive force between the molten toner and the heating roller 220b as it passes through the fixing unit 201E. With sheets such as ordinary paper, as shown in Figure 3(a), after being heated and pressurized by the heating roller 220b and the pressure roller 220a, the leading edge of the sheet separates from the heating roller 220b and the pressure roller 220a due to its stiffness. Therefore, it can be peeled off by the separating plate 220c. On the other hand, with thin paper sheets with excessive stiffness, as shown in Figure 3(b), after being heated and pressurized by the heating roller 220b and the pressure roller 220a, the leading edge of the sheet does not separate from the heating roller 220b, and it cannot be peeled off from the heating roller 220b by the separating plate 220c. Therefore, a problem may occur where the material gets wrapped around the heating roller 220b. In addition, synthetic paper made from synthetic resin instead of pulp may melt when high heat is applied in the fixing unit 201E, potentially contaminating the heating roller 220b.

[0028] As described above, in order to prevent malfunctions during image formation in the image forming apparatus 201 and to perform image formation appropriately, it is important to identify the type of sheet to be used before starting image formation. Furthermore, it is necessary to appropriately set the image formation conditions in the image forming apparatus 201, or to refuse to accept certain types of sheets.

[0029] [Configuration of the paper type identification device] Next, the configuration of the paper type identification device 100 will be explained using Figures 4, 5, and 6. Figure 4(a) is a cross-sectional view showing the paper type identification device according to this embodiment before the sheet is inserted, and Figure 4(b) is a schematic diagram showing the paper type identification device according to this embodiment viewed from above before the sheet is inserted. Figure 5(a) is a cross-sectional view showing the paper type identification device according to this embodiment with the sheet inserted, and Figure 5(b) is a schematic diagram showing the paper type identification device according to this embodiment with the sheet inserted viewed from above. Figure 6 is a schematic diagram showing the paper type identification device according to this embodiment with the sheet inserted viewed from the insertion direction.

[0030] The paper type identification device 100 is located next to the operation unit 502 at the top of the image forming apparatus body 201A (see Figure 1). When a user inserts a sheet S into the guide path 101, the physical properties of the sheet S (paper) are measured and acquired. The physical property measurement unit consists of a mechanical property measurement unit 102 and a surface property measurement unit 103. As the sheet S passes through these mechanical property measurement unit 102 and surface property measurement unit 103, physical properties such as basis weight, surface properties, and paper thickness of the sheet S (paper) can be measured and acquired.

[0031] As shown in Figure 4(a), the paper type identification device 100 comprises an upper block 109 as a guide member or first guide member, and a lower block 110 as a guide member or second guide member. The upper block 109 has an upper guide surface 109a. Furthermore, the lower block 110 has a lower guide surface 110a, and the pressing member 106, which will be described later, has a pressing surface 106a. These lower guide surface 110a and pressing surface 106a are arranged opposite the upper guide surface 109a to form a guide path 101 that guides the inserted sheet S. The upper block 109 also has a stopper portion 108 that the sheet S inserted into the guide path 101 abuts against. The pressing member 106 is biased toward the upper guide surface 109a (optical sensor 130, described later) and pressed by a spring 107, which is a biasing member that is compressed in the lower block 110.

[0032] Furthermore, as shown in Figures 4(a), 4(b), and 6, the mechanical property measurement unit 102 is equipped with an ultrasonic sensor 135 as a basis weight detection unit for measuring the basis weight of the inserted sheet S (see Figure 2). The mechanical property measurement unit 102 is also equipped with a paper thickness sensor 140 as a thickness detection unit for measuring the thickness of the inserted sheet S (see Figure 2). In addition, the surface property measurement unit 103 is equipped with an optical sensor 130 for measuring surface properties (surface roughness, glossiness, etc.) (see Figure 2).

[0033] Furthermore, as shown in Figures 4(a) and 4(b), the paper type identification device 100 includes an upstream paper sensor 104 as a first detection unit or movement detection unit and a downstream paper sensor 105 as a second detection unit or movement detection unit. The upstream paper sensor 104 detects the presence or absence of a sheet S by changing the signal of the detection result at a detection position X1 upstream of the mechanical property measurement unit 102 and the surface property measurement unit 103 in the insertion direction X of the sheet S, i.e., detecting the presence or absence of a sheet S. The downstream paper sensor 105 also detects the presence or absence of a sheet S by changing the signal of the detection result at a detection position X2 downstream of the mechanical property measurement unit 102 and the surface property measurement unit 103 in the insertion direction X of the sheet S, i.e., detecting the presence or absence of a sheet S. The upstream detection position X1 is located near the entrance of the guide path 101, and the downstream detection position X2 is located near the abutment portion 108 of the guide path 101. Specifically, the upstream paper sensor 104 detects that a sheet S has been inserted into the paper type identification device 100, and the downstream paper sensor 105 detects that the sheet S has been brought into contact with the stopper 108. The upstream paper sensor 104 and the downstream paper sensor 105 have different timings for detecting the sheet S, which allows them to detect the movement of the sheet S, and in other words, they constitute a movement detection unit.

[0034] (Measurement of basis weight) The ultrasonic sensor 135 of the mechanical property measurement unit 102 comprises an ultrasonic transmitter 136 located in the lower block 110 and an ultrasonic receiver 137 located in the upper block 109, with the guide path 101 in between. The ultrasonic sensor 135 transmits and receives ultrasonic waves through the sheet S inserted in the guide path 101 to detect the basis weight of the sheet S (paper). Basis weight is the mass per unit area of ​​the sheet S and can be expressed in [g / m^2].

[0035] Both the ultrasonic transmitter 136 and the ultrasonic receiver 137 consist of a piezoelectric element (also called a piezo element), which is an element that converts mechanical displacement and electrical signals, and electrode terminals. In the ultrasonic transmitter 136, when a pulse voltage of a predetermined frequency is input to the electrode terminals, the piezoelectric element oscillates, generating ultrasonic waves that propagate through the air. When the ultrasonic waves reach the sheet S, the sheet S vibrates due to the ultrasonic waves. In this way, the ultrasonic waves generated in the ultrasonic transmitter 136 propagate to the ultrasonic receiver 137 via the sheet S. The piezoelectric element of the ultrasonic receiver 137 generates an output voltage at its electrode terminals that corresponds to the amplitude of the received ultrasonic waves, which is corresponding to the basis weight of the paper. Compared to when there is no sheet S between the ultrasonic transmitter and receiver, the output voltage transmitted through the sheet S is attenuated, so the transmittance is calculated by taking the ratio of these values. Since the transmittance of ultrasonic waves changes according to the thickness of the sheet S, the basis weight of the sheet S (paper) can be estimated using the ultrasonic transmission coefficient-basis weight conversion formula. This is the operating principle when detecting the basis weight of the sheet S (paper) by sending and receiving ultrasonic waves using a piezoelectric element.

[0036] (Measuring paper thickness) The paper thickness sensor 140 of the mechanical property measurement unit 102 is a lever-type sensor. The lever rotates according to the thickness of the sheet S (paper), and an encoder linked to the lever rotates according to the amount of rotation, so that the encoder detects a value corresponding to the thickness of the sheet S. The paper thickness sensor 140 measures the paper thickness when the downstream paper sensor 105 detects the sheet S and detects that the sheet S has come into contact with the abutment part 108. For this reason, the paper thickness sensor 140 is positioned so that it is slightly upstream in the insertion direction X from the detection position X2 of the downstream paper sensor 105.

[0037] (Surface quality measurement) As shown in Figures 4(a), 4(b), and 6, the optical sensor 130 of the surface quality measurement unit has an LED 131 as a light source and a CIS 132 as a scanning unit arranged on the upper block 109 side. The optical sensor 130 measures the surface quality of the sheet S (paper) by irradiating the surface of the sheet S (paper) with light from the LED 131 and receiving the reflected light according to the unevenness of the surface of the sheet S with the CIS 132 via a focusing lens.

[0038] In measuring surface properties with the optical sensor 130, it is necessary to hold the surface of the sheet S at the optical focal point. Therefore, as described above, the posture of the sheet S is stabilized by the pressing member 106 biased by the spring 107. This reduces variations in the position and posture of the sheet S when measuring its surface with the optical sensor 130, enabling stable measurement of surface properties. The spring 107 is set to press the inserted sheet S toward the optical sensor 130 with a force of approximately 100 gf.

[0039] The scanning direction at the scanning position of the CIS132 is orthogonal to the insertion direction X of the sheet S. That is, in the CIS132, the dots of the image sensor are aligned in the scanning direction, and imaging is possible with a resolution corresponding to the pitch of the aligned dots. In this embodiment, the image sensor is arranged with a pitch of 300 dpi. The CIS132 can only read an image of one line per scan, which is insufficient for identifying the surface properties of the sheet S. This is because the CIS132 detects too many local irregularities on the sheet S, and if the surface properties are judged based only on an image of one line within the surface of the sheet S, the deviation of the output results for each measurement position is large, and the data from one line is not suitable for determining the surface properties. To solve this, the scanning of one line is performed multiple times within the surface of the sheet S, and the result of averaging the data from each line is used to grasp the overall surface property trend on the surface of the sheet S. To do this, the sheet S to be identified should be in a state where it is moving relative to the optical sensor 130 during measurement, i.e., dynamic measurement should be performed.

[0040] To accommodate this dynamic measurement, this embodiment provides an upstream paper sensor 104 and a downstream paper sensor 105 for detecting the sheet S, located upstream and downstream of the insertion direction X of the optical sensor 130 of the surface measurement unit 103 in the guide path 101. The relationship between the detection by these sensors and the measurement of the sheet S will be explained in the measurement process of the paper type identification device described later.

[0041] On the other hand, the detection of localized irregularities in the CIS132 makes it possible to capture the surface characteristics of papers with deep irregularities, such as embossed paper. In this case as well, dynamic measurement is necessary to understand the overall trend of the paper, but the CIS132 can also identify embossed paper, making it possible to handle a wide range of paper identification needs.

[0042] [Measurement process of paper type identification device] Next, the measurement process performed by the control unit 160 of the paper type identification device 100 will be explained using Figures 7, 8, 9, and 10. Figure 7 is a flowchart showing the measurement process of the paper type identification device according to this embodiment, Figure 8 is a diagram showing the start screen for paper setting according to this embodiment, Figure 9 is a diagram showing the relationship between the ultrasonic transmission coefficient and basis weight, and Figure 10 is a diagram showing the measurement error screen according to this embodiment.

[0043] First, when a user uses paper, the main control unit 400 of the image forming apparatus 201 displays a paper selection screen on the operation unit 502 as shown in Figure 8. When the user selects "Automatic paper detection," the main control unit 400 switches to the automatic paper detection mode by the paper type identification device 100 (S1), as shown in Figure 7, and commands the control unit 160 to start measurement (S2).

[0044] The control unit 160 of the paper type identification device 100 performs initialization processing in the mechanical property measurement unit 102 and the surface property measurement unit 103 in preparation for the insertion of a sheet S (paper) (S3). Next, the user inserts the sheet S into the guide path 101 of the paper type identification device 100 (S4), and waits until the upstream paper sensor 104 detects the insertion of the sheet S (No in S5). When the upstream paper sensor 104 detects the insertion of the sheet S (Yes in S5), the timer t starts counting from t=0.

[0045] The detection of sheet S by the upstream paper sensor 104 triggers the process (t=0). After a first predetermined time (t=t1) has elapsed, the optical sensor 130 performs multiple scans at predetermined cycle intervals according to a predetermined sequence to measure the surface of sheet S (S6). The measurement results are then processed by the ASIC in the control unit 160 and stored as surface quality data in the memory of the control unit 160. Here, as surface quality data, information such as the adjacent pixel difference integration value and brightness, as described later, is generated and stored.

[0046] Furthermore, triggered by the detection of sheet S by the upstream paper sensor 104 (t=0), the ultrasonic sensor 135 measures the transmittance of sheet S (paper) using ultrasound in a predetermined sequence after a second predetermined time (t=t2) (S7). The control unit 160 then converts the transmittance into basis weight information, and generates and stores the basis weight information in the memory of the control unit 160, similar to the surface properties data. To convert from ultrasonic transmittance to basis weight, the basis weight is determined using the ultrasonic transmission coefficient-basis weight conversion formula shown by the dashed line in Figure 9.

[0047] Next, the control unit 160, triggered by the detection of sheet S by the upstream paper sensor 104 (t=0), determines whether the timeout period (t=tout), which is the set time for timer t, has elapsed (S8). If timer t has not yet exceeded the timeout period (Yes in S8), it waits until the downstream paper sensor 105 detects sheet S (No in S10). If the downstream paper sensor 105 detects sheet S before timer t exceeds the timeout period (Yes in S10), the paper thickness of sheet S is measured by the paper thickness sensor 140 (S11), and paper thickness information is generated and stored in the memory of the control unit 160.

[0048] Furthermore, the control unit 160 determines that the sheet S had moved during measurement by the optical sensor 130 because the downstream paper sensor 105 detected the sheet S before the timeout period. In other words, it determines that the data was obtained correctly because scanning was performed not at the same location, but at multiple different locations (moved locations), resulting in more accurate data.

[0049] The control unit 160 then determines that all measurements have been completed successfully and notifies the main control unit 400 of the image forming apparatus 201 of the successful completion of the measurements via a signal. It also transmits the basis weight, surface properties, and paper thickness information (measurement data) generated and stored in the control unit 160 as measurement results to the main control unit 400 (S12). After that, the control unit 160 terminates the measurement process, and the main control unit 400 moves on to the paper type identification process to determine the paper type.

[0050] On the other hand, in step S8, if the timer t timeout period elapses before the downstream paper sensor 105 detects the sheet S (No. in S8), the measurement is stopped as an error (S9). That is, the control unit 160 determines that it has not obtained correct data about the surface properties of the paper, discards all data stored in the memory of the control unit 160, and sends error information to the main control unit 400 of the image forming apparatus 201. Then, as shown in Figure 10, the main control unit 400 displays a screen via the operation unit 502 prompting the user to reinsert the paper into the paper type identification device 100 to perform the measurement again. After the user confirms this instruction to reinsert the paper, the process returns to step S1 and the measurement process shown in Figure 7 is executed again.

[0051] As described above, in the measurement process according to this embodiment, the measurement of the optical sensor 130 is started when the upstream paper sensor 104 detects the sheet S, and the measurement of the optical sensor 130 is completed when the downstream paper sensor 105 detects the sheet S. This makes it possible to confirm that the measurement by scanning the sheet S in the optical sensor 130 was performed while the sheet S was moving, that is, it is possible to ensure that the surface properties of the paper are measured dynamically, thereby improving the accuracy of the measurement of the sheet's surface properties.

[0052] Furthermore, in the measurement process according to this embodiment, if the downstream paper sensor 105 does not detect the sheet S between the detection of the sheet S by the upstream paper sensor 104 and the timeout period, the measurement is stopped as an error. In this case, it means that the user's insertion of the sheet S stopped midway and was not inserted until it reached the stopper portion 108. Since the movement of the sheet S may have stopped midway, the scanning of the sheet S by the optical sensor 130 may be scanning the same position, resulting in incorrect measurement. Therefore, by stopping the measurement as an error, it is possible to prevent misidentification of the type of sheet S, and by prompting the user to measure again, the accuracy of measuring the surface properties of the sheet can be improved.

[0053] [Paper type identification process] Next, the paper type identification process performed by the main control unit 400 of the image forming apparatus 201 will be explained using Figures 11, 12, 13, 14, 15, and 16. Figure 11 is a flowchart showing the paper type identification process according to this embodiment, and Figure 12 is a diagram showing the relationship between the adjacent pixel difference integrated value, brightness, and sheet type. Figure 13 is a diagram showing the paper selection screen for paper settings according to this embodiment, and Figure 14 is a diagram showing the brand identification screen within the paper selection screen for paper settings. Figure 15 is a diagram showing the paper type data according to this embodiment, and Figure 16 is a diagram showing the paper reference data in which the relationship between the paper brand and the reference value of the measurement item according to this embodiment is recorded.

[0054] As described above, when the control unit 160 determines that correct measurement data has been obtained and the measurement data has been transmitted, the main control unit 400 performs paper type identification processing on the main control unit 400 (CPU) based on the received data to determine the type of paper.

[0055] First, as shown in Figure 11, the main control unit 400 classifies the paper type based on the surface quality measurement data (S21). Here, as an index of surface quality, as shown in Figure 12, a data table (matrix) is used, which is a pre-measured and classified data table of paper types with distinctive surface characteristics, with the adjacent pixel difference integrated value on the vertical axis and brightness on the horizontal axis. This adjacent pixel difference integrated value is the value obtained by accumulating the brightness difference of each adjacent pixel in the CIS132, and is an index that represents the unevenness of the sheet S (paper). Brightness is the integrated value (brightness) of the brightness value of each pixel received by the CIS132, and represents the brightness of the sheet S (paper).

[0056] For example, transparent films made of resins such as PET reflect less light from the LED 131, resulting in low brightness measurements. Also, with papers that have intentionally geometrically uneven surfaces, such as embossed paper, the unevenness increases the brightness difference between adjacent pixels, resulting in a large adjacent pixel difference cumulative value. Recycled paper also tends to be measured as having a rough surface because the grain direction of the paper is uneven and the pulp fibers become shorter after undergoing several recycling processes. Conversely, with coated paper, the surface coating layer makes the unevenness appear less pronounced, resulting in a small adjacent pixel difference cumulative value. In this way, the surface properties of the paper can be classified from the brightness information of each pixel in the CIS 132, making it possible to classify the paper according to the paper classification used in the image forming apparatus 201. The main control unit 400 then determines from the received measurement data which classification in the data table the adjacent pixel difference cumulative value and brightness of the paper belong to, and classifies the paper type based on its surface properties.

[0057] Next, the paper type is determined based on the basis weight of the sheet S (paper) in the received measurement data (S22). That is, the type of paper is determined by adding basis weight information to the paper classification based on surface properties described above. For example, if the paper type identification device 100 identifies GF-C081 paper manufactured by Canon Marketing Japan, the paper will be classified as plain paper 2.

[0058] Furthermore, the paper thickness of the sheet S (paper) in the received measurement data is used for determination (S23). In other words, the accuracy of basis weight estimation is improved by using the paper thickness information in the measurement data. For example, in coated paper, a white pigment such as clay (kaolin) or calcium carbonate and an adhesive (binder) such as starch are mixed together to form a coating, which is then applied to the surface of medium-grade paper, etc. Coated paper has a higher density than ordinary printing paper, which is mainly composed of pulp, and this affects the error in the ultrasonic transmission coefficient-basis weight conversion formula. Therefore, the accuracy of paper identification can be improved by using paper thickness information at the same time. In particular, adding paper thickness information is useful for identifying the brand of paper.

[0059] (Paper selection) Next, the process (S24) for determining the type information of the sheet S (paper) to be set in the image forming apparatus 201 in this embodiment will be described. As shown in Figure 13, the image forming apparatus 201 stores the types of paper settings that can be selected for each pre-set paper category. For example, the GF-C081 paper mentioned above is included in the paper category of plain paper 2 in terms of nominal basis weight, but it may be classified into a different paper category due to variations in the basis weight of the paper itself. Therefore, paper categories close to the category identified based on the measurement data (types of sheets different from the identified sheet type) are also displayed as candidates. Then, in this case, the paper category identified in accordance with the measurement of the paper type identification device 100 (types of sheets identified) are displayed as recommendations. When the user makes a selection operation from the paper categories displayed in this way (the main control unit 400 accepts the operation input), the type of sheet S used for image formation in the image forming apparatus 201 is set to the type of the selected paper category.

[0060] Furthermore, if the user selects "Go to Paper Brand Identification" in the lower left corner of the screen shown in Figure 13, the system will move to a paper brand identification screen, which is one example of a paper selection screen. The user can then confirm the paper brand on the paper brand identification screen shown in Figure 14 and select the paper brand, thereby setting the type of sheet S used for image formation in the image forming apparatus 201 to match the selected paper brand.

[0061] As described above, by selecting paper from the list of paper categories and paper brands, users can assign paper settings (sheet type settings) to the paper feed cassette 1 or manual feed tray 6, thereby enabling them to print with the correct print settings.

[0062] Furthermore, if the paper type or brand of sheet S that the user desires is not available on the paper selection screen shown in Figure 13 or Figure 14, the user can select "Automatically detect paper again" in the lower right corner of the screen and proceed back to the measurement process shown in Figure 7.

[0063] Furthermore, the paper type database 402 (see Figure 2) stores paper type data, as shown in Figure 15, which includes physical properties of various types of sheets, parameters for optimal image formation conditions, whether the paper can be fed into the image forming apparatus 201, and usable paper feed slots (paper feedable slots). In addition, the paper type database 402 (see Figure 2) also stores paper reference data, as shown in Figure 16, which associates reference values ​​such as basis weight, surface properties (integrated difference value of adjacent pixels, brightness), and paper thickness, which can be measured by the paper type identification device 100, with the brand information. The main control unit 400 refers to this paper type data and paper reference data and displays several highly similar candidates on the operation unit 502, allowing the user to easily select the type of sheet S and easily perform paper settings. Furthermore, once the paper type is determined, the paper classification is also determined. By determining the paper settings of the image forming apparatus 201 from the paper type data in Figure 15 and the paper reference data in Figure 16, it is possible to form (print) images with optimal quality without making mistakes in the paper settings.

[0064] [Possibility of other embodiments] In this embodiment, the paper type identification device 100 is merely an example and is not limited to this. In this embodiment, the paper type identification device 100 is equipped with a control unit 160 that processes information from the optical sensor 130, the ultrasonic sensor 135, and the paper thickness sensor 140 and transmits it to the main control unit 400 of the image forming apparatus 201. However, the measurement data obtained from each sensor may be transmitted directly to the main control unit 400, and various processing may be performed within the main control unit 400. Conversely, in this embodiment, the main control unit 400 is described as determining the type of sheet, but this is not limited to this, and the control unit 160 of the paper type identification device 100 may determine the type of sheet. In this case, it is conceivable to store the paper type database 402, which was previously provided by the image forming apparatus, in the paper type identification device 100.

[0065] Furthermore, although this embodiment describes an example where the detection of sheet S by the upstream paper sensor 104 is used as the trigger for starting the measurement, it is also possible to use the detection of sheet S by the downstream paper sensor 105 as the trigger for starting the measurement. In this case, the measurement would be performed when sheet S is pulled out from the paper type identification device 100. In short, the surface quality measurement of the sheet by the CIS 132 is started in response to a change in the detection result of either the upstream paper sensor 104 or the downstream paper sensor 105. Then, the measurement is completed in response to a change in the detection result of the other upstream paper sensor 104 or the downstream paper sensor 105.

[0066] Furthermore, in this embodiment, we have described a system in which a measurement error is treated if a timeout period elapses after the upstream paper sensor 104 detects the sheet S. However, the system is not limited to this, and for example, if the upstream paper sensor 104 detects the presence of sheet S, but the downstream paper sensor 105 does not detect the presence of sheet S, and the upstream paper sensor 104 detects the absence of sheet S, this may also be treated as a measurement error.

[0067] Furthermore, in this embodiment, an example was shown in which the settings of various control parameters in the image forming operation of the image forming apparatus 201 are determined by selecting the paper type and brand from the features detected by the paper type identification device 100. However, the invention is not limited to this, and the paper type identification device 100 may also directly set the various control parameters in the image forming operation from the measured paper feature quantities.

[0068] Furthermore, although this embodiment describes a system where the paper type database and main control unit are located within the image forming apparatus, these can also be located externally. For example, the paper type database and main control unit may reside in the cloud. In such a configuration, as long as the image forming apparatus is connected to the cloud via a network, it will always be possible to select the latest paper type settings and discrimination algorithm.

[0069] Furthermore, although this embodiment describes a configuration in which the paper type identification device 100 is installed in the image forming apparatus 201, it is not limited to this configuration. It may also be located outside the image forming apparatus 201 and configured to transmit and receive signals electrically via a network or the like.

[0070] Furthermore, in this embodiment, a configuration was described in which the lower guide surface 110a and the pressing surface 106a of the pressing member 106 are positioned opposite the upper guide surface 109a. However, the configuration is not limited to this, and the lower guide surface 110a may be omitted, and the pressing surface 106a of the pressing member 106 may be configured to be pressed against the upper guide surface 109a as a whole. Moreover, although a configuration in which the pressing member 106 is positioned on the lower block 110 was described, the opposite configuration is also possible, where the lower guide surface 110a of the lower block 110 is fixed, and the pressing member is positioned on the upper block 109, pressing the pressing surface of the pressing member against the lower guide surface 110a. In this case, it is preferable that the optical sensor 130 is positioned on the lower block 110. In short, the optical sensor 130 is positioned on one of the upper block 109 and the lower block 110, and one side surface in the thickness direction of the guide path 101 is formed. Furthermore, the other side of the upper block 109 and the lower block 110 should be provided with a biasing member that forms the other side surface in the thickness direction of the guide path 101 and biases the other side surface toward the one side surface.

[0071] In this embodiment, the ultrasonic transmitter 136 is located in the lower block 110 and the ultrasonic receiver 137 is located in the upper block 109. However, the opposite configuration is also possible, where the ultrasonic transmitter 136 is located in the upper block 109 and the ultrasonic receiver 137 is located in the lower block 110. In short, the ultrasonic transmitter 136 is located on one side of the sheet S in the thickness direction relative to the guide path 101, and the ultrasonic receiver 137 is located on the other side of the sheet in the thickness direction relative to the guide path.

[0072] Furthermore, in this embodiment, an upstream paper sensor 104 and a downstream paper sensor 105 were described to detect the movement of the sheet S during measurement by the optical sensor 130. However, the invention is not limited to this, and any configuration may be used as the movement detection unit to detect that the sheet S is moving relative to the scanning position of the CIS 312. For example, a configuration may be used to detect the movement of the sheet S using a roller that follows the sheet S and an encoder that detects the rotation of the roller. Alternatively, for example, a configuration may be used to read the movement of the sheet S using an image reading device or line sensor that can read in the insertion direction X.

[0073] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions. [Explanation of symbols]

[0074] 1...Feed cassette (sheet support part) / 6...Manual feed tray (sheet support part) / 100...Paper type identification device (identification device) / 101...Guide path / 104...Upstream paper sensor (first detection part, movement detection part) / 105...Downstream paper sensor (second detection part, movement detection part) / 107...Spring (biasing member) / 108...Butt stop part / 109...Upper block (guide member, first guide member) / 110...Lower block (guide (Component, Second Guide Component) / 131…LED (Light Source) / 132…CIS (Scanning Unit) / 135…Ultrasonic Sensor (Basis Weight Detection Unit) / 136…Ultrasonic Transmitter / 137…Ultrasonic Receiver / 140…Paper Thickness Sensor (Thickness Detection Unit) / 201…Image Forming Apparatus / 201B…Image Forming Unit / 400…Main Control Unit (Control Unit) / 502…Operation Unit (Operation Display Unit) / S…Sheet / X…Insertion Direction / tout…Setting Time

Claims

1. A guide member that forms a guide path for guiding an inserted sheet; A scanning unit that scans a sheet inserted into the guide path; a first detection unit that is disposed upstream of the scanning unit in a sheet insertion direction in the guide path and detects the presence or absence of a sheet; a second detection unit that is disposed downstream of the scanning unit in the insertion direction in the guide path and detects the presence or absence of a sheet, starting a measurement of the surface property of the sheet by the scanning unit in response to a change in the detection result of one of the first detection unit and the second detection unit, and completing the measurement in response to a change in the detection result of the other of the first detection unit and the second detection unit.

1. An identification device comprising:

2. if a set time has elapsed since the start of the measurement of the surface property before a change in the detection result of the other of the first detection unit and the second detection unit, the measurement is stopped as an error.

2. The identification device according to claim 1 .

3. When the measurement is completed, outputting information on the measurement result generated by the measurement; When the measurement is stopped, error information is output.

3. The identification device according to claim 2.

4. starting the measurement in response to detection of the sheet by the first detection unit, and completing the measurement in response to detection of the sheet by the second detection unit.

4. The identification device according to claim 1, wherein the identification device is a semiconductor integrated circuit.

5. a basis weight detection unit for detecting a basis weight of a sheet inserted into the guide path, a basis weight detection unit that starts detection in response to detection of the sheet by the first detection unit; 5. The identification device according to claim 4.

6. the basis weight detection unit has an ultrasonic transmitter arranged on one side of the guide path in the thickness direction of the sheet, and an ultrasonic receiver arranged on the other side of the guide path in the thickness direction of the sheet.

6. The identification device according to claim 5.

7. a thickness detection unit that detects the thickness of the sheet inserted into the guide path, In response to the second detection unit detecting the sheet, the thickness detection unit starts detection.

7. An identification device according to claim 4, wherein the identification device is a semiconductor integrated circuit.

8. the guide member has an abutment portion against which the sheet abuts downstream in the insertion direction, The second detection unit is disposed to detect the presence or absence of a sheet that has abutted against the abutment unit.

8. An identification device according to any one of the preceding claims.

9. The scanning unit includes a light source and a CIS that scans the surface of the sheet illuminated by the light source.

9. The identification device according to claim 1, wherein the identification device is a semiconductor integrated circuit.

10. The guide member includes a first guide member on which the scanning unit is disposed and which forms one side surface of the guide path in the thickness direction of the sheet, a second guide member which is disposed opposite to the first guide member and which forms the other side surface of the guide path in the thickness direction, and a biasing member which biases the second guide member toward the first guide member.

10. The identification device according to claim 1, wherein the identification device is a semiconductor integrated circuit.

11. A guide member that forms a guide path for guiding an inserted sheet; A scanning unit that scans a sheet inserted into the guide path; a movement detection unit that detects that the inserted sheet is moving, when the movement detection unit detects that the inserted sheet is moving at the scanning position of the scanning unit, the measurement of the surface property of the sheet by the scanning unit is completed.

1. An identification device comprising:

12. An identification device having, in an insertion direction in which a sheet is inserted, one end side being an opening through which the sheet is inserted and the other end side being abutting portion against which the sheet abuts, A reading sensor that reads the surface of the sheet; A first detection unit that detects the presence or absence of a sheet; a second detection unit that detects the presence or absence of a sheet, The first detection unit, the reading sensor, and the second detection unit are arranged in this order in the insertion direction.

1. An identification device comprising:

13. The reading sensor starts reading in response to detection of a sheet by the first detection unit, and ends reading in response to detection of a sheet by the second detection unit.

13. The identification device according to claim 12.

14. The reading sensor starts reading in response to the second detection unit no longer detecting the sheet, and ends reading in response to the first detection unit no longer detecting the sheet.

13. The identification device according to claim 12.

15. When the reading by the reading sensor is completed, a reading result is output.

13. The identification device according to claim 12.

16. If a set time has elapsed since the start of reading by the reading sensor before a change in the detection result of one of the first detection unit and the second detection unit that is not used in determining the start of reading, reading by the reading sensor is discontinued as an error.

13. The identification device according to claim 12.

17. When reading by the reading sensor is stopped, error information is output.

17. The identification device according to claim 16.

18. A basis weight detection unit for detecting the basis weight of a sheet, a basis weight detection unit that starts detection in response to detection of the sheet by the first detection unit; 13. The identification device according to claim 12.

19. The basis weight detection unit has an ultrasonic transmitter arranged on one side of a guide path that guides the sheet in a thickness direction of the sheet, and an ultrasonic receiver arranged on the other side of the guide path in the thickness direction of the sheet.

20. The identification device according to claim 18.

20. A thickness detection unit for detecting the thickness of an inserted sheet, In response to the second detection unit detecting the sheet, the thickness detection unit starts detection.

13. The identification device according to claim 12.

21. The reading sensor has a light source and a CIS that scans the surface of the sheet illuminated by the light source.

13. The identification device according to claim 12.

22. A first guide member in which the reading sensor is disposed and which forms one side surface in a thickness direction of the sheet with respect to a guide path that guides the sheet; a second guide member disposed opposite the first guide member and forming a surface on the other side of the guide path in the thickness direction; and a biasing member that biases the second guide member toward the first guide member.

13. The identification device according to claim 12.

23. An identification device according to any one of claims 1 to 22; a sheet support section for supporting a sheet whose surface properties have been measured by the identification device; and an image forming unit that forms an image on the sheet supported by the sheet supporting unit.

1. An image forming apparatus comprising:

24. a control unit that determines the type of sheet according to information on the measurement result generated by the measurement of the surface property; 24. The image forming apparatus according to claim 23.

25. an operation display unit that displays an image and receives an operation input; and the control unit, in response to the input of error information from the identification device, causes the operation display unit to display a message prompting the user to remeasure the surface property using the identification device.

25. The image forming apparatus according to claim 24.

26. When the control unit determines the type of sheet according to the information of the measurement result, the control unit displays the determined type of sheet and a type of sheet different from the determined type of sheet as candidates on the operation display unit, and accepts an operation input for selecting a type of sheet from the displayed types of sheet.

26. The image forming apparatus according to claim 25.

27. The identification device is disposed on an upper portion of the image forming device.

27. The image forming apparatus according to claim 23, wherein the image forming apparatus comprises:

Images