Optical sensor and method for manufacturing optical sensor

Abstract

To provide an optical sensor that can stably protect a mounted IC chip and improve workability during manufacture, and a method for manufacturing the same.SOLUTION: An optical sensor includes a circuit board, a light receiving and emitting unit mounted on the circuit board for emitting and receiving light, an IC chip mounted on the circuit board, and a coating layer made of a solidified coating agent and formed to cover and protect the IC chip, and the surface of the circuit board has a component mounting area and an attachment area arranged alongside the component mounting area and attached to the device main body, the IC chip is arranged in an area of the component mounting area adjacent to the attachment area, and the circuit board includes a first suppression unit arranged on the surface of the circuit board between the IC chip and the attachment area.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to optical sensors and methods for manufacturing the same. [Background technology]

[0002] An optical sensor is known that includes a light-emitting element that emits measurement light to be irradiated onto a measurement object and a light-receiving element that receives reflected light from the measurement light. The optical sensor is used, for example, to detect patch images formed on an intermediate transfer belt of a tandem image forming apparatus for measuring toner concentration and color shift. Patent Document 1 discloses an optical sensor that includes a sensor substrate that includes a light-emitting element and a light-receiving element for detecting reflected light from the patch image, and a circuit board that supports the sensor substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-128983 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide an optical sensor that can stably protect a mounted IC chip and improve workability during manufacturing, and a method for manufacturing the same. [Means for solving the problem]

[0005] An optical sensor according to one aspect of the present disclosure is an optical sensor mounted on a device main body, and comprises a circuit board, an optical receiving and emitting unit mounted on the circuit board for emitting and receiving light, an IC chip mounted on the circuit board, and a coating layer made of a solidified coating agent and formed to cover and protect the IC chip, wherein the surface of the circuit board has a component mounting area and an attachment area arranged alongside the component mounting area and attached to the device main body, the IC chip is arranged in an area of ​​the component mounting area adjacent to the attachment area, and the circuit board has a first suppression unit that suppresses placement of the IC chip on the surface of the circuit board between the IC chip and the attachment area.

[0006] A method for manufacturing an optical sensor according to another aspect of the present disclosure includes mounting an optical sensor light-emitting and receiving unit in a component mounting area of ​​a circuit board having the component mounting area and an attachment area for attachment to an apparatus main body, the optical sensor light-emitting and receiving unit emitting and receiving light in the component mounting area, mounting an IC chip in an area of ​​the component mounting area of ​​the circuit board adjacent to the attachment area, connecting terminals of the IC chip to the circuit board by wire bonding, forming a suppression portion on a surface of the circuit board between the IC chip and the attachment area, and forming a coating layer on the IC chip using the coating agent so as to cover the wire arranged by wire bonding and the IC chip while suppressing the coating agent from flowing into the attachment area using the suppression portion. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an optical sensor that can stably protect a mounted IC chip and improve workability during manufacturing, and a method for manufacturing the same. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows the internal structure of a color printer to which the optical sensor of the present disclosure is applied. [Figure 2]FIG. 2 is a perspective view showing an example of the arrangement of a concentration sensor, which is an example of an optical sensor. [Figure 3] 3A and 3B are schematic diagrams showing the principle of detecting black toner. [Figure 4] 4A and 4B are schematic diagrams showing the principle of color toner detection. [Figure 5] FIG. 5 is a simplified cross-sectional view showing a concentration sensor according to an embodiment of the present disclosure. [Figure 6] 6A and 6B are perspective views showing the appearance of a portion of a concentration sensor according to an embodiment of the present disclosure. [Figure 7] 7(A) is a top view of a portion of the concentration sensor shown in FIG. 6, FIG. 7(B) is a bottom view, and FIG. 7(C) is a side view. [Figure 8] FIG. 8(A) is a bottom view showing the concentration sensor according to the first embodiment of the present disclosure, and FIG. 8(B) is a side view of the same. [Figure 9] FIG. 9 shows data showing the value of the current that flows when a drive voltage is applied to an LED. [Figure 10] FIG. 10 is a graph plotting the data of FIG. 9, with the horizontal axis representing the drive voltage and the vertical axis representing the current. [Figure 11] FIG. 11 is an enlarged side view of the periphery of the IC chip of the concentration sensor according to the first embodiment of the present disclosure. [Figure 12] FIG. 12 is an enlarged view showing a state in which a coating agent is applied to the concentration sensor shown in FIG. [Figure 13] FIG. 13 is a flowchart showing a method for manufacturing a concentration sensor. [Figure 14] FIG. 14(A) is a bottom view showing the concentration sensor according to the second embodiment of the present disclosure, and FIG. 14(B) is a side view of the same. [Figure 15] FIG. 15 is a diagram showing a procedure for applying the coating agent shown in FIG. [Figure 16] 16(A) and (B) are diagrams showing the state of adhesion of the coating agent depending on the method of application of the coating agent. [Figure 17]FIG. 17 is an enlarged side view of the periphery of the IC chip of the concentration sensor according to the third embodiment of the present disclosure. [Figure 18] FIG. 18 is an enlarged plan view of the periphery of the IC chip of the concentration sensor according to the fourth embodiment of the present disclosure. [Figure 19] FIG. 19 is an enlarged plan view of the periphery of the IC chip of the concentration sensor according to the fifth embodiment of the present disclosure. [Figure 20] FIG. 20 is an enlarged plan view of the periphery of the IC chip of the concentration sensor according to the sixth embodiment of the present disclosure. [Figure 21] FIG. 21 is an enlarged plan view of the periphery of the IC chip of the concentration sensor according to the seventh embodiment of the present disclosure. [Figure 22] FIG. 22 is an enlarged plan view of the periphery of the IC chip of the concentration sensor according to the eighth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] An optical sensor according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. The optical sensor according to the present disclosure is a module that measures the physical properties of an object by irradiating the object with measurement light and receiving the reflected light. There are no particular limitations on the object to be measured, and the object may be a solid, semi-solid, liquid, powder, or the like. There are also no particular limitations on the physical properties to be measured, as long as they can be analyzed from the reflected light. For example, the optical sensor according to the present disclosure is suitable for measuring the color and density of the object to be measured. In the embodiment described below, an optical sensor that is installed in a color printer to detect the density of toner used in image formation will be exemplified.

[0010] [Color printer instructions] First, the configuration of a color printer to which the optical sensor of the present disclosure is applied will be described. FIG. 1 is a cross-sectional view that schematically shows the internal structure of a tandem color printer 1. The color printer 1 includes image forming units 2Y, 2C, 2M, and 2Bk, an optical scanning device 23, an intermediate transfer unit 28, and a fixing unit 29, all housed in a main body housing 10. A paper output tray 11 is provided on the top surface of the main body housing 10. A sheet output port 12 opens opposite the paper output tray 11. A manual paper feed tray 13 is provided on a side wall of the main body housing 10, and a paper feed cassette 14 that stores sheets for automatic paper feeding, etc., is provided in the bottom of the main body housing 10.

[0011] Image forming units 2Y, 2C, 2M, and 2Bk are units that form toner images of yellow, cyan, magenta, and black, respectively, and are arranged in tandem at a predetermined interval horizontally. Each image forming unit 2Y, 2C, 2M, and 2Bk includes a photosensitive drum 21 having a peripheral surface that supports an electrostatic latent image and a toner image, a charger 22 that charges the peripheral surface of the photosensitive drum 21, a developer 24 that applies developer to the electrostatic latent image to form a toner image, yellow, cyan, magenta, and black toner containers 25Y, 25C, 25M, and 25Bk, respectively, that supply toner of each color to the developer 24, a primary transfer roller 26 that performs primary transfer of the toner image formed on the photosensitive drum 21, and a cleaning device 27 that removes residual toner from the peripheral surface of the photosensitive drum 21. An optical scanning device 23 scans the peripheral surface of each photosensitive drum 21 with a beam in the main scanning direction as the scanned surface, forming an electrostatic latent image on the peripheral surface for forming a toner image.

[0012] The intermediate transfer unit 28 performs primary transfer of the toner images formed on the photosensitive drums 21. The intermediate transfer unit 28 includes a transfer belt 281 that rotates while contacting the circumferential surface of each photosensitive drum 21, and a drive roller 282 and a driven roller 283 around which the transfer belt 281 is wound. The toner images on the photosensitive drums 21 of each color are primarily transferred and superimposed onto the same location on the transfer belt 281. As a result, a full-color toner image is formed on the transfer belt 281. A secondary transfer roller 15 is disposed opposite the drive roller 282, sandwiching the transfer belt 281 between them to form a secondary transfer nip T. The full-color toner image on the transfer belt 281 is secondarily transferred onto a sheet at the secondary transfer nip T.

[0013] The fixing unit 29 includes a fixing roller 291 with a built-in heat source, and a pressure roller 292 that forms a fixing nip N together with the fixing roller 291. The fixing unit 29 applies heat and pressure to the sheet, onto which a toner image has been transferred in the secondary transfer nip T, in the fixing nip N, thereby performing a fixing process in which the toner is fused to the sheet. The sheet that has undergone the fixing process is discharged from the sheet discharge port 12 toward the paper discharge tray 11.

[0014] A density sensor 16 is disposed inside the main body housing 10. The density sensor 16 is an example of an optical sensor of the present disclosure. The density sensor 16 is disposed near the secondary transfer nip T, facing the outer circumferential surface of the transfer belt 281 on which the toner image is carried. The density sensor 16 optically detects the density of the toner image formed on the transfer belt 281 and converts it into an electrical signal.

[0015] FIG. 2 is a perspective view showing an example of the arrangement of the density sensor 16. In FIG. 2, the density sensor 16 is illustrated as a first density sensor 16A and a second density sensor 16B spaced apart from each other in the main scanning direction. The first density sensor 16A is disposed at a first density detection position DP1 on the toner carrying surface 28T of the transfer belt 281, and the second density sensor 16B is disposed at a second density detection position DP2, facing each other. The two density sensors 16A and 16B optically detect toner detection patches dp carried on the toner carrying surface 28T. The toner detection patches dp include, for example, density detection patches for detecting the toner concentration of each color and position detection patches for detecting the printing position of each color. The transfer belt 281 rotates in the direction indicated by the white arrow in FIG. 2. The first density sensor 16A detects the toner concentration along a first inspection line DL1 extending from the first density detection position DP1 in the sub-scanning direction. The second density sensor 16B detects the toner density along a second inspection line DL2 that extends in the sub-scanning direction from the second density detection position DP2. An embodiment in which only one of the first density sensor 16A and the second density sensor 16B is disposed opposite the transfer belt 281 may also be adopted.

[0016] [Toner detection principle] Next, the principle of optically detecting toner on transfer belt 281 will be described with reference to Figures 3 and 4. Figure 3 is a schematic diagram showing the detection principle of black toner BT, and Figure 4 is a schematic diagram showing the detection principle of color toner CT. A light-emitting element E1 and a light-receiving element E2 are arranged facing the toner carrying surface 28T of transfer belt 281. The light-emitting element E1 is, for example, an LED (Light Emitting Diode) that can emit light of a predetermined wavelength. The light-receiving element E2 is, for example, a PD (Photo Diode) that receives light, photoelectrically converts it, and outputs a current according to the amount of light.

[0017] FIG. 3A shows the light emission and reception state when there is no black toner BT on the transfer belt 281. The toner carrying surface 28T is a smooth surface that generates specular reflection when irradiated with light. Measurement light L1 is emitted from the light-emitting element E1. The measurement light L1 is irradiated at a predetermined emission angle θ1 toward the density detection position DP on the toner carrying surface 28T. The measurement light L1 is reflected by the toner carrying surface 28T, generating specularly reflected light L2. The specularly reflected light L2 is incident on the light-receiving element E2. The light-receiving element E2 outputs a current AM1 corresponding to the amount of light received.

[0018] FIG. 3B shows the light emission and reception state when black toner BT is present on the transfer belt 281. A portion of the measurement light L1 irradiated toward the toner carrying surface 28T is absorbed by the black toner BT. In other words, the specularly reflected light L2 is substantially not generated in the area of ​​the toner carrying surface 28T where black toner BT is present. As a result, the amount of specularly reflected light L2 incident on the light receiving element E2 decreases. The light receiving element E2 outputs a current AM2 corresponding to the reduced amount of light. Naturally, the relationship AM1>AM2 holds. Whether or not black toner BT is present is detected based on the fluctuation in the current output of the light emitting element E1 accompanying such a change in the amount of received specularly reflected light L2.

[0019] Figure 4(A) shows the light emission and reception state when no color toner CT is present on the transfer belt 281. Measurement light L1 is emitted from the light-emitting element E1. The emission optical system for measurement light L1 is adjusted so that measurement light L1 is irradiated onto the concentration detection position DP at an emission angle θ2 larger than the emission angle θ1 in Figure 3(A). Measurement light L1 is reflected by the toner carrying surface 28T, generating specularly reflected light L2. Light-receiving element E2 is positioned at a position where specularly reflected light L2 does not enter. Therefore, the output of light-receiving element E2 is essentially zero.

[0020] FIG. 4B shows the light emission and reception state when color toner CT is present on the transfer belt 281. A portion of the measurement light L1 irradiated toward the toner carrying surface 28T is irradiated onto the color toner CT and diffusely reflected. In other words, not all of the measurement light L1 becomes specularly reflected light L2, but a portion becomes diffusely reflected light L3. A portion of the generated diffusely reflected light L3 is incident on the light receiving element E2. The light receiving element E2 outputs a current AM3 corresponding to the amount of diffusely reflected light L3 received. The color toner CT is detected based on the change in output of the light receiving element E2 from 0 to AM3. The optical sensor described below applies the above-mentioned detection principle.

[0021] 5 is a cross-sectional view showing a portion of the concentration sensor 16 according to this embodiment. The concentration sensor 16 includes a sensor substrate 3, a lens unit 4, a first light-shielding wall 45, a second light-shielding wall 46, and a main substrate 105 (FIG. 8). As described above, the measurement target of the concentration sensor 16 is a toner patch printed on the toner carrying surface 28T of the transfer belt 281.

[0022] The sensor substrate 3 is mounted on a main substrate 105, which will be described in detail later, and functions as a light receiving and emitting unit that emits and receives light. The sensor substrate 3 includes a substrate 30 having a mounting surface 3M, and an element group 3E arranged in a row on the mounting surface 3M. A circuit pattern for mounting the element group 3E is printed on the mounting surface 3M of the substrate 30. The sensor substrate 3 is arranged so that the mounting surface 3M faces the toner carrying surface 28T. A semiconductor substrate such as a silicon substrate may be used as the substrate 30, and the sensor substrate 3 may be mounted in such a manner that each element of the element group 3E is directly formed on the semiconductor substrate.

[0023] The element group 3E includes a first light-emitting / light-receiving pair 31 for detecting black toner BT and a second light-emitting / light-receiving pair 32 for detecting color toners CT. The first light-emitting / light-receiving pair 31 consists of a first light-emitting element 33 and a first light-receiving element 34 arranged at a predetermined interval on the mounting surface 3M. The second light-emitting / light-receiving pair 32 consists of a second light-emitting element 35 and a second light-receiving element 36 arranged at a predetermined interval on the mounting surface 3M at a position different from the first light-emitting / light-receiving pair 31.

[0024] The first light-emitting element 33 and the second light-emitting element 35 are LEDs that emit light of a predetermined wavelength. The first light-receiving element 34 and the second light-receiving element 36 are PDs that output a current corresponding to the amount of light received. The elements of the element group 3E are arranged in a line in the main scanning direction shown in FIG. 2. Specifically, the elements of the element group 3E are arranged in a line on the mounting surface 3M in the order of the first light-emitting element 33, the first light-receiving element 34, the second light-receiving element 36, and the second light-emitting element 35. The elements of the element group 3E do not necessarily have to be arranged in a strict line, and may be arranged in a line with an offset that is equivalent to a line. The arrangement direction of the element group 3E may also be the sub-scanning direction.

[0025] The lens unit 4 is disposed in front of the mounting surface 3M, i.e., between the sensor substrate 3 and the toner carrying surface 28T. The lens unit 4 includes a first lens portion 41, a second lens portion 42, a third lens portion 43, and a fourth lens portion 44 as lenses that condense light. On the optical path of the first light-emitting / receiving pair 31, the first lens portion 41 is disposed in front of the first light-emitting element 33, and the second lens portion 42 is disposed behind the first light-receiving element 34. On the optical path of the second light-emitting / receiving pair 32, the third lens portion 43 is disposed in front of the second light-emitting element 35, and the fourth lens portion 44 is disposed behind the second light-receiving element 36. These four lens portions are held by a holder portion 40.

[0026] The first lens unit 41 collects light emitted by the first light-emitting element 33 to generate a first measurement light beam L11 that is irradiated as a spot at a predetermined position on the toner carrying surface 28T. The second lens unit 42 collects specularly reflected light L2 from the first measurement light beam L11 that is reflected by the toner carrying surface 28T and guides the light to the first light-receiving element 34. In other words, the first light-receiving element 34 is positioned to receive the specularly reflected light L2. The third lens unit 43 collects light emitted by the second light-emitting element 35 to generate a second measurement light beam L12 that is irradiated as a spot at a predetermined position on the toner carrying surface 28T. The fourth lens unit 44 collects diffusely reflected light L3 from the second measurement light beam L12 that is reflected by the toner carrying surface 28T and guides the light to the second light-receiving element 36. The second light-receiving element 36 is positioned to receive the optical image of the diffusely reflected light L3 generated by the fourth lens unit 44.

[0027] The first light-shielding wall 45 and the second light-shielding wall 46 are non-transparent members that do not allow light to pass through. The first light-shielding wall 45 is disposed in front of the mounting surface 3M, between the first light-emitting element 33 and the first light-receiving element 34. The first light-shielding wall 45 prevents light emitted from the first light-emitting element 33 from traveling directly toward the first light-receiving element 34 without passing through the toner carrying surface 28T. In other words, the first light-shielding wall 45 prevents light before being collected by the first lens unit 41 from being received by the first light-receiving element 34. The second light-shielding wall 46 is disposed in front of the mounting surface 3M, between the second light-emitting element 35 and the second light-receiving element 36. The second light-shielding wall 46 prevents light emitted from the second light-emitting element 35 from traveling directly toward the second light-receiving element 36. In other words, the second light-shielding wall 46 prevents light before being collected by the third lens unit 43 from being received by the second light-receiving element 36.

[0028] An open space OS is provided in front of the mounting surface 3M between the first light-emitting and light-receiving pair 31 and the second light-emitting and light-receiving pair 32, or in this embodiment, between the first light-receiving element 34 and the second light-receiving element 36. The open space OS is a non-light-shielding space in which there are essentially no light-shielding components. The open space OS is partitioned by the first light-shielding wall 45, the second light-shielding wall 46, and the lens unit 4. Note that the open space OS does not have to be a complete space, and small protrusions or structures that do not have an optical effect may be present.

[0029] [Description of Appearance of Part of the Concentration Sensor According to the First Embodiment (Appearance of the Sensor Substrate, Lens Unit, and Housing)] Next, the concentration sensor 16 will be described in detail with reference to Figures 6 and 7. Figure 6(A) is a perspective view from below showing the appearance of a portion of the concentration sensor 16 according to the first embodiment, and Figure 6(B) is a perspective view from above. Figure 7(A) is a top view of a portion of the concentration sensor 16, Figure 7(B) is a bottom view, and Figure 7(C) is a side view.

[0030] The concentration sensor 16 includes a housing 6 in addition to the sensor substrate 3 and lens unit 4 described above. The lens unit 4 and housing 6 each correspond to an example of a cover member in the present disclosure. As shown in FIG. 7(B), the lens unit 4 includes a lens portion 4R that focuses light and a holder portion 40 that holds the lens portion 4R. As described above, the lens portion 4R includes a first lens portion 41, a second lens portion 42, a third lens portion 43, and a fourth lens portion 44 (see FIG. 5). These four lens portions 41, 42, 43, and 44 are arranged in series in the arrangement direction of the element group 3E to form a lens block. The holder portion 40 has a rectangular parallelepiped shape that surrounds the lens block, and the upper surface of the holder portion 40 is recessed in the area of ​​the lens block.

[0031] The lens unit 4 includes a pair of first support columns 145 and a pair of second support columns 146 for positioning the lens portion 4R. For example, each of the pair of first support columns 145 and the pair of second support columns 146 is a cylindrical body. The pair of first support columns 145 and the pair of second support columns 146 protrude from the underside of the holder portion 40. Each of the first support columns 145 and each of the second support columns 146 extends from the lens portion 4R toward a circuit board 150 (described below). Each of the first support columns 145 protrudes from one diagonal corner of the rectangular lens unit 4. Each of the second support columns 146 is provided near the other diagonal corner of the lens unit 4 and is a convex portion that protrudes less from the underside of the holder portion 40 than the first support columns 145. The first support columns 145 are protrusions that mainly position the lens unit 4 in the horizontal direction (the direction along the board). The second support column 146 is a positioning protrusion for the lens unit 4 in the height direction.

[0032] The housing 6 is a rectangular parallelepiped housing that includes a bottom plate 61 and side plates 62 and has a cavity capable of accommodating the lens unit 4. The lens unit 4 is fitted into the housing 6. The bottom plate 61 faces the underside of the lens unit 4. The side plates 62 stand upright from the periphery of the bottom plate 61 and cover the side surfaces of the lens unit 4. The bottom plate 61 and the side plates 62 are adhesively fixed at the outer periphery of the bottom plate 61 and are integrated together.

[0033] [Explanation of the remaining part of the concentration sensor (main board)] Next, the main board 105 will be described with reference to FIG. 8. FIG. 8(A) is a bottom view showing the main board 105 according to the first embodiment of the present disclosure, and FIG. 8(B) is a side view of the same. The main board 105 of the concentration sensor 16 supports the sensor board 3 and includes various electronic components. The main board 105 is attached to the device body of the color printer 1. As shown in each view of FIG. 8, the main board 105 has a circuit board 150, and an IC chip 51, a connector 52, and contact pads 73 mounted on the circuit board 150. The contact pads 73 are an example of connection terminals in the present disclosure. Note that other electronic components are also mounted on the circuit board 150, but their description will be omitted here.

[0034] The circuit board 150 is made of a rectangular plate-like member extending in a predetermined longitudinal direction. This direction is the same as the direction in which the first light-emitting element 33, the first light-receiving element 34, the second light-emitting element 35, and the second light-receiving element 36 are arranged. The circuit board 150 has a first surface S1 (upper surface) and a second surface S2 (lower surface) that is the surface opposite the first surface S1 in the thickness direction. The first surface S1 and the second surface S2 each extend in the longitudinal direction and the width direction of the circuit board 150. As an example, the circuit board 150 is made of epoxy glass. Furthermore, the sensor substrate 3 shown in FIG. 5 is mounted on the first surface S1 of the circuit board 150 at approximately the center in the longitudinal direction, as shown in FIG. 8.

[0035] Meanwhile, the second surface S2 of the circuit board 150 has a component mounting area M1 and a pair of component mounting prohibited areas M2. The component mounting prohibited area M2 is an example of an attachment area of ​​the present disclosure. The component mounting prohibited area M2 is arranged next to the component mounting area M1 and is attached to the main body housing 10 (device main body) of the color printer 1.

[0036] Specifically, a first opening H1 and a second opening H2 are formed in the pair of component mounting prohibited areas M2. The first opening H1 is a circular opening in the circuit board 150. The second opening H2 is an elongated hole-shaped opening in the circuit board 150 on the opposite side from the first opening H1. Fixing bolts are inserted into the first opening H1 and the second opening H2 when the density sensor 16 is attached to the main housing 10 (apparatus main body) of the color printer 1. The outer end of the second opening H2 may be open to the edge of the circuit board 150. In other words, the second opening H2 may have a notched edge of the circuit board 150. The second opening H2 may be a circular opening in the circuit board 150, and the first opening H1 may be an elongated hole-shaped opening.

[0037] The circuit board 150 further has wiring 81 arranged inside the circuit board 150 or on the second surface S2. The wiring 81 is electrically connected to the circuit pattern of the substrate 30, the IC chip 51, the connector 52, and the contact pads 73. In other words, the wiring 81 electrically connects the first light-emitting element 33, the first light-receiving element 34, the second light-emitting element 35, the second light-receiving element 36, the IC chip 51, the connector 52, and the contact pads 73.

[0038] The circuit board 150 also has a circuit board main body 150a and a resin film 150b formed on the first surface S1 and the second surface S2 of the circuit board main body 150a to protect the circuit board main body 150a and the wiring 81. The resin film 150b is an example of a protective film of the present disclosure. One example of the resin film 150b is a known solder resist. The resin film 150b may be made of a green resin layer. The circuit board main body 150a may be made of a semiconductor substrate such as a silicon substrate. The circuit board 150 does not necessarily have to have the resin film 150b.

[0039] [Connector Description] The connector 52 is disposed in the component mounting area M1. The connector 52 receives a connector terminal (not shown) extending from the main body housing 10 of the color printer 1, enabling the transmission and reception of drive voltages and various signals between the main body housing 10 and the density sensor 16.

[0040] FIG. 9 shows data representing the current values ​​that flow when a drive voltage is applied to the LEDs (first light-emitting element 33, second light-emitting element 35). FIG. 10 is a graph plotting the data from FIG. 9, with the drive voltage on the horizontal axis and the current on the vertical axis. As shown in FIG. 10, when the drive voltage is between 0V and 0.15V, no current (0 mA) flows through the LEDs. This was because the design prevented the application of a drive voltage of 5V to the LEDs. However, for some reason, a voltage was applied to the LEDs, causing current to flow through them and light emission. In contrast, as described above, when the drive voltage is between 0V and 0.15V, no current flows through the LEDs. This reduces the possibility that a drive voltage of 0.15V or less will cause no current to flow through the LEDs, resulting in light emission. When the drive voltage is 0.15V or higher, the current exhibits a nearly constant slope relative to the drive voltage. Here, the specification to prevent current from flowing can be achieved, for example, by using a voltage detector such as a voltage detector that monitors the drive voltage and outputs a current when the drive voltage exceeds a set value (0.15 V in this case).

[0041] [IC chip explanation] The IC chip 51 includes a core chip, which is an integrated circuit. The IC chip 51 is mounted on the circuit board 150 using a COB (Chip On Board) method and is electrically connected by wire bonding. A coating layer 50S, which will be described in detail later, is formed on the IC chip 51. As shown in FIG. 8, the IC chip 51 is disposed in an area of ​​the component mounting area M1 adjacent to the component mounting prohibited area M2. More specifically, one side edge of the IC chip 51 is disposed adjacent to a first protrusion 50A (pattern printed area) described later. The IC chip 51 is disposed near the first protrusion 50A on the side opposite the connector 52. Of the first opening H1 and the second opening H2, the IC chip 51 is disposed closer to the second opening H2. As shown in FIG. 8A, the IC chip 51 and the connector 52 are disposed on opposite sides of each other in the short-side direction of the main board 105.

[0042] Next, the coating layer 50S in Fig. 8(A) will be described in detail. Fig. 11 is an enlarged side view of the periphery of the IC chip 51 of the concentration sensor 16 according to the first embodiment. Fig. 12 is an enlarged view showing the concentration sensor 16 shown in Fig. 11 in which a coating agent S has been applied. As shown in Fig. 12, the main substrate 105 further includes a coating layer 50S.

[0043] The coating layer 50S is made of a solidified coating agent S and is formed to cover and protect the wires W and the IC chip 51. As an example, the wires W are made of Au wires. Note that Fig. 12 shows the connection portion of the wires W on the circuit board 150 side (substrate-side connection portion WS).

[0044] As shown in FIG. 11, an IC chip 51 is placed on a circuit board 150 via Ag paste AP and electrically connected by wire bonding using wires W. Thereafter, a coating agent S is discharged from a needle 100 (application nozzle) to form a coating layer 50S (FIG. 12) so as to cover the wires W and the IC chip 51. As an example, an air pulse dispenser can be used for the needle 100. Also, as an example, the height h of the wires W relative to the circuit board 150 in FIG. 11 is about 0.5 mm to 0.6 mm.

[0045] [Explanation of the first suppression section] As described above, in the concentration sensor 16, the control IC (IC chip 51) is mounted on the circuit board 150 by wire bonding and then covered with the coating agent S. Conventionally, the coating agent S tends to spread along the surface of the circuit board 150 before solidification, which can lead to problems such as poor appearance of the concentration sensor 16, reduced protection performance for the control IC, and long manufacturing times due to poor workability during manufacturing.

[0046] As described above, when the density sensor 16 is attached to the main housing 10 (device main body) of the color printer 1, the fixing bolts are inserted through the first opening H1 and the second opening H2 formed in the component mounting prohibited area M2. In the first embodiment, as shown in FIG. 8 , the IC chip 51 is disposed near the component mounting prohibited area M2. Therefore, when the coating agent S is applied to the IC chip 51, it is necessary to prevent the coating agent S from flowing into the component mounting prohibited area M2 so that a solidified product of the coating agent S does not form in the component mounting prohibited area M2. The main board 105 further includes a pattern printed portion 500 made of a solidified printing paint. The printing paint may be a white paint. The viscosity of the printing paint is higher than that of the coating agent S. In other words, the printing paint is less likely to flow on the surface of the circuit board 150 than the coating agent S.

[0047] The pattern printing unit 500 has a pair of first protrusions 50A. The first protrusions 50A are an example of a first prevention unit of the present disclosure. The first protrusions 50A prevent the coating agent S from flowing into the component mounting prohibited area M2 when the coating agent S is applied to the IC chip 51.

[0048] Specifically, the first protrusions 50A protrude from the surface of the circuit board 150. As an example, the first protrusions 50A are white linear portions formed on the circuit board 150. The height of the first protrusions 50A relative to the circuit board 150 is about 30 to 50 mm.

[0049] Furthermore, the first protrusions 50A are disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the component mounting prohibited area M2. In other words, the first protrusions 50A are disposed in a peripheral area surrounding the IC chip 51. The area sandwiched between the pair of first protrusions 50A corresponds to the component mounting area M1. The areas longitudinally outward of each first protrusion 50A correspond to the pair of component mounting prohibited areas M2. In this way, in the first embodiment, the first protrusions 50A separate the component mounting area M1 from the component mounting prohibited area M2.

[0050] As described above, in this embodiment, the first protrusion 50A is disposed between the IC chip 51 and the component mounting prohibited area M2 as a first suppression section. Therefore, when the coating agent S is applied to the IC chip 51, the first protrusion 50A blocks the coating agent S and prevents it from flowing into the component mounting prohibited area M2. As a result, no solidified coating agent S forms around the first opening H1 or the second opening H2. Therefore, the fixing bolts are not obstructed by the solidified coating agent S and can be inserted into the appropriate positions of the first opening H1 or the second opening H2. Therefore, the density sensor 16 is mounted in an appropriate position on the main housing 10 (device main body) of the color printer 1. As a result, the density sensor 16 can accurately detect the density of the toner image.

[0051] Furthermore, in the first embodiment, the first convex portion 50A serving as the first suppression portion is made of a solidified printed paint, and therefore the first convex portion 50A can be easily formed on the circuit board 150 by applying the printed paint.

[0052] Furthermore, in the first embodiment, the first convex portion 50A as the first suppression portion is arranged in the peripheral region, which is the region surrounding the IC chip 51, so that the coating agent S is less likely to flow out of the IC chip 51, and therefore the coating agent S can be prevented from flowing into the component mounting prohibited region M2.

[0053] [Explanation of the second suppression section] Referring again to FIG. 8, the main board 105 will be described in detail. As shown in FIG. 8, a first hole K1 and a second hole K2 are formed in the component mounting area M1 so as to penetrate from the first surface S1 to the second surface S2. The first hole K1 and the second hole K2 are examples of through holes of the present disclosure. As an example, the first hole K1 is circular, and the second hole K2 is formed in an elongated hole shape along the longitudinal direction of the circuit board 150. The tip end of the first support 145 is inserted into each of the first hole K1 and the second hole K2. The inner diameter of the first hole K1 and the inner diameter of the second hole K2 in the lateral direction are set to correspond to the outer diameter of the tip end of the first support 145.

[0054] Of the first opening H1 and the second opening H2, the first hole K1 is formed in a position close to the first opening H1 in the component mounting area M1. On the other hand, of the first opening H1 and the second opening H2, the second hole K2 is formed in a position close to the second opening H2 in the component mounting area M1. As a result, the first hole K1 restrains one of the pair of first pillars 145 in the longitudinal direction and the lateral direction along the surface of the circuit board 150, and the second hole K2 restrains the other of the pair of first pillars 145 in the lateral direction of the circuit board 150, thereby positioning the lens unit 4.

[0055] In addition to the first hole K1 and the second hole K2 that penetrate from the first surface S1 to the second surface S2, a pair of contact portions may be formed on the first surface S1 to contact the tip surfaces of the pair of second pillars 146. The contact portions may be positioned with a slight step relative to the first surface S1. The tip surfaces of the second pillars 146 contact each contact portion to position the lens unit 4 in the thickness direction.

[0056] As described above, when the lens unit 4 is attached to the main substrate 105, the first support 145 is inserted into the second hole K2. As shown in Fig. 8, the IC chip 51 is disposed near the second hole K2, and therefore, when the coating agent S is applied to the IC chip 51, it is necessary to prevent the coating agent S from flowing into the second hole K2 so as to prevent a solidified substance of the coating agent S from being formed around the second hole K2.

[0057] The pattern printed portion 500 described above further includes a second protrusion 502a protruding from the surface of the circuit board 150. The second protrusion 502a is an example of a second suppression portion of the present disclosure. The second protrusion 502a suppresses the coating agent S from flowing into the second hole K2 when the coating agent S is applied to the IC chip 51. As an example, the second protrusion 502a is a white linear portion provided on the circuit board 150. The height of the second protrusion 502a relative to the circuit board 150 is approximately 30 to 50 mm. The second protrusion 502a is disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the second hole K2.

[0058] The main substrate 105 further includes an exposed portion 502b where the surface of the circuit board main body 150a is exposed. The exposed portion 502b is an example of the second suppression portion or second exposed portion of the present disclosure. The exposed portion 502b prevents the coating agent S from flowing into the second hole K2 when the coating agent S is applied to the IC chip 51. The exposed portion 502b is an exposed portion of the surface of the circuit board main body 150a where the resin film 150b is not disposed so as to surround the second hole K2. This surface has lower wettability with respect to the coating agent S than the wettability between the resin film 150b and the coating agent S. Because the low wettability makes it difficult for the coating agent S to flow across the surface, the coating agent S flowing from the IC chip 51 side tends to stagnate in the second exposed portion 502b, preventing the coating agent S from flowing into the second hole K2.

[0059] The exposed portion 502b is disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the second hole K2. Specifically, the exposed portion 502b is closer to the second hole K2 than the second protrusion 502a and is disposed around the entire periphery of the second hole K2.

[0060] As described above, in the first embodiment, the exposed portion 502b and the second convex portion 502a are disposed between the IC chip 51 and the second hole K2 as the second suppression portion. Therefore, the exposed portion 502b and the second convex portion 502a block the coating agent S and prevent it from flowing into the second hole K2. As a result, no solidified coating agent S is formed around the second hole K2, and the first support column 145 is not obstructed by the solidified coating agent S and can be inserted into the second hole K2 at an appropriate position. Therefore, the lens unit 4 is mounted at an appropriate position on the main substrate 105. As a result, the density sensor 16 can accurately detect the density of the toner image.

[0061] Furthermore, in the first embodiment, the exposed portion 502b is closer to the second hole portion K2 than the second convex portion 502a and is arranged around the entire circumference of the second hole portion K2. Therefore, even if the coating agent S overcomes the second convex portion 502a, the coating agent S that has overcome the second convex portion 502a will remain in the exposed portion 502b, thereby preventing the coating agent S from flowing toward the second hole portion K2.

[0062] [Explanation of the third suppression section] Further, the main substrate 105 will be described in detail with reference to Fig. 8. As shown in Fig. 8, the contact pads 73 are arranged in the component mounting area M1. The contact pads 73 are, for example, conductors having a circular shape in a plan view. The contact pads 73 are electrically connected to the wiring 81.

[0063] The contact pads 73 are electrically connected to the connector 52 via wiring 81. This allows an inspector to test whether the connector 52 and the sensor board 3 are electrically connected by touching a probe or the like to the contact pads 73 before mounting the density sensor 16 in the main body housing 10 of the color printer 1.

[0064] As described above, before mounting the density sensor 16 in the main body housing 10 of the color printer 1, an inspector applies a probe or the like to the contact pad 73 to accurately test whether or not the connector 52 and the sensor board 3 are electrically connected. As shown in Figure 8, the IC chip 51 is disposed near the contact pad 73, and therefore, when applying the coating agent S to the IC chip 51, it is necessary to prevent the coating agent S from reaching the contact pad 73 so that a solidified substance of the coating agent S does not form around the contact pad 73.

[0065] The pattern printing unit 500 further includes a third protrusion 503 that protrudes in a ring shape from the surface of the circuit board 150 so as to surround the contact pad 73. The third protrusion 503 is an example of a third suppression unit of the present disclosure. The third protrusion 503 suppresses the coating agent S from reaching the contact pad 73 when the coating agent S is applied to the IC chip 51. As an example, the third protrusion 503 is a white linear portion provided on the circuit board 150. The height of the third protrusion 503 relative to the circuit board 150 is approximately 30 to 50 mm. The third protrusion 503 is also disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the contact pad 73.

[0066] As described above, in the first embodiment, the third protrusion 503 serving as the third suppression section is disposed between the IC chip 51 and the contact pad 73, and therefore the coating agent S is blocked by the third protrusion 503, preventing it from reaching the contact pad 73. As a result, no solidified matter of the coating agent S is formed around the contact pad 73, and therefore the probe or the like can be applied to the contact pad 73 without being obstructed by the solidified matter of the coating agent S. Therefore, before attaching the concentration sensor 16 to the main body housing 10 of the color printer 1, an inspector can accurately test whether the connector 52 and the sensor board 3 are electrically connected by applying a probe or the like to the contact pad 73.

[0067] In addition, in the first embodiment, the third convex portion 503 serving as the third suppression portion is made of a solidified printed paint, and therefore the third convex portion 503 can be easily formed on the circuit board 150 by applying the printed paint.

[0068] [Manufacturing method of concentration sensor] Next, a method for manufacturing concentration sensor 16 will be described with reference to Fig. 13. Fig. 13 is a flowchart showing the method for manufacturing concentration sensor 16. As shown in Fig. 13, the method for manufacturing concentration sensor 16 includes a preparation step (step S101), a resin film formation step (step S102), a pattern printing portion formation step (step S103), an IC chip mounting step (step S104), a wire bonding step (step S105), and a coat layer formation step (step S106).

[0069] In the preparation step (step S101), the circuit board body 150a is prepared, that is, the circuit board 150 on which the resin film 150b is not formed is prepared.

[0070] In the resin film forming step (step S102), a solder resist is applied to the first surface S1 and the second surface S2 of the circuit board main body 150a, thereby forming a resin film 150b on the first surface S1 and the second surface S2 of the circuit board main body 150a. At this time, the entire periphery of the second hole portion K2 is masked, the solder resist is applied, and the mask is removed, thereby forming an exposed portion 502b on the circuit board 150. In other words, in the resin film forming step (step S102), the exposed portion 502b is formed as a suppression portion. Note that after the resin film 150b is formed, the exposed portion 502b may be formed by scraping off the resin film 150b.

[0071] In the pattern-printed portion forming step (step S103), a printing paint is applied to the surface of the circuit board 150 to form a pattern-printed portion 500 on the surface of the circuit board 150. In other words, in the pattern-printed portion forming step (step S103), a first convex portion 50A, a second convex portion 502a, and a third convex portion 503 are formed as suppression portions.

[0072] In the IC chip mounting step (step S104), an IC chip 51 is mounted in an area of ​​the component mounting area M1 of the circuit board 150 adjacent to the component mounting prohibited area M2.

[0073] In the wire bonding step (step S105), the terminals of the IC chip 51 and the circuit board 150 are connected by wire bonding.

[0074] In the coating layer formation process (step S106), the coating agent S is used to form a coating layer 50S on the IC chip 51 so as to cover the wire W arranged by wire bonding and the IC chip 51, while preventing the coating agent S from reaching the component mounting prohibited area M2, the second hole portion K2, and the contact pad 73 by the first convex portion 50A, the second convex portion 502a, the exposed portion 502b, and the third convex portion 503.

[0075] As described above, in the first embodiment, the first convex portion 50A, the second convex portion 502a, the exposed portion 502b, and the third convex portion 503 can be easily formed by the resin film forming process (step S102) and the pattern printing portion forming process (step S103). Furthermore, the first convex portion 50A, the second convex portion 502a, the exposed portion 502b, and the third convex portion 503 can prevent the coating agent S from reaching the component mounting prohibited area M2, the second hole portion K2, and the contact pad 73, making the method more applicable to automatic application of the coating agent S. Note that the prevention portion of the present disclosure may be formed in either the resin film forming process (step S102) or the pattern printing portion forming process (step S103).

[0076] [Concentration sensor according to the second embodiment] Furthermore, to prevent the coating agent S from reaching the component mounting prohibited area M2, it is desirable for the viscosity of the coating agent S to be low. In the second embodiment, with reference to FIGS. 14(A) and 14(B), a case will be described in which a first protrusion 50A serving as a first suppression section is disposed on the circuit board 50 and a coating agent S having a thixotropy of 4.5 or more and 6.5 or less is used. FIG. 14(A) is a rear view of a concentration sensor 16 according to an embodiment of the present disclosure, and FIG. 14(B) is a side view of the same. The main board 5 of the concentration sensor 16 supports the sensor board 3 and includes various electronic components. The main board 5 is fixed to the device body of the color printer 1. As shown in each view of FIG. 14, the main board 5 includes a circuit board 50, an IC chip 51 mounted on the circuit board 50, and a connector 52. Other electronic components are also mounted on the circuit board 50, but their description will be omitted here.

[0077] The circuit board 50 is made of a rectangular plate-like member extending in a predetermined longitudinal direction. This direction is the same as the direction in which the first light-emitting element 33, the first light-receiving element 34, the second light-emitting element 35, and the second light-receiving element 36 are arranged. As an example, the circuit board 50 is made of epoxy glass. The sensor board 3 shown in FIG. 5 is mounted on one surface of the circuit board 50, approximately in the center in the longitudinal direction, as shown in FIG. 14. Wiring and circuits (not shown) are formed on the circuit board 50, and electrically connect the elements of the sensor board 3, the IC chip 51, the connector 52, etc. to each other.

[0078] The circuit board 50 has a component mounting area M1 and a pair of component mounting prohibited areas M2. In addition, a pair of first protrusions 50A (pattern printed areas) are formed on the circuit board 50. As an example, the circuit board 50 is made of a green base material, and the first protrusions 50A are white linear areas applied to the board. In other words, the area sandwiched between the pair of first protrusions 50A corresponds to the component mounting area M1. The areas longitudinally outward of each first protrusion 50A correspond to the pair of component mounting prohibited areas M2. In this way, in the second embodiment, the component mounting area M1 and the component mounting prohibited areas M2 are separated by the first protrusions 50A.

[0079] As shown in FIG. 11, in order to eject the coating agent S from the needle 100, it is desirable that the viscosity of the coating agent S be low. On the other hand, as shown in FIG. 14, since the IC chip 51 is located near the component mounting prohibited area M2, it is necessary to suppress the flow of the coating agent S after application. For this reason, in the second embodiment, a coating agent S with low viscosity and high thixotropy is used. Thixotropy (TI value) indicates the property of viscosity change when an external force is applied, and a coating agent with higher thixotropy has a higher viscosity in a static state and a lower viscosity in a dynamic state. By using a coating agent S with high thixotropy, it is possible to achieve both good application performance and shape retention after application.

[0080] The thixotropy of the coating agent S is preferably 4.5 or more and 6.5 or less, and more preferably 5.0 or more and 6.0 or less, under the conditions of 2 rpm / 20 rpm. In this case, the flow of the coating agent S during application can be further suppressed. The thixotropy is calculated from the ratio of viscosity values ​​at two rotation speeds. As described above, in the second embodiment, the viscosity is measured at two rotation speeds, 2 rpm and 20 rpm.

[0081] Furthermore, the viscosity of the coating agent S is preferably 80 to 100 (Pa·sec) when rotating at 20 rpm, ensuring the fluidity of the coating agent S within the nozzle of the needle 100 and improving the workability of the application process.

[0082] Fig. 15 is a diagram showing the procedure for applying the coating agent S in Fig. 12. Figs. 16(A) and (B) are diagrams showing the adhesion state of the sealing resin depending on the method of applying the coating agent S. In the second embodiment, as shown in Fig. 15, starting from the outside of the substrate-side connection portion WS in wire bonding, the coating agent S is applied in a single stroke from the outside of the IC chip 51 toward the center, from S1 to S10 in Fig. 15. In other words, the coating agent S is continuously applied in a spiral shape from the outside of the wire W toward the center of the IC chip 51.

[0083] As a result, as shown by the arrows in Fig. 16(A), the coating agent S enters from the outside of the wire W, thereby densely covering the periphery of the IC chip 51. On the other hand, as shown in Fig. 16(B), if the coating agent S is applied from directly above the wire W, voids Q (spaces) are likely to be formed, which may make it difficult to adequately protect the IC chip 51.

[0084] As described above, in the second embodiment, the coating agent S with high thixotropy stably protects the mounted IC chip 51 and improves workability during manufacturing. In particular, because the coating agent S is less likely to flow after application, it is more likely to prevent the coating agent S from flowing into the component-mounting-prohibited area M2. As a result, solidified coating agent S is not formed around the first opening H1 and the second opening H2, and the fixing bolts are not obstructed by the solidified coating agent S, allowing the fixing bolts to be inserted into the appropriate positions of the first opening H1 and the second opening H2. This improves the ease of installation of the concentration sensor 16 through the first opening H1 and the second opening H2. Furthermore, compared to using other coating agents with low thixotropy, the need for repeated pre-curing processes and visual inspections after application is reduced. Furthermore, because the coating agent S is prevented from reaching the component-mounting-prohibited area M2, the coating agent S can be easily applied automatically.

[0085] In addition, in the second embodiment, the first convex portion 50A is arranged between the IC chip 51 and the component mounting prohibited area M2, so that the coating agent S is easily blocked by the first convex portion 50A, thereby further preventing the coating agent S from flowing into the component mounting prohibited area M2.

[0086] In the second embodiment, the IC chip 51 is disposed in a region of the first opening H1 and the second opening H2 that is adjacent to the second opening H2. The second opening H2 is longer than the first opening H1, improving the ease of attachment of the concentration sensor 16 when the concentration sensor 16 is mounted. In this case, the distance between the heads of bolts and screws (fastening parts) (not shown) inserted through the second opening H2 and the IC chip 51 is likely to change. In the second embodiment, a portion of the coating layer 50S covering the IC chip 51 is less likely to spread toward the second opening H2 side of the component mounting prohibited area M2, which also prevents interference between the coating layer 50S and the heads of the fastening parts.

[0087] [Manufacturing method of concentration sensor] The method for manufacturing the concentration sensor 16 includes the following steps: mounting a sensor substrate 3 (light receiving / emitting unit) that emits and receives light in a component mounting area M1 of a circuit board 50 having the component mounting area M1 and a component mounting prohibited area M2; mounting an IC chip 51 in an area of ​​the component mounting area M1 of the circuit board 50 adjacent to the component mounting prohibited area M2; connecting terminals of the IC chip 51 to the circuit board 50 by wire bonding; and forming a coating layer 50S on the IC chip 51 using a coating agent S having a thixotropy (2 rpm / 20 rpm) of 4.5 to 6.5 so as to cover the wires W arranged by the wire bonding and the IC chip 51. This manufacturing method may include a part of the manufacturing method described above.

[0088] Furthermore, in the manufacturing method, forming the coating layer (50S) includes applying the coating agent (S) from the outside of the wire (W).

[0089] Furthermore, in the manufacturing method, forming the coating layer 50S includes continuously applying the coating agent S in a spiral shape from the outside of the wire W toward the center of the IC chip 51.

[0090] The various structures of the concentration sensor 16 described in this disclosure can also constitute some of the features of the manufacturing method described above.

[0091] Although the concentration sensor 16 (optical sensor) and its manufacturing method according to the present disclosure have been described above, the present disclosure is not limited to this.

[0092] [Concentration sensor according to modified embodiment] FIG. 17 is an enlarged side view of the periphery of an IC chip in an optical sensor according to a third embodiment of the present disclosure. In the previous embodiment, as shown in FIG. 14, the component mounting area M1 and the component mounting prohibited area M2 are separated by a first protrusion 50A. However, as shown in FIG. 17, the component mounting area M1 and the component mounting prohibited area M2 may be separated by a groove 50B formed on the circuit board 50. The groove 50B is an example of a first suppression portion or a first groove portion according to the present disclosure. In this case, the flow of the coating agent S is likely to be retained and blocked by the groove 50B, further preventing the coating agent S from flowing into the component mounting prohibited area M2. The groove 50B may be recessed relative to the surface of the circuit board 50. Furthermore, if a resin film is formed on the surface of the circuit board, the exposed portion where the surface of the circuit board body is exposed is also an example of a groove portion.

[0093] FIG. 18 is an enlarged plan view of the periphery of the IC chip 51 of the concentration sensor 16 according to the fourth embodiment of the present disclosure. In the previous embodiment, the first protrusion 50A was disposed between the component mounting area M1 and the component mounting prohibited area M2, as shown in FIG. 12 . However, as shown in FIG. 18 , the exposed portion 450A may be disposed throughout the entire periphery of the IC chip 51 and between the component mounting area M1 and the component mounting prohibited area M2. In other words, the exposed portion 450A surrounds the IC chip 51 and separates the component mounting area M1 from the component mounting prohibited area M2. This also prevents the coating agent S from spreading around the IC chip 51, further preventing the coating agent S from flowing into the component mounting prohibited area M2. In the fourth embodiment, the exposed portion 502b is disposed in a ring shape surrounding the circular second hole K2.

[0094] 19 is an enlarged plan view of the periphery of the IC chip 51 of the concentration sensor 16 according to the fifth embodiment of the present disclosure. In the fourth embodiment, as shown in FIG. 18, the exposed portion 450A is disposed throughout the entire peripheral area of ​​the IC chip 51 and between the component mounting area M1 and the component mounting prohibited area M2. However, as shown in FIG. 19, the exposed portion 550A may be disposed with a portion of the peripheral area open to allow the coating agent S to flow from the IC chip 51 in the direction DD opposite the direction from the IC chip 51 toward the component mounting prohibited area M2. In this case, the coating agent S flows from the IC chip 51 in the direction DD opposite the direction from the direction toward the component mounting prohibited area M2, further preventing the coating agent S from flowing into the component mounting prohibited area M2. The open portion of the peripheral area is an example of a relief portion according to the present disclosure.

[0095] As described above, the portion of the exposed portion 550A that is formed by opening a portion of the surrounding area is not limited to the area opposite the component mounting prohibited area M2. As an example, an open portion may be formed along the lower side of the IC chip 51 in FIG. 19. In this case, an escape route for the coating agent S is also ensured during application, thereby preventing the coating agent S from flowing from the IC chip 51 toward the component mounting prohibited area M2 or the second hole K2.

[0096] 20 is an enlarged plan view of the periphery of the IC chip 51 and the second hole K2 of the concentration sensor 16 according to the sixth embodiment of the present disclosure. In the fourth embodiment, the exposed portion 450A and the exposed portion 502b are spaced apart as shown in FIG. 18. However, as shown in FIG. 20, the exposed portion 650A and the exposed portion 502b may be connected. The width WA of the exposed portion 650A disposed between the IC chip 51 and the second hole K2 (the sum of the widths of the exposed portion 650A and the exposed portion 502b) is wider than the width WB of the exposed portion 502b not disposed between the IC chip 51 and the second hole K2. In this case, the coating agent S is less likely to flow between the IC chip 51 and the second hole K2, which further prevents the coating agent S from flowing toward the second hole K2. In addition, the width WA of the exposed portion 650A arranged between the IC chip 51 and the second hole portion K2 has been described as being wider than the width WB of the exposed portion 502b that is not arranged between the IC chip 51 and the second hole portion K2. However, if a groove portion is arranged as a suppression portion instead of the exposed portion 650A and the exposed portion 502b, the depth of the groove portion arranged between the IC chip 51 and the second hole portion K2 may be deeper than the depth of the groove portion that is not arranged between the IC chip 51 and the second hole portion K2.

[0097] 18 to 20, convex portions (pattern printed portions) and groove portions may be arranged instead of 450A, 550A, and 650A. Also, each of 450A, 550A, and 650A may be formed by a combination of an exposed portion, a convex portion, and a groove portion.

[0098] 21 is an enlarged plan view of the periphery of the IC chip 51 of the concentration sensor 16 according to the seventh embodiment of the present disclosure. As shown in FIG. 21, the main substrate 105 may further include an electronic component 53 mounted in the component mounting area M1. The electronic component 53 is disposed near the IC chip 51. The electronic component 53 is disposed closer to the first protrusion 50A on the second opening H2 side than to the first protrusion 50A on the first opening H1 side. Therefore, when applying the coating agent S to the IC chip 51, it is necessary to prevent the coating agent S from reaching the electronic component 53 so that a solidified portion of the coating agent S does not form around the electronic component 53. Therefore, the main substrate 105 may further include an exposed portion 503b as a fourth prevention portion.

[0099] Specifically, the exposed portion 503b exposes the surface of the circuit board main body 150a. The exposed portion 503b is disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the electronic component 53. As a result, when the coating agent S is applied to the IC chip 51, the flow of the coating agent S is easily blocked, and the coating agent S can be prevented from reaching the electronic component 53. This prevents the electronic component 53 from being damaged when the coating agent S solidifies.

[0100] 22 is an enlarged plan view of the periphery of the IC chip 51 of the concentration sensor 16 according to the eighth embodiment of the present disclosure. As shown in FIG. 22, the main substrate 105 may further include a contact pad 73a disposed near the IC chip 51. The contact pad 73a is disposed closer to the first convex portion 50A on the second opening H2 side than to the first convex portion 50A on the first opening H1 side. Therefore, when applying the coating agent S to the IC chip 51, it is necessary to prevent the coating agent S from reaching the contact pad 73a so that a solidified portion of the coating agent S does not form around the contact pad 73a. Therefore, the main substrate 105 may further include a third convex portion 503a as a third prevention portion.

[0101] Specifically, the third convex portion 503a protrudes from the surface of the circuit board 150. As an example, the third convex portion 503a is a white linear portion provided on the circuit board 150. The third convex portion 503a is also disposed on the second surface S2 of the circuit board 150 between the IC chip 51 and the contact pads 73a. As a result, when the coating agent S is applied to the IC chip 51, the flow of the coating agent S is easily blocked, and the coating agent S can be prevented from reaching the contact pads 73a.

[0102] The first prevention portion for preventing the coating agent S from reaching the component mounting prohibited area M2 may be the first protrusion 50A (FIG. 8) as described above, the groove 50B as described above, an exposed portion (first exposed portion) having a configuration similar to the exposed portion 502b (FIG. 8), the first protrusion 50A and the groove 50B, the first protrusion 50A and the exposed portion, the exposed portion and the groove 50B, or the first protrusion 50A, the groove 50B, and the exposed portion. In this case, too, the flow of the coating agent S is easily blocked when the coating agent S is applied to the IC chip 51, and the coating agent S can be prevented from reaching the component mounting prohibited area M2.

[0103] Furthermore, as the second prevention portion for preventing the coating agent S from reaching the second hole portion K2, the second protrusion 502a (FIG. 8) as described above may be arranged, a groove portion (second groove portion) having a configuration similar to the groove portion 50B may be arranged, the exposed portion 502b as described above may be arranged, the second protrusion 502a and a groove portion may be arranged, the second protrusion 502a and an exposed portion 502b may be arranged, the exposed portion 502b and a groove portion may be arranged, or the second protrusion 502a, a groove portion, and an exposed portion 502b may be arranged. In this case as well, when the coating agent S is applied to the IC chip 51, the flow of the coating agent S is easily blocked, and the coating agent S can be prevented from reaching the second hole portion K2.

[0104] Furthermore, as the third prevention portion for preventing the coating agent S from reaching the contact pads 73, the third convex portion 503 as described above may be arranged, a groove portion (third groove portion) having a configuration similar to that of the groove portion 50B may be arranged, an exposed portion (third exposed portion) having a configuration similar to that of the exposed portion 502b may be arranged, the third convex portion 503 and a groove portion may be arranged, the third convex portion 503 and an exposed portion may be arranged, an exposed portion and a groove portion may be arranged, or the third convex portion 503, a groove portion and an exposed portion may be arranged. In this case as well, when the coating agent S is applied to the IC chip 51, the flow of the coating agent S is easily blocked, and the coating agent S can be prevented from reaching the contact pads 73.

[0105] Furthermore, the fourth prevention portion for preventing the coating agent S from reaching the electronic component 53 may be a fourth prevention portion having a convex portion configured similarly to the first convex portion 50A, a groove portion configured similarly to the groove portion 50B, an exposed portion 503b, a convex portion and a groove portion, a convex portion and an exposed portion 503b, an exposed portion 503b and a groove portion, or a convex portion, a groove portion, and an exposed portion 503b. In this case as well, when the coating agent S is applied to the IC chip 51, the flow of the coating agent S is easily blocked, and the coating agent S can be prevented from reaching the electronic component 53.

[0106] In the previous embodiment, the IC chip 51 and the connector 52 are disposed on the same side of the circuit board 50. However, the present disclosure is not limited to this. As an example, the connector 52 may be disposed on the opposite side of the IC chip 51, i.e., on the same side as the sensor substrate 3. In this case, the connector 52 may be disposed around the sensor substrate 3 or, exceptionally, at the edge of the component mounting prohibited area M2 so as not to interfere with the light emission and light reception functions of the sensor substrate 3. In this case, the connector 52, which is taller than the IC chip 51 relative to the circuit board 50, is not disposed around the IC chip 51. This allows for stable wire bonding and coating of the coating agent S on the IC chip 51. Furthermore, the Ag paste AP is not necessarily provided. Furthermore, the sensor substrate 3 is not necessarily provided. [Explanation of symbols]

[0107] 1 color printer 100 needles 16 Density sensor (light sensor) 3 Sensor board 30 Circuit Board 31, 32 First light-emitting / receiving pair, second light-emitting / receiving pair 33, 34 First light emitting element, first light receiving element 35, 36 Second light-emitting element, second light-receiving element 4 Lens unit (cover member) 5, 105 Main board 50, 150 circuit board 50A First convex part (first suppression part) 50B Groove (1st suppression part) 50S Coat Layer 51 IC chip 52 connectors 73 Contact pad (test terminal) 150a Circuit board body 150b Resin film (protective film) 502a: Second convex portion (second suppression portion) 502b Exposed part (second suppression part) AP Ag Paste H1 1st opening H2 2nd opening K2 2nd hole (through hole) Q Void S coating agent W Wire WS board side connection part

Claims

1. An optical sensor attached to the device body, A circuit board; a light receiving / emitting unit mounted on the circuit board for emitting and receiving light; an IC chip mounted on the circuit board; a coating layer made of a solidified coating agent and formed to cover the IC chip to protect the IC chip; Equipped with the surface of the circuit board has a component mounting area and an attachment area arranged alongside the component mounting area and attached to the device body; the IC chip is disposed in an area of ​​the component mounting area adjacent to the attachment area, The circuit board has a first suppression portion disposed on a surface of the circuit board between the IC chip and the mounting area.

2. the circuit board has a circuit board body and a protective film formed on a surface of the circuit board body to protect the circuit board body; 2. The optical sensor according to claim 1, wherein the first suppression portion is at least one of a first convex portion protruding from the surface of the circuit board, a first groove portion recessed into the surface of the circuit board, and a first exposed portion that has a lower wettability between the protective film and the coating agent than a wettability between the protective film and the coating agent and exposes the surface of the circuit board body.

3. 3. The optical sensor according to claim 2, wherein the first convex portion is a pattern printed portion that separates the component mounting area from the attachment area and is made of a solidified printing paint.

4. The optical sensor according to claim 1 , wherein the first suppression portion is disposed in a peripheral region that is a region surrounding the IC chip.

5. The optical sensor according to claim 4 , wherein the first suppression portion is disposed over the entire surrounding area.

6. The optical sensor according to claim 4 , wherein the first suppression portion is disposed so as to leave a part of the surrounding area open.

7. The optical sensor according to claim 6 , wherein the first suppression portion is disposed so as to leave a part of the surrounding area open in a direction opposite to a direction from the IC chip toward the attachment area.

8. Further provided is a cover member for covering the light emitting and receiving unit, The circuit board includes: a through hole through which a portion of the cover member is inserted; a second suppression portion disposed on the surface of the circuit board between the IC chip and the through hole; The optical sensor of claim 1 further comprising:

9. the circuit board has a circuit board body and a protective film formed on a surface of the circuit board body to protect the circuit board body; 9. The optical sensor according to claim 8, wherein the second suppression portion is at least one of a second convex portion protruding from the surface of the circuit board, a second groove portion recessed into the surface of the circuit board, and a second exposed portion that has a lower wettability between the protective film and the coating agent than a wettability between the protective film and the coating agent and exposes the surface of the circuit board body.

10. the second suppression portion is the second exposed portion, 10. The optical sensor of claim 9, wherein a width of the second exposed portion arranged between the IC chip and the through hole is wider than a width of the second exposed portion not arranged between the IC chip and the through hole.

11. the second suppression portion includes the second convex portion and the second exposed portion, The optical sensor according to claim 9 , wherein the second exposed portion is disposed closer to the through-hole than the second convex portion.

12. The circuit board includes: a connection terminal electrically connected to the light emitting and receiving unit; a third suppression portion disposed on the surface of the circuit board between the IC chip and the connection terminal; The optical sensor of claim 1 further comprising:

13. the third suppression portion is a third protrusion that protrudes from the surface of the circuit board, The optical sensor according to claim 12 , wherein the third convex portion is a pattern printed portion made of a solidified printing paint.

14. Further, an electronic component is mounted on the circuit board. a fourth suppression portion disposed on the surface of the circuit board between the IC chip and the electronic component; The optical sensor of claim 1 further comprising:

15. the circuit board has a circuit board body and a protective film formed on a surface of the circuit board body to protect the circuit board body; the fourth suppression portion includes a convex portion protruding from the surface of the circuit board, and an exposed portion having a wettability with the coating agent lower than a wettability between the protective film and the coating agent, and exposing the surface of the circuit board main body; the protruding portion is a pattern printed portion made of a solidified printing paint, The optical sensor according to claim 14 , wherein the exposed portion is disposed between the pattern printed portion and the electronic component.

16. A method for manufacturing an optical sensor, comprising: a circuit board having a component mounting area and an attachment area to be attached to a device body, the circuit board having a component mounting area, the component mounting area including a light receiving / emitting unit that emits and receives light; Mounting an IC chip in an area of ​​the component mounting area of ​​the circuit board adjacent to the attachment area; connecting a terminal of the IC chip to the circuit board by wire bonding; forming a suppression portion on a surface of the circuit board between the IC chip and the mounting area; forming a coating layer on the IC chip using the coating agent so as to cover the wires arranged by the wire bonding and the IC chip while preventing the coating agent from flowing into the mounting region using the prevention portion; A method for manufacturing an optical sensor, comprising:

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