Method of mounting electronic component, substrate and an optical scanning apparatus

The method of mounting an electronic component onto a substrate by a reflow process, the electronic component having at least one first terminal provided along one side of the electronic component and at least one second terminal provided along another side of the electronic component opposed to the one side, the substrate having a first copper foil pattern to which the at least one first terminal is soldered and a second copper foil pattern to which the at least one second terminal is soldered, the method including applying a first solder cream portion to the first copper foil pattern and applying a second solder cream portion to the second copper foil pattern.

BACKGROUND

Field of the Disclosure

The present disclosure relates to a method of mounting an electronic component on a substrate, the substrate, and an optical scanning apparatus having the substrate. Particular, the method of the present disclosure relates to a method of accurate reflow mounting of a component onto a printed circuit board.

Description of the Related Art

In image forming apparatuses such as conventional laser printers, a scanning optical device therein performs the following operations to form an image on a scanned surface. The scanning optical device optically modulates, according to an image signal, a laser beam emitted from a light source. The scanning optical device deflects the optically modulated laser beam toward the scanned surface using, for example, a light deflector having a rotating polygon mirror, and runs the laser beam. The laser beam deflected by the light deflector is run as a spot imaged on the surface of a photosensitive recording medium, for example through a scanning lens of an imaging optical system having an fθ characteristic. The timing of writing by the laser beam on the scanned surface is controlled based on a synchronization signal that is output from a detection unit provided on the scanned surface and that serves as a reference for the write position.

As described in Japanese Patent Application Laid-Open No. 2003-222811, generally, an image is written in an image forming apparatus a predetermined time after the detection of the falling edge of a signal output from a beam detector (hereafter referred to as a BD) serving as the detection unit. In order to prevent the variation in the position to which the BD is attached from affecting the variation in the position in the main-scanning direction, the scanning optical device is configured as follows. The upstream side of a light receiving portion of the BD in the main-scanning direction is hidden by a light shielding member, so that light enters the BD when a laser beam passes over an edge of the light shielding member irrespective of the attachment position of the BD.

Unfortunately, the scanning optical device described in the above conventional example has the problem of difficulty in accurately managing the attachment position of the BD. The light receiving portion of the BD provided in the scanning optical device needs to be of a size larger than the range of variation in the attachment position of the BD. The manufacture cost of the BD, which significantly depends on the size of the light receiving portion, is higher as the light receiving portion is larger. That is, the problem is that using a BD with a large light receiving portion increases the cost of the scanning optical device itself. For reducing the range of variation in the attachment position of the BD to avoid increasing the size of the light receiving portion of the BD, there is a need for a technique of increasing the accuracy of mounting an electronic component such as a BD onto a substrate.

SUMMARY

An aspect of the present invention is a method of mounting an electronic component onto a substrate in a reflow manner, the electronic component having at least one first terminal provided along one side and at least one second terminal provided along another side opposed to the one side, the substrate having a first copper foil pattern to which the first terminal is soldered and a second copper foil pattern to which the second terminal is soldered, the method including application of applying a first solder cream portion to the first copper foil pattern and applying a second solder cream portion to the second copper foil pattern, wherein the application includes: applying the first solder cream portion such that one end of the first solder cream portion facing the second solder cream portion extends toward the second copper foil pattern beyond one end of the first copper foil pattern facing the second copper foil pattern; and applying the second solder cream portion such that one end of the second solder cream portion facing the first solder cream portion extends toward the first copper foil pattern beyond one end of the second copper foil pattern facing the first copper foil pattern.

Another aspect of the present invention is a substrate on which at least one electronic component having at least one first terminal provided along one side of the electronic component and at least one second terminal provided along another side of the electronic component opposed to the one side, the substrate including a first copper foil pattern to which the at least one first terminal is soldered, a second copper foil pattern to which the at least one second terminal is soldered, a first solder portion applied onto the first copper foil pattern, and a second solder portion applied to the second copper foil pattern, wherein one end of the first solder portion facing the second solder portion is applied to extend toward the second copper foil pattern beyond one end of the first copper foil pattern facing the second copper foil pattern, and wherein one end of the second solder portion facing the first solder portion is applied to extend toward the first copper foil pattern beyond one end of the second copper foil pattern facing the first copper foil pattern.

A further aspect of the present invention is a scanning optical apparatus for emitting light an image bearing member, including an electronic component including a first substrate, a light source mounted on the first substrate, and an output unit configure to output a signal in response to receiving light emitted from the light source, the electronic component having at least one first terminal provided along one side of the electronic component and at least one second terminal provided along another side of the electronic component opposed to the one side; and a substrate on which the electronic component is mounted, wherein the substrate includes a first copper foil pattern to which the at least one first terminal is soldered, a second copper foil pattern to which the at least one second terminal is soldered, a first solder portion applied onto the first copper foil pattern, and a second solder portion applied to the second copper foil pattern, wherein one end of the first solder portion facing the second solder portion is applied to extend toward the second copper foil pattern beyond one end of the first copper foil pattern facing the second copper foil pattern, and wherein one end of the second solder portion facing the first solder portion is applied to extend toward the first copper foil pattern beyond one end of the second copper foil pattern facing the first copper foil pattern.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described in detail below with reference to the drawings. The scanning direction or the main-scanning direction refers to the direction in which light emitted from a scanning optical device is run by a deflection device. The main-scanning direction is also the direction along the rotational axis of a photosensitive drum. The sub-scanning direction refers to the rotational direction of the photosensitive drum, which is the direction orthogonal to the main-scanning direction.

A scanning optical device in a first embodiment will be described.FIG.1is a diagram for describing a scanning optical device101in the first embodiment. The scanning optical device101includes a laser emission substrate1and an anamorphic collimator lens2. The anamorphic collimator lens2, hereafter referred to as a collimator lens2, is an integrated unit of a collimator lens, a cylindrical lens, and a write-position signal detection lens (hereafter referred to as a BD lens)14. The scanning optical device101includes an aperture3, a rotating polygon mirror4, a deflection device5, a beam detector (hereafter referred to as a BD)6serving as an output unit, an fθ lens (a scanning lens)7, and an optical case9. The rotating polygon mirror4has multiple (for example, four inFIG.1) reflective surfaces12. The BD6has a light receiving portion (seeFIGS.2A,2B and2Cto be described below), which detects input of laser light in order to output a signal (hereafter referred to as a synchronization signal) serving as a reference for the write position of the laser light in the scanning direction. The optical case9houses the above optical members. The scanning optical device101forms an electrostatic latent image on the surface of a photosensitive drum8, which is a photosensitive member.

A semiconductor laser1aserving as a light source is mounted on the laser emission substrate1. A laser beam L emitted from the semiconductor laser1ais collimated by the collimator lens2into light substantially parallel or convergent in the main-scanning direction and convergent in the sub-scanning direction. Further, the laser beam L, as a focal-line beam extending long in the main-scanning direction and having a beam width restricted through the aperture3, forms an image on the reflective surfaces12of the rotating polygon mirror4. The rotating polygon mirror4is controlled by the deflection device5to rotate at a constant speed. The laser beam L forming the image on the reflective surfaces12of the rotating polygon mirror4is deflected and run to reach the BD6and the photosensitive drum8(dashed and single-dotted lines inFIG.1). The laser beam L enters the BD6through the BD lens14of the collimator lens2. The fθ lens7, formed of a non-spherical lens, is designed to gather light so that the beam passing through the fθ lens7forms a spot on the photosensitive drum8, and to keep the speed of scanning the surface of the photosensitive drum8constant. The photosensitive drum8is driven to rotate about the cylinder axis, thereby allowing sub-scanning by the laser light. The scanning optical device101thus forms an electrostatic latent image on the surface of the photosensitive drum8.

[Opening in Optical Case, and Light Receiving Portion of BD]

FIGS.2A,2B and2Care diagrams enlarging the BD6and its surroundings. The BD6has a light receiving portion10. The BD6is mounted on the laser emission substrate1. The laser emission substrate1is attached to a side plate of the optical case9, which has an opening9aat a position corresponding to the light receiving portion10of the BD6. The laser beam L passing through the BD lens14is formed into a round spot S1by the BD lens14and is run in the direction of dashed-line arrows inFIGS.2A,2B and2C(the scanning direction). Part of the light receiving portion10of the BD6, upstream in the scanning direction of the spot S1, is shaded by the optical case9. When the moving spot S1passes over an edge of the opening9ain the optical case9, the light enters the light receiving portion10to cause the BD6to output a signal (hereafter referred to as a horizontal synchronization signal).

FIGS.2A,2B and2Cillustrate the BD6attached to different positions in the scanning direction.FIG.2Aillustrates the BD6attached to a position displaced upstream in the main-scanning direction.FIG.2Billustrates the BD6attached to a position that is substantially the designed center position.FIG.2Cillustrates the BD6attached to a position displaced downstream in the main-scanning direction. As described above, the laser light enters the light receiving portion10when the moving spot S1passes over the edge of the opening9ain the optical case9. Therefore, the differences in the attachment position of the BD6make no difference in the output timing of the horizontal synchronization signal. However, the light receiving portion10of the BD6needs to be of a size larger than the range of variation in the attachment position of the BD6.

If the light receiving portion10is shorter in length in the scanning direction than the range of variation in the attachment position of the BD6, the following problem arises. For example, consider the BD6attached to a position displaced upstream in the main-scanning direction as shown inFIG.2A. If the light receiving portion10is shorter in length in the scanning direction than the range of variation in the attachment position, the light receiving portion10is completely hidden behind the optical case9(to the left of the opening9a). The BD6then cannot receive the light with the light receiving portion10and therefore cannot output the horizontal synchronization signal. Conversely, consider the BD6attached to a position displaced downstream in the main-scanning direction as shown inFIG.2C. If the light receiving portion10is shorter in length in the scanning direction than the range of variation in the attachment position of the BD6, the upstream side of the light receiving portion10is not shaded by the optical case9. That is, the spot S1reaches the edge of the opening9aand then the light receiving portion10at different points of time. The BD6therefore outputs the horizontal synchronization signal when the spot S1passes over the upstream side of the light receiving portion10, rather than when the spot S1passes over the edge of the opening9ain the optical case9. The first embodiment aims to increase the accuracy of the attachment position of the BD6so that the range of variation in the attachment position of the BD6is kept within the size of the light receiving portion10.

Factors that determine the attachment position of the BD6will be described with reference toFIG.3. Factors that determine the attachment position of the BD6include

(1) the variation in the position of the laser emission substrate1on the optical case9, and

(2) the variation in the mounting position of the BD6on the laser emission substrate1.

FIG.3is a diagram of the optical case9viewed from the direction of the laser emission substrate1. The laser emission substrate1is externally attached to a side plate of the optical case9. The optical case9has a positioning boss103and a position fixing hole102, while the laser emission substrate1has an attachment reference hole105and an attachment hole104. The above-listed factor, (1) the variation in the position of the laser emission substrate1on the optical case9, depends on the fit between the attachment reference hole105and the positioning boss103, and the fit between the attachment hole104and the position fixing hole102. A screw106is screwed into and fixed to the position fixing hole102penetrating through the attachment hole104. While the management manner of the dimensions of the attachment reference hole105and the positioning boss103is important, in practice, the dimensions are typically managed with an attachment tolerance of, e.g., about ±0.1 mm

The first embodiment reduces the range of the above-listed factor, (2) the variation in the mounting position of the BD6on the laser emission substrate1. That is, the first embodiment proposes a method of mounting the BD6, which is an electronic component, onto the laser emission substrate1, which is a substrate. In addition to the BD6, components such as the semiconductor laser1a, a laser control driver IC, a chip resistor, and connectors (which are all not shown) are mounted onto the laser emission substrate1. Each component is mounted by an automatic machine at predetermined mounting coordinates with reference to the attachment reference hole105. X and Y inFIG.3denote coordinates of the position where the BD6should be mounted (for example, the center position of the BD6) with reference to the center coordinates of the attachment reference hole105. To accurately mount the BD6at the coordinates X, Y on the laser emission substrate1, it is important to mount the component in proper alignment with a land pattern for mounting the BD6.

The geometry of the BD6will be described with reference toFIGS.4A,4B and4C. The BD6used in the first embodiment is of chip-on-board (COB) type; the bare chips of a photodiode406and an arithmetic circuit405are directly mounted onto a substrate410. The substrate410is rectangular as shown inFIGS.4A,4B and4C, for example.FIG.4Ais a diagram of the BD6viewed from a bare chip mounting surface (the front side). The bare chips of the photodiode406and the arithmetic circuit405are mounted in the central area of the substrate410and connected, via gold wires407, to pads402provided on the substrate410. The pads402are connected to a pattern on the back side of the substrate410via a pattern403and through holes404.

FIG.4Bis a phantom view of the back side of the BD6, which is connected to terminals401via the through holes404and the pattern403covered by a resist408. The terminals401represent bare copper foils not covered by the resist408, and serve as joints for mounting the BD6onto the laser emission substrate1. The terminals401are provided on the back side, which is the surface opposite to the mounting surface of the substrate410. The terminals401are provided on two opposing sides of the four sides of the substrate410. The substrate410in the first embodiment has a total of six terminals401, three on each side, for example. That is, the BD6, which is an electronic component, has at least one terminal401a, which is a first terminal, provided along one side of the substrate410(three terminals401aare provided in the first embodiment). The BD6, which is an electronic component, has at least one terminal401b, which is a second terminal, provided along another side of the substrate410opposed to the one side (three terminals401bare provided in the first embodiment).FIG.4Cis a side view of the BD6. As shown inFIG.4C, the bare chips are protected by a molded transparent acrylic resin409that covers the positions where the bare chips are mounted.

FIGS.5A and5Bare diagrams for describing mounting the BD6onto the laser emission substrate1in a reflow manner. As shown in a perspective view ofFIG.5A, patterns for mounting the BD6are provided on the laser emission substrate1. The BD6is mounted in an orientation such that the surface having the terminals401(the back side) of the BD6contacts the laser emission substrate1. Features of the first embodiment will be described with reference to a cross-sectional view ofFIG.5B.

The laser emission substrate1(a substrate) has: a copper foil pattern413a, which is a first copper foil pattern, to which the terminals401aare soldered; and a copper foil pattern413b, which is a second copper foil pattern, to which the terminals401bare soldered. The copper foil patterns413aand413bmay be collectively referred to as copper foil patterns413. The copper foil patterns413are covered by a resist414except where solder cream portions412are applied. The solder cream portions412and the copper foil patterns413are provided to correspond to the terminals401of the BD6. The BD6in the first embodiment has three terminals401on one side of the substrate410and three terminals401on another side of the substrate410. The solder cream portions412and the copper foil patterns413are provided, on the laser emission substrate1, to correspond to the above six terminals401. Because the terminals401are provided on the opposing sides of the substrate410, the solder cream portions412and the copper foil patterns413are provided in an opposing arrangement on the laser emission substrate1, as shown inFIG.5A. That is, solder cream portions412a, which are first solder cream portions, are applied to the copper foil pattern413a, and solder cream portions412b, which are second solder cream portions, are applied to the copper foil pattern413b(an application step).

A feature of the first embodiment is a positional relationship among the solder cream portions412, the terminals401, and the copper foil patterns413as described below, in which

D1: the distance between the opposing solder cream portions412,

D2: the distance between the opposing terminals401, and

D3: the distance between the opposing copper foil patterns413.

Because the distance D1is shorter than the distances D2and D3, the solder cream portions412are applied to extend inwardly (toward the center of the substrate410) beyond the terminals401and the copper foil patterns413. Usually, the solder cream portions412are not purposely applied to extend beyond the copper foil patterns413, because the extendedly applied extra solder cream may create a short circuit between terminals or create solder balls. In the first embodiment, however, the solder cream portions412are intentionally applied to extend beyond the copper foil patterns413for a predetermined length, for example 0.3 mm Applying the solder cream portions412to extend beyond the copper foil patterns413increases the accuracy of the mounting position of the BD6in reflowing.

As above, the solder cream portions412aare applied such that one end of each solder cream portion412afacing the corresponding solder cream portion412bextends toward the solder cream portion412bbeyond one end of the corresponding terminal401afacing the corresponding terminal401b. The solder cream portions412bare applied such that one end of each solder cream portion412bfacing the corresponding solder cream portion412aextends toward the solder cream portion412abeyond one end of the corresponding terminal401bfacing the corresponding terminal401a. The solder cream portions412aare applied such that the end of each solder cream portion412aextends beyond one end of the copper foil pattern413afacing the copper foil pattern413b. The solder cream portions412bare applied such that the end of each solder cream portion412bextends beyond one end of the copper foil pattern413bfacing the copper foil pattern413a.

As shown in Formula (1), the distance D1between the end of each solder cream portion412aand the end of each solder cream portion412bis shorter than the distance D2between the end of each terminal401aand the end of each terminal401b(D1<D2). The distance D1between the end of each solder cream portion412aand the end of each solder cream portion412bis shorter than the distance D3between the end of the copper foil pattern413aand the end of the copper foil pattern413b(D1<D3).

In reflowing, the extendedly applied solder cream portions412are fused and drawn toward the copper foil patterns413due to the self-alignment effect. At this point, the BD6on the solder cream portions412also moves toward the copper foil patterns413along with the solder cream portions412. In the first embodiment, as shown in Formula (1), the distance D2is equal to or shorter than the distance D3(D2≤D3). Due to the self-alignment effect of the fused solder cream portions412, in reflowing, the BD6moves to a position such that the inner lines of the terminals401exactly align with the inner lines of the copper foil patterns413, or a position such that the midpoint of the distance D2exactly aligns with the midpoint of the distance D3.

FIGS.6A and6Billustrate the results of verifying an advantageous effect of the reflow method in the first embodiment. The results inFIGS.6A and6Bshow deviations (±ΔX, ±ΔY) of the coordinates of the mounting positions of the BD6measured after reflowing from the designed mounting coordinates X, Y of the BD6.FIG.6Aillustrates deviations in the cases where the solder cream portions412were applied not to extend toward the center of the substrate410beyond the terminals401and the copper foil patterns413. By contrast,FIG.6Billustrates deviations in the cases where the solder cream portions412were applied to extend toward the center of the substrate410beyond the terminals401and the copper foil patterns413. Under either condition, the terminals401and the copper foil patterns413were in the relationship D2=D3.

As can be seen by comparingFIGS.6A and6B, in the cases where the solder cream portions412were applied to inwardly extend beyond the terminals401and the copper foil patterns413, the range of variation in the mounting position was reduced in both X direction and Y direction. Specifically, it can be seen that the range of variation in the mounting position was improved from ±0.20 mm or greater inFIG.6Ato ±0.05 mm or smaller inFIG.6B.

In order to prevent the extendedly applied extra solder cream portions412from creating a short circuit between the terminals401or creating solder balls, the first embodiment has the following feature. That is, no resist or pattern, except the copper foil patterns413for mounting, is provided on the surface of the laser emission substrate1that contacts the BD6. More specifically, no resist or pattern is provided between the opposing copper foil patterns413provided on the laser emission substrate1. That is, no resist or copper foil pattern is formed between the end of each solder cream portion412aand the end of each solder cream portion412b. Providing such copper foil pattern or resist on the surface of the laser emission substrate1that contacts the BD6would change how the solder flows when the extendedly applied solder cream portions412is fused and drawn toward the copper foil patterns413due to the self-alignment effect. This would lead to solder balls or to a short circuit between the terminals401.

As described above, the method of reflow mounting in the first embodiment can increase the accuracy of the mounting position of the BD6on the laser emission substrate1, thereby increasing the accuracy of attaching the BD6to the optical case9. Thus, according to the first embodiment, the accuracy of mounting an electronic component onto a substrate can be increased.

A second embodiment describes a case where a BD6of lead frame type is used. Components similar to those in the first embodiment will be given the same symbols and not be described again. The second embodiment also aims to increase the accuracy of mounting the BD6onto the laser emission substrate1.FIGS.7A and7Bare diagrams for describing mounting the BD6of lead frame type. As shown in a perspective view inFIG.7A, the BD6of lead frame type has a structure in which a transparent acrylic resin409covers both a lead frame and a sensor IC416, such as a photodiode, mounted on the lead frame. Part of the lead frame extends off the transparent acrylic resin409to form lead frame terminals415serving as joints for mounting the BD6onto the laser emission substrate1. The lead frame terminals415are clinched. For example, three lead frame terminals415a, which are first lead frame terminals, are provided on one side of the transparent acrylic resin409. For example, three lead frame terminals415b, which are second lead frame terminals, are provided on another side of the transparent acrylic resin409opposite to the one side. The lead frame terminals415aand415bmay be collectively referred to as lead frame terminals415. In the second embodiment, a total of six lead frame terminals415exist. Solder cream portions412(412aand412b) and copper foil patterns413(413aand413b) are provided on the laser emission substrate1in an opposing arrangement for the corresponding six lead frame terminals415.

FIG.7Bshows a cross-sectional view. The copper foil patterns413are covered by a resist414except where the solder cream portions412are applied. A feature of the second embodiment is a positional relationship among the solder cream portions412, the lead frame terminals415, and the copper foil patterns413as described below, in which

D1: the distance between the opposing solder cream portions412,

D2′: the distance between the areas in the opposing lead frame terminals415where the lead frame terminals415contact the laser emission substrate1(clinched portions), and

D3: the distance between the opposing copper foil patterns413.

The distances D1, D2′ and D3have a relationship in Formula (2).
D1<D2′≤D3  Formula (2)

Because the distance D1is shorter than the distances D2and D3, the solder cream portions412are applied to inwardly extend beyond the lead frame terminals415(their clinched or contact portions) and the copper foil patterns413. Usually, the solder cream portions412are not purposely applied to extend beyond the copper foil patterns413, because the extendedly applied extra solder cream portions412may create a short circuit between the lead frame terminals415or create solder balls. In the second embodiment, however, the solder cream portions412are intentionally applied to extend, for example for 0.3 mm. This is done because extendedly applying the solder cream portions412increases the accuracy of the mounting position of the BD6in reflowing.

As above, the distance D1between the end of each solder cream portion412aand the end of each solder cream portion412bis shorter than the distance D2′ between one end of each lead frame terminal415aand one end of each lead frame terminal415b(D1<D2′). Here, one end of each lead frame terminal415arefers to the end facing the corresponding lead frame terminal415bin the area where the lead frame terminal415acontacts the copper foil pattern413a. One end of each lead frame terminal415brefers to the end facing the corresponding lead frame terminal415ain the area where the lead frame terminal415bcontacts the copper foil pattern413b. In reflowing, the extendedly applied solder cream portions412are fused and drawn toward the copper foil patterns413due to the self-alignment effect. At this point, the BD6on the solder cream portions412also moves toward the copper foil patterns413along with the solder cream portions412.

In the second embodiment, the distance D2′ is equal to or shorter than the distance D3(D2′≤D3). Due to the self-alignment effect of the fused solder cream portions412, in reflowing, the BD6moves in the following manner. If the distance D2′ is equal to the distance D3, the BD6moves to a position such that the inner lines of the areas where the lead frame terminals415contact the laser emission substrate1exactly align with the inner lines of the copper foil patterns413. If the distance D2′ is shorter than the distance D3, the BD6moves to a position such that the midpoint of the distance D2exactly aligns with the midpoint of the distance D3. Again, in the second embodiment, no resist or copper foil pattern is formed between the end of each solder cream portion412aand the end of each solder cream portion412b.

As described above, for a BD of lead frame terminal type, the method of reflow mounting in the second embodiment can increase the accuracy of the mounting position of the BD6on the laser emission substrate1. This increases the accuracy of attaching the BD6to the optical case9. Thus, according to the second embodiment, the accuracy of mounting an electronic component onto a substrate can be increased.

Third Embodiment

[Description of Laser Beam Printer]

FIG.8illustrates a schematic configuration of a laser beam printer as an exemplary image forming apparatus having the scanning optical device101in the first and second embodiments. A laser beam printer1000(hereafter referred to as a printer1000) includes a photosensitive drum8, the scanning optical device101, a charge device1020, and a developing device1030. The photosensitive drum8is a photosensitive member on which the scanning optical device101forms an electrostatic latent image. The charge device1020uniformly charges the photosensitive drum8. The developing device1030serving as a developing unit develops, with toner, the electrostatic latent image formed on the photosensitive drum8, thereby forming a toner image. A sheet P serving as a recording material is supplied from a cassette1040, and the toner image formed on the photosensitive drum8(the photosensitive member) is transferred onto the sheet P by a transfer device1050serving as a transfer unit. The unfixed toner image transferred onto the sheet P is fixed by a fixing device1060, and the sheet P is ejected onto a tray1070. The scanning optical device101, the photosensitive drum8, the charge device1020, the developing device1030, and the transfer device1050constitute an image forming unit. The printer1000includes a power supply device1080, which supplies power to driving units such as motors and to a control unit5000. The control unit5000has a CPU (not shown) and controls image forming operations by the image forming unit and operations of conveying the sheet P, for example. It is to be noted that image forming apparatuses to which the scanning optical device of the present invention can be applied are not limited to those configured as illustrated inFIG.8.

Thus, according to the third embodiment, the accuracy of mounting an electronic component onto a substrate can be increased.

This application claims the benefit of Japanese Patent Application No. 2020-001342, filed Jan. 8, 2020, which is hereby incorporated by reference herein in its entirety.