Patent Description:
<CIT> discloses a focusing device of an optical write device that matches, with the surface of an image carrier, the focal point of light emitted from multiple light-emitting devices arranged in parallel in correspondence with pixels in the main scanning direction of the image forming area. The focusing device includes a storage member that stores a pattern image, an image forming member that forms an electrostatic latent image pattern corresponding to the pattern image stored in the storage member onto the surface of an image carrier, a surface-potential measuring member that measures the surface potential of the electrostatic latent image pattern area on the surface of the image carrier formed by the image forming member, and a position-changing mechanism that changes the position of an optical write device with respect to the surface of the image carrier to match the focal point of light from the light-emitting devices with the surface of the image carrier based on the surface potential measured by the surface-potential measuring member.

<CIT> discloses an image forming apparatus including an image carrier, a light-emitting-diode (LED) print head disposed close to the surface of the image carrier to emit light to expose the image carrier to image information, a first positioning member fixed to a body of the image forming apparatus to support the image carrier, and a second positioning member disposed on the LED print head while being in contact with the first positioning member to restrict the distance between the image carrier and the LED print head. An elastic member is disposed between the second positioning member and the LED print head to urge the second positioning member in a predetermined direction away from the LED print head.

<CIT> discloses an optical head positioning device that includes a cylindrical photoconductor drum extending in the longitudinal direction, an optical head extending in parallel with the photoconductor drum, and at least one spacer disposed in contact with the photoconductor drum to restrict the distance between the optical head and the surface of the photoconductor drum. <CIT> relates to an image forming apparatus that includes: an image holder; an exposure member that has an exposure portion exposing the image holder; a first positioning unit that determines a distance in a first direction, which is a direction of an optical axis of the exposure member, between the exposure member and the image holder; and a second positioning unit that determines a position of the exposure member with respect to the image holder in a second direction being a direction of an axis line of the image holder, and a position of the exposure member with respect to the image holder in a third direction being perpendicular to both the first direction and the second direction, and that determines the distance between the exposure member and the image holder at a position substantially closer to the exposure member than the position of the first positioning unit.

Accordingly, it is an object of the present disclosure to provide an exposure device and an image forming apparatus capable of further reducing misregistration of a light emitter in a direction perpendicular to a light emission direction than a structure where a contact member is fixed to a support member. Optional features of the invention are provided by the dependent claims. The following disclosure serves a better understanding of the present invention.

According to a first aspect of the present disclosure, there is provided an exposure device including: at least one light emitter that includes a substrate and a light-emitting device disposed on the substrate; and a position adjuster that includes a contact member having an outer periphery in contact with the substrate, a support member that rotatably supports the contact member, and at least one mover that is in contact with the support member to move the support member in a light emission direction of the light emitter.

According to a second aspect of the present disclosure, in the exposure device according to the first aspect, a coefficient of friction between the contact member and the substrate is smaller than a coefficient of friction between the support member and the contact member.

According to the invention the substrate extends in a first direction, the at least one light-emitting device includes a plurality of light-emitting devices disposed at a plurality of positions in the first direction, the support member is a shaft, and the position adjuster includes at least one receiving portion that receives the shaft while allowing the shaft to rotate about an axis extending in a direction perpendicular to the first direction and allowing the shaft to move in the light emission direction.

According to a third aspect of the present disclosure, in the exposure device according to the first aspect, the mover is movable in the first direction, and the mover includes a converter that converts a moving force in the first direction into a moving force of moving the shaft in the light emission direction.

According to a fourth aspect of the present disclosure, in the exposure device according to the third aspect, the converter is at least one slope that is disposed at a portion of the mover in contact with the shaft and that is inclined with respect to the first direction.

According to a fifth aspect of the present disclosure, in the exposure device according to the fourth aspect, the at least one slope included in the mover includes a pair of slopes, and the pair of slopes are in contact with both end portions of the shaft with the contact member in between.

According to a sixth aspect of the present disclosure, in the exposure device according to any one of the third to fifth aspects, the at least one receiving portion includes receiving portions opposing each other in a cross direction of the substrate, the opposing receiving portions receive the shaft, and the contact member is disposed between the opposing receiving portions of the shaft.

According to a seventh aspect of the present disclosure, in the exposure device according to any one of the third to fourth aspects, the at least one mover includes two movers arranged in a direction perpendicular to the first direction, and the contact member is disposed between the two movers.

According to an eighth aspect of the present disclosure, in the exposure device according to any one of the first to seventh aspects, the contact member has an outer diameter larger than an outer diameter of a shaft serving as the support member.

According to a ninth aspect of the present disclosure, in the exposure device according to the first aspect or any one of the third to eighth aspects, the position adjuster includes a feeder that moves the mover in the first direction, and the feeder and the contact member overlap each other in the light emission direction.

According to a tenth aspect of the present disclosure, in the exposure device according to the ninth aspect, the feeder is a screw member that extends in the first direction and moves the mover in the first direction by rotating about an axis, and the position adjuster further includes a driving source that drives the screw member to rotate.

According to an eleventh aspect of the present disclosure, in the exposure device according to the first aspect or any one of the third to tenth, a straight line that passes a contact point between the contact member and the substrate and a contact point between the mover and the shaft extends in the light emission direction.

According to a twelfth aspect of the present disclosure, there is provided an image forming apparatus includes an image carrier; the exposure device according to any one of the first to eleventh aspects capable of exposing the image carrier to light to form an electrostatic latent image, and adjusting a distance between the image carrier and a light-emitting device; and a developing device that develops the electrostatic latent image on the image carrier.

The exposure device according to the first aspect of the present disclosure further reduces misregistration of a light emitter in a direction perpendicular to the light emission direction than in a structure where a contact member is fixed to the support member.

The exposure device according to the second aspect of the present disclosure further reduces misregistration of a light emitter in a direction perpendicular to the light emission direction than in a structure where a coefficient of friction between the contact member and the substrate is larger than or equal to a coefficient of friction between the support member and the contact member.

The exposure device according to the first aspect of the present disclosure further reduces the length in the first direction than in a structure where the shaft extends in the first direction.

The exposure device according to the third aspect of the present disclosure further reduces the size of the device in the light emission direction than in a structure where the shaft is moved in the light emission direction by the mover moving in the light emission direction.

The exposure device according to the fourth aspect of the present disclosure reduces a coefficient of friction between the mover and the shaft.

The exposure device according to the fifth aspect of the present disclosure further reduces inclination of the shaft than in a structure where the slope of the mover is disposed only on one of both sides of the shaft with the contact member in between.

The exposure device according to the sixth aspect of the present disclosure further reduces distortion of the substrate resulting from position adjustment in the light emission direction performed by the contact member on the substrate, than in a structure where the contact member is disposed on the outer side of the opposing receiving portions of the shaft.

The exposure device according to the seventh aspect of the present disclosure reduces distortion of the substrate resulting from position adjustment in the light emission direction performed by the contact member on the substrate while the contact member and the mover are kept in a good balance.

The exposure device according to the eighth aspect of the present disclosure prevents the shaft from interfering with the substrate regardless of when the substrate is widened in the cross direction compared to the structure where the outer diameter of the contact member is smaller than or equal to the outer diameter of the shaft.

The exposure device according to the ninth aspect of the present disclosure further reduces a loss of the moving force of the mover transmitted to the shaft than in a structure where the feeder and the contact member are misaligned in the light emission direction.

The exposure device according to the tenth aspect of the present disclosure enables fine adjustment of the amount of movement of the mover in the first direction compared to the structure where the mover is moved in the first direction by driving a belt to which the mover is attached to rotate.

The exposure device according to the eleventh aspect of the present disclosure reduces misregistration of the light emitter in the direction perpendicular to the light emission direction compared to a structure where the straight line that passes the contact point between the contact member and the substrate and the contact point between the mover and the shaft is inclined with respect to the light emission direction.

The image forming apparatus according to the twelfth aspect of the present disclosure is capable of forming accurate images compared to a structure not including the exposure device according to any one of the first to twelfth aspect.

An exemplary embodiment of the present disclosure (hereinafter referred to as an exemplary embodiment) will be described.

<FIG> is a schematic diagram of a structure of an image forming apparatus <NUM> including an exposure device <NUM> according to a first exemplary embodiment. The structure of the image forming apparatus <NUM> will be described first. Then, the exposure device <NUM> included in the image forming apparatus <NUM> will be described. The image forming apparatus <NUM> is, for example, an image forming apparatus forming images with multiple colors. An example of the image forming apparatus <NUM> is a full-color printer for commercial printing for which a particularly high image quality is desired.

The image forming apparatus <NUM> is a wide-image forming apparatus capable of handling media with a width exceeding the width of a recording medium P for B3 longitudinal feed (that is, the width exceeding <NUM>). For example, the image forming apparatus <NUM> handles recording media P of the size larger than or equal to <NUM> for A2 longitudinal feed and smaller than or equal to <NUM> for B0 cross feed. For example, the image forming apparatus <NUM> handles recording media P of <NUM> for B2 cross feed.

The image forming apparatus <NUM> illustrated in <FIG> is an example of an image forming apparatus that forms images on recording media. More specifically, the image forming apparatus <NUM> is an electrophotographic image forming apparatus that forms toner images (an example of images) on the recording media P. Toner is an example of powder. More specifically, the image forming apparatus <NUM> includes an image forming unit <NUM> and a fixing device <NUM>. Portions in the image forming apparatus <NUM> (the image forming unit <NUM> and the fixing device <NUM>) will be described below.

The image forming unit <NUM> has a function of forming toner images on the recording media P. More specifically, the image forming unit <NUM> includes toner image forming units <NUM> and a transfer device <NUM>.

The image forming unit <NUM> includes multiple toner image forming units <NUM> illustrated in <FIG> to form toner images of different colors. In the present exemplary embodiment, the image forming unit <NUM> includes the toner image forming units <NUM> for four colors of yellow (Y), magenta (M), cyan (C), and black (K). The letters Y, M, C, and K following the reference signs in <FIG> denote the colors to which the components correspond.

The toner image forming units <NUM> for the different colors have the same structure except for using different toner. Thus, in <FIG>, components of the toner image forming unit <NUM> are denoted with reference sings as a representative of all the toner image forming units <NUM> for different colors.

More specifically, the toner image forming unit <NUM> for each color includes a photoconductor drum <NUM> that rotates in a first direction (for example, counterclockwise direction in <FIG>). The photoconductor drum <NUM> is an example of an image carrier. The toner image forming unit <NUM> for each color also includes a charging device <NUM>, the exposure device <NUM>, and a developing device <NUM>.

In the toner image forming unit <NUM> for each color, the charging device <NUM> electrically charges the photoconductor drum <NUM>. The exposure device <NUM> exposes the photoconductor drum <NUM> electrically charged by the charging device <NUM> with light to form an electrostatic latent image on the photoconductor drum <NUM>. The developing device <NUM> develops the electrostatic latent image formed on the photoconductor drum <NUM> by the exposure device <NUM> to form a toner image.

The photoconductor drum <NUM> rotates while carrying the electrostatic latent image formed in the above manner on the outer periphery to transport the electrostatic latent image to the developing device <NUM>. A specific structure of the exposure device <NUM> will be described later.

The transfer device <NUM> illustrated in <FIG> is a device that transfers toner images formed by the toner image forming units <NUM> onto the recording media P. More specifically, the transfer device <NUM> first-transfers the toner images on the photoconductor drums <NUM> for different colors to a transfer belt <NUM> serving as an intermediate transfer body in a superposed manner, and second-transfers the superposed toner images to a recording medium P. More specifically, as illustrated in <FIG>, the transfer device <NUM> includes the transfer belt <NUM>, first transfer rollers <NUM>, and a second transfer roller <NUM>.

Each first transfer roller <NUM> is a roller that transfers the toner image on the photoconductor drum <NUM> for the corresponding color to the transfer belt <NUM> at a first transfer position T1 between the photoconductor drum <NUM> and the first transfer roller <NUM>. In the present exemplary embodiment, an application of a first-transfer electric field between the first transfer roller <NUM> and the photoconductor drum <NUM> transfers the toner image formed on the photoconductor drum <NUM> to the transfer belt <NUM> at the first transfer position T1.

The transfer belt <NUM> receives the toner image from each photoconductor drum <NUM> for the corresponding color on the outer peripheral surface. More specifically, the transfer belt <NUM> has the following structure. As illustrated in <FIG>, the transfer belt <NUM> has an annular shape, and is wound around multiple rollers <NUM> to have its position fixed.

The transfer belt <NUM> rotates in the direction of arrows A with, for example, a driving roller 39D of multiple rollers <NUM> being driven to rotate by a driving unit (not illustrated). Among the multiple rollers <NUM>, a roller 39B illustrated in <FIG> is an opposing roller 39B opposing the second transfer roller <NUM>.

The second transfer roller <NUM> is a roller that transfers the toner image transferred to the transfer belt <NUM> to the recording medium P at a second transfer position T2 between the opposing roller 39B and the second transfer roller <NUM>. In the present exemplary embodiment, an application of a second-transfer electric field between the opposing roller 39B and the second transfer roller <NUM> transfers the toner image transferred to the transfer belt <NUM> to the recording medium P at the second transfer position T2.

The fixing device <NUM> illustrated in <FIG> is a device that fixes the toner image transferred to the recording medium P by the second transfer roller <NUM> to the recording medium P. More specifically, as illustrated in <FIG>, the fixing device <NUM> includes a heating roller 16A serving as a heating member and a pressing roller 16B serving as a pressing member. The fixing device <NUM> heats and presses the recording medium P with the heating roller 16A and the pressing roller 16B to fix the toner image formed on the recording medium P to the recording medium P.

Subsequently, the structure of the exposure device <NUM> according to exemplary embodiments will be described. <FIG> is a perspective view of the structure of the exposure device <NUM>. <FIG> is a plan view of the exposure device <NUM> viewed in the vertical direction. In the following description, the direction of arrow Y in the drawings indicates the width direction of the exposure device <NUM>, and the direction of arrow Z indicates the height direction of the exposure device <NUM>. The direction of arrow X perpendicular to the apparatus width direction and the apparatus height direction indicates the depth direction of the exposure device <NUM>. The width direction and the height direction are merely defined for illustration convenience, and not used to limit the structure of the exposure device <NUM>.

The entire structure of the exposure device <NUM> will be described first, and then components of the exposure device <NUM> will be described.

The exposure device <NUM> includes a light emitter <NUM> and a position adjusters <NUM> as illustrated in <FIG>.

As illustrated in <FIG> and <FIG>, the light emitter <NUM> includes a substrate <NUM> extending in a first direction (a direction of arrow X in the present exemplary embodiment) and multiple light radiators <NUM> disposed on one side of the substrate <NUM> in the direction of arrow Z (upper side in the vertical direction in <FIG> and <FIG>). In the present exemplary embodiment, the light emitter <NUM> includes three light radiators <NUM> extending in a first direction of the substrate <NUM>. The substrate <NUM> is a long rectangular member in a plan view in <FIG>. The light radiators <NUM> have the same structure, and are long rectangular members in a plan view in <FIG>.

For example, the three light radiators <NUM> are misaligned in a first direction (direction of arrow X) of the substrate <NUM>, and misaligned in the width direction perpendicular to the first direction of the substrate <NUM>, that is, misaligned in the cross direction (direction of arrow Y) of the substrate <NUM>. The light emitter <NUM> is disposed in the axial direction of the photoconductor drum <NUM> (refer to <FIG>). The length of the light emitter <NUM> in the first direction (direction of arrow X) is longer than the length of the photoconductor drum <NUM> in the axial direction. At least one of the three light radiators <NUM> faces the surface (outer peripheral surface) of the photoconductor drum <NUM>. Thus, light emitted from the light emitter <NUM> is applied to the surface of the photoconductor drum <NUM>.

In <FIG> and <FIG> and other drawings, the light emitter <NUM> is illustrated with a side of the substrate <NUM> where the light radiators <NUM> are disposed on the upper side in the vertical direction, and light is emitted upward from the light radiators <NUM>. On the other hand, in the image forming apparatus <NUM> in <FIG>, the exposure device <NUM> is illustrated upside down in the vertical direction. Specifically, in <FIG>, the exposure device <NUM> is disposed while having a side of the substrate <NUM> where the light radiators <NUM> are disposed on the lower side in the vertical direction, and light is emitted downward toward the photoconductor drum <NUM> from the light radiators <NUM>.

In the present exemplary embodiment, the three light radiators <NUM> are staggered when viewed from above in the vertical direction of the exposure device <NUM> (refer to <FIG>). More specifically, two light radiators <NUM> are disposed at both end portions of the substrate <NUM> in the first direction (direction of arrow X) and at a first side of the substrate <NUM> in the cross direction (direction of arrow Y). One light radiator <NUM> is disposed at the middle of the substrate <NUM> in the first direction (direction of arrow X) and at a second side of the substrate <NUM> in the cross direction (direction of arrow Y). End portions of the two light radiators <NUM> disposed at the first side of the substrate <NUM> in the cross direction (direction of arrow Y) and end portions of the light radiator <NUM> disposed at the second side of the substrate <NUM> in the cross direction (direction of arrow Y) overlap each other when viewed in the cross direction (direction of arrow Y) of the substrate <NUM>. Specifically, the irradiation areas that are irradiated with light from the three light radiators <NUM> overlap each other in the first direction (direction of arrow X) of the substrate <NUM>.

As illustrated in <FIG> and <FIG>, the exposure device <NUM> includes harnesses <NUM> electrically connected to the three light radiators <NUM>, multiple brackets <NUM> that hold the harnesses <NUM>, and a lower covering <NUM> covering the harnesses <NUM> and the brackets <NUM>. The harnesses <NUM> form an assemblage or a bundle of multiple wires used for power supply. The brackets <NUM> are attached to the substrate <NUM>, and extend from the substrate <NUM> to the second side (lower side in the vertical direction in <FIG>) in the direction of arrow Z. The lower covering <NUM> is attached to the second side (lower side in the vertical direction in <FIG>) of the substrate <NUM> in the direction of arrow Z.

As illustrated in <FIG> and <FIG>, the exposure device <NUM> includes side coverings <NUM> that cover the sides of the three light radiators <NUM>. The side coverings <NUM> have a plate shape and lower end portions attached to both sides of the substrate <NUM> in the cross direction (direction of arrow Y). The exposure device <NUM> includes cleaning devices <NUM> that clean lenses <NUM> of the light radiators <NUM>. The lenses <NUM> will be described below.

As illustrated in <FIG> and <FIG>, the exposure device <NUM> includes multiple spacers <NUM> held between the substrate <NUM> and the light radiators <NUM>, and fastening members <NUM> that fasten the light radiators <NUM> to the substrate <NUM> with the multiple spacers <NUM> interposed therebetween. The fastening members <NUM> each have, for example, a helical groove for fastening. In other words, each fastening member <NUM> is a member with a screw mechanism, such as a screw or a bolt.

Although not illustrated, positioning shafts extending upward in the vertical direction are disposed at both ends of the substrate <NUM> in the first direction (direction of arrow X). The positioning shafts are received in insertion portions formed in bearings at both ends of the photoconductor drum <NUM>, to fix the position of the light emitter <NUM> with respect to the photoconductor drum <NUM> in the direction perpendicular to the light emission direction. More specifically, the position of the light emitter <NUM> is fixed in the Y direction with respect to the photoconductor drum <NUM>.

As illustrated in <FIG>, the substrate <NUM> is formed from a thin rectangular-parallelepiped member. The substrate <NUM> is disposed to face the photoconductor drum <NUM> (<FIG>) along the full length in the axial direction.

Recesses <NUM> that receive the spacers <NUM> are formed in a surface 42A of the substrate <NUM> on the upper side in the vertical direction (direction of arrow Z) (refer to <FIG>). For example, three spacers <NUM> are disposed at intervals in the first direction (direction of arrow X) for each of the light radiators <NUM>. In the present exemplary embodiment, three spacers <NUM> are disposed for each of the three light radiators <NUM>.

Each of the recesses <NUM> includes a slope 80A that forms a bottom surface and is inclined with respect to the surface 42A of the substrate <NUM>, a vertical wall 80B disposed at a downward end of the slope 80A, and two opposing vertical walls (not illustrated) on both sides of the slope 80A (refer to <FIG>). For example, the slopes 80A facing the two light radiators <NUM> disposed on the first side of the substrate <NUM> in the cross direction are inclined in the direction opposite to the direction in which the slope 80A facing the one light radiator <NUM> disposed on the second side of the substrate <NUM> in the cross direction is inclined. In the light emitter <NUM>, the slopes 80A inclined opposite to each other adjust light to be applied to the center portion of the photoconductor drum <NUM> (refer to <FIG>) using the two light radiators <NUM> disposed on the first side of the substrate <NUM> in the cross direction and the one light radiator <NUM> disposed on the second side of the substrate <NUM> in the cross direction.

When the light emitter <NUM> includes only one light radiator <NUM>, the light emission direction of the light emitter <NUM> toward the photoconductor drum <NUM> corresponds to the optical axis direction of the light radiator <NUM>. On the other hand, when the light emitter <NUM> includes multiple light radiators <NUM> as in the present exemplary embodiment, the direction toward the focal point from the middle point in the cross direction (Y direction) of the substrate <NUM> between the principal points of the light radiators <NUM> when viewed in the first direction (X direction) of the substrate <NUM> is a light emission direction. In the present exemplary embodiment, the positions and the angles of the light emitters <NUM> are adjusted so that the direction toward the center of the photoconductor drum <NUM> is aligned with the light emission direction.

In the present exemplary embodiment, the substrate <NUM> is formed from a metal block. Instead of including typical sheet metal that is shaped by bending, the metal block in the present exemplary embodiment has a shape used as a substrate of the exposure device <NUM> and a thickness that is not substantially bendable. For example, the substrate <NUM> is formed from a metal block with a thickness of higher than or equal to <NUM>% of the width of the substrate <NUM>. More specifically, the substrate <NUM> may be formed from a metal block with a thickness of higher than or equal to <NUM>% and lower than or equal to <NUM>% of the width of the substrate <NUM>.

Unlike a full-color printer for commercial printing, an existing wide-image forming apparatus is used to output monochrome images for which a high image quality is not desired, and thus includes a substrate formed from sheet metal. On the other hand, the image forming apparatus <NUM> according to the exemplary embodiment is a full-color printer for commercial printing for which a high image quality is desired. Thus, to reduce the effect of deflection of the substrate <NUM> on the image quality, a metal block that is more rigid than sheet metal is used.

The substrate <NUM> is formed from, for example, steel or stainless steel. Alternatively, the substrate <NUM> may be formed from a metal block made of steel or stainless steel. For example, the metal block may be made of aluminum that is lighter in weight and has higher thermal conductivity than steel or stainless steel. In the present exemplary embodiment, heat generated by light sources <NUM> is mostly radiated by support bodies <NUM>. Thus, the substrate <NUM> is formed from steel or stainless steel by giving priority in rigidity rather than thermal conductivity or weight.

The thickness of the substrate <NUM> in the vertical direction (direction of arrow Z) is preferably larger than the thickness of the support bodies <NUM> forming the light radiators <NUM>. Thus, the rigidity of the substrate <NUM> (flexural rigidity in the direction of arrow Z) is larger than the rigidity of the light radiators <NUM>. The thickness of the substrate <NUM> in the vertical direction (direction of arrow Z) is preferably larger than or equal to <NUM>, more preferably larger than or equal to <NUM>, and further more preferably larger than or equal to <NUM>.

As illustrated in <FIG>, recessed portions <NUM> set back toward the spacers <NUM>, that is, toward the recesses <NUM> are formed in an underside 42B of the substrate <NUM> opposite to the surface 42A. The recessed portions <NUM> are formed at positions corresponding to the recesses <NUM> of the substrate <NUM>. The recessed portions <NUM> are obliquely formed from the underside 42B of the substrate <NUM> toward the center portion of the substrate <NUM> in the cross direction (Y direction). For example, the recessed portions <NUM> are circular when viewed from the underside 42B of the substrate <NUM>. The inner diameter of each recessed portion <NUM> is larger than the outer diameter of a head 58A of the corresponding fastening member <NUM>. A through-hole <NUM> in the substrate <NUM> through which a shank 58B of each fastening member <NUM> extends is formed in a bottom surface 82A of the corresponding recessed portion <NUM>. The through-hole <NUM> is open in the slope 80A of each recess <NUM>.

As illustrated in <FIG>, the three light radiators <NUM> have the same structure, as described above. For example, the two light radiators <NUM> on the first side of the substrate <NUM> in the cross direction (direction of arrow Y) and the one light radiator <NUM> on the second side of the substrate <NUM> in the cross direction (direction of arrow Y) are disposed to be symmetrical with respect to the cross direction (direction of arrow Y) of the substrate <NUM>.

As illustrated in <FIG>, each of the light radiators <NUM> includes a support body <NUM> extending in the first direction (direction of arrow X), and a light-emitting device substrate <NUM> supported on a surface of the support body <NUM> opposite, in the vertical direction (direction of arrow Z), to the surface facing the substrate <NUM> (supported on the upper surface in the vertical direction in the present exemplary embodiment). The multiple light sources <NUM> are arranged on the light-emitting device substrate <NUM> in the first direction. In the present exemplary embodiment, each of the light sources <NUM> includes multiple light-emitting devices. For example, each light source <NUM> is a light-emitting device array including a semiconductor substrate and multiple light-emitting devices arranged on the semiconductor substrate in the first direction. In the present exemplary embodiment, the light-emitting device arrays each formed from the light source <NUM> are disposed on the light-emitting device substrate <NUM> in a manner staggered in the first direction. Instead of a light-emitting device array, each light source <NUM> may be a single light-emitting device. Each light-emitting device is formed from, for example, a light-emitting diode, a light emitting thyristor, or a laser element. When arranged in the first direction, the light-emitting devices have, for example, a resolution of <NUM> dpi. The light-emitting device substrate <NUM> is a substrate for allowing at least one of the multiple light sources <NUM> to emit light. <FIG> illustrates only one light source <NUM> disposed on each of the light radiators <NUM>, and omits illustration of other light sources.

Each of the light radiators <NUM> includes a pair of attachments <NUM> disposed on the surface of the light-emitting device substrate <NUM> opposite to the surface on which the support body <NUM> is disposed, and a lens <NUM> held between upper end portions of the pair of attachments <NUM>.

The pair of attachments <NUM> and the lens <NUM> extend in the first direction (direction of arrow X) of the support body <NUM> (refer to, for example, <FIG>). The lens <NUM> is disposed to oppose the multiple light sources <NUM> while leaving a space between the lens <NUM> and the multiple light sources <NUM>. In the exposure device <NUM>, light emitted from the multiple light sources <NUM> passes through the lens <NUM>, and is applied to the surface of the photoconductor drum <NUM> (refer to <FIG>) serving as an irradiated object.

Each support body <NUM> is formed from a rectangular parallelepiped member. In the present exemplary embodiment, as in the substrate <NUM>, the support body <NUM> is formed from a metal block. For example, the support body <NUM> is formed from steel or stainless steel. Alternatively, the substrate <NUM> may be formed from a metal block made of a material other than steel or stainless steel. For example, the metal block may be made of aluminum that is lighter in weight and has higher thermal conductivity than steel or stainless steel. However, when the substrate <NUM> and the support body <NUM> have different coefficients of thermal expansion, distortion or deflection may occur. Thus, in view of reducing distortion or deflection, the substrate <NUM> and the support body <NUM> are preferably formed from the same material.

A threaded hole <NUM> into which the shank 58B of each fastening member <NUM> is fastened is formed in the surface of the support body <NUM> facing the substrate <NUM> (refer to <FIG>). The threaded hole <NUM> is formed at a position opposing the corresponding through-hole <NUM> in the substrate <NUM>.

While the fastening members <NUM> are received in the recessed portions <NUM> in the substrate <NUM> and the shanks 58B of the fastening members <NUM> extend through the through-holes <NUM> in the substrate <NUM>, the shanks 58B of the fastening members <NUM> are fastened to the threaded holes <NUM> of the support body <NUM> with the spacers <NUM> interposed therebetween. Thus, the light radiators <NUM> are fastened to the substrate <NUM> with the fastening members <NUM> in the recessed portions <NUM> of the substrate <NUM>. While the light radiators <NUM> are fastened to the substrate <NUM> with the fastening members <NUM>, the spacers <NUM> are interposed between the substrate <NUM> and the support bodies <NUM>.

A method for fastening, with the fastening members <NUM>, the light radiators <NUM> from the surfaces (light emitting surfaces) of the support bodies <NUM> to the surface of the substrate <NUM> is conceivable. However, unlike a support body made of a resin material or formed from sheet metal, each support body <NUM> according to the present exemplary embodiment is formed from a metal block with a heavy mass. Thus, the fastening members <NUM> are correspondingly to have a large size and mass. This structure involves leaving a space for the large-sized fastening members <NUM> over the surface of the support body <NUM>, and size increase of the support body <NUM>. To avoid this, in the present exemplary embodiment, each support body <NUM> is fastened from the underside.

In a structure including the fastening members <NUM> at not only both ends of the support body <NUM> but also at the center portion, the existence of the light source <NUM> at the center portion prevents fastening of the support body <NUM> from the surface side. Thus, the structure where both ends and the center portion of the support body <NUM> are fastened only involves fastening from the underside of the substrate <NUM>.

When viewed in the optical axis direction of the light sources <NUM>, the threaded holes <NUM> and the recessed portions <NUM> of the substrate <NUM> are located to overlap the light sources <NUM>. Compared to the structure where the threaded holes <NUM> and the recessed portions <NUM> are located not to overlap the light sources <NUM>, this structure facilitates dissipation of heat generated from the light sources <NUM> to the substrate <NUM> through the fastening members <NUM>.

As illustrated in <FIG>, <FIG>, <FIG>, and <FIG>, a driving substrate <NUM> is attached to the support body <NUM> of each light radiator <NUM> with fittings <NUM>. The driving substrate <NUM> is an example of a substrate. The driving substrate <NUM> extends in the first direction (direction of arrow X). The length of each driving substrate <NUM> in the first direction is shorter than the length of the corresponding support body <NUM> in the first direction (refer to <FIG>). Each driving substrate <NUM> is a substrate that drives the corresponding light radiator <NUM>, and formed from, for example, an application specific integrated circuit (ASIC) substrate.

Each fitting <NUM> includes a fastening bolt 70A and a tube 70B disposed between the support body <NUM> and the driving substrate <NUM> (refer to <FIG>). For example, the tube 70B is made of metal, and joined to the driving substrate <NUM> by, for example, soldering. Although not illustrated, the driving substrate <NUM> has openings continuous with the through-holes of the tubes 70B. The shank of each fastening bolt 70A extends through the tube 70B. The shank of the fastening bolt 70A extends through the tube 70B from the side closer to the driving substrate <NUM>, and is fastened to the support body <NUM> to attach the driving substrate <NUM> to the support body <NUM>. The driving substrate <NUM> is attached to the support body <NUM> with two fittings <NUM> disposed at both ends of the driving substrate <NUM> in the first direction.

The surface of the driving substrate <NUM> (that is, flat surface) extends along an inner side portion 60A of the support body <NUM> in the cross direction (direction of arrow Y) of the substrate <NUM> (refer to <FIG>). The inner side portion 60A of the support body <NUM> refers to the side of the substrate <NUM> closer to the center portion in the cross direction.

The tube 70B of each fitting <NUM> forms a gap between the inner side portion 60A of the support body <NUM> and the surface (flat surface) of the driving substrate <NUM>. Specifically, the driving substrate <NUM> is attached to the inner side portion 60A of the support body <NUM> of the corresponding light radiator <NUM> with the fittings <NUM> without in direct contact with the inner side portion 60A.

The inner side portion 60A of the support body <NUM> is a slope inclined inward with respect to the surface 42A of the substrate <NUM>. As in the case of the inner side portion 60A, the flat surface of the driving substrate <NUM> is also inclined inward with respect to the surface 42A of the substrate <NUM>.

The driving substrate <NUM> is disposed on each of the three light radiators <NUM> at the inner side portion 60A of the support body <NUM>.

As illustrated in <FIG> and <FIG>, in a side view, the driving substrate <NUM> disposed on one light radiator <NUM> is located not to overlap another light radiator <NUM> adjacent to the light radiator <NUM>. The driving substrates <NUM> of the three light radiators <NUM> disposed on the substrate <NUM> have the same length in the first direction (direction of arrow X), and are shorter than a portion of the light radiator <NUM> disposed at the center portion in the first direction that does not overlap the light radiators <NUM> on both sides in the first direction.

As illustrated in <FIG>, <FIG>, and <FIG>, three flexible cables <NUM> are connected to the light-emitting device substrate <NUM> disposed on the support body <NUM>. The three flexible cables <NUM> extend to the outer side of the support body <NUM> from the upper portion of the inner side portion 60A of the support body <NUM>. The three flexible cables <NUM> extending to the outer side of the support body <NUM> are electrically connected to three driving elements <NUM> disposed on the driving substrate <NUM>. Examples usable as the driving elements <NUM> include integrated circuits.

At a portion of each driving substrate <NUM> other than both ends in the first direction (direction of arrow X), a connector <NUM> to which a flat cable <NUM> from the outer side of the corresponding light radiator <NUM> is electrically connected is disposed. A connection port of the connector <NUM> extends in a direction crossing the surface (flat surface) of the driving substrate <NUM>. A connection portion of the flat cable <NUM> is insertable into and removable from the connector <NUM> in the direction crossing the surface (flat surface) of the driving substrate <NUM>. The flat cable <NUM> is an example of a wire.

As illustrated in <FIG>, the flat cable <NUM> connected to the connector <NUM> extends from the driving substrate <NUM> in a direction away from the support body <NUM>. The substrate <NUM> has through portions <NUM> that extend through in the vertical direction (direction of arrow Z) at positions corresponding to the positions of the driving substrate <NUM> where the flat cables <NUM> are connected. The through portions <NUM> are formed in the substrate <NUM> on the side of the driving substrate <NUM> in the cross direction (direction of arrow Y) of the substrate <NUM> and at positions on the side of the driving substrate <NUM> opposite to the side where the light radiators <NUM> are disposed (that is, positions where the light radiators <NUM> are not disposed). The flat cables <NUM> are inserted into the through portions <NUM> of the substrate <NUM> to be routed to the inner side of the lower covering <NUM> facing the underside 42B of the substrate <NUM>. In other words, the flat cables <NUM> are disposed in the inner side of the lower covering <NUM>.

As illustrated in <FIG> and <FIG>, each flat cable <NUM> is connected with the connector <NUM> interposed therebetween to the driving substrate <NUM> disposed on each of the three light radiators <NUM>. The substrate <NUM> has the through portions <NUM> on the side of the driving substrates <NUM> attached to the three light radiators <NUM>. The flat cable <NUM> for each of the three light radiators <NUM> is received in the corresponding through portion <NUM> in the substrate <NUM>, and extends to the inner side of the lower covering <NUM> facing the underside 42B of the substrate <NUM> (refer to <FIG>).

For example, the light radiators <NUM> have a dimension in the height direction longer than the dimension in the width direction that is perpendicular to the first direction (perpendicular to the direction of arrow X). Specifically, the light radiators <NUM> have a dimension in the vertical direction (direction of arrow Z) longer than the dimension in the cross direction (direction of arrow Y). Thus, the center of gravity of the light radiators <NUM> is higher than when the light emitter has a dimension in the height direction shorter than the dimension in the width direction perpendicular to the first direction.

As illustrated in <FIG>, the spacers <NUM> are held between the substrate <NUM> and the light radiators <NUM> in the optical axis direction of the light sources <NUM>. For example, each spacer <NUM> has a plate shape, and is made of a single member. In the present exemplary embodiment, each spacer <NUM> has a U shape when viewed in the optical axis direction of the light sources <NUM>. Each spacer <NUM> includes a body 56A and a hole 56B in one side of the body 56A.

Each spacer <NUM> is disposed on the slope 80A of the corresponding recess <NUM> in the substrate <NUM>. Each spacer <NUM> has a thickness larger than or equal to the depth of the recess <NUM> at the position where the spacer <NUM> is disposed on the slope 80A. The fastening members <NUM> fasten the light radiators <NUM> to the substrate <NUM> while imposing a compression load on the spacers <NUM>.

As illustrated in <FIG>, the brackets <NUM> have a function of holding the flat cables <NUM>. The brackets <NUM> are examples of a holding member. More specifically, each bracket <NUM> includes a U-shaped support portion 48A, protruding from the underside 42B of the substrate <NUM> in a direction away from the light radiators <NUM>, and a pair of attachment portions 48B bent inward (that is, toward the inner side of the substrate <NUM> in the cross direction) from the upper end portion of the support portion 48A. The support portion 48A has a flat-surface portion <NUM> facing the underside 42B of the substrate <NUM> at the middle of the lower portion of the U shape. The support portion 48A has a portion opposite to the flat-surface portion <NUM> open toward the substrate <NUM>. The pair of attachment portions 48B are attached to the substrate <NUM> with fastening members <NUM> while being in surface contact with the underside 42B of the substrate <NUM>.

The brackets <NUM> are spaced apart from each other in the first direction (direction of arrow X) of the substrate <NUM> (refer to <FIG>). Each flat cable <NUM> is held at the flat-surface portion <NUM> of the support portion 48A. The flat cables <NUM> are supported by the multiple brackets to be arranged in the first direction (direction of arrow X) of the substrate <NUM> in the inner side of the lower covering <NUM>.

As illustrated in <FIG> and <FIG>, the lower covering <NUM> covers the harnesses <NUM> and the flat cables <NUM> electrically connected to the three light radiators <NUM>. The lower covering <NUM> is attached to the lower side of the substrate <NUM> in the vertical direction (that is, on the underside 42B of the substrate <NUM> illustrated in <FIG>). The lower covering <NUM> protrudes from the substrate <NUM> in a direction away from the light radiators <NUM>, and covers part of the underside 42B of the substrate <NUM>. In the present exemplary embodiment, the lower covering <NUM> has a U-shaped cross section. The upper end portions of the lower covering <NUM> are attached to both sides of the substrate <NUM> in the cross direction (direction of arrow Y) with multiple fastening members <NUM>. The lower covering <NUM> is attachable to and removable from the substrate <NUM> by fastening or removing the multiple fastening members <NUM>.

The lower covering <NUM> raises the substrate <NUM> when having the bottom placed on a horizontal plane. When the substrate <NUM> formed from a metal block is raised, the center of gravity of the exposure device <NUM> is raised.

As illustrated in <FIG>, <FIG>, and <FIG>, the side coverings <NUM> are disposed on both edges of the substrate <NUM> in the cross direction (direction of arrow Y). The side coverings <NUM> extend in the first direction (direction of arrow X) on the sides of the three light radiators <NUM>. Thus, the side coverings <NUM> have a function of protecting the three light radiators <NUM> from the outside.

In a side view of the exposure device <NUM> (when viewed in the direction of arrow Y), the side coverings <NUM> are disposed to overlap the three light radiators <NUM>. The side coverings <NUM> are longer in the first direction (direction of arrow X) than the longitudinal area of the substrate <NUM> where the three light radiators <NUM> are disposed (refer to <FIG> and <FIG>).

As illustrated in <FIG>, a support portion <NUM> that supports the corresponding side covering <NUM> is disposed on the inner side of the side covering <NUM>. An attachment <NUM> is disposed on the surface 42A of the substrate <NUM> at the end in the cross direction (direction of arrow Y) to support the support portion <NUM>. The support portion <NUM> is in contact with the corresponding side covering <NUM> to support the side covering <NUM> so that the side covering <NUM> does not fall toward the light radiators <NUM>. The support portions <NUM> are disposed on the side coverings <NUM> on both sides of the substrate <NUM> in the cross direction. Although not illustrated, the support portions <NUM> are disposed at intervals in the first direction (direction of arrow X) of the side coverings <NUM>.

As illustrated in <FIG>, the position adjuster <NUM> is a mechanism for adjusting the distance between the light emitter <NUM> and the photoconductor drum <NUM>. More specifically, the position adjuster <NUM> adjusts the position of the light emitter <NUM> with respect to the photoconductor drum <NUM>. More specifically, the position adjuster <NUM> moves the light emitter <NUM> in the light emission direction to adjust the position of the light emitter <NUM> with respect to the photoconductor drum <NUM>. In the present exemplary embodiment, the light emission direction of the light emitter <NUM> is substantially the same as the Z direction.

As illustrated in <FIG>, the position adjuster <NUM> includes a contact member <NUM>, a support member <NUM>, and a mover <NUM>.

As illustrated in <FIG>, the contact member <NUM> is a member having an outer peripheral surface 132A in contact with the surface 42A of the substrate <NUM>. The contact member <NUM> has a disk shape, and is rotatably supported by the support member <NUM>. More specifically, the contact member <NUM> is supported by the support member <NUM> to rotate relative to the support member <NUM>. For example, the contact member <NUM> according to the present exemplary embodiment is a ball bearing.

The support member <NUM> is a member that rotatably supports the contact member <NUM>. The support member <NUM> supports the contact member <NUM> while allowing the contact member <NUM> to rotate relative to the support member <NUM>. As illustrated in <FIG> and <FIG>, the support member <NUM> is a substantially cylindrical shaft, and has both ends in the axial direction received by a pair of receiving portions <NUM>. More specifically, the pair of receiving portions <NUM> are disposed to oppose each other in the X direction or the cross direction of the substrate <NUM>. The pair of receiving portions <NUM> allow the support member <NUM> to rotate about the axis or the X direction, and to move in the light emission direction. In other words, the contact member <NUM> is disposed between the pair of receiving portions <NUM> of the support member <NUM>.

As illustrated in <FIG>, the pair of receiving portions <NUM> are long wall holes formed in a pair of support plates <NUM> opposing each other in the X direction with the contact member <NUM> in between. These long holes have a length in the Z direction. Thus, the receiving portions <NUM> are capable of supporting the support member <NUM> while allowing both ends of the support member <NUM> in the axial direction to rotate and to move in the light emission direction. Safety lock stoppers (not illustrated) are attached to both ends of the support member <NUM> in the axial direction.

As illustrated in <FIG>, an outer diameter D1 of the contact member <NUM> is larger than an outer diameter D2 of the support member <NUM>.

As illustrated in <FIG>, the mover <NUM> is a member that is in contact with the support member <NUM> to move the support member <NUM> in the light emission direction of the light emitter <NUM>.

The mover <NUM> is movable in the X direction. More specifically, the position adjuster <NUM> includes a feeder <NUM> and a driving source <NUM>, and the feeder <NUM> moves the mover <NUM> in the X direction. In the present exemplary embodiment, the feeder <NUM> is a feed screw serving as an example of a screw member. The feeder <NUM> extends through a coupling plate <NUM> that couples ends of the pair of support plates <NUM> in the X direction. The driving source <NUM> is coupled to one end of the feeder <NUM> in the axial direction. The driving source <NUM> drives the feeder <NUM> to rotate. The driving source <NUM> according to the present exemplary embodiment is, for example, an electric motor, but the present disclosure is not limited to this structure. The driving source <NUM> is attached to an attachment plate <NUM> protruding from the coupling plate <NUM> to the first side (to the left in <FIG>, or to the near side in the apparatus depth direction) in the X direction. In the present exemplary embodiment, the pair of support plates <NUM>, the coupling plate <NUM>, and the attachment plate <NUM> constitute a housing <NUM> of the position adjuster <NUM>. This housing <NUM> is attached to a frame, not illustrated, included in the image forming unit <NUM>.

The mover <NUM> includes converters <NUM> that convert the moving force in the X direction provided by the feeder <NUM> into the moving force of the support member <NUM> to move in the light emission direction. More specifically, the converters <NUM> are slopes disposed at portions of the mover <NUM> that are in contact with the support member <NUM> and that are inclined with respect to the X direction. More specifically, as illustrated in <FIG>, the mover <NUM> includes a pair of converters <NUM> (a pair of slopes), and the pair of converters <NUM> are in contact with both portions of the support member <NUM> in the axial direction with the contact member <NUM> in between. For example, the mover <NUM> according to the present exemplary embodiment is rectangular parallelepiped, and has a groove 136A at a portion corresponding to the contact member <NUM>. The groove 136A receives part of the outer periphery of the contact member <NUM>, and extends in the X direction. The pair of converters <NUM> are disposed on both sides of the support member <NUM> with the groove 136A in between.

As illustrated in <FIG>, the substrate <NUM> is pressed toward the position adjuster <NUM> by a presser <NUM> disposed on the side opposite to the side where the position adjuster <NUM> is disposed. More specifically, the substrate <NUM> is held with pressure between the position adjuster <NUM> and the presser <NUM> in the Z direction. When the mover <NUM> moves in the X direction, the slopes serving as the converters <NUM> provide the moving force in the Z direction to the support member <NUM> via the outer peripheral surface of the support member <NUM>. When the moving force in the Z direction is provided to the support member <NUM>, the moving force is transmitted from the support member <NUM> to the substrate <NUM> via the contact member <NUM> to push back the presser <NUM>. Thus, the substrate <NUM> moves in the Z direction, that is, the position of the substrate <NUM> is adjusted.

As illustrated in <FIG>, the contact member <NUM> and the feeder <NUM> that extend through the mover <NUM> overlap in the light emission direction. As illustrated in <FIG>, in the present exemplary embodiment, for example, a straight line SL that passes a contact point between the contact member <NUM> and the substrate <NUM> and a contact point between the mover <NUM> and the support member <NUM> extends in the light emission direction of the light emitter <NUM>.

The coefficient of friction between the contact member <NUM> and the substrate <NUM> is smaller than the coefficient of friction between the support member <NUM> and the contact member <NUM>. More specifically, in the present exemplary embodiment, the contact member <NUM> is a ball bearing. Thus, the contact member <NUM> rotates relative to the support member <NUM> before friction occurs between the contact member <NUM> and the substrate <NUM>.

The ends of the pair of support plates <NUM> in the Z direction are coupled together with a coupling plate <NUM>. The coupling plate <NUM> has an opening 147A. Part of the outer periphery of the contact member <NUM> protrudes through the opening 147A. The protruding part of the contact member <NUM> is in contact with the surface 42A of the substrate <NUM>.

In the image forming apparatus <NUM> according to the present exemplary embodiment, the distance from the light emitter <NUM> to the surface of the photoconductor drum <NUM> is measured by measuring devices not illustrated disposed at both ends of the substrate <NUM>, and the measurement information is transmitted to a controller not illustrated. The controller operates the position adjusters <NUM> based on the measurement information. More specifically, the controller adjusts the driving amount of the driving source <NUM> based on the measurement information. When the values measured by the measuring devices fall within a predetermined set range, the controller stops the operation of the driving source <NUM>. The position adjustment on the light emitter <NUM> may be performed by the position adjuster <NUM> at a timing when the light emitter <NUM> is attached to the photoconductor drum <NUM> or at a timing a predetermined time length (period) after the attachment.

Subsequently, the operations and effects of the present exemplary embodiment will be described.

In the exposure device <NUM> according to the present exemplary embodiment, the contact member <NUM> is supported by the support member <NUM> to be rotatable relative to the support member <NUM>. Thus, compared to a structure where the contact member <NUM> is fixed to the support member <NUM>, the exposure device <NUM> according to the present exemplary embodiment reduces misregistration of the light emitter <NUM> in the direction perpendicular to the light emission direction.

In the exposure device <NUM>, the coefficient of friction between the contact member <NUM> and the substrate <NUM> is smaller than the coefficient of friction between the support member <NUM> and the contact member <NUM>. Thus, regardless of when movement of the mover <NUM> imposes a force in the Z direction on the support member <NUM>, the contact member <NUM> rotates relative to the support member <NUM>, and prevents an excessively large frictional force from occurring between the contact member <NUM> and the substrate <NUM>. Thus, compared to a structure where the coefficient of friction between the contact member <NUM> and the substrate <NUM> is larger than or equal to the coefficient of friction between the support member <NUM> and the contact member <NUM>, the exposure device <NUM> prevents misregistration of the light emitter <NUM> in the direction perpendicular to the light emission direction.

Compared to the structure where the support member <NUM> extends in the first direction, the exposure device <NUM> has a shorter length in the first direction.

Compared to the structure where the support member <NUM> is moved in the light emission direction by the mover <NUM> moving in the light emission direction, the exposure device <NUM> has a smaller size in the apparatus light emission direction.

In the exposure device <NUM>, the coefficient of friction between the contact member <NUM> and the substrate <NUM> is smaller than the coefficient of friction between the support member <NUM> and the contact member <NUM>. This structure enables reduction of friction between the mover <NUM> and the support member <NUM>.

Compared to the structure where the converter <NUM> formed from a slope of the mover <NUM> is disposed only on one of both sides of the support member <NUM> with the contact member <NUM> in between, the exposure device <NUM> enables reduction of inclination of the support member <NUM>.

Compared to the structure where the contact member <NUM> is disposed on the outer side of the opposing receiving portions <NUM> of the support member <NUM>, the exposure device <NUM> reduces distortion of the substrate <NUM> resulting from position adjustment in the light emission direction performed by the contact member <NUM> on the substrate <NUM>.

Compared to the structure where the outer diameter D1 of the contact member <NUM> is smaller than or equal to the outer diameter D2 of the support member <NUM>, the exposure device <NUM> prevents the support member <NUM> from interfering with the substrate <NUM> regardless of when the substrate <NUM> is widened in the cross direction.

Compared to the structure where the feeder <NUM> and the contact member <NUM> are misaligned in the light emission direction, the exposure device <NUM> reduces a loss of the moving force of the mover <NUM> transmitted to the support member <NUM>.

Compared to the structure where the mover <NUM> is moved in the first direction by driving a belt to which the mover <NUM> is attached to rotate, the exposure device <NUM> enables fine adjustment of the amount of movement of the mover <NUM> in the first direction.

Compared to the structure where the straight line SL that passes the contact point between the contact member <NUM> and the substrate <NUM> and the contact point between the mover <NUM> and the support member <NUM> is inclined with respect to the light emission direction, the exposure device <NUM> reduces misregistration of the light emitter <NUM> in the direction perpendicular to the light emission direction.

The image forming apparatus <NUM> including the above exposure device <NUM> is capable of forming accurate images.

The position adjuster <NUM> according to any of the exemplary embodiments includes the contact member <NUM> disposed between the pair of converters <NUM> of the mover <NUM>, but the present disclosure is not limited to this structure. For example, as in a position adjuster <NUM> illustrated in <FIG> and <FIG>, two contact members <NUM> may be disposed on the support member <NUM> while being spaced apart from each other in the axial direction. This structure also obtains the operational effects the same as those of the position adjuster <NUM>.

The position adjuster <NUM> according to any of the exemplary embodiments moves the support member <NUM> in the light emission direction by moving the mover <NUM> in the X direction, but the present disclosure is not limited to this structure. For example, as in a position adjuster <NUM> illustrated in <FIG> and <FIG>, the support member <NUM> may be moved in the light emission direction with a mover <NUM> formed from an eccentric cam. More specifically, a rotation shaft <NUM> of the mover <NUM> is rotatably supported by the pair of support plates <NUM>. The rotation shaft <NUM> is designed to receive a driving force from a driving source <NUM>. The driving source <NUM> is attached to an attachment plate <NUM> protruding from one support plate <NUM>. The driving source <NUM> may be any member capable of driving the rotation shaft <NUM> to rotate. For example, the driving source <NUM> may be an electric motor. The driving source <NUM> and the rotation shaft <NUM> may be connected together with a belt or a gear. In the position adjuster <NUM>, when the mover <NUM> rotates about the rotation shaft <NUM>, the moving force in the Z direction is imposed on the support member <NUM> that is in contact with the mover <NUM>. Specifically, the mover <NUM> is pushed and the position of the substrate <NUM> in the Z direction is adjusted. Also in this case, the operational effects the same as those of the position adjuster <NUM> are obtained.

In the position adjuster <NUM> according to any of the exemplary embodiments, the mover <NUM> includes the pair of converters <NUM>, but the present disclosure is not limited to this structure. For example, the multiple movers each including the converter <NUM> may be moved by respective feeders in the X direction to move the support member <NUM> in the light emission direction. Also in this case, the operational effects the same as those of the position adjuster <NUM> are obtained. In addition, distortion of the substrate resulting from position adjustment performed by the contact member on the substrate in the light emission direction is reduced while the contact member and the mover are kept in a good balance.

The exemplary embodiment includes a feed screw is used as an example of the feeder <NUM>, but the present disclosure is not limited to this structure. The feeder <NUM> may be any member capable of moving the mover <NUM> in the X direction. For example, the feeder <NUM> may be formed from a spring or a cylinder.

In the exposure device and the image forming apparatus according to any of the exemplary embodiments, three light emitters are disposed on the substrate, but the present disclosure is not limited to this structure. For example, one, two, four, or more light emitters may be disposed on the substrate. The positions of multiple light emitters disposed on the substrate may be set as appropriate.

In the exposure device and the image forming apparatus according to any of the exemplary embodiments, the substrate is formed from a metal block, but the present disclosure is not limited to this structure. The material or shape of the substrate may be changed. For example, the substrate may be formed from resin, or another metal material such as sheet metal. Components of the light emitter or the shape of each component of the light emitter may be changed. The support body of the light emitter is formed from a metal block, but the present disclosure is not limited to this structure. The material or shape of the support body may be changed. For example, the support body may be formed from resin, or another metal material such as sheet metal.

The exposure device and the image forming apparatus according to any of the exemplary embodiments are usable for any of the following purposes to which photolithography is applied: forming a color filter in a process of manufacturing a liquid crystal display (LCD), exposing a dry film resist (DFR) to light in a process of manufacturing a thin film transistor (TFT), exposing a dry film resist (DFR) to light in a process of manufacturing a plasma display panel (PDP), exposing a photosensitive member such as a photoresist in a process of manufacturing a semiconductor device, exposing a photosensitive member such as a photoresist in a process of plate-making in printing such as photogravure printing other than offset printing, and exposing a photosensitive member to light in a process of manufacturing components of a timepiece. Photolithography indicates a technology of exposing a surface of an object on which a photosensitive member is placed to light into a pattern to generate a pattern including a portion exposed to light and a portion not exposed to light.

Claim 1:
An exposure device (<NUM>) comprising:
at least one light emitter (<NUM>) that includes:
a substrate (<NUM>); and
a light-emitting device (<NUM>) disposed on the substrate (<NUM>); and
a position adjuster (<NUM>) for adjusting a distance between the at least one light emitter (<NUM>) and a photoconductor drum, including:
a contact member (<NUM>) having an outer periphery in contact with the substrate (<NUM>);
a support member (<NUM>) that rotatably supports the contact member (<NUM>); and
at least one mover (<NUM>) that is in contact with the support member (<NUM>) to move the support member (<NUM>) in a light emission direction of the light emitter (<NUM>), wherein
the substrate (<NUM>) extends in a first direction,
the at least one light-emitting device (<NUM>) includes a plurality of light-emitting devices disposed at a plurality of positions in the first direction,
the support member (<NUM>) is a shaft, characterized in that
the position adjuster (<NUM>) includes at least one receiving portion (<NUM>) that receives the shaft while allowing the shaft to rotate about an axis extending in a direction perpendicular to the first direction and allowing the shaft to move in the light emission direction.