Patent Description:
An image forming apparatus disclosed by <CIT> includes an apparatus housing having an door that is movable between a closed position and an open position; an attaching object including an image carrier configured to carry an image, the attaching object being detachably attached into the apparatus housing in a direction intersecting the axial direction of the image carrier and through an opening provided in the door; an image drawing device provided facing the image carrier and configured to draw an image on the image carrier; and a guiding mechanism configured to move the image drawing device in conjunction with the opening and closing of the door, the guiding mechanism guiding the image drawing device to a drawing position when the door is closed and to a retracted position when the door is opened, the retracted position being retracted from a space provided for the attaching and detaching of the attaching object. The guiding mechanism includes a first guiding mechanism and a second guiding mechanism. While the door is moving from the closed position to a middle position defined between the closed position and the open position, the first guiding mechanism guides the image drawing device along a first guiding portion provided on the attaching object. While the door is moving from the middle position to the open position, the second guiding mechanism guides the image drawing device along a second guiding portion provided on the apparatus housing. Document <CIT> discloses an image forming device constituted by including the intermediate transfer belt, image forming stations Pa to Pc arranged to be opposed on a plane part on the upside of the belt, and a black image forming station Pd to be opposed on a plane par on the downside of the belt.

Accordingly, it is an object of the present disclosure to provide an image forming apparatus in which image forming units are detachable and attachable more easily than in an apparatus in which the direction of detaching and attaching of the light-emitting unit is the same for all the image forming units.

According to a first aspect of the present disclosure, there is provided an image forming apparatus including a first image forming unit including a rotatable first image carrier and a first light-emitting unit, the first light-emitting unit including a first base member and a plurality of first light-emitting devices, the first base member extending in an axial direction of the first image carrier, the plurality of first light-emitting devices being provided on the first base member and being configured to apply light to an outer circumferential surface of the first image carrier; and a second image forming unit including a rotatable second image carrier and a second light-emitting unit, the second light-emitting unit including a second base member and a plurality of second light-emitting devices, the second base member extending in an axial direction of the second image carrier, the plurality of second light-emitting devices being provided on the second base member and being configured to apply light to an outer circumferential surface of the second image carrier. A direction of detaching and attaching of the first light-emitting unit from and to the first image forming unit and a direction of detaching and attaching of the second light-emitting unit from and to the second image forming unit are different from each other.

According to a second aspect of the present disclosure, in the image forming apparatus according to the first aspect of the present disclosure, the first light-emitting unit is detachable from the first image forming unit by being moved in a first direction in which the first light-emitting unit moves away from the first image carrier. The second light-emitting unit is detachable from the second image forming unit by being moved in a second direction in which the second light-emitting unit moves away from the second image carrier and, at a predetermined position in the second direction, being further moved in a direction intersecting the second direction.

According to a third aspect of the present disclosure, in the image forming apparatus according to the second aspect of the present disclosure, the first direction is a direction opposite to a direction of light emission from the first light-emitting unit. The second direction is a direction opposite to a direction of light emission from the second light-emitting unit.

According to a fourth aspect of the present disclosure, in the image forming apparatus according to the third aspect of the present disclosure, seen in an axial direction of the second image carrier, the second light-emitting unit that is at the predetermined position in the second direction is detachable from the second image forming unit by being moved in the direction intersecting the second direction.

According to a fifth aspect of the present disclosure, the image forming apparatus according to any of first to fourth aspects of the present disclosure further includes a transfer member to which images are to be transferred from the first image forming unit and the second image forming unit. The first image forming unit is one of a plurality of first image forming units. The second image forming unit is one of a plurality of second image forming units. Either the plurality of first image forming units or the plurality of second image forming units is provided on an upper side of the transfer member. An other of the plurality of first image forming units and the plurality of second image forming units is provided on a lower side of the transfer member. The first light-emitting units are detachable from the first image forming units by being moved in a direction parallel to a direction of gravity. The second light-emitting units are detachable from the second image forming units by being moved in a direction parallel to the direction of gravity.

According to a sixth aspect of the present disclosure, in the image forming apparatus according to the fifth aspect of the present disclosure citing the second aspect of the present disclosure, the plurality of first image forming units are provided on the upper side of the transfer member. The plurality of second image forming units are provided on the lower side of the transfer member. The first direction is heading upward in the direction of gravity. The second direction is heading downward in the direction of gravity.

According to a seventh aspect of the present disclosure, in the image forming apparatus according to the fifth or sixth aspect of the present disclosure, the transfer member includes a horizontal portion that extends in a horizontal direction, and an angled portion that is angled with respect to a vertical direction. The plurality of first image forming units are arranged at intervals from one another along the horizontal portion. The plurality of second image forming units are arranged at intervals from one another along the angled portion.

According to the first aspect of the present disclosure, the image forming units are detachable and attachable more easily than in a configuration in which the direction of detaching and attaching of the light-emitting unit is the same for all the image forming units.

According to the second aspect of the present disclosure, the light-emitting units are easily detachable from and attachable to the image forming units, regardless of the position of installation of the apparatus.

According to the third aspect of the present disclosure, even if there is not enough space, the detaching of the first light-emitting unit and the second light-emitting unit from the first image forming unit and the second image forming unit is achieved more easily than in a configuration in which the first direction intersects the direction of light emission from the first light-emitting unit and the second direction intersects the direction of light emission from the second light-emitting unit.

According to the fourth aspect of the present disclosure, even if there is not enough space, the detaching of the second light-emitting unit from the second image forming unit is achieved more easily than in a configuration in which the second light-emitting unit is detachable from the second image forming unit by being moved in the axial direction of the image carrier at a predetermined position in the second direction.

According to the fifth aspect of the present disclosure, the spaces to be secured for the detaching or attaching of the first light-emitting units and the second light-emitting units are smaller than in a configuration in which the first light-emitting units and the second light-emitting units are detachable by being moved in the horizontal direction.

According to the sixth aspect of the present disclosure, the spaces to be secured below the transfer member for the detaching and attaching of the image forming units are smaller than in a configuration in which the plurality of first image forming units are also provided below the transfer member.

According to the seventh aspect of the present disclosure, the detaching and attaching of the second light-emitting units from and to the second image forming units is achieved more easily than in a configuration in which the plurality of first image forming units are also arranged along the angled portion of the transfer member.

<FIG> schematically illustrates an image forming apparatus <NUM> including exposure devices <NUM> according to an exemplary embodiment. A configuration of the image forming apparatus <NUM> will first be described. Then, the exposure devices <NUM> included in the image forming apparatus <NUM> will be described. The image forming apparatus <NUM> forms an image composed of, for example, a plurality of colors and is a full-color printer intended for, for example, commercial printing that is to be of high image quality.

The image forming apparatus <NUM> is capable of handling wide recording media, P, having a width greater than the portrait width of B3 media (i.e., a width greater than <NUM>). For example, the image forming apparatus <NUM> is capable of handling recording media P having a width ranging from <NUM>, which is the portrait width of A2 media, to <NUM>, which is the landscape width of B0 media, inclusive. As a specific example, the image forming apparatus <NUM> is capable of handling recording media P having a width of <NUM>, which is the landscape width of B2 media.

The image forming apparatus <NUM> illustrated in <FIG> is an exemplary image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus <NUM> is an electrophotographic image forming apparatus that forms a toner image (an exemplary image) on a recording medium P. Toners are exemplary particles. The image forming apparatus <NUM> includes an image forming section <NUM> and a fixing device <NUM>. Relevant elements (the image forming section <NUM> and the fixing device <NUM>) of the image forming apparatus <NUM> will now be described.

The image forming section <NUM> has a function of forming a toner image on a recording medium P. The image forming section <NUM> includes a plurality of toner-image-forming units <NUM> and a transfer device <NUM>.

The plurality of toner-image-forming units <NUM> illustrated in <FIG> are provided for forming toner images in respective colors. In the present exemplary embodiment, four toner-image-forming units <NUM> are provided for four colors of yellow (Y), magenta (M), cyan (C), and black (K). Reference characters (Y), (M), (C), and (K) provided in <FIG> each indicate for which of the foregoing colors the element denoted is provided.

The toner-image-forming units <NUM> for the respective colors all have the same configuration, except the toners to be used. Therefore, in <FIG>, reference signs for details are given to the toner-image-forming unit <NUM>(K), representing all the toner-image-forming units <NUM>.

The toner-image-forming units <NUM> each include a photoconductor drum <NUM>, which is rotatable in one direction (counterclockwise in <FIG>, for example). The photoconductor drum <NUM> is an exemplary image carrier. The toner-image-forming units <NUM> each further include a charging device <NUM>, an exposure device <NUM>, and a developing device <NUM>.

In each of the toner-image-forming units <NUM>, the charging device <NUM> charges the photoconductor drum <NUM>. Furthermore, the exposure device <NUM> exposes the photoconductor drum <NUM> charged by the charging device <NUM> to light, thereby forming an electrostatic latent image on the photoconductor drum <NUM>. Furthermore, the developing device <NUM> develops the electrostatic latent image formed on the photoconductor drum <NUM> by the exposure device <NUM> into a toner image.

The photoconductor drum <NUM> carrying the electrostatic latent image formed as above on the outer circumference thereof rotates to transport the electrostatic latent image to the developing device <NUM>. Details of the exposure device <NUM> will be described separately below.

The transfer device <NUM> illustrated in <FIG> transfers toner images formed by the respective toner-image-forming units <NUM> to a recording medium P. Specifically, in the transfer device <NUM>, toner images formed on the respective photoconductor drums <NUM> are first-transferred to a transfer belt <NUM> (an intermediate transfer body) in such a manner as to be superposed one on top of another, and the combination of the toner images (hereinafter simply referred to as "toner image") is second-transferred to a recording medium P. As illustrated in <FIG>, the transfer device <NUM> includes the transfer belt <NUM>, first transfer rollers <NUM>, and a second transfer roller <NUM>.

The first transfer rollers <NUM> transfer the toner images on the respective photoconductor drums <NUM> to the transfer belt <NUM> at respective first transfer positions T1, which are defined between the photoconductor drums <NUM> and the respective first transfer rollers <NUM>. In the present exemplary embodiment, a first-transfer electric field is generated between each of the first transfer rollers <NUM> and a corresponding one of the photoconductor drums <NUM>. With the first-transfer electric field, the toner image formed on the photoconductor drum <NUM> is transferred to the transfer belt <NUM> at the first transfer position T1.

The transfer belt <NUM> receives the toner images from the respective photoconductor drums <NUM> by the outer circumferential surface thereof. As illustrated in <FIG>, the transfer belt <NUM> has an annular shape and is positioned by being stretched around a plurality of rollers <NUM>.

The plurality of rollers <NUM> include a driving roller 39D, for example. When the driving roller 39D is driven by a driving unit (not illustrated) to rotate, the transfer belt <NUM> circulates in a direction represented by arrow A. As illustrated in <FIG>, the plurality of rollers <NUM> further include a counter roller 39B, which is positioned against the second transfer roller <NUM>.

The second transfer roller <NUM> transfers the toner image on the transfer belt <NUM> to a recording medium P at a second transfer position T2, which is defined between the counter roller 39B and the second transfer roller <NUM>. In the present exemplary embodiment, a second-transfer electric field is generated between the counter roller 39B and the second transfer roller <NUM>. With the second-transfer electric field, the toner image transferred to the transfer belt <NUM> is transferred to a recording medium P at the second transfer position T2.

As illustrated in <FIG>, the transfer belt <NUM> (an exemplary transfer member) according to the present exemplary embodiment includes a horizontal portion 24A, which extends in the horizontal direction; and an angled portion 24B, which is angled with respect to the vertical direction.

The fixing device <NUM> illustrated in <FIG> fixes the toner image transferred to a recording medium P by the second transfer roller <NUM> on the recording medium P. As illustrated in <FIG>, the fixing device <NUM> includes a heating roller 16A (a heating member) and a pressing roller 16B (a pressing member). In the fixing device <NUM>, the heating roller 16A and the pressing roller 16B apply heat and pressure to the recording medium P, thereby fixing the toner image on the recording medium P.

Configurations of the exposure devices <NUM> according to the present exemplary embodiment will now be described. <FIG> is a side view of a representative one of the exposure devices <NUM>. The following description is based on a definition that, in relevant drawings, the Y axis represents the width direction of the exposure device <NUM> (hereinafter referred to as the device-width direction), the Z axis represents the height direction of the exposure device <NUM> (hereinafter referred to as the device-height direction), and the X axis represents the depth direction of the exposure device <NUM> (hereinafter referred to as the device-depth direction) that is orthogonal to both the device-width direction and the device-height direction. Note that the device-width direction and the device-height direction are defined for the convenience of description, and the configuration of the exposure device <NUM> is not limited by such directions.

First, an outline of the exposure device <NUM> will be described, followed by description of relevant elements included in the exposure device <NUM>.

Referring to <FIG>, the exposure device <NUM> includes a light-emitting unit <NUM>, a position adjusting unit <NUM>, and a pressing unit <NUM>.

Referring to <FIG>, the light-emitting unit <NUM> includes a base member <NUM> and a plurality of light emitters <NUM>. The base member <NUM> extends in one direction (the X direction, in the present exemplary embodiment). The light emitters <NUM> are provided on a surface of the base member <NUM> that is on one side in the Z direction. In the present exemplary embodiment, three light emitters <NUM> are provided on the base member <NUM>. The light emitters <NUM> each extend in the one direction of the base member <NUM>. The base member <NUM> has a long, narrow, rectangular shape in plan view as illustrated in <FIG>. The light emitters <NUM> all have the same configuration and each have a long, narrow, rectangular shape in plan view as illustrated in <FIG>.

As an exemplary arrangement, the three light emitters <NUM> are staggered both in the one direction of the base member <NUM>, i.e., in the long-side direction (the X direction) of the base member <NUM> and in the width direction of the base member <NUM> that is orthogonal to the one direction of the base member <NUM>, i.e., in the short-side direction (the Y direction) of the base member <NUM>. The light-emitting unit <NUM> extends in the axial direction of the photoconductor drum <NUM> (see <FIG>). The length of the light-emitting unit <NUM> in the one direction is greater than or equal to the axial length of the photoconductor drum <NUM>. At least one of the three light emitters <NUM> is positioned facing the surface (outer circumferential surface) of the photoconductor drum <NUM>. Thus, light emitted from the light-emitting unit <NUM> is applied to the surface of the photoconductor drum <NUM>.

If the light-emitting unit <NUM> has a single light emitter <NUM>, the direction of light emission from the light-emitting unit <NUM> to the photoconductor drum <NUM> is regarded as the direction of the optical axis of the single light emitter <NUM>. If the light-emitting unit <NUM> has a plurality of light emitters <NUM> as in the present exemplary embodiment, the direction of light emission is regarded as, seen in the one direction (X direction) of the base member <NUM>, the direction of a virtual line extending from the midpoint between the principal points of the light emitters <NUM> in the short-side direction (Y direction) of the base member <NUM> to a point to be focused on. In the present exemplary embodiment, the position and angle of the light-emitting unit <NUM> are adjusted such that a virtual line extending in the direction of light emission passes through the center of the photoconductor drum <NUM>.

In the present exemplary embodiment, the three light emitters <NUM> are arranged in a staggered manner in the plan view of the light-emitting unit <NUM> (see <FIG>). More specifically, two of the three light emitters <NUM> that are at the two respective ends of the base member <NUM> in the one direction are positioned on one side in the short-side direction of the base member <NUM>. The remaining one light emitter <NUM> in a central part of the base member <NUM> in the one direction is positioned on the other side in the short-side direction of the base member <NUM>. Seen in the short-side direction of the base member <NUM>, one end of each of the two light emitters <NUM> positioned on the one side in the short-side direction of the base member <NUM> overlaps a corresponding one of the ends of the one light emitter <NUM> positioned on the other side in the short-side direction of the base member <NUM>. That is, in the one direction of the base member <NUM>, the areas of light emission from the three respective light emitters <NUM> overlap one another in part.

In the present exemplary embodiment, description of elements provided for activating the light-emitting unit <NUM>, including a driving circuit board, a power source, and wires, is omitted.

The light emitters <NUM> illustrated in <FIG> each have a plurality of light sources (not illustrated) arrayed in the one direction (X direction). The light sources according to the present exemplary embodiment include, for example, a plurality of light-emitting devices. An example of such a light source is a light-emitting-device array including a semiconductor substrate and a plurality of light-emitting devices that are arrayed in the one direction on the semiconductor substrate. The light source is not limited to such a light-emitting-device array and may be formed of a single light-emitting device. The light-emitting devices may be light-emitting diodes, light-emitting thyristors, laser devices, or the like that are arrayed in the one direction in such a manner as to achieve a resolution of, for example, <NUM> dpi.

In the light-emitting unit <NUM>, light beams emitted from the respective light sources pass through a lens unit (not illustrated) and are applied to the surface of the photoconductor drum <NUM> (see <FIG>), which is the object of light application.

Referring to <FIG>, a positioning member <NUM> is provided between the base member <NUM> and the photoconductor drum <NUM>. The positioning member <NUM> determines the position of the light-emitting unit <NUM> with respect to the photoconductor drum <NUM> in a direction orthogonal to the direction of light emission. More specifically, the positioning member <NUM> determines the position of the light-emitting unit <NUM> in the Y direction, which is one of the directions that are orthogonal to the direction of light emission. In the present exemplary embodiment, the positioning member <NUM> is provided at each of the two ends of the base member <NUM> in the long-side direction (X direction) of the base member <NUM>. <FIG> illustrates one of the two positioning members <NUM> that is provided at one of the two ends of the base member <NUM> in the long-side direction (X direction), specifically, on the near side in the device-depth direction.

The positioning member <NUM> determines the position thereof with respect to the photoconductor drum <NUM> in the Y direction by coming into contact with a drum flange <NUM>. Specifically, the positioning member <NUM> is a round columnar projection projecting from the front surface, 42A, of the base member <NUM> toward the drum flange <NUM>. The shape of the positioning member <NUM> is not limited to such a round columnar projection. The positioning member <NUM> may have any other shape such as a prism shape or an elliptic columnar shape. The positioning member <NUM> in the form of a round columnar projection is to be fitted into a restraining portion <NUM>, which is provided in the drum flange <NUM>. In the present exemplary embodiment, the drum flange <NUM> is one of a pair of drum flanges <NUM>, by which the two respective axial ends of the photoconductor drum <NUM> are rotatably supported. The pair of drum flanges <NUM> are attached to an apparatus body (a frame, not illustrated, of the image forming section <NUM> in the present exemplary embodiment).

As illustrated in <FIG>, the restraining portion <NUM> is a recess extending in the X direction. In other words, the restraining portion <NUM> is a groove extending in the X direction and having two open ends. When the positioning member <NUM> is fitted into the restraining portion <NUM>, the positioning member <NUM> is restrained from moving in the Y direction by wall surfaces in the restraining portion <NUM> that are opposite each other in the Y direction. That is, the positioning member <NUM> determines the position of the light-emitting unit <NUM> in the Y direction by being restrained in the restraining portion <NUM>.

Referring to <FIG>, the position adjusting unit <NUM> adjusts the distance between the light-emitting unit <NUM> and the photoconductor drum <NUM>. Specifically, the position adjusting unit <NUM> adjusts the position of the light-emitting unit <NUM> with respect to the photoconductor drum <NUM> in a direction parallel to the direction of light emission. More specifically, the position adjusting unit <NUM> moves the light-emitting unit <NUM> in the direction parallel to the direction of light emission, thereby adjusting the position of the light-emitting unit <NUM> with respect to the photoconductor drum <NUM> in the direction parallel to the direction of light emission. In the present exemplary embodiment, the direction of light emission from the light-emitting unit <NUM> substantially coincides with the Z direction.

Referring to <FIG>, the position adjusting unit <NUM> includes a contact member <NUM>, a shaft <NUM>, and a movable member <NUM>.

As illustrated in <FIG>, the contact member <NUM> has an outer circumferential surface 132A, at which the contact member <NUM> comes into contact with the front surface 42A of the base member <NUM>. The contact member <NUM> has a disc shape and is rotatably supported by the shaft <NUM>. Specifically, the contact member <NUM> is supported by the shaft <NUM> in such a manner as to be capable of undergoing relative rotation on the shaft <NUM>. The contact member <NUM> according to the present exemplary embodiment is, for example, a ball bearing.

The shaft <NUM> supports the contact member <NUM> such that the contact member <NUM> is capable of undergoing relative rotation on the shaft <NUM>. As illustrated in <FIG> and <FIG>, the shaft <NUM> is a substantially round columnar member and is received at the two axial ends thereof by a pair of receiving portions <NUM>. The pair of receiving portions <NUM> are positioned opposite each other in the Y direction, i.e., the short-side direction of the base member <NUM>. The pair of receiving portions <NUM> receive the shaft <NUM> such that the shaft <NUM> is rotatable about the Y axis and is movable in the direction parallel to the direction of light emission. More specifically, the contact member <NUM> is positioned between the pair of receiving portions <NUM> that receive the shaft <NUM>.

As illustrated in <FIG>, the pair of receiving portions <NUM> are the walls of elongated holes provided respectively in a pair of supporting plates <NUM>, which are provided across the contact member <NUM> from each other in the Y direction. The elongated holes are elongated in the Z direction. Therefore, the shaft <NUM> supported at the two axial ends thereof is rotatable and is movable in the direction parallel to the direction of light emission. The two axial ends of the shaft <NUM> are provided with respective stoppers (not illustrated) that prevent the shaft <NUM> from coming off.

Referring to <FIG>, the movable member <NUM> comes into contact with the shaft <NUM> and causes the shaft <NUM> to move in the direction parallel to the direction of light emission from the light-emitting unit <NUM>.

The movable member <NUM> is movable in the X direction. The position adjusting unit <NUM> includes a feeding member <NUM> and a drive source <NUM>. The movable member <NUM> is caused to move in the X direction with the aid of the feeding member <NUM>. The feeding member <NUM> according to the present exemplary embodiment is a feed screw serving as an exemplary screw member. The feeding member <NUM> extends through a connecting plate <NUM>, which connects the X-direction ends of the pair of supporting plates <NUM> to each other. The drive source <NUM> is connected to one axial end of the feeding member <NUM>. The drive source <NUM> drives the feeding member <NUM> to rotate. While the drive source <NUM> according to the present exemplary embodiment is, for example, an electric motor, the present disclosure is not limited to such a case. The drive source <NUM> is attached to an attaching plate <NUM>, which projects from the connecting plate <NUM> on one side in the X direction (the left side in <FIG>, i.e., the near side in the device-depth direction). In the position adjusting unit <NUM> according to the present exemplary embodiment, the pair of supporting plates <NUM>, the connecting plate <NUM>, and the attaching plate <NUM> form a housing <NUM>. The housing <NUM> is attached to a frame (not illustrated) included in the image forming section <NUM>.

The movable member <NUM> has a converting portion <NUM>, which converts a moving force in the X direction that is exerted by the feeding member <NUM> into a moving force that causes the shaft <NUM> to move in the direction parallel to the direction of light emission. Specifically, the converting portion <NUM> is a slope angled with respect to the X direction and provided at a part of the movable member <NUM> that comes into contact with the shaft <NUM>. More specifically, referring to <FIG>, the converting portion <NUM> included in the movable member <NUM> is one of a pair of converting portions <NUM> (a pair of slopes). The pair of converting portions <NUM> are positioned across the contact member <NUM> from each other and are in contact with the shaft <NUM> on the respective sides in the axial direction of the shaft <NUM>. The movable member <NUM> according to the present exemplary embodiment has, for example, a cubic shape with a groove 136A, which extends in the X direction and is provided in a portion facing the contact member <NUM>. A part of the outer circumference of the contact member <NUM> is to be received by the groove 136A. That is, the pair of converting portions <NUM> are positioned across the groove 136A of the movable member <NUM> from each other.

Referring to <FIG>, the base member <NUM> is pressed by the pressing unit <NUM> toward the position adjusting unit <NUM>. The pressing unit <NUM> is positioned across the base member <NUM> from the position adjusting unit <NUM>. That is, the base member <NUM> is held and pressed in the Z direction between the position adjusting unit <NUM> and the pressing unit <NUM>. When the movable member <NUM> moves in the X direction, the slopes serving as the converting portions <NUM> move on the outer circumferential surface of the shaft <NUM> and exert a moving force that causes the shaft <NUM> to move in the Z direction. The moving force in the Z direction thus applied to the shaft <NUM> is transmitted through the contact member <NUM> to the base member <NUM>, whereby a pressing protrusion 129A, included in the pressing unit <NUM>, is pushed into the pressing unit <NUM>. Consequently, the base member <NUM> is moved in the Z direction, that is, the position of the base member <NUM> is adjusted. Referring to <FIG>, the pressing unit <NUM> according to the present exemplary embodiment includes the pressing protrusion 129A, a housing 129B, and an urging member 129C. The pressing protrusion 129A comes into contact with the back surface, 42B, of the base member <NUM> and presses the base member <NUM> in the direction of light emission. The housing 129B allows the pressing protrusion 129A to be housed therein. The urging member 129C is provided inside the housing 129B and urges the pressing protrusion 129A in the direction of light emission. The urging member 129C may be, for example, a coil spring. However, the present disclosure is not limited to such a configuration. The coil spring employed as the urging member 129C may be replaced with an electrical actuator or the like.

Referring to <FIG>, seen in the direction of light emission, the feeding member <NUM> extending through the movable member <NUM> coincides with the contact member <NUM>.

The coefficient of friction between the contact member <NUM> and the base member <NUM> is smaller than the coefficient of friction between the shaft <NUM> and the contact member <NUM>. Specifically, since the contact member <NUM> according to the present exemplary embodiment is a ball bearing, the contact member <NUM> undergoes relative rotation on the shaft <NUM> before friction occurs between the contact member <NUM> and the base member <NUM>.

The pair of supporting plates <NUM> are connected to each other at the respective Z-direction ends thereof by a connecting plate <NUM>. The connecting plate <NUM> has an opening 147A, through which a part of the outer circumference of the contact member <NUM> projects to the outside. A point at the part of the contact member <NUM> that projects to the outside is in contact with the front surface 42A of the base member <NUM>.

The drive source <NUM> is positioned across the position adjusting unit <NUM> from the positioning member <NUM> in the X direction (the drive source <NUM> is positioned on the near side in the device-depth direction).

Referring to <FIG>, the light-emitting unit <NUM> according to the present exemplary embodiment includes measuring devices <NUM>, which are provided adjacent to corresponding ones of the light emitters <NUM> in the width direction of the base member <NUM> (the Y direction). The measuring devices <NUM> each measure the distance from the light-emitting unit <NUM> to the surface of the photoconductor drum <NUM>.

In the image forming apparatus <NUM> according to the present exemplary embodiment, the distance from the light-emitting unit <NUM> to the surface of the photoconductor drum <NUM> is measured by each of the measuring devices <NUM> provided at the two respective ends of the base member <NUM>, and respective pieces of information acquired by the measurement are transmitted to a controller (not illustrated). The controller activates the position adjusting units <NUM> with reference to the respective pieces of information acquired by the measurement. Specifically, the controller adjusts the amounts of driving by the drive sources <NUM> with reference to the respective pieces of information acquired by the measurement. When the values acquired by the measuring devices <NUM> fall within a preset range, the controller stops the operation of the drive sources <NUM>. The adjustment of the position of the light-emitting unit <NUM> by using the position adjusting units <NUM> may be executed when the light-emitting unit <NUM> is attached to the photoconductor drum <NUM> or after a predetermined period of time elapses from when the light-emitting unit <NUM> is attached to the photoconductor drum <NUM>.

Now, a configuration featured in the image forming apparatus <NUM> according to the present exemplary embodiment will be described.

In the image forming apparatus <NUM> illustrated in <FIG>, the direction of detaching and attaching of the light-emitting unit <NUM> is different between that for the toner-image-forming units 22Y and <NUM> and that for the toner-image-forming units 22C and <NUM>. Specifically, the direction of detaching and attaching of the light-emitting unit 41Y from and to the toner-image-forming unit 22Y is the same as the direction of detaching and attaching of the light-emitting unit <NUM> from and to the toner-image-forming unit <NUM>. Furthermore, the direction of detaching and attaching of the light-emitting unit 41C from and to the toner-image-forming unit 22C is the same as the direction of detaching and attaching of the light-emitting unit <NUM> from and to the toner-image-forming unit <NUM>. However, the direction of detaching and attaching of the light-emitting unit 41Y from and to the toner-image-forming unit 22Y is different from the direction of detaching and attaching of the light-emitting unit 41C from and to the toner-image-forming unit 22C.

The toner-image-forming units 22Y and <NUM> according to the present exemplary embodiment are exemplary first image forming units according to the present disclosure. Correspondingly, the photoconductor drums 32Y and <NUM> according to the present exemplary embodiment are exemplary first image carriers according to the present disclosure. Furthermore, the light-emitting units 41Y and <NUM> according to the present exemplary embodiment are exemplary first light-emitting units according to the present disclosure.

On the other hand, the toner-image-forming units 22C and <NUM> according to the present exemplary embodiment are exemplary second image forming units according to the present disclosure. Correspondingly, the photoconductor drums 32C and <NUM> according to the present exemplary embodiment are exemplary second image carriers according to the present disclosure. Furthermore, the light-emitting units 41C and <NUM> according to the present exemplary embodiment are exemplary second light-emitting units according to the present disclosure.

Referring to <FIG>, in the image forming apparatus <NUM> according to the present exemplary embodiment, the toner-image-forming units 22Y and <NUM> are provided on the upper side of the transfer belt <NUM>. Specifically, the toner-image-forming units 22Y and <NUM> are arranged side by side at an interval therebetween along the horizontal portion 24A of the transfer belt <NUM>.

In the image forming apparatus <NUM> according to the present exemplary embodiment, as illustrated in <FIG>, the toner-image-forming units 22C and <NUM> are provided on the lower side of the transfer belt <NUM>. Specifically, the toner-image-forming units 22C and <NUM> are arranged side by side at an interval therebetween along the angled portion 24B of the transfer belt <NUM>.

The light-emitting units 41Y and <NUM> are detachable from the respective toner-image-forming units 22Y and <NUM> by being moved in a first direction, in which the light-emitting unit 41Y and <NUM> move away from the respective photoconductor drums 32Y and <NUM>. Herein, the first direction for the toner-image-forming unit 22Y according to the present exemplary embodiment refers to, for example, a direction opposite to the direction of light emission from the light-emitting unit 41Y. The first direction for the toner-image-forming unit <NUM> according to the present exemplary embodiment refers to the direction opposite to the direction of light emission from the light-emitting unit <NUM> and heading upward in the direction of gravity. Specifically, to detach the light-emitting unit 41Y from the toner-image-forming unit 22Y, the urging members 129C included in the pressing units <NUM> that are positioned as illustrated in <FIG> are compressed. That is, the spring forces applied to the light-emitting unit 41Y are removed. Thus, as illustrated in <FIG>, the light-emitting unit 41Y is disabled from being held and pressed between the pressing units <NUM> and the position adjusting units <NUM>. In other words, the light-emitting unit 41Y is ready to be disabled from being positioned with respect to the photoconductor drum 32Y. In this state, the light-emitting unit 41Y is temporarily supported by the contact members <NUM> included in the respective position adjusting units <NUM>. Then, as illustrated in <FIG>, the pressing units <NUM> are retracted from the path of movement of the light-emitting unit 41Y. Herein, the path of movement of the light-emitting unit 41Y extends in the direction of detaching and attaching of the light-emitting unit 41Y, i.e., the first direction, which is the direction opposite to the direction of light emission from the light-emitting unit 41Y. After the pressing units <NUM> are retracted, the light-emitting unit 41Y is moved in the first direction. Thus, the light-emitting unit 41Y is detached from the toner-image-forming unit 22Y.

The process of detaching the light-emitting unit <NUM> from the toner-image-forming unit <NUM> is the same as the process of detaching the light-emitting unit 41Y from the toner-image-forming unit 22Y. Therefore, description of the process of detaching the light-emitting unit <NUM> from the toner-image-forming unit <NUM> is omitted.

The light-emitting units 41C and <NUM> are detachable from the respective toner-image-forming units 22C and <NUM> by being moved in a second direction, in which the light-emitting units 41C and <NUM> are moved away from the respective photoconductor drums 32C and <NUM>, and, at a predetermined position in the second direction, being further moved in a direction intersecting the second direction. Herein, the second direction for the toner-image-forming unit 22C according to the present exemplary embodiment refers to, for example, a direction opposite to the direction of light emission from the light-emitting unit 41C. The second direction for the toner-image-forming unit <NUM> according to the present exemplary embodiment refers to a direction opposite to the direction of light emission from the light-emitting unit <NUM> and heading downward in the direction of gravity. Specifically, to detach the light-emitting unit 41C from the toner-image-forming unit 22C, the urging members 129C included in the pressing units <NUM> are compressed as illustrated in <FIG>. That is, the spring forces applied to the light-emitting unit 41C are removed. Thus, as illustrated in <FIG>, the light-emitting unit 41C is disabled from being held and pressed between the pressing units <NUM> and the position adjusting units <NUM>. In other words, the light-emitting unit 41C is ready to be disabled from being positioned with respect to the photoconductor drum 32C. In this state, the light-emitting unit 41C moves in the second direction and comes into contact with an end face, 129B1, of the housing 129B of each of the pressing units <NUM>. In other words, the light-emitting unit 41C is temporarily supported by the end faces 129B1 of the housings 129B of the pressing units <NUM>. Seen in the X direction (as illustrated in <FIG>), the light-emitting unit 41C in such a state is moved in a direction intersecting the second direction. Thus, the light-emitting unit 41C is detached from the toner-image-forming unit 22C. Specifically, the light-emitting unit 41C that is at a predetermined position in the second direction (the position where the light-emitting unit 41C is temporarily supported by the housing 129B) is detachable from the toner-image-forming unit 22C by being moved in a direction intersecting the second direction, i.e., in the Y direction in the present exemplary embodiment.

The process of detaching the light-emitting unit 41C from the toner-image-forming unit 22C is the same as the process of detaching the light-emitting unit <NUM> from the toner-image-forming unit <NUM>. Therefore, description of the process of detaching the light-emitting unit <NUM> from the toner-image-forming unit <NUM> is omitted.

Now, functions exerted by the present exemplary embodiment will be described.

In the image forming apparatus <NUM> including the exposure devices <NUM> according to the present exemplary embodiment, the direction of detaching and attaching of the light-emitting units 41Y and <NUM> from and to the toner-image-forming units 22Y and <NUM> is different from the direction of detaching and attaching of the light-emitting units 41C and <NUM> from and to the toner-image-forming units 22C and <NUM>. Therefore, in the image forming apparatus <NUM>, the toner-image-forming units 22Y, <NUM>, 22C, and <NUM> are detachable and attachable more easily than in a configuration in which the direction of detaching and attaching of the light-emitting unit is the same for all the toner-image-forming units.

In the image forming apparatus <NUM>, the light-emitting units 41Y and <NUM> are detachable from the respective toner-image-forming units 22Y and <NUM> by being moved in the first direction in which the light-emitting units 41Y and <NUM> are moved away from the respective photoconductor drums 32Y and <NUM>. Furthermore, the light-emitting units 41C and <NUM> are detachable from the respective toner-image-forming units 22C and <NUM> by being moved in the second direction in which the light-emitting units 41C and <NUM> are moved away from the respective photoconductor drums 32C and <NUM> and, at a predetermined position in the second direction, being further moved in the direction intersecting the second direction. Therefore, in the image forming apparatus <NUM>, the light-emitting units 41Y, <NUM>, 41C, and <NUM> are easily detachable from and attachable to the toner-image-forming units 22Y, <NUM>, 22C, and <NUM>, regardless of the position of installation of the apparatus <NUM>.

In the image forming apparatus <NUM>, the first direction is the direction opposite to the direction of light emission from the light-emitting units 41Y and <NUM>, and the second direction is the direction opposite to the direction of light emission from the light-emitting units 41C and <NUM>. Therefore, in the image forming apparatus <NUM>, even if there is not enough space, the detaching of the light-emitting units 41Y and <NUM> from the toner-image-forming units 22Y and <NUM> and the detaching of the light-emitting units 41C and <NUM> from the toner-image-forming units 22C and <NUM> are achieved more easily than in a configuration in which the first direction intersects the direction of light emission from the light-emitting units 41Y and <NUM> and the second direction intersects the direction of light emission from the light-emitting units 41C and <NUM>.

In the image forming apparatus <NUM>, seen in the X direction, the light-emitting units 41C and <NUM> are detachable from the toner-image-forming units 22C and <NUM> by being moved in the direction intersecting the second direction at respective predetermined positions in the second direction. Therefore, in the image forming apparatus <NUM>, even if there is not enough space, the detaching of the light-emitting units 41C and <NUM> from the toner-image-forming units 22C and <NUM> is achieved more easily than in a configuration in which the light-emitting units 41C and <NUM> are detachable from the toner-image-forming units 22C and <NUM> by being moved in the X direction at a predetermined position in the second direction.

In the image forming apparatus <NUM>, the light-emitting units 41Y and <NUM> are detachable from the toner-image-forming units 22Y and <NUM> by being moved in a direction parallel to the direction of gravity. Furthermore, the light-emitting units 41C and <NUM> are detachable from the toner-image-forming units 22C and <NUM> by being moved in a direction parallel to the direction of gravity. Therefore, in the image forming apparatus <NUM>, the spaces to be secured for the detaching or attaching of the light-emitting units 41Y and <NUM> and the light-emitting units 41C and <NUM> are smaller than in a configuration in which the light-emitting units 41Y and <NUM> and the light-emitting units 41C and <NUM> are detachable by being moved in the horizontal direction.

In the image forming apparatus <NUM>, the toner-image-forming units 22Y and <NUM> are provided on the upper side of the transfer belt <NUM>, and the first direction in which the light-emitting units 41Y and <NUM> are detachable from the toner-image-forming units 22Y and <NUM> is heading upward in the direction of gravity. Furthermore, the toner-image-forming units 22C and <NUM> are provided on the lower side of the transfer belt <NUM>, and the second direction in which the light-emitting units 41C and <NUM> are detachable from the toner-image-forming units 22C and <NUM> is heading downward in the direction of gravity. Therefore, in the image forming apparatus <NUM>, the spaces to be secured below the transfer belt <NUM> for the detaching and attaching of the toner-image-forming units <NUM> are smaller than in a configuration in which the toner-image-forming units 22Y, <NUM>, 22C, and <NUM> are all provided below the transfer belt <NUM>.

In the image forming apparatus <NUM>, the toner-image-forming units 22Y and <NUM> are arranged along the horizontal portion 24A of the transfer belt <NUM>, and the toner-image-forming units 22C and <NUM> are arranged along the angled portion 24B of the transfer belt <NUM>. Therefore, in the image forming apparatus <NUM>, the detaching and attaching of the light-emitting units 41C and <NUM> from and to the toner-image-forming units 22C and <NUM> is achieved more easily than in a configuration in which the toner-image-forming units 22Y and <NUM> are also arranged along the angled portion 24B of the transfer belt <NUM>.

While the light-emitting units 41Y and <NUM> of the toner-image-forming units 22Y and <NUM> according to the above exemplary embodiment are detachable by being moved in the first direction, the present disclosure is not limited to such a configuration. For example, as with the case of the toner-image-forming units 22C and <NUM>, the toner-image-forming units 22Y and <NUM> may be configured such that the light-emitting units 41Y and <NUM> are detachable by first being moved in the first direction and then, at a predetermined position, being moved in a direction intersecting the first direction.

While the image forming apparatus <NUM> according to the above exemplary embodiment includes, as illustrated in <FIG>, the toner-image-forming units 22Y and <NUM> arranged along the horizontal portion 24A of the transfer belt <NUM> and the toner-image-forming units 22C and <NUM> arranged along the angled portion 24B of the transfer belt <NUM>, the present disclosure is not limited to such a configuration. For example, an image forming apparatus <NUM> illustrated in <FIG> is also applicable, in which the toner-image-forming units 22Y, <NUM>, 22C, and <NUM> are arranged side by side at intervals from one another along the horizontal portion 24A of the transfer belt <NUM>. In such a case, at least one of the toner-image-forming units 22Y, <NUM>, 22C, and <NUM> may be detachable by being moved in the first direction, whereas the remaining ones may be detachable by first being moved in the second direction and then in a direction intersecting the second direction.

While the above exemplary embodiment relates to a configuration in which the first direction for the toner-image-forming unit 22Y is the direction opposite to the direction of light emission from the light-emitting unit 41Y and heading upward in the direction of gravity, the present disclosure is not limited to such a configuration. The first direction for the toner-image-forming unit 22Y is not limited, as long as the direction in which the light-emitting unit 41Y moves away from the photoconductor drum 32Y is the first direction. For example, the first direction for the toner-image-forming unit 22Y may be heading upward in the direction of gravity, or may be heading upward in the direction of gravity while being at a predetermined angle (for example, +/-<NUM> degrees) with respect to the direction opposite to the direction of light emission from the light-emitting unit 41Y. This also applies to the first direction for the toner-image-forming unit <NUM>.

While the above exemplary embodiment relates to a configuration in which the second direction for the toner-image-forming unit 22C is the direction opposite to the direction of light emission from the light-emitting unit 41C and heading downward in the direction of gravity, the present disclosure is not limited to such a configuration. For example, the second direction for the toner-image-forming unit 22C is not limited, as long as the direction in which the light-emitting unit 41C moves away from the photoconductor drum 32C is the second direction. For example, the second direction for the toner-image-forming unit 22C may be heading downward in the direction of gravity, or may be heading downward in the direction of gravity while being at a predetermined angle (for example, +/-<NUM> degrees) with respect to the direction opposite to the direction of light emission from the light-emitting unit 41C. This also applies to the second direction for the toner-image-forming unit <NUM>. In a configuration in which the light-emitting unit 41C is first moved in the second direction and is then moved in a direction intersecting the second direction, the intersecting direction may be, for example, any of the X direction, the Y direction, and the Z direction or may be a direction defined by a combination of components in the foregoing directions.

While the image forming apparatus according to the above exemplary embodiment relates to a configuration in which three light emitters are provided on a base member, the present disclosure is not limited to such a configuration. For example, any of the following is applicable: a configuration in which one light emitter is provided on a base member, a configuration in which two light emitters are provided on a base member, and a configuration in which four or more light emitters are provided on a base member. The positions of the plurality of light emitters provided on the base member are defined in any way.

The features of the image forming apparatus according to the above exemplary embodiment may also be applied to elements intended for photolithography, which is performed in the following: for example, the formation of a color filter in a process of manufacturing a liquid-crystal display (LCD), exposure to be performed on a dry film resist (DFR) in a process of manufacturing a thin-film transistor (TFT), exposure to be performed on a dry film resist (DFR) in a process of manufacturing a plasma display panel (PDP), exposure to be performed on a photosensitive material such as photoresist in a process of manufacturing a semiconductor device, exposure to be performed on a photosensitive material such as photoresist in platemaking for printing such as gravure printing other than offset printing, and exposure to be performed on a photosensitive material in a process of manufacturing clock components. Photolithography refers to a technique in which pattern exposure is performed on a surface of a substance over which a photosensitive material is provided, whereby a pattern including regions that have been exposed to light and regions that have not been exposed to light is obtained.

The image forming apparatus described above may be used with either a photon-mode photosensitive material, with which information is directly recorded by exposure, or a heat-mode photosensitive material, with which information is recorded with heat generated by exposure. The light source of the image forming apparatus may be an LED device or a laser device, depending on the object of exposure.

Claim 1:
An image forming apparatus (<NUM>, <NUM>) comprising:
a first image forming unit (22Y, <NUM>) including a rotatable first image carrier (32Y, <NUM>) and a first light-emitting unit (41Y, <NUM>), the first light-emitting unit (41Y, <NUM>) including a first base member and a plurality of first light-emitting devices, the first base member extending in an axial direction of the first image carrier (32Y, <NUM>), the plurality of first light-emitting devices being provided on the first base member and being configured to apply light to an outer circumferential surface of the first image carrier (32Y, <NUM>); and
a second image forming unit (22C, <NUM>) including a rotatable second image carrier (32C, <NUM>) and a second light-emitting unit (41C, <NUM>), the second light-emitting unit (41C, <NUM>) including a second base member and a plurality of second light-emitting devices, the second base member extending in an axial direction of the second image carrier (32C, <NUM>), the plurality of second light-emitting devices being provided on the second base member and being configured to apply light to an outer circumferential surface of the second image carrier (32C, <NUM>),
the image forming apparatus (<NUM>, <NUM>) being characterized in that a direction of detaching and attaching of the first light-emitting unit (41Y, <NUM>) from and to the first image forming unit (22Y, <NUM>) and a direction of detaching and attaching of the second light-emitting unit (41C, <NUM>) from and to the second image forming unit (22C, <NUM>) are different from each other.