Patent Application
20190346809
The present disclosure relates to an image forming apparatus having a movement mechanism for moving an optical print head from an exposure position for exposing a photosensitive drum to an evacuation position farther away from the photosensitive drum than the exposure position.
Image forming apparatuses such as printers and copying machines have an optical print head having a plurality of light emitting elements for exposing a photosensitive drum. Some optical print heads include a light emitting diode (LED) and organic electro luminescence (EL) as an example of a light emitting element. In some typical technique, those light emitting elements are arranged, for example, in a row or in two rows in zigzags along the direction of the rotational axis of the photosensitive drum. An optical print head is provided with a plurality of lenses for condensing light emitted from a plurality of light emitting elements onto a photosensitive drum. The plurality of lenses is arranged to face the surface of the photosensitive drum along the arrangement direction of light emitting elements between the plurality of light emitting elements and the photosensitive drum. The light emitted from the plurality of light emitting elements condenses on the surface of the photosensitive drum through the lenses, and an electrostatic latent image is formed on the photosensitive drum.
Since the photosensitive drum is a consumable, it is periodically replaced with a new one. A worker, such as a user or service engineer, in charge of photosensitive drum replacement can perform maintenance works for an image forming apparatus by replacing a drum unit having a photosensitive drum. A drum unit is configured to be attachable to and detachable from the main body of the image forming apparatus with the drum unit being inserted to and removed from a side face of the main body of the image forming apparatus. When the optical print head is positioned at the exposure position (the position which approaches to face the drum surface) for exposing the photosensitive drum to light, the distance between the lens and the surface of the photosensitive drum is very short. Thus, in replacing the drum unit, if the optical print head has not been moved to the evacuation position farther away from the photosensitive drum than the exposure position, the optical print head contacts the photosensitive drum, possibly causing damage to the surface of the photosensitive drum or the lens. To prevent the contact between the optical print head and the photosensitive drum in replacing the drum unit, the optical print head needs to be sufficiently away from the photosensitive drum when the optical print head is positioned at the evacuation position.
Japanese Patent Application Laid-Open No. 2013-134370 discusses a movement mechanism for moving an optical print head between an exposure position and an evacuation position. The movement mechanism includes a holding member and a slide member (sliding portion) which slides in the direction of the rotational axis of the photosensitive drum. The movement mechanism further includes a pair of first link members and a second link member on each of the front and the back sides.
The pair of the first link members (third link member) and the second link member (first link member) disposed on a front part of the movement mechanism will be described below. The pair of the first link members and the second link member are rotatably connected with each other centering on respective pivot portions to configure a pantograph mechanism. On a front part of the slide member, the pair of first support members is disposed in such a manner that the members are laterally disposed across a gap. Each of the mating first support members is provided with a first guide boss having an insertion hole formed therein. The second link member is provided with an insertion slot on one end side. The second link member is disposed between the mating first support members, and an insertion shaft is inserted into the two insertion holes and the insertion slot. Thus, the second link member is rotatably connected to the slide member. On the other hand, the other end side of the second link member is rotatably connected to a fitting hole provided on the holding member. One end side of the pair of the first link members is rotatably connected to a main body side fitting portion fixed to the main body. The other end side of the pair of the first link members is rotatably and anteroposteriorly movably connected to a guide hole provided on the holding member.
In the above-described configuration, when the slide member slides, the pair of the first link members and the second link member rotate relative to each other, and the optical print head reciprocally moves between the exposure and the evacuation positions.
However, the configuration discussed in Japanese Patent Application Laid-Open No. 2013-434370 has the following issue. With the rotation of the first and the third link members, a region (intersection region) where the first and the third link members laterally overlap with each other moves in a direction away from the photosensitive drum. With this movement of the intersection region, the optical print head also moves in a direction away from the photosensitive drum. In the configuration discussed in the Japanese Patent Application Laid-Open No. 2013-134370, a part of the slide member is positioned in the region where the region anteroposteriorly overlapping with the first link member behind the first link member laterally overlaps with the region anteroposteriorly overlapping with the third link member in front of the third link member. Thus, the intersection region can be positioned only above the slide member. As a result, there has been a limitation on the amount by which the optical print head is movable in a direction away from the photosensitive drum.
According to an aspect of the present disclosure, an image forming apparatus includes a photosensitive drum configured to be rotatable relative to a main body of the image forming apparatus. An optical print head is configured to be movable from an exposure position for exposing the photosensitive drum to light to a retracted position farther away from the photosensitive drum than the exposure position. A sliding portion is configured to movably slide from a front part of the main body of the image forming apparatus to a back part of the main body along a longitudinal direction of the optical print head. A first link member rotatably connected to the sliding portion and the optical print head. A second link member rotatably connected to the sliding portion and the optical print head. One end side of the first link member in a longitudinal direction of the first link member is rotatably connected to a front part of the sliding portion in a longitudinal direction of the optical print head, and the other end side of the first link member in a longitudinal direction of the first link member is rotatably connected to a front part of the optical print head in a longitudinal direction of the optical print head, and the one end side of the first link member in a longitudinal direction of the first link member is positioned downstream, in a sliding movement direction in which the sliding portion slides, of the other end side of the first link member in the longitudinal direction of the first link member. Furthermore, one end side of the second link member in a longitudinal direction of the second link member is rotatably connected to a back part of the sliding portion in a longitudinal direction of the optical print head, and the other end side of the second link member in a longitudinal direction of the second link member is rotatably connected to a back part of the optical print head in a longitudinal direction of the optical print head, and the one end side of the second link member in a longitudinal direction of the second link member is positioned at a downstream side of the other end side of the second link member in a longitudinal direction of the second link member in the sliding movement direction. And, a third link member is rotatably connected to the main body of the image forming apparatus and the first link member. Additionally, one end side of the third link member in the longitudinal direction of the third link member which arranged on an upstream side of the one end side of the first link member in the longitudinal direction of the first link member in the sliding movement direction is rotatable connected to the main body of the image forming apparatus, and the other end side of the third link member in the longitudinal direction of the third link member which arranged on downstream side of the one end side of the third link member in the longitudinal direction of the third link member in the sliding movement direction is connected to the first link member. As a result, the first link member, the second link member, and the third link member rotate in association with sliding movement of the sliding portion, and move the optical print head from the exposure position to the retracted position. When the optical print head is positioned at the retracted position, at least a part of a region where the first and the third link members overlap with each other in a pivotal axis direction overlaps with the sliding portion in the pivotal axis direction, the pivotal axis direction being the direction of a pivotal axis of the third link member rotating relative to the first link member.
Further features and aspects of the present disclosure will become apparent from the following description of example embodiments with reference to the attached drawings.
Various example embodiments for embodying the present disclosure will be described below with reference to the accompanying drawings. The components described in the following example embodiments are illustrative and are not meant to limit the scope of the present disclosure to the following example embodiments.
An overall configuration of an image forming apparatus 1 will be described below.
The image forming apparatus 1 illustrated in
The image forming apparatus 1 illustrated in
The image forming apparatus 1 includes an intermediate transfer belt 107 on which toner images formed on the photosensitive drums 103 are transferred, and primary transfer rollers 108 (primary transfer rollers 108Y, 108M, 1080, and 108K) for sequentially transferring toner images formed on the photosensitive drums 103 onto the intermediate transfer belt 107. The image forming apparatus 1 further includes a secondary transfer roller 109 for secondarily transferring a toner image on the intermediate transfer belt 107 to recording paper P conveyed from a paper feed unit 101, and a fixing unit 100 for fixing the secondarily transferred image to the recording paper P.
The exposure unit 500Y exposes the surface of the photosensitive drum 103Y charged by the charging unit 104Y to light. Thus, an electrostatic latent image is formed on the photosensitive drum 103Y. Then, the development unit 106Y develops the electrostatic latent image formed on the photosensitive drum 103Y with yellow toner. An yellow toner image developed on the surface of the photosensitive drum 103Y is transferred onto the intermediate transfer belt 107 by the primary transfer roller 108Y. A magenta, a cyan, and a black toner image are also transferred onto the intermediate transfer belt 107 in similar image forming processes.
The toner images of respective colors transferred onto the intermediate transfer belt 107 are conveyed to a secondary transfer portion T2 by the intermediate transfer belt 107. The secondary transfer roller 109 disposed at the secondary transfer portion T2 is applied with a transfer bias for transferring a toner mage onto the recording paper P. The toner image conveyed to the secondary transfer portion T2 is transferred from the paper feed unit 101 to the conveyed recording paper P by the transfer bias of the secondary transfer roller 109. The recording paper P with the toner image transferred thereon is conveyed to the fixing unit 100. The fixing unit 100 fixes the toner image to the recording paper P with heat and pressure. The recording paper P having undergone fixing processing by the fixing unit 100 is discharged onto a discharge unit 111.
Referring now to
Development units 641Y, 641M, 641C, and 641K as different units from the drum units 518 are attached to the image forming apparatus 1 according to the present example embodiment (hereinafter these development units are collectively referred to as “development units 641”). A development unit 641 according to the present example embodiment is a cartridge in which the development unit 106 illustrated in
As illustrated in
Herein, with respect to the image forming apparatus 1 or components thereof according to the present example embodiment, the term “front (side)” is associated with the side on which the drum units 518 are inserted into and removed from the apparatus main body, i.e., the side on which the user stands when operating the image forming apparatus 1, and the back side is opposite the front side.
The front side plate 642 is provided with an opening so that the drum units 518 and the development units 641 can be inserted into and removed from the image forming apparatus 1 on the front side of the image forming apparatus 1. The drum units 518 and the development units 641 are attached to predetermined positions (attachment positions) in the main body of the image forming apparatus 1 through the opening. The image forming apparatus 1 includes covers 558Y, 558M, 558C, and 558K for covering the front side of both the drum units 518 and the development units 641 attached at the attachment positions (hereinafter these covers are collectively referred to as “covers 558”). One end side of a cover 558 is fixed to the main body of the image forming apparatus 1 by a hinge in such a manner that the cover 558 is rotatable relative to the main body of the image forming apparatus 1 by the hinge. The worker opens the cover 558, takes out the drum unit 518 or the development unit 641 from the main body, inserts a new drum unit 518 or a new development unit 641, and closes the cover 558, thus completing a replacement work.
As illustrated in
An exposure unit 500 including an optical print head 105 will be described below. Examples of exposure methods applied to electrophotographic image forming apparatuses include a laser beam scanning exposure method in which the irradiation beam of a semiconductor laser is deflected by a rotating polygon mi and a photosensitive drum is exposed to light through an f-θ lens. The “optical print head 105” according to the present example embodiment is used for an LED exposure method in which the photosensitive drum 103 is exposed to light by light emitting elements, such as LEDs, arranged along the direction of the rotational axis of the photosensitive drum 103. The optical print head 105 is not used for the above-described laser beam scanning exposure method.
The exposure unit 500 according to the present example embodiment is disposed vertically below the rotational axis of the photosensitive drum 103, and an LED 503 included in the optical print head 105 exposes the photosensitive drum 103 to light from below. However, the exposure unit 500 may be disposed vertically above the rotational axis of the photosensitive drum 103, and the LED 503 may expose the photosensitive drum 103 to light from above (refer to
Referring to
When the first contact pin 514 and the second contact pin 515 abut against the drum unit 518, a gap is formed between the lens array 506 and the photosensitive drum 103, thus determining the position of the optical print head 105 relative to the photosensitive drum 103 at the time of image forming. The movement mechanism 640 includes a first link mechanism 861, a second link mechanism 862, and a slide member (sliding portion) 525. The first link mechanism 861 includes link members 651 and 653. The second link mechanism 862 includes link members 652 and 654. The slide member 525 slides in the front-back direction with an opening/closing operation of the cover 558 (not illustrated). In association with the slide motion (sliding movement) of the slide member 525, the first link mechanism 861 and the second link mechanism 862 are driven to move the optical print head 105 up and down. Operations of the movement mechanism 640 will be described in detail below. The portions of the frame member of the drum unit 518 against which the contact pins 514 and 515 abut are provided with fitting holes. For example, the tips of the contact pins 514 and 515 fit into the fitting holes by about 5 mm. Thus, the optical print head 105 is accurately positioned relative to the photosensitive drum 103.
Prior to the description of the structure of the optical print head 105, the holder 505 will be described below. The holder 505 holds the substrate 502 and the lens array 506 (described below). While the holder 505 is made of resin from the viewpoint of the weight and cost reduction of the optical print head 105 itself in the present example embodiment, the holder 505 may be made of a metal.
The exposure unit 500 is disposed vertically below the rotational axis of the photosensitive drum 103, and the LED 503 included in the optical print head 105 exposes the photosensitive drum 103 to light from below. The exposure unit 500 may be disposed vertically above the rotational axis of the photosensitive drum 103, and the LED 503 included in the optical print head 105 may expose the photosensitive drum 103 to light from above.
The substrate 502 held by the holder 505 will be described below.
The substrate 502 is provided with LED chips 639 mounted thereon. As illustrated in
The LED chips 639 mounted on the substrate 502 will be described in more detail below. As illustrated in FIGS. 4B1 and 4B2, the LED chips 639-1 to 639-29 (including a total of 29 LED chips) are arranged on one side surface of the substrate 502. In each of the LED chips 639-1 to 639-29, a plurality of LEDs (examples of light emitting elements) is arranged in a single row along the longitudinal direction of the LED chips 639. Each of the LED chips 639-1 to 639-29 includes 516 LEDs. A distance k2 between the centers of adjacent LEDs in the longitudinal direction of each LED chip 639 corresponds to the resolution of the image forming apparatus 1. The resolution of the image forming apparatus 1 according to the present example embodiment is 1200 dots per inch (dpi). Thus, in each of the LED chips 639-1 to 639-29, LEDs are arranged in a single row in such a manner that the distance between the centers of adjacent LEDs is 21.16 μm in the longitudinal direction of the LED chips 639. Accordingly, the optical print head 105 according to the present example embodiment provides an exposure range of about 316 mm. The photosensitive layer of a photosensitive drum 103 is formed with a width of 316 mm or more. Since the length of long sides of A4 size recording paper and the length of short sides of A3 size recording paper are 297 mm, the optical print head 105 according to the present example embodiment has an exposure range over which image forming on A4- and A3-size recording paper is possible.
The LED chips 639-1 to 639-29 are arranged in alternation in two rows along the direction of the rotational axis of the photosensitive drum 103. More specifically, as illustrated in FIG. 4B1, odd-numbered LED chips 639-1, 639-3, . . . , and 639-29 counted from left to right are mounted in a row in the longitudinal direction of the substrate 502, and even-numbered LED chip 639-2, 639-4, . . . , and 639-28 are mounted in a row in the longitudinal direction of the substrate 502. By arranging the LED chips 639 in this way, as illustrated in FIG. 4B2, a distance k1 between the center of the LED disposed at one end of one of adjacent LED chips 639 and the center of the LED disposed at the other end of the other of adjacent LED chips 639 can be made equal to the distance k2 between the centers of adjacent LEDs on one LED chip 639 in the longitudinal direction of the LED chips 639.
Although, in the configuration according to the present example embodiment, a plurality of LEDs is used as an exposure light source, organic electro luminescence (EL) elements may be used as an exposure light source.
The lens array 506 will be described below. FIG. 4C1 is a schematic view illustrating the lens array 506 when viewed from the side of the photosensitive drum 103, FIG. 4C2 is a perspective view schematically illustrating the lens array 506. As illustrated in FIG. 4C1, the plurality of lenses is arranged in two rows along the arrangement direction of the plurality of the LEDs 503. The lenses are arranged in zigzags in such a way that one of lenses in one row contacts two lenses adjacent in the lens arrangement direction in the other row. Each lens is a column-shaped rod lens made of glass. The material of the lenses is not limited to glass and may also be plastic. The shape of the lenses is not limited to a column and may be a polygon, such as a hexagonal column.
The dotted line Z illustrated in FIG. 4C2 indicates the optical axis of a lens. The optical print head 105 is moved by the above-described movement mechanism 640 in a direction almost along the optical axis of the lens indicated by the dotted line Z. The optical axis of a lens herein means the line connecting the center of the light emitting plane of the lens and the focus of the lens. As illustrated in FIG. 4C2, radiation light emitted from the LEDs 503 is incident on the lenses included in the lens array 506. The lenses have the function of condensing the incident radiation light on the surface of the photosensitive drum 103. The attachment position of the lens array 506 relative to a lens attachment portion 701 at the assembly time of the optical print head 105 is adjusted so that the distance between the light emitting plane of the LEDs and the light incidence plane of the lenses becomes substantially equal to the distance between the light emitting plane of the lenses and the surface of the photosensitive drum 103.
As described above with reference to Figs, 2A and 2B, in replacing a drum unit 518, the drum unit 518 is slid in the direction from the back to the front side of the apparatus main body in the image forming apparatus 1 according to the present example embodiment. If the drum unit 518 is moved in a state where the optical print head 105 is positioned near the surface of the photosensitive drum 103, the surface of the photosensitive drum 103 contacts the optical print head 105, possibly causing damage to the surface of the photosensitive drum 103. In addition, the frame member of the drum unit 518 contacts the lens array 506, possibly causing damage also to the lens array 506. To address this, a structure for making the optical print head 105 reciprocally move between the exposure position (
With the above-described structure, the slide member 525 is regulated in the vertical movement relative to the third support portion 526, and is slidable relative to the third support portion 526 by the length of the oblong hole 691 in the front-back direction.
A slide auxiliary member 539 having a storage space 562 ranging from the left-hand side to downward is attached on one end side of the slide member 525. The slide auxiliary member 539 is fixed to the slide member 525 by a screw from the left-hand side. A pressure portion 561 provided on the cover 558 (described below) is stored in the storage space 562. The relation between the storage space 562 and the pressure portion 561 and structural characteristics thereof will be described below together with the cover 558.
The first link mechanism 861 will be described below with reference to
The link member 651 includes a bearing portion 610, a projection 655, and a connection pivot portion 538. The bearing portion 610 is disposed on one end side of the link member 651 in the longitudinal direction of the link member 651. The projection 655 is formed on the other end side of the link member 651 in the longitudinal direction of the link member 651. The projection 655 is a column-shaped projection extending in the direction of the pivotal axis of the link member 651. The connection pivot portion 538 is disposed between the bearing portion 610 and the projection 655 in the longitudinal direction of the link member 651. The projection 655 may be replaced with a structure in which one end side of the link member 651 in the longitudinal direction thereof is bent in the direction of the pivotal axis.
The bearing portion 610 is provided with a circular hollow hole extending in the lateral direction illustrated in
The projection 655 is a column-shaped projection erected from the link member 651. The projection 655 is rotatably connected to the front side of the holder 505 of the optical print head 105.
The link member 653 is provided with a connection pivot portion 530. The connection pivot portion 530 is disposed on one end side of the link member 653 in the longitudinal direction of the link member 653. The connection pivot portion 530 is a column-shaped projection erected from the link member 653 to the left-hand side illustrated in
A shaft having a function similar to the support shaft 531 is provided on a back part of the third support portion 526. A hole having a function similar to the oblong hole 691 is formed on a back part of the slide member 525. A structure equivalent to the structure provided on a front part of the movement mechanism 640 is provided on a back part of the movement mechanism 640. The configuration of the second link mechanism 862 is the same as the configuration of the first link mechanism 861 described above. The link members 652 and 654 included in the second link mechanism 862 correspond to the link members 651 and 653, respectively. In the structure of the movement mechanism 640, either the link member 653 or 654 may be omitted.
In summary, one end side of the link member 651 (the side on which the bearing portion 610 is formed) is rotatably connected to the front part of the slide member 525, and the other end (the side on which the projection 655 is formed) thereof is rotatably connected to the front part of the optical print head 105. The link member 651 is obliquely disposed in such a manner that one end side of the link member 651 is positioned downstream, in the slide motion direction (toward the back side), of the other end side thereof One end side of the link member 652 is rotatably connected to the back part of the slide member 525, and the other end side thereof is rotatably connected to the back part of the optical print head 105. The link member 652 is obliquely disposed in such a manner that one end side of the link member 652 is positioned downstream, in the slide motion direction (toward back side), of the other end side thereof.
On end side of the link member 653 (the side on which the connection pivot portion 530 is formed) is rotatably connected to a front part of the third support portion 526, and the other end side thereof is rotatably connected between one end side and the other end side of the link member 651. The link member 653 is obliquely disposed in such a manner that one end side of the link member 653 is positioned upstream, in the slide motion direction (toward the front side), of the other end side thereof. The connecting portion of the link member 653 and the third support portion 526 is positioned behind the front side end of the slide member 525, in the apparatus main body. More specifically, the slide member 525 is disposed so as to pass on the right-hand side of the link member 653. The slide member 525 may be disposed so as to pass on the left-hand side of the link member 653. Similarly, one end side of the link member 654 is rotatably connected to a front part of the third support portion 526, and the other end side thereof is rotatably connected between one end side and the other end side of the link member 652. The link member 654 is obliquely disposed in such a manner that one end side of the link member 654 is positioned upstream, in the slide motion direction (toward the front side), of the other end side thereof.
in the above-described configuration, when the slide member 525 slides from the front to the back side relative to the third support portion 526, the fitting pivot portion 534 fit into the bearing portion 610 together with the slide member 525 slides from the front to the back side relative to the third support portion 526. Thus, when the first link mechanism 861 is viewed from the right-hand side as illustrated in
Meanwhile, when the slide member 525 slides from the back to the front side relative to the third support portion 526, the fitting pivot portion 534 fit into the bearing portion 610 together with the slide member 525 slides from the back to the front side relative to the third support portion 526. Thus, when the first link mechanism 861 is viewed from the right-hand side as illustrated in
The first link mechanism 861 may be structured in reverse in the front-back direction. More specifically, one end side of the first link member 651 may be disposed in front of one end side of the third link member 653. The second link mechanism 862 may be structured in reverse in the front-back direction. More specifically, one end side of a third link member maybe disposed in front of one end side of the fourth link member. With this arrangement, when the slide member 525 slides from the front to the back side, the optical print head 105 moves from the evacuation to the exposure position. When the slide member 525 slides from the back to the front side, the optical print head 105 moves from the exposure to the evacuation position. In this case, the cover 558 (described below) pushes the slide member 525 from the front to the back side during the movement from the open to the closed state, and pulls the slide member 525 from the back to the front side during the movement from the closed to the open state.
As illustrated in
Here, (1) L1 denotes the distance between the rotation center axis of the connection pivot portion 538 and the rotation center axis of the bearing portion 610, (2) L2 denotes the distance between the rotation center axis of the connection pivot portion 538 and the rotation center axis of the connection pivot portion 530. (3) L3 denotes the distance between the rotation center axis of the connection pivot portion 538 and the rotation center axis of the projection 655. According to the present example embodiment, the first link mechanism 861 includes the Scott Russell mechanism (refer to
(Example Positional Relations between Link Members and Slide Member)
Positional relations between the link members 651 to 654 and the slide member 525 will be described below with reference to
One end side of the link member 710 is provided with a bearing portion 718 into which a projection formed on a front part of the slide member 719 fits. The bearing portion 718 is, for example, a cylinder-shaped bearing with a hollow hole formed therein. The projection formed in the slide member 719 fits into the bearing portion 718. The bearing portion 718 is equivalent to the bearing portion 610 in the movement mechanism 640. The link member 710 rotates relative to the slide member 719 centering on the center axis of the projection fitting into the bearing portion 718. In other words, the link member 710 is rotatably connected to the front part of the slide member 719. Although not illustrated in
One end side of the link member 711 is rotatably connected to a member fixed to the apparatus main body at a position behind the front side end of the slide member 719. A connection pivot portion 717 is disposed on one end side of the link member 711. The connection pivot portion 717 fits into a bearing fixedly disposed on the apparatus main body. The connection pivot portion 717 is equivalent to the connection pivot portion 538 in the movement mechanism 640. The link member 711 is disposed in such a manner that the other end side of the link member 711 overlaps with one end side of the link member 710 in the lateral direction (the direction of the pivotal axis for the rotation of the link member 710 relative to the slide member 719). A region 715 (intersection region) as a shaded portion illustrated in
The positions of the link members 710 and 711 illustrated in
Referring now to
One end side of the link member 721 is provided with a bearing portion 728 into which a projection formed on a front part of the slide member 729 fits. The bearing portion 728 is, for example, a cylinder-shaped bearing with a hollow hole formed therein. The projection formed in the slide member 729 fits into the bearing portion 728. The bearing portion 728 is equivalent to the bearing portion 610 in the movement mechanism 640. This projection fits into a hole formed in the slide member 729 to form the bearing portion 728. The link member 721 rotates relative to the slide member 729 centering on the center axis of the projection fitting into the bearing portion 728. In other words, the link member 721 is rotatably connected to the front part of the slide member 729. Although not illustrated in
One end side of the link member 720 is rotatably connected to a member fixed to the apparatus main body at a position behind the front side end of the slide member 729 and forms a connection pivot portion 727. The link member 720 is disposed so that the other end side of the link member 720 overlaps with one end side of the link member 721 in the lateral direction (the direction of the pivotal axis for the rotation of the link member 721 relative to the slide member 729). A region 725 (intersection region) as a shaded portion illustrated in
The positions of the link members 720 and 721 illustrated in
Referring now to
A region 730 as a shaded portion illustrated in
To prevent the link members 720 and 721 from contacting the slide member 729 as in the conventional mechanism, a method for disposing the slide member 729 below the link members 720 and 721 may be considered. This means a method for disposing the slide member 729 at a position where the slide member 729 overlaps with the region 730 in the vertical direction (the direction perpendicular to both the longitudinal direction of the optical print head 105 and the direction of the pivotal axis of the link member 721). However, disposing the slide member 729 in this way is not desirable since the entire exposure unit increases in size in the vertical direction. In addition, as a result of the vertically increased size of the entire exposure unit, the optical print head 105 will be disposed closer to the photosensitive drum 103. In the movement mechanism 640 according to the present example embodiment, the slide member 525 is not disposed at a position where the slide member 525 vertically overlaps with the link members 651 to 654.
A cover 558 will be described below with reference to
As illustrated in
As illustrated in
The configuration for sliding the slide member 525 is not limited to the cover 558. For example, the slide member 525 may be configured to slide in association with the opening and closing of a front door (not illustrated). The slide member 525 may be configured to slide in association with the rotation of a rotation member such, as a lever, instead of a covering member, such as the cover 558 and a door.
As illustrated in
According to the present example embodiment, the optical print head 105 can be evacuated from the photosensitive drum 103 to a further extent than the conventional structure according to the comparative example illustrated in
While the present disclosure has been described with reference to example embodiments, it is to be understood that the disclosure is not limited to the disclosed example embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-093254, filed May 14, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-093254 | May 2018 | JP | national |
