JP2008209862A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein an image forming apparatus, including an image drum unit in its body and an exposure head on its upper cover has a positioning hole in one of them and a post on the other, and the positioning hole and the post are fitted together, thereby achieving relative positioning, which fails in predetermined perfect fitting, resulting in blooming of the exposure part of a photoreceptor drum and hence degradation in printing quality. <P>SOLUTION: The image forming apparatus includes the image drum unit 15, which has an exposure head mounting part 15c with the post 23b at one end; the exposure head 30 having the positioning hole 39 in which the post 23b fits; a head holder 54 rotatably supported by the body of the upper cover 70; and springs 29. The springs 29 are disposed on both side of a rotating fulcrum 65 in the lengthwise direction of the head holder 54. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to a configuration of an exposure head holding mechanism.

  2. Description of the Related Art Some conventional image forming apparatuses using an electrophotographic system include an open / close cover on an upper surface and an exposure head held inside the open / close cover. In this type of image forming apparatus, an image drum unit including a photosensitive drum is provided in the apparatus, the exposure head and the image drum unit are fitted with the cover closed, and the exposure head and the image drum unit are spaced apart from each other. Positioned. Further, a post is formed in the exposure head, and a hole is formed in the image drum unit, and these are fitted and positioned to each other (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-181165 (page 6, FIG. 6)

  However, in the conventional technique, if the center of the post of the exposure head and the center of the positioning hole of the image drum unit are shifted, the post is rubbed with the positioning hole and a frictional force is generated on the side surface of the post. The part of the exposure head where friction occurs is caught in the positioning hole, and the distance between the exposure head and the photosensitive drum deviates from the optimum distance that does not cause defocusing. As a result, defocusing occurs in the exposed area of the photosensitive drum, and printing is performed. There was a problem that quality fell.

  The object of the present invention is to solve these problems and to smoothly join the exposure head and the image drum unit when the open / close cover provided with the exposure head is closed, thereby stabilizing the distance between the exposure head and the photosensitive member. An object of the present invention is to provide an image forming measure that can be a predetermined distance.

An image forming apparatus according to the present invention is an image forming apparatus including a lid body that is openably and closably held in an apparatus main body,
A photoconductor, an exposure head mounting portion having a fitting portion disposed at least at one end thereof, a photosensitive unit provided in the apparatus main body, and a fitting portion that fits the fitting portion. When the exposure head and the exposure head are held and the lid is closed, the fitting portion is rotated by a rotation support portion provided in the lid at a position where the fitting portion can be fitted with the fitted portion. And a head holding member that is freely supported.

  According to the present invention, the positioning of the photosensitive unit and the exposure head can be performed smoothly and stably when the lid provided with the exposure head is closed.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram showing the main configuration of Embodiment 1 of an image forming apparatus configured according to the present invention.

  In FIG. 1, the image forming apparatus 1 has a configuration as a color electrophotographic printer capable of printing four colors of black (K), yellow (Y), magenta (M), and cyan (C). Inside the image forming apparatus 1, a substantially S-shaped sheet conveyance path 1100 having sheet conveyance rollers 1101 to 1104 is formed, and a recording sheet is accommodated in an upstream end portion of the sheet conveyance path 1100. The paper tray 11 is detachably disposed with respect to the main body of the image forming apparatus 1, and a stacker 25 is provided at the downstream end.

  In the paper transport path 1100, a hopping roller 2 that feeds and feeds recording paper from the paper tray 11 one by one, a transport belt unit 13 that transports the fed recording paper to the transfer belt 13a by electrostatic effect, and A fixing unit 14 for fixing the toner image on the recording paper is provided.

  Black (K), yellow (Y), magenta (M), cyan (in order from the upstream side in the conveyance direction of the recording paper, at a position sandwiching the recording paper conveyed by the conveyance belt unit 13 by the conveyance belt unit 13a. C) Image drum units 15K, 15Y, 15M, and 15C (photograph units are collectively referred to as image drum units 15) are arranged in a row, and serve as photoreceptor units that store toner of each color and form toner images of respective colors. The forming apparatus 1 is detachably arranged with respect to the main body.

  As will be described later, the upper cover 70 serving as a lid body is rotatably supported by the main body of the image forming apparatus 1 with a rotation support shaft 89 formed on one end side thereof, and the other end side moves in the directions of arrows A and B. It is held openable. The upper cover 70 is formed with the stacker 25 for receiving recorded recording paper on the outer side thereof, and a head holder as a head holding member for holding an exposure head 30K for black (K) on the inner side surface. 54K, a head holder 54Y that holds an exposure head 30Y for yellow (Y), a head holder 54M that holds an exposure head 30M for magenta (M), and a head holder 54C that holds an exposure head 30C for cyan (C). Is provided. The exposure heads 30K, 30Y, 30M, and 30C are collectively referred to as the exposure head 30, and the head holders 54K, 54Y, 54M, and 54C are collectively referred to as the head holder 54.

  As shown in the figure, when the upper cover 70 is closed, the exposure heads 30K, 30Y, 30M and 30C are positioned at positions facing the image drum units 15K, 15Y, 15M and 15C, respectively. Has been placed. The mounting method of the head holder 54 and the exposure head 30 and the positional relationship with the image drum unit 15 will be described in detail later.

  As described above, with respect to each of the detachable or movable components such as the paper tray 11, the image drum unit 15, or the upper cover 70 of the image forming apparatus 1, the portions excluding the components are imaged. It is called the forming apparatus main body.

  In the present embodiment, the image drum units 15K, 15Y, 15M, and 15C have the same configuration and differ only in the color of the contained toner. Therefore, here, a black (K) developing device 15K is taken as an example. The internal structure will be described below.

  The XYZ coordinates in FIG. 1 take the X axis in the transport direction when the recording paper 1116 (FIG. 2) passes through the developing device image drum unit 15, and take the Y axis in the rotational axis direction of the photosensitive drum 19 described later. The Z axis is taken in a direction perpendicular to both the axes. Further, when XYZ coordinates are shown in other drawings to be described later, the axial directions of these coordinates indicate a common direction. That is, the XYZ axes in each figure indicate the arrangement direction when the depicted portion of each figure constitutes the image forming apparatus 1 shown in FIG.

  FIG. 2 is a schematic configuration diagram schematically showing the black (K) image drum unit 15K, the transfer roller 1130, the exposure head 30K, and the printed recording paper 1116.

  As shown in the figure, the image drum unit 15K is covered with a cover 34, and a photosensitive drum 19 is rotatably disposed in the direction of the arrow, and the photosensitive drum 19 is surrounded from the upstream side in the rotation direction. In order, the surface of the photosensitive drum 19 is brought into contact with a constant pressure to supply and charge the charge roller 16, and the charged surface of the photosensitive drum 19 is electrostatically irradiated with light from a light source such as an LED head. An exposure head 30K for forming a latent image is provided. The exposure head 30K is disposed on the upper cover 70 (FIG. 1) as described above.

  Furthermore, a toner 1114 of a predetermined color (here, black) is attached to the surface of the photosensitive drum 19 on which the electrostatic latent image is formed to generate development, and toner development on the photosensitive drum 19 is performed on the recording paper 1116. A cleaning blade 1120 that removes residual transfer toner 1115 remaining when the toner is transferred to the toner and drops it to a waste toner collecting unit 1113 is provided. For this reason, the cleaning blade 1120 is formed of an elastic body, and the edge portion thereof is arranged so as to contact the surface of the photosensitive drum 19 with a constant pressure. Note that the rotating body used in each of these devices rotates by receiving power from a drive source (not shown) via a gear or the like.

  The developing unit 1111 stores the toner 1114, the toner cartridge 12 that supplies the toner 1114 from the toner supply port 1122 formed in the lower portion thereof, the toner storage unit 1112 that stores the toner 1114 supplied from the toner cartridge 12, and the developing roller 17, a toner supply roller 18 that supplies toner 1114 to the developing roller 17, and a developing blade 1121 that thins the toner 1114 on the developing roller 17, and an electrostatic latent image formed on the surface of the photosensitive drum 19 The toner 1114 visualizes, that is, develops. The image drum unit 15K is configured to detachably dispose the toner cartridge 12 above the toner supply roller 18.

  The developing roller 17 and the toner supply roller 18 are arranged in parallel with each other so as to be in contact with each other with a constant pressure, and rotate in the directions of the arrows (same direction) shown in FIG. Further, as shown in the figure, the developing blade 1121 and the developing roller 17 are arranged in parallel to each other so that, for example, a bent portion of the developing blade 1121 contacts the peripheral surface of the developing roller 17 with a constant pressure. Note that the rotating body used in each of these devices rotates by receiving power from a drive source (not shown) via a gear or the like.

  As shown in FIG. 1, transfer rollers 1130 formed of conductive rubber or the like are placed on the recording paper 1116 (FIG. 2) at positions facing the photosensitive drums 19 of the four image drum units 15 described above. They are arranged in pressure contact with each other through a transfer belt 13a that is electroabsorbed and conveyed. These transfer rollers 1130 transfer the toner development on the photosensitive drums 19 to the recording paper 1116 (FIG. 2). At the time of this transfer, the surface potentials of the respective photosensitive drums 19 and the respective photosensitive drums are disposed. A potential for applying a potential difference to the surface potential of each transfer roller 1130 is applied.

  The fixing unit 14 includes a heating roller and a backup roller inside, and fixes the toner 1117 transferred onto the recording paper 1116 (FIG. 2) by applying pressure and heating. The recording sheet 1116 fixed here is conveyed to the recording sheet stacker 25 by the sheet conveying rollers 1103 and 1104 at the subsequent stages.

  Next, a method for attaching the head holder 54 and the exposure head 30 mounted on the upper cover 70 and a positional relationship with the image drum unit 15 will be described below. 3 is an external perspective view of the main body of the upper cover 70 with the head holder 54 and the exposure head 30 removed, as viewed obliquely from below. FIG. 4 shows the main body of the upper cover 70 viewed from the opposite side to FIG. FIG. 5 is a cross-sectional view of a main part schematically showing a cross-section of the main part of the upper cover 70 body shown in FIG. 4 taken along line QQ. As described above, with respect to each of the detachable or movable components such as the head holder 54 and the exposure head 30 of the upper cover 70, a portion excluding the components is referred to as an upper cover main body.

  The upper cover 70 is provided with a pair of left and right rotation support shafts 89a and 89b that are rotatably supported by the main body of the image forming apparatus 1 (they are collectively referred to as the rotation support shafts 89). Yes. The rotation support shaft 89 is on the downstream side (X-axis plus direction) of the sheet conveyance of the upper cover 70, serves as a center of rotation when the upper cover 70 opens and closes, and is a mechanism (not shown) provided in the main body of the image forming apparatus 1. Attached to the unit. Further, between the upper cover 70 and the mechanical unit, a biasing means (not shown) for biasing the upper cover 70 in the direction of the arrow A around the Y axis (FIG. 1), that is, the direction of opening the upper cover 70 is provided. Has been.

  In the upper cover 70, each of the head holder 54K, the head holder 54Y, the head holder 54M, and the head holder 54C described above is attached with a mounting portion 701K, a mounting portion 701Y, a mounting portion 701M, and the like. A mounting portion 701C (when these are collectively referred to as “mounting portion 701”) is formed. As shown in FIG. 4, each of these attachment portions 701 has an attachment portion 701C disposed at a distance L83 from the attachment position 106 in the X-axis direction, and an attachment portion 701M disposed at a distance L84 from the attachment portion 701C. The mounting portion 701Y is disposed at a distance L84 from the mounting portion 701M, and the mounting portion 701K is disposed at a distance L84 from the mounting portion 701Y.

  Further, as shown in FIG. 5, each attachment portion 701 has a distance L85 from the center of the attachment position 106 at a position in the front direction (Y-axis plus direction) in FIG. 1 and a distance L86 below the outer surface of the upper cover 70 ( A mounting hole 702 having a radius r7 centering on the position in the negative Z-axis direction is formed.

  FIG. 6 shows that the upper cover 70 (FIG. 1) held in a predetermined position on the main body of the image forming apparatus 1 and rotatably urged in the direction of arrow A around the Y axis is set to a closed rotational position (closed position). FIG. 7 is an external perspective view of the cover opening / closing mechanism 78 that locks and releases the lock, and FIG. 7 is an operation explanatory view showing a state in which the cover opening / closing mechanism 78 is held by the main body of the image forming apparatus 1.

  As shown in FIG. 7, the rotation shaft 79 of the cover opening / closing mechanism 78 is rotatably held at a predetermined position on the upstream side (X-axis minus direction) of the sheet conveyance of the main body of the image forming apparatus 1. Further, the cover opening / closing mechanism 78 is urged in the direction of the arrow A around the Y axis by an urging means (not shown), and as shown in the figure, the rotation in the same direction is restricted at the lock position where the projection 67 is located above. Has been. At this time, the pair of protrusions 67 engage with a pair of engagement holes 80 (FIG. 3) formed at the tip of the upper cover 70 to lock the upper cover 70 in the closed position. The image forming apparatus 1 shown in FIG. 1 shows a state in which the upper cover 70 is locked at the closed position.

  When opening the upper cover 70, the lock release button 68 is pressed, and the cover opening / closing mechanism 78 rotates in the direction of arrow B around the Y axis against the urging force. As a result, the engagement between the pair of protrusions 67 and the pair of engagement holes 80 of the upper cover 70 is released, and the upper cover 70 biased in the direction of arrow A around the Y axis rotates in the same direction. Rotate to an open position described later.

  Next, the configuration of the head holder 54 will be described. 8 is an external perspective view of the head holder 54 as viewed obliquely from below, FIG. 9 is an external view of the head holder 54 shown in FIG. 8 as viewed from the direction of arrow N, and FIG. 10 is a view of the head holder 54 shown in FIG. FIG. 11 is a cross-sectional view of an essential part schematically showing a cross section of the head holder 54 shown in FIG. 10 taken along line GG. FIG. 12 is a cross-sectional view of the head holder 54 shown in FIG. 10 taken along line EE. It is principal part sectional drawing shown roughly.

  As shown in these drawings, a spring 29 (FIG. 31) is placed on the lower surface 60 of the head holder 54 between the exposure head 30 and the exposure head 30 in order to urge the later-described exposure head 30 with a constant force. Protrusions 61a and 61b are formed. A pair of rotating shaft protrusions 94 a and 94 b are formed on the attachment surface 93 of the head holder 54. The pair of rotary shaft protrusions 94a and 94b are press-fitted into the mounting hole 702 of the mounting portion 701 provided in the upper cover 70 shown in FIG. Exit. As a result, the head holder 54 is mounted on the upper cover 70 body and is rotatably supported by the mounting portion 701. For this reason, as shown in FIG. 15, the pair of rotating shaft protrusions 94a and 94b is formed with a groove portion having a groove width L27 slightly longer than the thickness of the attachment portion 701. FIG. 16 is an explanatory diagram showing the mounting position relationship at this time.

  At this time, the side surfaces 102a and 102b of the rotation shaft protrusions 94a and 94b are in contact with the edge of the mounting hole 702, and the side surfaces 103a and 103b and the mounting surface 93 are in contact with the surface 107 and the surface 108 of the mounting portion 701. Therefore, in order to smoothly rotate the head holder 54, the side surfaces 103a and 103b and the mounting surface 93 of the rotation shaft protrusions 94a and 94b of the head holder 54 are formed smoothly, and the side surfaces 102a and 102b are smoothly and arcuately formed. Is formed.

  Accordingly, the head holder 54 is rotatably held around the center of the mounting hole 702 of the mounting portion 701 as a rotation center, and the rotation fulcrum 65 (FIG. 10) of the head holder 54 itself is the center of the arc of the side surfaces 102a and 102. Become. The protrusions 61a and 61b for suspending the spring 29 (FIG. 31) are formed at a distance y from the rotation fulcrum 65 in the Y-axis direction.

  As shown in FIG. 10, the head holder 54 is formed with guide portions 88 and 98 for guiding the movement of the exposure head 30 in the longitudinal direction at both ends in the longitudinal direction. As shown in FIG. 11 and a partial cross-sectional view of the cross section taken along line G1-G1 of the head holder 54 shown in FIG. 11, a guide groove 97a for attaching the exposure head 30 and guiding its movement is provided in the guide portion 88. Is formed. As shown in FIG. 11, the guide groove 97a has a height L19 from the position of the distance L22 in the vertical direction from the lower surface 60 of the head holder 54, and a width L20 that extends from the center of the width of the guide portion 88 by a distance L23 to the left and right. And as shown in FIG. 13, it is a rectangular parallelepiped cavity part of the depth L21.

  On the other hand, as shown in FIG. 12 and a partial sectional view 14 of the section taken along the line G2-G2 of the head holder 54 shown in FIG. 12, a guide groove for attaching the exposure head 30 to the guide portion 98 and guiding its movement is shown. 97b is formed. As shown in FIG. 12, the guide groove 97b has a height L19 from the position of the distance L22 in the vertical direction from the lower surface 60 of the head holder 54, and a width L20 extending from the thickness center 26 of the guide portion 98 to the left and right by the distance L23. And a rectangular parallelepiped hollow portion having a depth L21 as shown in FIG.

  Next, the configuration of the exposure head 30 will be described. FIG. 17 is an external view of the exposure head 30 as viewed from the side opposite to the paper conveyance direction, that is, from the fixing unit 14 side. As shown in the figure, the exposure head 30 includes a lens 33 extending in the longitudinal direction at the lower portion thereof. The lens 33 collects light on the surface of the photosensitive drum 19 (FIG. 2), and its tip protrudes from the lower surface 47. On the lower surface, in the longitudinal direction, a cam 32 is rotatably disposed by a support plate 38 in the vicinity of one end portion, and a cam 35 is rotatably disposed by a support plate 36 in the vicinity of the other end portion.

  18 is a partially enlarged top view in the vicinity of the right end portion in FIG. 17, and FIG. 19 is a partial cross sectional view showing a section in the vicinity of the right end portion of the exposure head 30 taken along the line PP in FIG. 20 is a perspective view of the cam 35, and FIG. 21 is a perspective view of the support plate. On the other hand, FIG. 22 is a partially enlarged top view in the vicinity of the left end portion in FIG. 17, and FIG. 23 is a partial cross sectional view showing a cross section in the vicinity of the left end portion of the exposure head 30 taken along the line PP in FIG. 24 is a perspective view of the cam 32, and FIG. 25 is a perspective view of the support plate 38.

  As shown in FIG. 19, the exposure head 30 has a cylindrical intermediate portion 35a of the cam 35 shown in FIG. 20 positioned by a V-shaped groove 47b formed in the lower surface 47 on the lower right side thereof, and further, the support shown in FIG. The cam 35 is rotatably held by pressing the cylindrical intermediate portion 35a by the urging portion 36a of the plate 36. As will be described later, the rotational position of the cam 35 is determined by adjusting the rotational position of the cam 35 and the distance between the lens 33 and the photosensitive drum 19 is adjusted, and the lower surface 47 rotates the cam 35 b. It is formed so as not to interfere.

  Similarly, as shown in FIG. 23, the exposure head 30 positions the cylindrical both end portions 32a of the cam 32 shown in FIG. 24 by the V-shaped groove 47a formed on the lower surface 47 on the lower left surface thereof, and further FIG. The cam 32 is rotatably held by pressing the cylindrical end portions 32a by the urging portion 38a of the support plate 38 shown in FIG. As will be described later, the rotational position of the cam 32 is adjusted to determine the rotational position of the cam portion 32b, and the distance between the lens 33 and the photosensitive drum 19 is adjusted, and the lower surface 47 rotates the cam portion 32b. It is formed so as not to interfere.

  Further, the exposure head 30 is provided with projections 31a and 31b for attaching the exposure head 30 to a head holder 54 (FIG. 10) and regulating the movement of the exposure head 30. As shown in FIGS. 22 and 23 for the protrusion 31a and as shown in FIGS. 18 and 19 for the protrusion 31b, each protrusion 31 is a rectangular parallelepiped having a width L151, a height L152, and a length L153. 31b is formed in a smaller size than the guide groove 97a of the guide part 88 of the head holder 54 and the guide groove 97b of the guide part 98 which are loosely fitted respectively. Thus, when the exposure head 30 is held by the head holder 54, the exposure head 30 is held in a predetermined range so as to be displaceable in the front-rear, left-right, up-down, and tilt directions.

  As shown in FIG. 17, the exposure head 30 is fitted with a post 23 a and a post 23 b (FIG. 26) in the image drum unit 15, which will be described later, to position the exposure head 30 with respect to the image drum unit 15. A long hole 37 and a positioning hole 39 are formed. Tapers 37 a (FIG. 23) and 39 a (FIG. 19) are formed in the openings of the long hole 37 and the positioning hole 39 to allow a certain amount of positional deviation during the fitting process. Further, on the upper surface 46 of the exposure head 30, projections 43a and 43b for suspending the spring 29 (FIG. 31) between the head holder 54 and the head holder 54 are opposed to the projections 61a and 61b (FIG. 10) of the head holder 54, respectively. It is formed in the position to do. A spring 26 (FIG. 31) in a compressed state is spanned between the projection 61a and the projection 43a and between the projection 61b and the projection 43b with a spring constant K, and the exposure head 30 is attached to the head holder 54 in the vertical direction. It is fast.

  Next, the configuration of the image drum unit 15 will be further described. FIG. 26 is an external perspective view of the image drum unit 15 and will be described with reference to FIG.

  As described with reference to FIG. 2, the image drum unit 15 includes a charging roller 16, a developing roller 17, a toner supply roller 18, and a photosensitive drum 19 for forming an image, and these are covered with a cover 34. ing. As shown in FIG. 26, the image drum unit 15 includes a toner cartridge mounting portion 15a for detachably mounting the toner cartridge 12 (FIG. 2), an exposure head mounting portion 15c for mounting the exposure head 30 (FIG. 17), and a photosensitive drum. 19 has an opening 15b that faces the exposure head mounting portion 15c. The exposure head mounting portion 15c includes a post 23a that fits into the long hole 37 and the positioning hole 39 (FIG. 17) of the exposure head 30 mounted to the exposure head mounting portion 15c. The post 23b is planted. Each tip end of the post 23a and the post 23b is formed with a taper for allowing a certain amount of misalignment during the fitting process.

  Further, in order to reduce the respective collision angles of the post 23a and the long hole 37 and the post 23b and the positioning hole 39 that are generated when the cover 70 is closed, the height of the posts 23a and 23b is set to the rotational support shaft 89 described in FIG. Or less than one-tenth of the distance L83 in the X-axis direction from the center to the mounting portion 701C.

  Above both end portions of the photosensitive drum 19, frames 21 and 22 are arranged to keep the distance between the exposure head 30 and the photosensitive drum 19 constant. These frames 21 and 22 are not in contact with the photosensitive drum 19 and are held by the exposure head mounting portion 15c of the cover 34 so that the height positional relationship with the photosensitive drum 19 does not change.

  FIG. 27 shows the relationship between the frame 21 and the cam 32 held by the exposure head 30 when the upper cover 70 is closed and the exposure head 30 is mounted on the exposure head mounting portion 15c of the image drum unit 15 as will be described later. It is a figure for demonstrating. As shown in the figure, the top 21 has a convex cross section, and the upper surface 50 is formed by a curved surface having a curvature r1 greater than or equal to the curvature r of the photosensitive drum 19, and has a distance t from the upper surface 50 to the photosensitive drum surface. The upper surface 50 is in contact with the cam portion 32b of the cam 32 held on the lower surface 47 (FIG. 23) of the exposure head 30, and by adjusting the rotation angle of the cam 32, the exposure head 30 and the photosensitive drum 19 are in contact with each other. The distance can be adjusted.

  On the other hand, in FIG. 28, the upper cover 70 is closed as will be described later, and the frame 22 and the cam 35 held by the exposure head 30 when the exposure head 30 is mounted on the exposure head mounting portion 15c of the image drum unit 15 are shown. It is a figure for demonstrating a relationship. As shown in the figure, the top 22 has a concave cross section, and the upper surfaces 51 and 52 are formed with curved surfaces having a curvature r1 equal to or larger than the curvature r of the photosensitive drum 19, and the distance t from the upper surfaces 51 and 52 to the photosensitive drum surface. Have A pair of cam portions 35b of the cam 35 held on the lower surface 47 (FIG. 19) of the exposure head 30 are in contact with the upper surfaces 51 and 52, respectively, and the rotation angle of the cam 35 is adjusted, so that the exposure head 30 and The distance from the photosensitive drum 19 can be adjusted.

  FIG. 29 is a diagram for explaining the distance L between the photosensitive drum 19 and the lens 33. As shown in the figure, the distance from the photosensitive drum 19 to each upper surface of the frames 21 and 22 is t, the distance from the frames 21 and 22 to the exposure head surface 705 is j, and the distance from the exposure head surface 705 to the surface of the lens 33 is When the distance is p, when the cams 32 and 35 of the exposure head 30 ride on the frames 21 and 22, the distance L from the surface of the lens 33 of the exposure head 30 to the surface of the photosensitive drum 19 is L = t + j−p. It becomes. Assuming that the maximum distance from the lens 33 where the out-of-focus blur does not occur to the photosensitive drum 19 is La and the minimum distance is Lb, this distance L is obtained by adjusting the rotation angle of the cams 32 and 35 to vary the distance j. It is set within the range of La> L> Lb.

  In the above configuration, first, the printing operation of the image forming apparatus 1 will be described with reference to FIG.

  When printing is started, the image forming apparatus 1 feeds the recording paper from the paper tray 11 by the hopping roller 2, and feeds the recording paper to the paper transport path 1100 by the paper transport rollers 1101 to 1104 and the transport belt unit 13. Along the downstream side. In the conveyance process by the conveyance belt unit 24, the toner images individually formed by the image drum units 15K, 15Y, 15M, and 15C are sequentially transferred onto the recording surface of the recording paper by the transfer roller 1130, and further, the recording surface is recorded by the fixing unit 14. After fixing the toner image on the top, the printed recording paper is conveyed to the stacker 25.

  Next, the operation when the upper cover 70 is opened and closed by replacement or maintenance of the toner cartridge 12 will be described below with reference to the operation explanatory diagram 30.

  When the upper cover 70 opens and closes, the exposure head 30 held by the upper cover 70 moves while drawing an arc as shown by an arrow in FIG. The center of the post 23a of the image drum unit 15 is on the rotation locus of the center of the long hole 37 in the exposure head 30, and the center of the post 23b of the image drum unit 15 is on the rotation locus of the center of the positioning hole 39 in the exposure head 30. is there.

  As described above, the guide grooves 88 and 98 of the head holder 54 (for example, FIG. 10) are larger than the projections 31a and 31b of the exposure head 30 (for example, FIG. 17) and guide grooves in which the exposure head 30 can move. 97a and 97b, and the long holes 37, the positioning holes 39, and the edges of the posts 23a and 23b are respectively tapered. For this reason, as described above, in the process in which the upper cover 70 is closed and the long hole 37 and the post 23a and the positioning hole 39 and the post 23b are respectively fitted, a certain amount of misalignment occurs and a misalignment occurs. Can be fitted.

Further, the heights of the posts 23a and 23b are set to 1/10 or less of the distance L83 in the X-axis direction from the center of the rotation support shaft 89 described in FIG. 4 to the attachment portion 701C. Accordingly, the collision angle of the exposure head 30 when the long hole 37 and the post 23a and the positioning hole 39 and the post 23b are respectively fitted is tan ⁻¹ (1/10) ≈6 °, that is, less than 6 °. At this time, the force contributing to the fitting is cos (6 °) ≈0.99 times the force applied to the upper cover 70 when there is no load.

  On the other hand, the frictional force applied to the side surfaces of the posts 23a and 23b is sin (6 °) ≈0.10 times the force applied to the upper cover 70 when there is no load. Accordingly, the frictional force generated when the long hole 37 and the post 23a and the positioning hole 39 and the post 23b are in contact with each other has a coefficient of friction applied to the side surfaces of the posts 23a and 23b of 0. Since it is as small as 10, the force does not affect the exposure head 30. Therefore, the long hole 37 can move up and down along its shape when mated with the post 23a, and the positioning hole 39 can move up and down along its shape when mated with the post 23b.

  Next, the operation when the upper cover 70 is opened from the closed state will be described with reference to FIG.

  When the upper cover 70 is opened, as shown in FIG. 31, the protrusions 31a and 32b on both ends of the exposure head 30 are guide grooves 97a and guides 98 formed on the guide 88 of the head holder 54, respectively. The exposure head 30 is lifted by being caught in each lower portion of the groove 97b. At this time, the force that lifts the upper cover 70, that is, the force that urges the upper cover 70 in the direction of the arrow A around the Y axis (FIG. 1) by the urging means (not shown) is between the elongated hole 37 and the post 23 a and the positioning. The exposure head 30 is rotated along the rotation trajectory shown in FIG. 29 without being caught by the posts 23a and 23b without being affected by the load increase due to the friction force acting between the hole 39 and the post 23b. To do.

  Next, the operation when the upper cover 70 is closed from the opened state will be described with reference to the operation explanatory diagrams 32 to 35.

  Since the exposure head 30 is held by the head holder 54 so as to be displaceable in the front, back, left, right, up, and down directions within a predetermined range, the dimension between the respective parts changes, and the center of the post 23b and the positioning hole 39 The center may be off. As described above, when the center of the post 23b and the center of the positioning hole 39 are shifted, as shown in FIG. 32, the taper 39a (FIG. 19) of the positioning hole 39 of the exposure head 30 is imaged when the cover 70 is closed. The contact with the taper of the post 23b of the drum unit 15 causes the exposure head 30 to be guided, and the positioning hole 39 and the post 23b are fitted. However, if the center of the positioning hole 39 and the center of the post 23b are shifted, after the positioning hole 39 enters the post 23b, in the fitting process, the positioning hole 39 of the exposure head 30 as shown in FIG. Since the frictional force F0 is generated on the side surface, the exposure head 30 does not fall down and stops when the frictional force F0 and the force F1 pressed by the spring 29b are balanced.

  On the other hand, the long hole 37 and the post 23a have a cylindrical shape, whereas the long hole 39 of the exposure head 30 is long in the longitudinal direction (Y-axis direction), and further taper to the edges of the post 23a and the long hole 37. Therefore, the post 23a can easily enter the slot 37 of the exposure head 30. Further, since a force for pressing the cover is also applied from the upper cover 70, the long hole 37 of the exposure head 30 advances in the vertical direction along the post 23a under the pressing force of the spring 29a. Eventually, when the cam 32 near the elongated hole 37 comes into contact with the frame 21 on the photosensitive drum 19 and the vertical movement is restricted and positioned, the spring 29a becomes more compressed as shown in FIG. The vicinity of the long hole 37 of the exposure head 30 is urged to the exposure head mounting portion 15c (see FIG. 26) of the image drum unit 15 by the urging force F2.

  Thus, immediately before the cover 70 is closed, the movement is stopped by friction before the cam 35 reaches the top 22, so that the length x2 of the spring 29a is the spring on the positioning hole 39 side as shown in FIG. It shrinks from the length x1 of 29b. At this time, the force F2 applied to the long hole 37 of the exposure head 30 is larger than the force F1 applied to the positioning hole 39, and the head holder 54 that holds the exposure head 30 can rotate around the rotation fulcrum 65. 54 generates a moment M1 around the rotation fulcrum 65, and a force F3 generated by the moment M1 is transmitted to the exposure head 30 via the spring 29b. The force F3 applied to the spring 29b by the moment M1 at this time becomes K (x2-x1).

  As a result, not only the force F3 generated by the moment M1 is applied, but also a rotational motion is applied, so that the catch between the post 23 and the positioning hole 30 is easily released. That is, the friction force F0 and the force F3 generated by the moment M1 change as F0 <F3, so that the post 23b and the positioning hole 39 are accurately fitted. In this way, the exposure head 30 advances in the vertical direction as shown in FIG. 35 by accurately fitting the positioning hole 39 and the post 23b, and the cam 35 near the positioning hole 39 is moved to the top of the photosensitive drum 19. Thus, the movement is restricted and positioned, and an optimum distance from the defocusing photosensitive drum 19 where no defocusing occurs is maintained. When the upper cover 70 is closed and locked, the springs 29a and 29b are both compressed as shown in FIG. 35, and the exposure head 30 is biased to the exposure head mounting portion 15c of the image drum unit 15. The state is kept.

  As described above, according to the image forming apparatus of the first embodiment, since the head holder 54 that holds the exposure head 30 is rotatably supported with respect to the upper cover 70, it is formed at the end of the exposure head. When the formed positioning hole is fitted to the post formed on the image drum side, the exposure head can be positioned smoothly and stably in accordance with the opening and closing of the cover by suppressing the catching by friction.

Embodiment 2. FIG.
FIG. 36 is a configuration diagram showing a mounting configuration of the upper cover 70 and the head holder 54 in the image forming apparatus according to the second embodiment of the present invention.

  The image forming apparatus according to the second embodiment is mainly different from the image forming apparatus 1 according to the first embodiment (FIG. 1) in that a pair of springs are provided between the upper cover 70 and the head holder 54. Is a point. Therefore, in the image forming apparatus according to the present embodiment, the same reference numerals are given to portions common to the image forming apparatus 1 (FIG. 1) according to the first embodiment, or the description is omitted here. Omitted, the differences are emphasized.

  As shown in FIG. 36, in order to stabilize the rotational position of the head holder 54 rotatably held at the rotation fulcrum 65 by the upper cover 70, a spring is provided between the opposite ends of the upper cover 70 and the head holder 54. A pair of springs 201a and 201b having a constant K2 are attached at positions separated from the rotation fulcrum 65 in both directions by a distance y1 in the Y-axis direction. Here, as shown in FIG. 36, the rotation position of the head holder 54 where the lengths of the pair of springs 201a and 201b are the same and the upper cover 70 and the head holder 54 are parallel to each other is hereinafter referred to as a reference rotation position. . Here, the pair of springs 201a and 201b are set to have a reference length L99 that balances in a slightly compressed state when the head holder 54 is at the reference rotation position and has the same length. It shall be.

  Next, the operation when the upper cover 70 is closed from the opened state will be described with reference to the configuration diagram 36 and the operation explanatory diagrams 37 to 39.

  As shown in FIG. 37, when the head holder 54 is at the reference rotation position, the gravity gravity W <b> 1 of the head holder 54 and the exposure head 30 is applied to the rotation support shaft 65. From this state, as shown in FIG. 38, when a force F5 is applied to one end of the head holder 54, the head holder 54 rotates and the spring 201b on the applied holder is shortened to generate a reaction force F6. The spring 201a becomes longer and an attractive force F6 is generated. When the force F5 is released, the head holder 54 receives the attractive force F6 and the reaction force F6 of the springs 201a and 201b at both ends of the head holder 54 and rotates around the rotation fulcrum. Thereafter, the head holder 54 returns to the reference rotation position where the lengths of the springs 201a and 201b are both the natural length L99.

  As shown in FIG. 39, immediately before the upper cover 70 is closed, as described in the first embodiment, the periphery of the long hole 37 of the exposure head 30 is biased by the urging force F2, and the exposure head mounting portion 15c ( 26), the length x2 of the spring 29a is shortened from the length x1 of the spring 29b on the positioning hole 39 side where the movement is stopped by friction before the cam 35 reaches the top 22.

The force F2 applied to the long hole 37 of the exposure head 30 is larger than the force F1 applied to the positioning hole 39. Further, since the spring 201 is attached, and the frame 21 is in contact with the cam 32 and the frame 22 is not in contact with the cam 35, a difference in elongation occurs between the springs 29a and 29b, and there is also a difference in the elongation of the springs 201a and 201b. appear. At this time, since the spring 201a extends by x4, a vertical force F7 = K2 × (x4) is generated in the spring 201a, and since the spring 201b contracts by x3, the vertical force F8 = K2 × ( x3) works. Since the head holder 54 that holds the exposure head 30 is rotatable, a moment M 2 is generated around the rotation fulcrum 65 in the holder 54. The force F9 applied to the spring 29b from the holder 54 generated by this moment M2 is F9 = K (x2-x1) + K2 (x4 + x3)
It becomes.

  As a result, not only the force F9 generated by the moment M2 is applied, but also a rotational motion is applied, so that the catch between the post 23 and the positioning hole 30 is easily released. That is, the frictional forces F0 and F9 change as F0 <F9, so that the post 23b and the positioning hole 39 are accurately fitted. Thus, the exposure head 30 advances in the vertical direction when the positioning hole 39 and the post 23b are accurately fitted, and the cam 35 near the positioning hole 39 contacts the frame 22 of the photosensitive drum 19 and moves. Is regulated, and an optimum distance from the defocusing photosensitive drum 19 where no defocusing occurs is maintained. When the upper cover 70 is closed and locked, the springs 29a and 29b are both compressed and the exposure head 30 is kept biased by the exposure head mounting portion 15c of the image drum unit 15. .

  As described above, according to the image forming apparatus of the second embodiment, since the head holder 54 that holds the exposure head 30 is rotatably supported with respect to the upper cover 70, it is formed at the end of the exposure head. When the positioning hole is fitted to a post formed on the image drum side, the exposure head can be positioned smoothly and stably with the opening and closing of the cover while suppressing the catching by friction. Furthermore, not only the position of the head holder is stabilized by inserting a spring between the upper cover and the head holder, but also the stability of the head positioning can be expected by increasing the force for pushing the exposure head.

Embodiment 3 FIG.
FIG. 40 is a configuration diagram showing a mounting configuration of the upper cover 170 and the head holder 154 in the image forming apparatus according to the third embodiment based on the present invention.

  The main difference between the image forming apparatus of the third embodiment and the image forming apparatus 1 (FIG. 1) of the first embodiment is that the mounting position of the head holder 154 with respect to the upper cover 170 is changed. Therefore, in the image forming apparatus according to the present embodiment, the same reference numerals are given to portions common to the image forming apparatus 1 (FIG. 1) according to the first embodiment, or the description is omitted here. Omitted, the differences are emphasized.

  As shown in FIG. 40, in the present embodiment, the positions of the rotary shaft protrusions 94a and 94b (see FIG. 8) formed on the head holder 154 are located between the positioning hole 39 and the long hole 37 in the Y-axis direction. It is formed at a position separated by a predetermined distance from the center to the positioning hole 39 side. Accordingly, the position of the attachment portion 701 of the upper cover 170 that supports the head holder 154 is also formed in the same direction so that the head holder 154 is set to a predetermined position of the image forming apparatus. That is, in the image forming apparatus of the present embodiment, as shown in FIG. 40, the position of the rotation fulcrum 89 is a distance y9 from the distance y10 to the center of the long hole 37 to the center of the positioning hole 39 in the Y-axis direction. Is formed to be shorter.

  Next, the operation when the upper cover 170 is closed from the opened state will be described with reference to the configuration diagram 40 and the operation explanatory diagram 41.

As shown in FIG. 41, immediately before the upper cover 170 is closed, if the positioning hole 39 interferes with the post 23b and stops moving here, the holder 54 rotates and the post 23a first fits in the long hole 37. The cam 32 of the exposure head 30 contacts the frame 21 on the image drum 15, a moment M8 is generated in the holder 54, and the force F6 applied to the positioning hole 39 is F6 = F2 × (y10 / y9)
It becomes.

  Therefore, since the distance y10 is set longer than the distance y9 here, the force generated by the moment is larger than the force when the rotation fulcrum 89 is in the middle of the positioning hole 39 and the long hole 37, that is, y10 = y9. Become. The force with which the head holder 154 pushes the head 30 via the spring 29b is larger than when the rotation fulcrum is in the middle of the positioning hole 39 and the long hole 37, and the exposure head 30 advances downward.

  As a result, not only the force F6 generated by the moment M8 is applied, but also a rotational motion is applied, so that the catch between the post 23 and the positioning hole 30 is easily released. That is, the friction force F0 and the force F6 generated by the moment M8 change as F0 <F6, so that the post 23b and the positioning hole 39 are accurately fitted. Thus, the exposure head 30 advances in the vertical direction when the positioning hole 39 and the post 23b are accurately fitted, and the cam 35 near the positioning hole 39 contacts the frame 22 of the photosensitive drum 19 and moves. Is regulated, and an optimum distance from the defocusing photosensitive drum 19 where no defocusing occurs is maintained. When the upper cover 170 is closed and locked, the springs 29a and 29b are both compressed and the exposure head 30 is kept biased by the exposure head mounting portion 15c of the image drum unit 15. .

  As described above, according to the image forming apparatus of the third embodiment, since the head holder 54 that holds the exposure head 30 is rotatably supported with respect to the upper cover 70, it is formed at the end of the exposure head. When the formed positioning hole is fitted to the post formed on the image drum side, the exposure head can be positioned smoothly and stably in accordance with the opening and closing of the cover by suppressing the catching by friction. Furthermore, since the force for pushing the exposure head easily can be increased by shifting the rotation fulcrum, the head positioning stability can be improved.

  In each of the above-described embodiments, an example in which a long hole and a positioning hole are provided on the exposure head side and a post is formed on the image drum side is shown, but the present invention is not limited to this, for example, a post on the head side, Various forms can be taken, such as a structure in which holes are formed on the image drum side.

  In the above description of the embodiment, the words “up”, “down”, “left”, “right”, “front”, “back” are used for convenience, and image formation is performed. The absolute positional relationship in the state in which the device is arranged is not limited.

1 is a schematic configuration diagram showing a main configuration of Embodiment 1 of an image forming apparatus configured based on the present invention. FIG. 2 is a schematic configuration diagram schematically illustrating a black (K) image drum unit, a transfer roller, an exposure head, and printed recording paper. It is the external appearance perspective view which looked at the upper cover main body of the state from which the head holder and the exposure head were removed from diagonally downward. It is the block diagram which looked at the upper cover main body from the opposite side to FIG. It is principal part sectional drawing which shows roughly the principal part cross section which cuts the upper cover main body shown in FIG. 4 by QQ line. FIG. 3 is an external perspective view of a cover opening / closing mechanism that is rotatably held at a predetermined position of the image forming apparatus main body and locks an upper cover in a closed rotation position and opens the lock. FIG. 10 is an operation explanatory diagram illustrating a state in which the cover opening / closing mechanism is held by the image forming apparatus main body. It is the external appearance perspective view which looked at the head holder by this invention from diagonally downward. It is the external view which looked at the head holder shown in FIG. 8 from the arrow N direction. FIG. 9 is an external view of the head holder shown in FIG. 8 as viewed from the paper conveyance direction. It is principal part sectional drawing which shows roughly the cross section which cuts the head holder shown in FIG. 10 by a GG line. It is principal part sectional drawing which shows roughly the cross section which cuts the head holder shown in FIG. 10 by EE line. FIG. 12 is a partial cross-sectional view showing a cross section of the head holder shown in FIG. 11 taken along line G1-G1. It is a fragmentary sectional view which shows the cross section which cuts the head holder shown in FIG. 12 by G2-G2. It is the elements on larger scale which expanded the vicinity of a rotating shaft protrusion. It is explanatory drawing which shows the mounting positional relationship at the time of mounting | wearing a head holder with an upper cover main body. FIG. 4 is an external view of the exposure head as viewed from the side opposite to the paper transport direction, that is, from the fixing unit side. FIG. 18 is a partially enlarged top view in the vicinity of a right end portion in FIG. 17. It is a fragmentary sectional view which shows the cross section of the right end part vicinity which cuts an exposure head by the PP line of FIG. It is a perspective view of a cam. It is a perspective view of a support plate. FIG. 18 is a partially enlarged top view in the vicinity of the left end portion in FIG. 17. FIG. 23 is a partial cross-sectional view showing a cross section near the left end portion of the exposure head taken along the line PP in FIG. 22. It is a perspective view of a cam. It is a perspective view of a support plate. 1 is an external perspective view of an image drum unit according to the present invention. FIG. 6 is a diagram for explaining a relationship between a frame and a cam held by the exposure head when the upper cover is closed and the exposure head is mounted on the exposure head mounting portion of the image drum unit. FIG. 6 is a diagram for explaining a relationship between a frame and a cam held by the exposure head when the upper cover is closed and the exposure head is mounted on the exposure head mounting portion of the image drum unit. It is a figure for demonstrating the distance L between a photosensitive drum and a lens. It is operation | movement explanatory drawing used for operation | movement description when opening and closing an upper cover. It is operation | movement explanatory drawing with which it uses for operation | movement description when an upper cover is opened from the closed state. It is operation | movement explanatory drawing with which it uses for operation | movement description when an upper cover is closed from the open state. It is operation | movement explanatory drawing with which it uses for operation | movement description when an upper cover is closed from the open state. It is operation | movement explanatory drawing with which it uses for operation | movement description when an upper cover is closed from the open state. It is operation | movement explanatory drawing with which it uses for operation | movement description when an upper cover is closed from the open state. It is a block diagram which shows the attachment structure of the upper cover and head holder in the image forming apparatus of Embodiment 2 based on this invention. FIG. 12 is an operation explanatory diagram for explaining an operation when the upper cover is closed from the opened state in the second embodiment. FIG. 12 is an operation explanatory diagram for explaining an operation when the upper cover is closed from the opened state in the second embodiment. FIG. 12 is an operation explanatory diagram for explaining an operation when the upper cover is closed from the opened state in the second embodiment. It is a block diagram which shows the attachment structure of the upper cover and head holder in the image forming apparatus of Embodiment 3 based on this invention. FIG. 10 is an operation explanatory diagram for explaining an operation when the upper cover is closed from the opened state in the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 2 Hopping roller, 11 Paper tray, 12 Toner cartridge, 13 Conveyor belt unit, 13a Transfer belt, 14 Fixing unit, 15 Image drum unit, 15a Toner cartridge mounting part, 15b Opening, 15c Exposure head mounting part, 16 charging roller, 17 developing roller, 18 toner supply roller, 19 photosensitive drum, 21, 22 frames, 23a, 23b post, 25 stacker, 26 thickness center, 29 spring, 30 exposure head, 31a, 31b protrusion, 32 cam, 32a cylindrical end portions, 32b cam portion, 33 lens, 34 cover, 35 cam, 35a cylindrical intermediate portion, 35b cam portion, 36 support plate, 36a biasing portion, 37 oblong hole, 38 support plate, 38a biasing portion 39 Positioning holes, 43a, 43 Projection, 46 Upper surface, 47 Lower surface, 47a, 47b V-shaped groove, 50 Upper surface, 51, 52 Upper surface, 54 Head holder, 60 Lower surface, 61a, 61b Projection, 65 Rotation fulcrum, 67 Projection portion, 68 Lock release button, 70 Upper Cover, 78 cover opening / closing mechanism, 79 rotation shaft, 80 engagement hole, 88 guide portion, 89 rotation support shaft, 93 mounting surface, 94a, 94b rotation shaft protrusion, 97a, 97b guide groove, 98 guide portion, 102a, 102b side surface, 106 mounting position, 154 head holder, 170 upper cover, 201a, 201b spring, 701 mounting section, 702 mounting hole, 1100 paper transport path, 1101-1104 paper transport roller, 1111, developing section, 1112 toner storage section, 1113 Waste toner collection unit, 1114 toner 1115 residual toner, 1116 recording paper, 1117 been transferred toner, 1120 a cleaning blade, 1121 developing blade, 1122 the toner supply port, 1130 a transfer roller.

Claims (7)

In an image forming apparatus provided with a lid that can be freely opened and closed in the apparatus body,
A photoconductor unit, and a photoconductor unit provided in the apparatus main body having an exposure head mounting portion in which a fitting portion is disposed at least at one end portion;
An exposure head including a fitting portion to be fitted to the fitted portion;
When the exposure head is held and the lid body is closed, the fitting portion is rotatably supported by a rotation support portion provided in the lid body at a position where the fitting portion can be fitted to the fitted portion. An image forming apparatus comprising: a head holding member. The head holding member holds the exposure head displaceably within a predetermined range;
A plurality of first spring members that are spanned between the head holding member and the exposure head, and bias the exposure head toward the exposure head mounting portion when at least the lid is closed;
The image forming apparatus according to claim 1, wherein the plurality of first spring members are disposed on both sides of the rotation support portion in a longitudinal direction of the head holding member.   A second spring member is provided between the lid body and the head holding member, and biases the head holding member in a direction to return the lid body to a predetermined reference rotation position. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein the fitting portion is a positioning hole, and the fitted portion is a first post.   The exposure head mounting portion includes a second post at an end opposite to the end where the first post is formed, and the exposure head has a long hole that can be fitted to the second post. The image forming apparatus according to claim 4, wherein the image forming apparatus is provided.   6. The image forming apparatus according to claim 5, wherein in the longitudinal direction of the head holding member, the rotation holding portion is provided at a position closer to the positioning hole than a center between the center of each of the positioning hole and the long hole. .   The head holding member rotatably holds the first cam near one end on the side facing the exposure head mounting portion and the second cam near the other end, and the exposure head mounting portion The first piece is disposed at a position where the first cam can be brought into contact with the first cam, and the second piece is arranged at a position where the second piece can be brought into contact with the second cam. An image forming apparatus according to claim 1.

Images