JP5482215B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a facsimile, a printer, and a copying machine, and more particularly to an image forming apparatus in which a unit can be attached to and detached from the apparatus main body.

  In an image forming apparatus such as a facsimile, a printer, and a copying machine, in order to facilitate maintenance / inspection work or replacement work of each constituent member, the constituent members are unitized and detachable from the apparatus main body. Examples of these units include a photoreceptor unit, a developing unit, a charging unit, an intermediate transfer belt unit, and a cleaning unit.

  When transmitting the driving force from the main unit to the unit, when the unit is mounted on the main unit, the driven gear provided on the unit meshes with the driving gear provided on the main unit, and the driving force from the driving gear to the driven gear. Many mechanisms are used to transmit this.

  However, when the unit is mounted on the apparatus main body, the end surfaces of the driven gear and the drive gear abut each other, and the unit may not be normally mounted on the apparatus main body. In particular, when both gears are bevel gears, such a problem is likely to occur.

  Therefore, conventionally, as shown in FIG. 9, for example, the end faces of the two gears 91 and 92 to be engaged are chamfered so that the end faces of the gears can be smoothly engaged when the unit is mounted on the apparatus main body. I was doing. In Patent Document 1, a driving gear is provided so as to be movable in the direction of the rotation axis, and an urging means for urging the driving gear in the direction of removing the unit is provided. When the unit is mounted on the apparatus main body, the driven gear is driven. When the gear comes into contact with the gear, the driving gear moves backward while rotating against the biasing force, and when the gear is in a position where the gears mesh with each other, the driven gear rotates along the teeth of the driving gear and enters. Proposed.

JP 2004-78087 A

  However, in the method of chamfering the end face of the gear, the effective meshing width between the gears decreases. Therefore, in order to make the effective meshing width equal to or greater than a predetermined value, it is necessary to increase the gear width, which increases the size of the device. . Also in the proposed technique, it is necessary to secure a space in which the drive gear can retreat, and the apparatus becomes large.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to smoothly mesh the gears when the unit is mounted on the apparatus main body, and to increase the size of the apparatus. Another object is to provide an image forming apparatus.

An image forming apparatus according to the present invention that achieves the above object includes an apparatus main body including a first gear and a unit including a second gear, and the unit rotates relative to the apparatus main body. An image forming apparatus that is detachable in a direction, wherein the apparatus main body includes a guide member that guides attachment / detachment of the unit to / from the apparatus main body, and the guide member is inserted into the apparatus main body when the unit is inserted into the apparatus main body. However, by guiding the unit in a direction in which the distance between the rotation axes of the second gear and the first gear increases immediately before the second gear and the first gear overlap in the direction orthogonal to the rotation axis direction, When the first gear the unit is moved to a position that does not and meshing overlap in the direction orthogonal to the rotation axis direction, then the unit is especially to be moved from the position, in a position to mesh To.

  An urging member that urges the unit in a direction in which the second gear and the first gear mesh with each other may be further provided in the apparatus main body.

  Here, the guide member is a pair of rail-shaped members that guide while supporting both sides of the unit in the width direction, and a convex portion is provided on one of the pair of rail-shaped members, and the second gear and the second gear are provided by the convex portion. The unit may be inclined in a direction in which the distance between the rotation axes of the first gears is increased.

  Further, when a protrusion is formed in one of the apparatus main body and the unit, a hole is formed in the other, and the unit is inserted into the apparatus main body, the protrusion has a play in the hole. When the unit is urged by the urging member, the projection comes into contact with the peripheral surface of the hole, and the second gear and the first gear mesh with each other. Is preferably positioned.

  Further, when the mounting of the unit to the apparatus main body is completed, the unit may be out of contact with the guide member.

  The first gear and the second gear may be bevel gears.

In the image forming apparatus according to the present invention, when the unit is inserted into the apparatus main body, the unit is engaged from the position where the second gear and the first gear overlap and do not mesh in the direction orthogonal to the rotation axis direction. Therefore, the end faces of the first gear and the second gear do not collide with each other, the two gears mesh smoothly, and the size of the apparatus is not increased.

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a perspective view which shows the external appearance of an image formation unit. It is a general | schematic sectional view of an image formation unit. It is a perspective view which shows the structure of an apparatus main body. It is a figure which shows the through-hole and hole part which are formed by attaching an auxiliary | assistant frame to a rear side board. It is a perspective view of the apparatus main body part by which an image forming unit is attached or detached. FIG. 7 is an enlarged perspective view of the vicinity of the first gear in FIG. 6. It is a figure which shows the state change of an image formation unit at the time of attaching an image formation unit to an apparatus main body. It is a figure which shows the meshing | engagement of the gears which chamfered the edge part.

  Hereinafter, the image forming apparatus of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a schematic diagram showing an embodiment of an image forming apparatus according to the present invention. The image forming apparatus D in FIG. 1 is a so-called tandem color printer. Of course, in addition to a printer, the present invention can also be applied to a copying machine having a scanner, a facsimile, or a multi-function machine having these functions combined. Further, the image forming method is not limited to the tandem method, and other methods, for example, four developing devices are arranged around the rotation shaft, and these are sequentially opposed to the electrostatic latent image carrier to be full color. A so-called four-cycle method of creating an image or a monochrome method of creating a monochrome image with one developing device may be used.

  The image forming apparatus D includes an endless intermediate transfer belt 33 having conductivity. The intermediate transfer belt 33 is hung on a pair of rollers 31 and 32 disposed on both the left and right sides in the drawing. The roller 32 is connected to a motor (not shown), and the roller 32 rotates counterclockwise by driving the motor, whereby the intermediate transfer belt 33 and the roller 31 in contact therewith are driven to rotate. A secondary transfer roller 34 is in pressure contact with the outside of the belt portion supported by the roller 32. The toner image formed on the intermediate transfer belt 33 at the nip portion (secondary transfer region) between the secondary transfer roller 34 and the intermediate transfer belt 33 is transferred onto the conveyed paper P.

  A belt cleaning device 9 for cleaning the surface of the intermediate transfer belt 33 is provided outside the belt portion supported by the roller 31. The belt cleaning device 9 includes a cleaning blade that presses against the roller 31 via the intermediate transfer belt 33, and removes and collects untransferred residual toner at a contact portion of the cleaning blade with the intermediate transfer belt 33.

  Below the intermediate transfer belt 33 suspended between the rollers 31 and 32, yellow (Y), magenta (M), cyan (C), black ( K) four image forming units 2Y, 2M, 2C, and 2K (hereinafter, sometimes collectively referred to as “image forming unit 2”) are detachably disposed on the apparatus main body 10. In these image forming units 2, a toner image of a corresponding color is created using each color developer.

  The image forming unit 2 has a cylindrical photosensitive member 20 as an electrostatic latent image carrier. A charging device 21, a developing device 23, a primary transfer roller 24, and a photoconductor cleaning device 25 are arranged around the photoconductor 20 in this order along the rotation direction (clockwise direction). The photoconductor cleaning device 25 includes a cleaning blade 251 (shown in FIG. 3), and one end of the photoconductor cleaning device 25 is brought into contact with the outer peripheral surface of the photoconductor 20 to remove and collect toner remaining on the surface of the photoconductor 20. . The primary transfer roller 24 is in pressure contact with the photoconductor 20 with the intermediate transfer belt 33 interposed therebetween to form a nip portion (primary transfer region). An exposure device 22 is disposed below the image forming unit 2.

  In the embodiment shown in this figure, a roller charging type is used as the charging device 21, but the type of the charging device 21 is not particularly limited, and a corona discharge charging charger, a blade-shaped charging member, Of course, a brush-like charging member or the like may be used.

  Above the intermediate transfer belt 33, hoppers 26 </ b> Y, 26 </ b> M, 26 </ b> C, and 26 </ b> K that store toner to be supplied to the developing devices 23 of the respective colors are arranged. A paper feed cassette 50 is detachably disposed as a paper feed device below the exposure device 22. The sheets (sheets) P stacked and accommodated in the sheet feeding cassette 50 are sent one by one to the conveyance path in order from the uppermost sheet by the rotation of the sheet feeding roller 51 disposed in the vicinity of the sheet feeding cassette 50. The paper P sent out from the paper feed cassette 50 is conveyed to the registration roller pair 52 and is sent out to the secondary transfer area at a predetermined timing.

  The image forming apparatus D can be switched between a monochrome mode in which a monochrome image is formed using one color toner (for example, black) and a color mode in which a color image is formed using four color toners.

  An image forming operation example in the color mode will be briefly described. First, in each image forming unit 2, the outer peripheral surface of the photoreceptor 20 that is rotationally driven at a predetermined peripheral speed is charged by the charging device 21. Next, light corresponding to image information is projected from the exposure device 22 on the surface of the charged photoconductor 20 to form an electrostatic latent image. Subsequently, the electrostatic latent image is made visible by toner as a developer supplied from the developing device 23. When the toner image of each color formed on the surface of the photoreceptor 20 in this way reaches the primary transfer region by the rotation of the photoreceptor 20, the toner image is transferred from the photoreceptor 20 to the intermediate transfer belt in the order of yellow, magenta, cyan, and black. 33 is transferred (primary transfer) and superimposed.

  Residual toner remaining on the photoconductor 20 without being transferred to the intermediate transfer belt 33 is scraped off by the photoconductor cleaning device 25 and removed from the outer peripheral surface of the photoconductor 20.

  The superimposed four color toner images are conveyed to the secondary transfer region by the intermediate transfer belt 33. On the other hand, the paper P is conveyed from the registration roller pair 52 to the secondary transfer area in accordance with the timing. Then, the four color toner images are transferred (secondary transfer) from the intermediate transfer belt 33 to the paper P in the secondary transfer region. The paper P on which the four color toner images are transferred is conveyed to the fixing device 1. In the fixing device 1, the paper P passes through the nip portion between the fixing roller 11 and the pressure roller 12. During this time, the paper P is heated and pressurized, and the toner image on the paper P is melted and fixed on the paper P. The paper P on which the toner image is fixed is discharged to a paper discharge tray 54 by a discharge roller pair 53.

  On the other hand, residual toner remaining on the intermediate transfer belt 33 without being transferred onto the paper P is scraped off by the belt cleaning device 34 and removed from the outer peripheral surface of the intermediate transfer belt 33. Thereafter, the rotational drive of each photoconductor 20 and the intermediate transfer belt 33 is stopped.

  FIG. 2 is a perspective view of the image forming unit 2, and FIG. 3 is a schematic cross-sectional view of the image forming unit 2. As can be understood from FIG. 2, a cylindrical protrusion 28 is formed at the distal end of the image forming unit 2 in the insertion direction of the apparatus main body, and the photoreceptor 20 is exposed on the upper surface of the image forming unit 2. . A second gear 27 having an oblique diameter and substantially the same diameter as that of the photosensitive member 20 is attached to one end side of the photosensitive member 20. As can be understood from FIG. 3, the image forming unit 2 is formed by attaching a charging device 21, a developing device 23, and a photoconductor cleaning device 25 around the photoconductor 20. The developing device 23 includes a developing roller 231, a regulating member 233 that regulates the amount of developer to the developing area, and a supply roller 232 that supplies the developer to the developing roller 231, and a shaft formed on the photoreceptor 20. It is provided at the center so as to be swingable. The photoconductor cleaning device 25 includes a cleaning blade 251 mounted in a counter direction with respect to the rotation direction of the photoconductor 20, and residual toner on the photoconductor 20 scraped by the cleaning blade 251 into a waste toner box (not shown). And a screw member 252 to be conveyed.

  FIG. 4 is a perspective view of the structure 4 that is used in the image forming apparatus D of FIG. 1 and in which the front side plate 41, the rear side plate 42, and the frame 43 are connected. In FIG. 1, the front side of the paper surface is referred to as “front side”, and the back side of the paper surface is referred to as “rear side”. The structure 4 shown in FIG. 4 is assembled such that the lower end portion of the front plate 41 and the lower end portion of the rear plate 42 are connected by a frame 43 so that the front plate 41 and the rear plate 42 face each other substantially in parallel. Yes. A large opening 44 is formed in the front side plate 41, and the image forming unit 2 (shown in FIG. 2) enters and exits from the apparatus main body 10 (shown in FIG. 1). In addition, a plurality of holes are formed in the rear side plate 42, and various members constituting the apparatus are supported while being positioned on the rear side plate 42 by corresponding holes.

  On the other hand, since the image forming unit 2 needs to be supported with high positional accuracy, a through hole 61 (shown in FIG. 5) and a notch 62 are formed so as to cover predetermined holes formed in the front side plate 41 and the rear side plate 42. An auxiliary frame 6b formed with (shown in FIG. 5) is further attached. As a result, as shown in FIG. 5, the through hole 45 for projecting the first gear 82 (shown in FIG. 6) and the projection 28 (shown in FIG. 2) of the image forming unit 2 are engaged. A so-called home base-shaped hole 46 is formed.

  An exposure device 22 (shown in FIG. 1) is attached to the upper surface of the frame 43 of the structure 4 in FIG. 4, and a frame 7 (see FIG. 6) that detachably supports the image forming unit 2 on the upper side of the exposure device 22. Is shown). As shown in FIG. 6, a driving gear train 81 is disposed on the back side of the rear plate 42 and the auxiliary frame 6b, and transmits driving force to the image forming unit 2 from a through hole 45 (shown in FIG. 5). A first gear 82 for protruding is projected. The frame 7 is formed with a pair of rail-like members 71a (71b) that guides the image forming unit 2 while supporting both sides in the width direction when the image forming unit 2 is attached and detached. Further, when the image forming unit 2 is attached to the apparatus main body 10, a roller 72 and a roller 73 that press the bottom surface of the image forming unit 2 to urge the image forming unit 2 upward are paired with a pair of rail-like members 71a (71b). ) Between the front side and the rear side. The rollers 72 and 73 are urged upward by a pressing spring 75 (biasing member, shown in FIG. 8). And as shown in FIG. 7, the convex part 74 is formed in the rear side part of one rail-shaped member 71a. As a result, the inserted image forming unit 2 is tilted from the substantially horizontal state to one side. In addition, you may form the convex part 74 not only from a rear side part but from the front side part. Alternatively, the image forming unit 2 may be tilted to one side without forming the convex portions 74 by making the pair of rail-shaped members have different heights.

  Next, the movement of the image forming unit 2 when the image forming unit 2 is attached to the apparatus main body 10 in the image forming apparatus having such a configuration will be described. FIG. 8 shows a front view, a side sectional view, and a rear view of the image forming unit 2 showing a state when the image forming unit 2 is mounted on the apparatus main body 10.

First, the image forming unit 2 is inserted into the apparatus main body 10 while the bottom surface is supported by a pair of rail-like members 71a and 71b provided in the apparatus main body 10 (FIG. 8A). Then, immediately before the second gear 27 provided at the front end of the photoconductor 20 overlaps the first gear 82 provided in the apparatus main body 10 in the direction orthogonal to the rotation axis direction, one rail-like member 71a is provided. The bottom surface of the image forming unit 2 rides on the formed convex portion 74, and the image forming unit 2 is tilted in the direction in which the distance d between the rotation axes of the second gear 27 and the first gear 82 is increased ((b) in the figure). This prevents the end surfaces of the first gear 82 and the second gear 27 from abutting when the image forming unit 2 is inserted into the apparatus main body 10. The inclination degree of the image forming unit 2 can be adjusted by the height of the convex portion 74, and the distance d between the rotation axes is as short as possible within a range where the first gear 82 and the second gear 27 do not contact each other. This is desirable from the viewpoint of miniaturization of the apparatus.

  When the image forming unit 2 inclined to one side is further inserted into the apparatus main body 10, the roller 73 (roller 72) contacts the bottom surface of the image forming unit 2, and the image forming unit 2 rides on the roller 73 (roller 72). It moves upward ((b) in the figure). The urging force of the pressing spring 75 attached to the roller 73 (roller 72) is set to be larger than the weight of the image forming unit 2, and the image forming unit 2 comes into contact with the roller 73 (roller 72). Even do not shrink. At the same time, the protrusion 28 formed on the front side of the image forming unit 2 is engaged with the hole 46 formed on the rear plate 42 of the apparatus main body 10. Then, as the image forming unit 2 moves upward, the protrusion 28 of the image forming unit 2 moves along the inclined surface on the upper side of the hole 46. Thereby, the inclination of the image forming unit 2 due to the convex portion 74 is gradually eliminated, and at the same time, the second gear 27 and the first gear 82 gradually mesh with each other.

  When the image forming unit 2 is further inserted into the apparatus main body 10, the protrusion 28 of the image forming unit 2 enters the apex portion of the hole 46, and the upward movement of the image forming unit 2 is restricted and positioned. . Further, as a result of restricting the upward movement of the image forming unit 2, the roller 73 (the roller 72) moves downward against the urging force of the push spring 75 ((c) in the figure). Accordingly, the second gear 27 and the first gear 82 are normally meshed, and the image forming unit 2 is fixed in a state of being positioned on the apparatus main body 10. At this time, the image forming unit 2 is held in a state of being separated from the pair of rail-like members 71a and 71b, more specifically in a state of being separated from the pair of rail-like members 71a and 71b by the height of the convex portion 74 or more. The

  When the image forming unit 2 is removed from the apparatus main body 10, the state of the image forming unit 2 changes in the reverse order to the state change. That is, when the image forming unit 2 is pulled out from the state where it is mounted on the apparatus main body 10, the upward urging by the roller 73 (the roller 72) is gradually released, and the convex portion 74 is formed on one bottom surface of the image forming unit 2. The image forming unit 2 gradually tilts in the direction in which the gears are separated from the state in which the second gear 27 and the first gear 82 are engaged. When the image forming unit 2 is further pulled out from the apparatus main body 10, the contact between the bottom surface of the image forming unit 2 and the convex portion 74 is also released, and the image forming unit 2 is made substantially horizontal by the pair of rail-like members 71 a and 71 b. It will be retained. Thereafter, the image forming unit 2 is guided from the pair of rail-like members 71a and 71b and pulled out from the apparatus main body 10 while being held substantially horizontally.

  According to the image forming apparatus of the present invention, when the unit is mounted on the apparatus main body, both the gears can be smoothly meshed with each other without causing the end faces of the gears to collide with each other, and the size of the apparatus is not increased. Useful.

2 Imaging unit (unit)
D image forming apparatus 10 apparatus main body 27 second gear 28 protrusion 46 hole 71a, 71b rail-shaped member (guide member)
74 Convex part 75 Push spring (biasing member)
82 1st gear

Claims (6)

In an image forming apparatus having an apparatus main body including a first gear and a unit including a second gear, the unit being detachable from the apparatus main body in the direction of the rotation axis of the second gear.
The apparatus main body has a guide member for guiding attachment / detachment of the unit to / from the apparatus main body,
When the unit is inserted into the apparatus main body, the guide member moves between the rotation axis of the second gear and the first gear immediately before the second gear and the first gear overlap in the direction perpendicular to the rotation axis direction. By guiding the unit in the direction in which the distance increases, the second gear and the first gear move to a position where the second gear and the first gear overlap and do not mesh in the direction orthogonal to the rotation axis direction, and then the unit An image forming apparatus that moves from a position to a meshing position.   The image forming apparatus according to claim 1, wherein the apparatus main body further includes a biasing member that biases the unit in a direction in which the second gear and the first gear mesh. The guide member is a pair of rail-shaped members that guide while supporting both sides of the unit in the width direction, and a convex portion is provided on one of the pair of rail-shaped members, and the convex portion provides a second gear. the image forming apparatus according to claim 1 or 2, wherein tilting said unit in a direction rotating center distance between the first gear is increased. A protrusion is formed on one of the apparatus main body and the unit, a hole is formed on the other, and when the unit is inserted into the apparatus main body, the protrusion is engaged in a state where there is play in the hole. When the unit is urged by the urging member, the projection is brought into contact with the peripheral surface of the hole, and the unit is positioned at a position where the second gear and the first gear mesh. The image forming apparatus according to claim 2 . When mounted to the main assembly of the unit is completed, the image forming apparatus according to claim 1, wherein the unit is put into the guide member and the non-contact. The image forming apparatus according to any one of claims 1 to 5 first gear and the second gear is a helical gear.