JP4867956B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including an image forming unit that forms an image on a recording medium, and more specifically, a frame that supports the image forming unit fixes a sheet metal frame and a resin frame to each other at a plurality of fixing points. The present invention relates to an image forming apparatus configured as described above.

  Conventionally, in an image forming apparatus such as a laser printer, it has been considered that a photosensitive drum or the like constituting an image forming unit is supported by a frame formed by fixing a sheet metal frame and a resin frame to each other. That is, since the resin frame can be easily processed into a complicated shape, the degree of freedom in design can be increased. However, the resin frame has low rigidity. Therefore, by fixing the resin frame to a highly rigid sheet metal frame at a plurality of fixing points, the resin frame can be reinforced and the positional accuracy of each part can be improved.

  However, since the linear expansion coefficient differs between the resin frame and the sheet metal frame, the temperature change of the image forming apparatus causes a difference in the dimensions of the resin frame and the sheet metal frame between the plurality of fixed portions, and the two are mutually connected. The fixed frame may be warped. Therefore, it has been proposed to form a screw boss protruding on the opposite side of the sheet metal frame on the resin frame at the fixed location, and to form a recess recessed on the opposite side of the sheet metal frame around the screw hole of the screw boss. In this case, the screw boss can be bent and deformed in a direction along the surface of the sheet metal frame, and the above dimensional difference can be absorbed (see, for example, Patent Document 1).

In addition, as a configuration for absorbing a dimensional difference due to a difference in linear expansion coefficient, an annular groove is provided around the boss portion, and a bridge portion that can deform the outer portion and the boss portion facing each other with the annular groove interposed therebetween. It has also been proposed to connect via. In this case, when the bridge portion is bent and deformed, the boss portion can be displaced with respect to the outer portion, and a dimensional difference due to a difference in linear expansion coefficient can be absorbed (see, for example, Patent Document 2).
JP 2008-9260 A Japanese Utility Model Publication No. 60-32408

  However, in the configuration described in Patent Document 1, when the resin frame repeats thermal expansion / contraction, the screw may be displaced in the insertion direction, and the screw may be loosened. Moreover, when an annular groove and a bridge are provided around the boss portion as described in Patent Document 2, the apparatus becomes large in the direction of the joining surface between the sheet metal frame and the resin frame. Therefore, the present invention absorbs a dimensional difference due to a difference in linear expansion coefficient without increasing the size of the image forming apparatus having a frame in which a sheet metal frame and a resin frame are fixed to each other. The purpose was to suppress the loosening of the fixture due to the contraction.

  The image forming apparatus of the present invention made to achieve the above object is constituted by fixing an image forming means for forming an image on a recording medium, a sheet metal frame and a resin frame to each other at a plurality of fixing points. The sheet metal frame and the resin frame have reference points that are positioned at positions facing each other regardless of their thermal expansion / contraction, and are provided at the respective fixing points. A fixing tool is inserted into each of the drilled holes and fixed to each other. At least one of the fixing locations, the holes drilled in the resin frame are inserted from the opposite side of the sheet metal frame. Large in at least one direction so as to allow displacement of the resin frame in a direction approaching or separating from the reference point with respect to the fixture and the sheet metal frame. An annular contact that suppresses contact between the edge of the hole and the sheet metal frame by projecting in an annular shape surrounding the hole in the direction of the sheet metal frame and contacting the sheet metal frame. The fixing tool has an amount of insertion of the fixing tool into the hole, the head of the fixing tool is in close contact with or pressed against the edge, and the edge is pressed against the sheet metal frame. An insertion amount regulating means for regulating the amount of insertion not to be performed is provided.

  In the image forming apparatus of the present invention configured as described above, the frame that supports the image forming unit is configured by fixing the sheet metal frame and the resin frame to each other at a plurality of fixing points, and the sheet metal frame and the resin frame are , And a reference point positioned at a position facing each other regardless of thermal expansion / contraction. And in at least one of the fixing points, a hole that is formed in the resin frame and into which the fixing tool is inserted from the side opposite to the sheet metal frame is close to the fixing tool and the sheet metal frame from the reference point or The resin frame is configured to have a large diameter in at least one direction so as to allow the displacement of the resin frame in the direction of separation. For this reason, the resin frame can be displaced with respect to the fixture and the sheet metal frame at the fixing portion, and a dimensional difference due to a difference in linear expansion coefficient between the resin frame and the sheet metal frame can be absorbed.

  In addition, the resin frame is formed with an annular contact portion that protrudes in the direction of the sheet metal frame in an annular shape surrounding the hole of the fixed portion, and the annular contact portion contacts the sheet metal frame, thereby Contact between the edge and the sheet metal frame is suppressed. Further, the amount of insertion of the fixture into the hole is determined by the amount of insertion in which the head of the fixture is in close contact with or pressed against the edge by the insertion amount regulating means, and the edge is not pressed against the sheet metal frame. Regulated by

  Therefore, in a state where the fixture is inserted into the hole up to the insertion amount regulated by the insertion regulating means, the edge of the hole on the resin frame side is floated from the sheet metal frame by the annular contact portion, and the edge is fixed to the fixture. It can be brought into close contact or pressure contact with the head. By fixing the sheet metal frame and the resin frame in this way, the vicinity of the one fixed portion of the resin frame is caused to cause frictional force from the sheet metal frame via the annular contact portion and While receiving each frictional force from the head, it can move relative to the sheet metal frame within the range of the hole having a large diameter as described above.

  Accordingly, in the present invention, the sheet metal frame and the resin frame can be fixed with an appropriate strength while absorbing the dimensional difference due to the difference in linear expansion coefficient and suppressing the bending of the frame as described above. Further, in the present invention, since it is only necessary to provide the annular contact portion on the resin frame, the apparatus is not increased in size as compared with the case where the annular groove or the bridge portion is provided as described above, and the fixing tool due to thermal expansion / contraction is reduced. Since displacement in the insertion direction is difficult to occur, it is possible to suppress loosening of the fixture.

  Although the present invention is not limited to the following configuration, the resin frame and the sheet metal frame are mutually connected by a fixture that does not have the insertion amount regulating means at the fixing location closest to the reference point. It may be fixed so that it cannot be displaced. That is, the dimensional difference due to the difference in linear expansion coefficient is minimized at the fixed location closest to the reference point. Therefore, by adopting a general configuration for the holes and fixtures in such a fixing location, the manufacturing cost of the image forming apparatus can be reduced well.

  In this case, the fixture provided with the insertion amount regulating means is configured such that the head has a larger diameter than the fixture without the insertion amount regulating means, and the fixing location closest to the reference point. Then, on the side of the resin frame on which the fixture is inserted, the insertion of the fixture is permitted without interfering with the head of the fixture that does not have the insertion amount regulating means. The interference part which interferes with the head of the fixing tool provided with and prevents insertion of the fixing tool may be formed. In this case, if the fixing tool provided with the insertion amount regulating means is erroneously inserted into the hole of the resin frame at the fixing location closest to the reference point, the insertion is blocked by the interference portion. For this reason, at the time of assembling the frame, it is possible to prevent the operator from mistakenly fixing the fixture at the fixed location closest to the reference point and other fixed locations. Therefore, it is possible to improve the efficiency of the frame assembly work.

  In each of the image forming apparatuses, the image forming unit includes a plurality of image forming units arranged in series corresponding to a plurality of colors, and the reference point is located at the center of the image forming units at both ends. May be provided at a position close to the image forming unit. In this case, the sheet metal frame and the resin frame are positioned at positions facing each other regardless of their thermal expansion / contraction, at a reference point provided at a position close to the central image forming portion. For this reason, it is possible to suppress the color misregistration while maintaining the positional relationship of the image forming units corresponding to the respective colors as accurately as possible.

  In addition, on the side of the resin frame on which the fixing tool is inserted, a receiving portion that receives the fixing tool that has dropped from the hole may be formed around each hole. In this case, when the frame is assembled, when the fixing tool is inserted while the sheet metal frame or the resin frame is set up vertically, the fixing tool can be prevented from dropping to the work table. It can be suppressed by receiving. For this reason, the assembly work of a frame can be made efficient.

  Further, at the reference point, a shaft protruding from the resin frame or the sheet metal frame may be fitted into a positioning hole formed in the sheet metal frame or the resin frame. In this case, the sheet metal frame and the resin frame at the reference point can be positioned more accurately by the structure in which the shaft is fitted in the positioning hole.

1. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a central sectional view showing a configuration of a printer 1 as an example of an image forming apparatus to which the present invention is applied. In the following description, when referring to a direction, the direction shown in FIG. 1 is used as a reference. Moreover, the left-right direction and the width direction are the same direction.

  The printer 1 is a direct tandem type color LED printer. As shown in FIG. 1, in a main casing 2 as an example of a frame of the printer 1, four photosensitive drums 3 as examples of photosensitive members are arranged in series along the front-rear direction.

  In the following description, the four photosensitive drums 3 correspond to the respective colors (black, yellow, magenta, cyan) of the toner image, the photosensitive drum 3K (black), the photosensitive drum 3Y (yellow), and the photosensitive drum. The body drum 3M (magenta) and the photosensitive drum 3C (cyan) are distinguished as necessary. Each photoconductor drum 3 is provided with a scorotron charger 4, an LED unit 5, and a developing roller 6 facing each other.

  The surface of the photosensitive drum 3 is uniformly charged by the scorotron charger 4 and then exposed to light emitted from the LED unit 5. Thereby, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 3. The electrostatic latent image is visualized by toner carried on the developing roller 6, and a toner image as an example of a developer image is carried on the surface of the photosensitive drum 3.

  A sheet P as an example of a recording medium is accommodated in a sheet feeding cassette 7 in the main body casing 2. The paper P stored in the paper feed cassette 7 is fed to the transport belt 8 by various rollers. The conveyor belt 8 is disposed between the photosensitive drums 3K, 3Y, 3M, and 3C and the transfer roller 9 facing them. The toner image on the surface of each photoconductive drum 3 is transferred onto the paper P transported to the transport belt 8 by the transfer bias applied to the transfer roller 9 and sequentially overlapped.

  The sheet P on which the four color toner images are transferred is conveyed to the fixing unit 10. The toner image transferred onto the paper P is thermally fixed by the fixing unit 10. Thereafter, the paper P is discharged to the paper discharge tray 11 by various rollers.

2. Configuration of Process Cartridge Next, FIG. 2 is a rear left perspective view showing the configuration of a process cartridge 12 as an example of an image forming unit including the photosensitive drum 3 and the developing roller 6. FIG. 3 is a left side view showing the configuration of the developing cartridge 14 (with a gear cover 55 described later). FIG. 4 is a left side view showing the configuration of the developing cartridge 14 (with the gear cover 55 detached). FIG. 5 is a rear right perspective view showing the internal structure of the main casing 2 with the developing cartridge 14 removed.

  As shown in FIG. 1, the printer 1 includes four process cartridges 12 corresponding to the respective colors. In the following description, the four process cartridges 12 are distinguished from each other as a process cartridge 12K (black), a process cartridge 12Y (yellow), a process cartridge 12M (magenta), and a process cartridge 12C (cyan). .

  The process cartridges 12 are detachably mounted in the main casing 2 and are arranged in series along the front-rear direction. That is, the four process cartridges 12 are sequentially arranged in the main casing 2 so as to be the process cartridge 12K, the process cartridge 12Y, the process cartridge 12M, and the process cartridge 12C from the front to the rear.

A top cover 15 is provided on the upper wall of the main casing 2 together with the LED unit 5 so as to be freely opened and closed. Each process cartridge 12 can be attached to and detached from the main casing 2 by opening the top cover 15. As shown in FIGS. 1 and 2, the process cartridge 12 includes a drum cartridge 13 and a developing cartridge 14 that is detachably attached to the drum cartridge 13.
(1) Drum Cartridge The drum cartridge 13 includes a drum frame 16, a photosensitive drum 3 and a scorotron charger 4 provided on the drum frame 16. As shown in FIGS. 2 and 5, the drum frame 16 integrally includes a drum support portion 17 disposed on the lower rear side and a developing cartridge housing portion 18 disposed on the upper front side.
(1-1) Drum Support Unit The drum support unit 17 extends in the width direction and has a substantially box shape that opens from the lower rear side to the upper front side. The top wall 19 and the top wall 19 are spaced from each other. A bottom wall 20 disposed at a distance is provided, and a top wall 19 and both side walls 21 that connect both ends of the bottom wall 20 in the width direction are provided. The photosensitive drum 3 is disposed along the width direction between the top wall 19 and the bottom wall 20 and is rotatably supported on both side walls 21 (see FIG. 1).

  The left side wall 21 is provided with a drum-side input coupling 22 for driving the photosensitive drum 3 as shown in FIG. The drum-side input coupling 22 is coaxially disposed at the left end portion of the photosensitive drum 3 and is coupled to the photosensitive drum 3 so as not to be relatively rotatable. The drum-side input coupling 22 is provided so as to protrude leftward from the left side wall 21.

  The left side wall 21 is provided with a coupling cover 23 for protecting the drum side input coupling 22. The coupling cover 23 has a substantially cylindrical shape and is provided so as to protrude leftward from the left side wall 21 so as to surround the drum-side input coupling 22.

  The coupling cover 23 is formed such that an upper end surface on the front side (hereinafter referred to as a front upper end surface 24 of the cover) protrudes leftward from an end surface on the lower side of the rear side (hereinafter referred to as a rear lower end surface 25 of the cover). ing. The front upper end surface 24 of the cover is formed in a substantially U shape with the rear lower portion opened in the left side view. The rear lower end surface 25 of the cover is formed in a substantially U shape with the front upper part opened in the left side view.

  Between the cover front upper end surface 24 and the cover rear lower end surface 25, there is provided a cover inclined end surface 26 that is inclined rightward from the front upper side toward the rear lower side. The cover inclined end surfaces 26 are provided at intervals so as to sandwich the drum-side input coupling 22. The cover inclined end surface 26 includes a cover inclined end surface 26 on the lower front side and a cover inclined end surface 26 on the rear upper side, which connect both ends of the cover front upper end surface 24 and both ends of the cover rear lower end surface 25 respectively. Yes.

The outer peripheral edge 27 of the semicircular arc portion defined by the front lower half portion of the cover rear lower end surface 25, the front lower cover inclined end surface 26, and the front lower half portion of the cover front upper end surface 24 is formed from the lower rear side. It inclines so that it may curve in a circular arc shape toward the front upper side. Further, the scorotron charger 4 (see FIG. 1) extends along the width direction and is supported by the top wall 19.
(1-2) Developing Cartridge Storage Unit As shown in FIGS. 2 and 5, the developing cartridge storage unit 18 is disposed to face each other with an interval in the width direction so that the developing cartridge 14 is detachably mounted. Both side walls 31 and a front upper wall 32 constructed along the front upper end of both side walls 31. Note that the side walls 31 of the developing cartridge housing portion 18 are formed continuously with the side walls 21 of the drum support portion 17.

  The left side wall 31 is provided with a coupling insertion plate 33 arranged further to the left from the side wall 31. The coupling insertion plate 33 is formed continuously with the left side wall 31, and is formed in a substantially rectangular shape extending in parallel with the left side wall 31 on the left side of the left side wall 31. The coupling insertion plate 33 is disposed to face the development side input coupling 56 (described later) in the width direction.

The front lower portion of the coupling insertion plate 33 is formed wider than the rear upper portion, and the opening 34 having a substantially circular shape in side view so that the developing side output coupling 79 can be inserted into the front lower portion. Is formed. Moreover, the upper end edge 35 of the rear upper part of the coupling insertion plate 33 is inclined from the rear upper part to the front lower part. Furthermore, the front upper wall 32 is provided between the side walls 31 so as to be curved along the front upper end portion of the side walls 31.
(2) Developer Cartridge The developer cartridge 14 includes a housing 40, and a developing roller 6, a supply roller 41, a layer thickness regulating blade 42, and an agitator 43 provided in the housing 40 (see FIG. 1). ).
(2-1) Housing The housing 40 is formed in a box shape that is opened at the lower rear side. In the case 40, as shown in FIG. 1, the space above the front side is partitioned as a toner storage chamber 44 for storing toner, and the space below the back side is partitioned as a developing chamber 45 where the developing roller 6 and the like are provided. Has been.

  The toner storage chamber 44 is filled with toner, and an agitator 43 is rotatably provided. The agitator 43 includes an agitator shaft 46 and a stirring blade 47 that extends from the agitator shaft 46 in the radial direction. The agitator 43 is rotatably supported by the casing 40 by both ends of the agitator shaft 46 being rotatably supported by both side walls 52 (see FIG. 2) of the casing 40.

  In the developing chamber 45, a developing roller 6, a supply roller 41, and a layer thickness regulating blade 42 are provided. The developing roller 6 is disposed at the lower rear end of the housing 40 so as to be exposed from the lower rear side of the housing 40. The developing roller 6 includes a developing roller shaft 48 and a rubber roller 49 provided around the developing roller shaft 48. The developing roller 6 is rotatably supported by the housing 40 by both ends of the developing roller shaft 48 being rotatably supported by both side walls 52 of the housing 40.

The supply roller 41 is disposed to face the upper front side of the developing roller 6. The supply roller 41 includes a supply roller shaft 50 and a sponge roller 51 provided around the supply roller shaft 50. The supply roller 41 is rotatably supported by the housing 40 by both ends of the supply roller shaft 50 being rotatably supported by both side walls 52 of the housing 40. The base end portion of the layer thickness regulating blade 42 is supported by the housing 40, and the distal end portion thereof is pressed against the developing roller 6 from above.
(2-2) Gear Mechanism Portion As shown in FIG. 4, the developing cartridge 14 includes a gear mechanism portion 54 for rotating the developing roller 6, the supply roller 41, and the agitator 43, and as shown in FIG. A gear cover 55 that covers the gear mechanism 54 is provided.

  That is, as shown in FIG. 4 in which the gear cover 55 is omitted in FIG. 3, the gear mechanism portion 54 is provided on the left side wall 52 of the housing 40. The gear mechanism section 54 includes a developing side input coupling 56, a supply roller gear 57, a first intermediate gear 58, a developing roller gear 59, a second intermediate gear 60, an agitator gear 61, and a detection gear 62.

  The developing side input coupling 56 is disposed between the developing roller shaft 48 and the agitator shaft 46 and is rotatably supported on the left side wall 52. The supply roller gear 57 meshes with the development side input coupling 56 below the development side input coupling 56, and is provided at the shaft end portion of the supply roller shaft 50 so as not to be relatively rotatable.

  The first intermediate gear 58 meshes with the supply roller gear 57 at the lower rear side of the supply roller gear 57 and is rotatably supported on the left side wall 52. The developing roller gear 59 meshes with the first intermediate gear 58 below the first intermediate gear 58 and is provided at the shaft end portion of the developing roller shaft 48 so as not to be relatively rotatable.

  On the other hand, the second intermediate gear 60 meshes with the development side input coupling 56 at the rear upper side of the development side input coupling 56 and is rotatably supported by the left side wall 52. The agitator gear 61 meshes with the second intermediate gear 60 at the upper front side of the second intermediate gear 60 and is provided at the shaft end portion of the agitator shaft 46 so as not to be relatively rotatable.

  The detection gear 62 is disposed above the front side of the agitator gear 61 and is rotatably supported on the left side wall 52. As shown in FIGS. 4 and 6, the detection gear 62 includes a disc-shaped main body 63, a missing gear 64 provided on the right side surface of the main body 63, and a detection projecting leftward from the main body 63. The unit 65 is integrally provided.

  The main body 63 is provided with a substantially cylindrical support cylinder 66 that protrudes rightward from the center thereof. A support shaft (not shown) protruding leftward from the left side wall 52 is inserted into the support cylinder portion 66 so as to be relatively rotatable. As a result, the detection gear 62 is rotatably supported on the left side wall 52.

  The toothless gear 64 is formed in a substantially cylindrical shape that protrudes rightward from the main body 63. The toothless gear 64 has a toothed portion 67 and a toothless portion 68 defined along the outer peripheral surface of the toothless gear 64. The tooth portion 67 is partitioned over about 2/3 of the outer peripheral surface of the toothless gear 64, and the toothless portion 68 extends over about 1/3 of the outer peripheral surface of the toothless gear 64. It is divided as a part without. An agitator gear 61 meshes with the tooth portion 67, and the driving force from the agitator gear 61 is transmitted. The agitator gear 61 does not mesh with the toothless portion 68, and transmission of driving force from the agitator gear 61 is interrupted.

  The detection unit 65 includes a cylindrical portion 69 that protrudes leftward from the axis of the main body 63 and two protrusions 70 that protrude toward the left from the left end portion of the cylindrical portion 69. Each protrusion 70 is formed in a substantially L-shape that extends in the radial direction from the outer peripheral surface of the cylindrical portion 69 and then protrudes to the left. The two protrusions 70 are arranged so as to form an obtuse angle with respect to the cylindrical portion 69.

  In addition, the protrusion 70 has a tooth portion so that it can come into contact with a contact portion 85 (described later) while the detection gear 62 can rotate, that is, while the tooth portion 67 is engaged with the agitator gear 61. 67 is set.

  In the detection gear 62, a coil spring (not shown) is wound around the support cylinder portion 66 of the main body portion 63, and the downstream end portion in the rotation direction of the tooth portion 67 is always engaged with the agitator gear 61. Thus, the detection gear 62 is urged. Therefore, the tooth portion 67 and the agitator gear 61 are meshed with each other since the developing cartridge 14 is new.

  As shown in FIG. 3, the gear cover 55 is provided on the left side wall 52 of the developing cartridge 14 so as to cover the gear mechanism portion 54. The gear cover 55 is cut out so as to expose the developing roller gear 59. A gear cover opening 71 for exposing the developing side input coupling 56 is formed below the gear cover 55. Further, a detection gear cover portion 72 that covers the detection gear 62 is formed on the upper side of the gear cover 55.

The detection gear cover portion 72 is formed so as to bulge toward the left so that the detection gear 62 can be accommodated, and a protruding portion that moves in the circumferential direction along with the rotation of the detection gear 62 at the lower portion on the rear side. A substantially rectangular detection window 73 for exposing 70 is opened.
(2-3) Mounting of Developer Cartridge to Drum Cartridge Then, when the developer cartridge 14 is mounted in the developer cartridge housing portion 18, the developing roller 6 is located on the front side of the photosensitive drum 3 as shown in FIG. It is pressed from. Further, as shown in FIG. 2, the development side input coupling 56 faces the opening 34 of the coupling insertion plate 33 in the width direction, and the development side input cup via the opening 34 of the development side output coupling 79. Advance and retreat with respect to the ring 56 is allowed.

3. Structure of Main Body Casing A pair of resin frames 300 (only the left resin frame 300 is shown in FIG. 5) are arranged in the main body casing 2 in the width direction with an interval at which the process cartridge 12 can be mounted. Yes. A sheet metal frame 100 as an example of a sheet metal frame is disposed between the resin frame 300 and the process cartridge 12 as will be described later, but the sheet metal frame 100 is omitted in FIG.

  A pair of resin frames 300 are formed with guide portions 77 for guiding the attachment and detachment of the process cartridge 12. The guide portions 77 are respectively provided at intervals in the front-rear direction corresponding to the four process cartridges 12. Each guide portion 77 is formed of a rib that protrudes inward in the width direction from the resin frame 300 so as to incline from the front upper side to the rear lower side.

The process cartridge 12 is guided to a guide portion 77 and a guide hole 101 (see FIG. 7) described later, and is attached to the main casing 2 along a direction from the front upper side to the rear lower side (hereinafter referred to as a mounting direction). The Further, the process cartridge 12 is detached from the main casing 2 along a direction from the lower rear side to the upper front side (hereinafter, referred to as a separation direction). In the following description, the attaching / detaching direction includes both the attaching direction and the detaching direction.
(1) Drum-side output coupling and development-side output coupling The left resin frame 300 is provided with four drum-side output couplings 78 corresponding to the four drum-side input couplings 22 (FIG. 2). Each drum-side output coupling 78 is disposed so as to face each drum-side input coupling 22 from the left side when the process cartridge 12 is attached to the main body casing 2.

  As shown by the arrow in FIG. 2, the drum-side output coupling 78 advances to the right side toward the drum-side input coupling 22 and is fitted to the drum-side input coupling 22 in conjunction with the closing of the top cover 15. In conjunction with the opening of the top cover 15, the drum side input coupling 22 is retracted to the left. Further, a motor (not shown) provided in the main body casing 2 is connected to the drum side output coupling 78, and a driving force from the motor is transmitted.

  The left resin frame 300 is provided with four development-side output couplings 79 corresponding to the four development-side input couplings 56 (see FIG. 2). Each developing-side output coupling 79 is disposed so as to face each developing-side input coupling 56 from the left side when the process cartridge 12 is attached to the main casing 2.

  As shown by the arrow in FIG. 2, the development side output coupling 79 is advanced rightward toward the development side input coupling 56 in conjunction with the closing of the top cover 15, and the opening of the coupling insertion plate 33. It is fitted to it via 34. Further, in conjunction with the opening of the top cover 15, it is retracted to the left from the development side input coupling 56. Furthermore, a motor (not shown) provided in the main body casing 2 is connected to the development side output coupling 79, and a driving force from the motor is transmitted.

The configuration for moving the drum-side output coupling 78 and the development-side output coupling 79 to advance / retreat as described above and the configuration for transmitting the driving force of the motor to them will be described in detail later.
(2) Information Transmission and Detection Mechanism for Developing Cartridge As shown in FIGS. 5 and 6, the resin frame 300 is provided with a swing member 80 and an optical sensor 81.
(2-1) Oscillating Member As shown in FIG. 5, four oscillating members 80 are provided corresponding to the four process cartridges 12 in the left resin frame 300. Each swinging member 80 is disposed so as to face each detection gear 62 from the left side when the process cartridge 12 is attached to the main casing 2. As shown in FIG. 6, the swing member 80 is integrally provided with a swing shaft 82 and a swing lever 83 provided on the swing shaft 82.

  The swing shaft 82 has a round bar shape, and is disposed so as to extend along a direction parallel to the attaching / detaching direction, as shown in FIG. 5, and is rotatably supported by the left resin frame 300. As shown in FIG. 6, the swing lever 83 has a mounting portion 84 attached to the swing shaft 82, a projecting contact portion 85 that extends from the mounting portion 84 to the front upper side, and a rear lower side from the mounting portion 84. Arm portion 86.

  The attachment portion 84 is formed in a flat plate shape, is disposed so as to be orthogonal to the axial direction of the swing shaft 82, and is integrally attached to the swing shaft 82. The abutting portion 85 is formed in a flat plate shape and is disposed above the mounting portion 84, and its right end protrudes to the right from the mounting portion 84 and tapers toward the right. It is formed in a V shape. Specifically, in a normal state (described later), the contact portion 85 is disposed along a direction parallel to the attachment / detachment direction in the right side view, and the right end portion thereof is angled with each other along the attachment / detachment direction. Are formed, that is, a front upper end surface 91 and a rear lower end surface 92 are formed.

  The front upper end surface 91 is formed so as to protrude toward the process cartridge 12 from the upstream side toward the downstream side in the mounting direction. Further, the ridge line portion that defines the rear upper edge of the front upper end surface 91 is defined as a mounting side contact portion 93 that contacts the outer peripheral edge 27 of the coupling cover 23 of the process cartridge 12 at the time of mounting. The mounting side contact portion 93 is inclined so as to protrude toward the process cartridge 12 from the upstream side toward the downstream side in the mounting direction.

  The rear lower end surface 92 is formed so as to protrude toward the process cartridge 12 from the upstream side toward the downstream side in the separation direction. Further, the ridge line portion defining the rear upper end edge of the rear lower end surface 92 is defined as a separation side contact portion 94 that comes into contact with the upper end edge 35 of the coupling insertion plate 33 of the process cartridge 12 at the time of separation. The separation side contact portion 94 is inclined so as to protrude toward the process cartridge 12 from the upstream side toward the downstream side in the separation direction.

  The arm portion 86 is formed in a substantially elongated flat plate shape and is disposed so as to extend downward from the left end portion of the mounting portion 84. A substantially rectangular light shielding plate 87 that protrudes rearward is provided at the lower end of the arm portion 86.

In the swing member 80, a coil spring (not shown) is wound around the swing shaft 82, and the contact portion 85 is always urged so as to protrude rightward from the left resin frame 300. That is, the contact portion 85 is normally disposed in the attachment / detachment locus of the process cartridge 12 with respect to the main body casing 2.
(2-2) Optical Sensor Four optical sensors 81 are provided corresponding to the four swing members 80 in the left resin frame 300. Specifically, the optical sensor 81 is provided on a substrate (not shown) attached to the right side surface of the left resin frame 300. As shown in FIG. 6, the optical sensor 81 is disposed so as to face the swing member 80 from the left side.

  The optical sensor 81 is formed in a U shape in sectional view, and the bottom of the U shape is fixed to the substrate, and the light emitting element 88 and the light receiving element 89 are spaced from each other at both ends of the U shape. It is provided so as to face each other.

  In the optical sensor 81, when the swing member 80 is in a normal state (see FIG. 6A), a light shielding plate 87 is disposed between the light emitting element 88 and the light receiving element 89. Therefore, the detection light emitted from the light emitting element 88 is shielded by the light shielding plate 87 and the light reception by the light receiving element 89 is blocked. On the other hand, when the swinging member 80 swings so that the abutting portion 85 moves forward and downward against the urging force of a coil spring (not shown) (see FIG. 6D), the light is blocked. The plate 87 is retracted from between the light emitting element 88 and the light receiving element 89. Therefore, the detection light emitted from the light emitting element 88 is received by the light receiving element 89. In this manner, the optical sensor 81 detects the swing of the swing member 80. The detection signal of the light receiving element 89 corresponds to whether or not the developing cartridge 14 is new as follows, and is input to a CPU (not shown) and applied to various controls.

4). Operation of attaching / detaching process cartridge and detecting operation of information on developing cartridge Next, an operation of attaching / detaching the process cartridge 12 to which the new developing cartridge 14 is attached to the main casing 2 and information on the attached process cartridge 12 will be described. The operation to be detected will be described.
(1) Mounting operation of process cartridge to main body casing When the top cover 15 (see FIG. 1) is opened and the process cartridge 12 is mounted to the main body casing 2, the abutting portion 85 is normally in the process cartridge 12 during the mounting. The outer peripheral edge 27 of the coupling cover 23 of the process cartridge 12 (specifically, the outer peripheral edge defined by the front lower half portion of the rear lower end face 25 of the cover) 27) abuts on the mounting side contact portion 93 of the abutment portion 85.

  Then, the contact portion 85 receives a pressing force and resists the urging force of a coil spring (not shown) so as to retract from the attachment / detachment locus of the process cartridge 12 using the swing shaft 82 as a swing fulcrum. It is swung downward on the front side. As a result, the contact portion 85 is retracted from the attachment / detachment locus of the process cartridge 12, and the attachment of the process cartridge 12 to the main casing 2 is allowed.

When the coupling cover 23 of the process cartridge 12 passes through the contact portion 85, the contact portion 85 uses the swing shaft 82 as a swing fulcrum by the biasing force of a coil spring (not shown). Is swung upward and rearward so as to advance into the attachment / detachment locus. As a result, the contact portion 85 is again placed in the normal state.
(2) Operation for detecting transmission of information relating to developing cartridge Next, when the top cover 15 is closed after the process cartridge 12 is mounted, the warming-up operation is then started under the control of the CPU, and the agitator 43 is rotated. A turning operation is performed. That is, a motor (not shown) provided in the main body casing 2 is driven, and the driving force is transmitted to the drum side output coupling 78 and the development side output coupling 79.

  Then, the driving force is transmitted to the drum-side input coupling 22 in which the drum-side output coupling 78 is fitted, and the photosensitive drum 3 is rotated. The driving force is transmitted to the development side input coupling 56 in which the development side output coupling 79 is fitted, and the development roller 6, the supply roller 41, and the agitator 43 are rotated.

  Then, the supply roller gear 57 meshing with the developing side input coupling 56 is rotated, and the supply roller 41 is rotated. Further, the developing roller gear 59 meshing with the developing side input coupling 56 via the first intermediate gear 58 is rotated, and the developing roller 6 is rotated. Further, the agitator gear 61 that meshes with the developing side input coupling 56 via the second intermediate gear 60 is rotated, and the agitator 43 is rotated. As the agitator 43 rotates, the toner in the toner storage chamber 44 is stirred and fluidized.

  Further, along with the rotation of the developing side input coupling 56, the rotational driving force is transmitted to the detection gear 62 meshing with the agitator gear 61, and the detection gear 62 is rotationally driven by a predetermined driving amount from the rotational driving start to the rotational driving stop. Is done.

  That is, as shown in FIG. 6, the detection gear 62 is only while the agitator gear 61 and the tooth portion 67 are engaged, that is, from the upstream end portion in the rotational direction of the tooth portion 67 to the downstream end portion in the rotational direction. Is rotated in the direction of the arrow only during. Specifically, the detection gear 62 stops after rotating about 2/3 in one direction corresponding to the tooth portion 67. The detection gear 62 is maintained in a stopped state by a stopper (not shown).

  Then, when the rotation of the detection gear 62 is started, as shown in FIG. 6B, along with the rotation of the detection gear 62, the two protrusions 70 move in the circumferential direction along the front-rear and vertical directions. The protrusion 70 on the front side of the detection gear 62 abuts against the abutting portion 85 in a normal state from the upper rear side toward the lower front side.

  Then, as shown in FIG. 6 (c), the swing lever 83 uses the swing shaft 82 as a swing fulcrum and resists the urging force of a coil spring (not shown), so that the contact portion 85 is moved downward on the front side. And it swings along the front-back and left-right direction so that the arm part 86 goes to the rear side upper direction. Then, the light shielding plate 87 disposed between the light emitting element 88 and the light receiving element 89 of the optical sensor 81 is moved to the right rear side so as to retract from between them.

  When the swing lever 83 further swings, as shown in FIG. 6D, the light shielding plate 87 is retracted from between the light emitting element 88 and the light receiving element 89 and is shielded by the light shielding plate 87 until then. The detected light is received by the light receiving element 89.

  Thereafter, when the contact of the front-side protrusion 70 with the contact portion 85 is released, the swing lever 83 is applied by the biasing force of a coil spring (not shown) with the swing shaft 82 as a swing fulcrum. The swinging member 80 is returned to the normal state by swinging so that the contact portion 85 is upward on the rear side and the arm portion 86 is downward on the front side. Then, the detection light is shielded by the light shielding plate 87, and reception of the detection light by the light receiving element 89 is blocked.

  Although not shown, the detection gear 62 rotates until the rear projection 70 abuts against the abutment 85 and is released until the abutment gear 61 and the teeth are released. The meshing with the portion 67 is released, and the rotation of the agitator gear 61 and the toothless portion 68 is opposed to each other. Thereby, the warm-up operation including the glass turning operation is completed.

  At this time, similarly to the above, the light shielding plate 87 is temporarily retracted from between the light emitting element 88 and the light receiving element 89, and the detection light is once received by the light receiving element 89. Is shielded by the light shielding plate 87, and the light receiving element 89 receives the detection light. As a result, information that the developing cartridge 14 is new is transmitted from the detection gear 62 to the optical sensor 81 via the swing member 80.

  On the other hand, even when the process cartridge 12 is once detached by removing the jammed paper P and mounted again, the detection gear 62 is opposed to the missing tooth portion 68 and the agitator gear 61 by a stopper (not shown). The stop state is maintained as arranged. For this reason, even if the process cartridge 12 is remounted and the gear wheel is rotated, the detection gear 62 is not rotated and the above information is not detected.

5. Next, as shown in the exploded perspective view of FIG. 7, a sheet metal frame 100 that supports the process cartridge 12 is fixed inside the pair of left and right resin frames 300, and the left side is shown. The drum drive metal plate 200 is fixed to the outside (left side) of the resin frame 300. In FIG. 7, only the left resin frame 300 and the sheet metal frame 100 are shown. Although not shown, the electric system of the printer 1 is fixed to the outside (right side) of the right resin frame 300 instead of the drum drive metal plate 200.

  As shown in FIG. 7, the pair of left and right sheet metal frames 100 have guide holes 101 for guiding and positioning the process cartridge 12, and are connected to each other by four flanged pipes 110 extending in the width direction. A fixed / separate linear motion cam 120 is provided inside each sheet metal frame 100 to switch the pressure roller / contact of the developing roller 6 against the photosensitive drum 3 by sliding in the front-rear direction. The configuration of the fixed / separating linear cam 120 is detailed in, for example, Japanese Patent Application Nos. 2007-340751, 2007-340761, and 2007-340762.

The drum drive metal plate 200 includes a gear train 210 for transmitting the driving force of the motor to each of the four drum-side output couplings 78 and the development-side output couplings 79. A side output coupling 79 is rotatably supported. Further, a driving linear motion cam 220 for advancing / retracting the drum side output coupling 78 and the development side output coupling 79 as described above is mounted on the resin frame 300 so as to be able to reciprocate linearly in the front-rear direction.
(2) Driving linear motion cam Next, the configuration of the driving linear motion cam 220 will be described. FIG. 8A is a perspective view illustrating the configuration of the driving linear cam 220, and FIGS. 8B and 8C are plan views illustrating the operation of the driving linear cam 220.

  As shown in FIG. 8, the drive linear cam 220 is a member that extends long in the front-rear direction, and is attached to the resin frame 300 (see FIG. 7) so as to be capable of reciprocating linear movement in the front-rear direction. Further, as shown in FIG. 8, the driving linear motion cam 220 includes a rectangular plate-like main body portion 221 elongated in the front-rear direction, four first cam portions 222 formed integrally with the main body portion 221, and And four second cam portions 223 formed integrally with the main body portion 221.

  The main body 221 is provided in parallel with the resin frame 300. The main body 221 has four insertion / extraction holes 224 at positions facing the four development-side output couplings 79 in the left-right direction. Each insertion / extraction hole 224 is formed in the shape of a long hole extending in the front-rear direction, and has a dimension that allows the front end of the development-side output coupling 79 to be inserted / removed in the vertical direction. As shown in FIGS. 8A and 8B, in the state where the driving linear cam 220 is disposed at a relatively forward position, the development-side output coupling 79 is provided at the rear end of each insertion / extraction hole 224. opposite. On the other hand, as shown in FIG. 8C, the development-side output coupling 79 faces the front end portion of each insertion / extraction hole 224 in a state where the driving linear cam 220 is disposed at a relatively rear position.

  The first cam portion 222 is provided on the left side surface (surface opposite to the surface facing the resin frame 300) of the main body portion 221 corresponding to each insertion / extraction hole 224. The first cam portion 222 is formed in a substantially U shape in a side view along a substantially half circumference on the front side at the periphery of the insertion / extraction hole 224. Further, as shown in FIG. 8, the first cam portion 222 has an inclined portion 225 that is inclined so as to be separated from the main body portion 221 toward the front, and a flat portion 226 that is parallel to the main body portion 221 from the front end of the inclined portion 225. And is formed in a substantially trapezoidal shape in plan view.

  The second cam portion 223 is provided at the lower end portion of the left side surface of the main body portion 221 corresponding to each drum-side output coupling 78. As shown in FIGS. 8B and 8C, the second cam portion 223 is formed behind each first cam portion 222 so as not to overlap the first cam portion 222 in plan view. Further, as shown in FIGS. 8B and 8C, the second cam portion 223 includes an inclined portion 227 that is inclined so as to be separated from the main body portion 221 toward the front, and the main body portion 221 from the front end of the inclined portion 227. And a flat portion 228 that is parallel to the surface, and is formed in a substantially trapezoidal shape in plan view.

  As shown in FIGS. 8A and 8B, in the state where each first cam portion 222 is positioned forward with respect to each development side output coupling 79, the tip of each development side output coupling 79 is The rear end of the insertion / extraction hole 224 is inserted, and the flange 79 a is in contact with the left side surface of the main body 221 of the driving linear motion cam 220. That is, each developing-side output coupling 79 is provided so as to be able to advance and retreat in the left-right direction with respect to the gear train 210, and has a flange 79a in the vicinity of the tip, and is biased in the advance direction (right direction) by the coil spring 79b. ing. Therefore, in the state where the first cam portions 222 and the development-side output couplings 79 do not overlap in the left-right direction as described above, the flange portion 79a contacts the left side surface of the main body portion 221 by the action of the coil spring 79b. The development side output coupling 79 advances to the position.

  The drum-side output coupling 78 is provided so as to be able to advance and retreat in the left-right direction with respect to the gear train 210. A step surface 78a is provided in the vicinity of the tip, and is energized in the advancing direction (right direction) by a coil spring (not shown). Has been. As described above, in the state where each first cam portion 222 is positioned in front of each developing-side output coupling 79, the step surface 78a abuts on the left side surface of the main body portion 221 of the drive linear cam 220. The front end of the drum-side output coupling 78 protrudes to the right with respect to the main body 221 below the main body 221. That is, in this state, the drum-side output coupling 78 and the development-side output couplings 79 all extend to the right and are fitted to the drum-side input coupling 22 and the development-side input coupling 56. .

  Next, when the driving linear cam 220 is moved rearward from this state, the inclined portion 225 of each first cam portion 222 comes into contact with the flange portion 79a of each developing-side output coupling 79, and each second The inclined portion 227 of the cam portion 223 contacts the step surface 78 a of each drum-side output coupling 78.

  When the driving linear cam 220 is further moved rearward, each flange 79a rides on the inclined portion 225 of each first cam portion 222, and each developing-side output coupling 79 is subjected to the biasing force of the coil spring 79b. Move in the retracting direction (left direction). Further, the stepped surface 78a of each drum-side output coupling 78 rides on the inclined portion 227 of each second cam portion 223, and each drum-side output coupling 78 also resists the biasing force of a coil spring (not shown). To move in the retreat direction (left direction).

  In the state shown in FIG. 8C, the flange 79 a comes into contact with the flat portion 226 of the first cam portion 222, and only the front end portion of the development side output coupling 79 is inserted into the front end portion of the insertion / extraction hole 224. Yes. Further, each drum-side output coupling 78 has a stepped surface 78 a that abuts against the flat portion 228 of the second cam portion 223, and only the tip of the drum-side output coupling 78 is slightly to the right with respect to the main body portion 221. It protrudes. That is, each drum-side output coupling 78 and each development-side output coupling 79 are retracted to the left.

Further, as shown in FIG. 8A, the driving linear motion cam 220 is connected to a top cover arm 230 that swings integrally with the top cover 15 via a link 235, and according to opening and closing of the top cover 15. To move back and forth. For this reason, when the top cover 15 is opened, the drive linear cams 220 are moved rearward so that each process cartridge 12 can be replaced. When the top cover 15 is closed, the drive linear cams 220 are moved forward. The developing roller 6, the photosensitive drum 3 and the like can be driven. In FIGS. 8B and 8C, the top cover arm 230 is not shown.
(3) Frame Connection Structure (3-1) Configuration Related to Reference Axis Next, a structure for connecting the drum driving sheet metal 200 and the sheet metal frame 100 to the left and right side surfaces of the left resin frame 300 will be described. As shown in the exploded perspective view of FIG. 9, two cylindrical reference shafts 241 and 242 are erected and fixed to the right side surface of the drum drive metal plate 200 integrally with the drum drive metal plate 200 in the left-right direction. ing. In FIG. 9, the gear train 210 including the drum-side output coupling 78 and the development-side output coupling 79 is not shown.

  The reference shaft 241 as an example of the shaft is erected at a position adjacent to the lower side of the third photosensitive drum 3M from the front and the transfer roller 9 corresponding thereto. Further, in the resin frame 300 and the sheet metal frame 100, circular holes 341 and 141 as examples of positioning holes having an inner diameter substantially equal to the outer diameter of the reference shaft 241 are positions where the reference shaft 241 is inserted (left and right). (Position facing the direction). The reference shaft 242 is erected on the peripheral edge of the front end and the upper end of the drum drive metal plate 200 farthest from the reference shaft 241. In addition, at the periphery of the upper end and the front end of the resin frame 300 and the sheet metal frame 100, an elongated hole 342 having a large diameter in the front-rear direction is approximately equal to the outer diameter of the reference shaft 242 in the vertical direction. , 142 (see FIGS. 7, 12, and 14) are formed at positions where the reference shaft 242 is inserted through the center (positions facing in the left-right direction).

  By inserting the reference shaft 241 into the holes 341 and 141 and the reference shaft 242 into the holes 342 and 142, respectively, the three members of the drum driving sheet metal 200, the resin frame 300, and the sheet metal frame 100 are positioned. By inserting the reference shafts 241 and 242 and fixing the screws, which will be described later, the three members of the drum driving sheet metal 200, the resin frame 300, and the sheet metal frame 100 are assembled as shown in FIG.

  Further, due to the positioning by the reference shafts 241 and 242, as shown in the sectional view of FIG. 11, the drum-side output coupling 78 is connected to the drum-side input coupling 22, and the development-side output coupling 79 is connected to the development-side input coupling 56. And facing each other. FIG. 11 is a cross-sectional view of the AA step cross section of FIG. 9 with some members omitted. Further, the swing member 80 is also disposed at a predetermined position with respect to the guide hole 101 of the sheet metal frame 100 as shown in FIG. Arranged in positional relationship.

  As shown in FIGS. 10 and 11, a pair of left and right resin frames 300 are provided with a receiving surface 345 for receiving the paper cassette 7 from below. The receiving surface 345 supports the paper cassette 7 so that it can be pulled out. The Further, as shown in FIGS. 9 and 11, a plurality of screw holes 346 having internal threads formed on the inner surface are formed on the left side surface of the left resin frame 300. In the drum driving sheet metal 200, circular holes 246 are formed so as to face the screw holes 346, and general screws 410 (see FIG. 11) are screwed into the screw holes 346 through the holes 246. The drum driving sheet metal 200 is fixed to the resin frame 300. When a tapping screw is used instead of the general screw 410, a simple circular hole may be used instead of the screw hole 346.

Although not shown in FIGS. 9 to 11, due to the positioning by the reference shafts 241 and 242, the drive linear cam 220 is in the above-described positional relationship with respect to the drum-side output coupling 78 and the development-side output coupling 79. Placed in. That is, as shown in FIG. 12, a rib 347 that receives the main body portion 221 of the drive linear cam 220 from below is formed on the left side surface of the resin frame 300 in the front-rear direction, and is engaged with the main body portion 221 from above. A hook 348 is also formed. Therefore, as shown schematically in FIG. 13, the main body 221 is attached to the resin frame 300 so as to be capable of reciprocating linearly in the front-rear direction by means of ribs 347 and hooks 348. As a result of the positioning by the reference shafts 241 and 242, the main body 221 faces the drum side output coupling 78 and the development side output coupling 79 as described above. In FIG. 13, for the sake of explanation, the configuration of each unit is schematically illustrated and a part of the configuration is omitted, and is not necessarily consistent with the other drawings.
(3-2) Fixing Structure of Resin Frame and Sheet Metal Frame On the other hand, the insertion amount of the resin frame 300 and the sheet metal frame 100 is regulated by having a step portion 421 (see FIG. 11) as an example of the insertion amount regulating means. These are fixed using three step screws 420 and one general screw 430 having no step portion (see FIG. 9). The step screw 420 and the general screw 430 both correspond to an example of a fixture.

  12 is a left side view showing the configuration of the left resin frame 300, and FIG. 14 is a left side view showing the configuration of the left sheet metal frame 100. As shown in FIG. In each figure, the aforementioned reference axes 241 and 242 are also shown in cross section.

  As shown in FIGS. 9 and 12, the general screw 430 is inserted below the vicinity of the insertion position (hole 341) of the reference shaft 241 in the resin frame 300, and one step screw 420 is connected to the reference shaft in the resin frame 300. 242 is inserted in front of the vicinity of the insertion position (hole 342). The other step screw 420 is inserted at a position adjacent to the lower side of the first photosensitive drum 3K and the transfer roller 9 corresponding to the first step drum 420 from the front. It is inserted at a position facing the corner.

  Further, as shown in FIGS. 9, 11, and 14, the sheet metal frame 100 is formed with screw holes 140 each having a female screw on the inner surface at a position where each step screw 420 or general screw 430 is inserted. Has been. Further, as indicated by broken lines in FIG. 14, holes 320 and 330 that allow the step screws 420 or the general screws 430 to pass through are formed in the resin frame 300 at positions where the step screws 420 or the general screws 430 are inserted. It is installed. Here, the inner diameter of each hole 320 is configured to be slightly larger than the outer diameter of the stepped portion 421 of the stepped screw 420. In particular, the hole 320a formed near the reference shaft 242 has a longer length in the front-rear direction. It is configured as a hole. Further, the inner diameter of the hole 330 is configured to be slightly larger than the outer diameter of the screw portion 432 of the general screw 430 (see FIG. 15A).

  Next, FIG. 15B is an enlarged view of a portion B in FIG. 12, and FIG. 15A is a cross-sectional view taken along the line DD. FIG. 16A is an enlarged view of a portion C in FIG. 12, and FIG. 16B is a cross-sectional view taken along line EE. As shown in FIG. 15A, the edge portion 331 of the hole 330 is clamped between the head portion 433 and the sheet metal frame 100 by tightening the general screw 430, and the resin frame 300 is fixed to the sheet metal frame at this fixed position. 100 is fixed so as not to be displaced. Further, on the outer periphery of the edge 331 of the resin frame 300, as shown in FIGS. 9 and 15, a catch that protrudes to the left larger than the entire length of the general screw 430 in a cylindrical shape centered on the hole 330. A portion 333 is formed. Furthermore, the following rib 335 as an example of an interference part is formed on the inner wall surface of the receiving part 333.

  That is, as shown in FIGS. 15 and 16, the head 423 of the shoulder screw 420 has a larger diameter than the head 433 of the general screw 430. Therefore, on the inner wall surface of the receiving portion 333 into which the general screw 430 is inserted, a rib 335 extending in the protruding direction (left-right direction) of the receiving portion 333 and protruding from four directions toward the center is formed as follows. Yes. The distance between the tips of the ribs 335 allows the insertion of the general screw 430 without interfering with the head 433 of the general screw 430, and interferes with the head 423 of the corrugated screw 420 to interfere with the head of the corrugated screw 420. The dimensions are set to prevent insertion. For this reason, when the printer 1 is assembled, the operator can be prevented from erroneously inserting the step screw 420 into the hole 330.

  On the other hand, as shown in FIGS. 9 and 16, a receiving portion 323 that protrudes to the left in a cylindrical shape that is larger than at least the entire length of the step screw 420 is formed on the outer periphery of the edge portion 321 of the hole 320. However, the rib as described above is not formed on the inner wall surface of the receiving portion 323. For this reason, the step screw 420 can be inserted into the hole 320. Furthermore, even when the assembly work is performed with the sheet metal frame 100 and the resin frame 300 standing vertically by the receiving portions 333 and 323 formed in this way, the step screw 420 or the general screw dropped from the hole 320 or 330. 430 can be received.

  Further, as shown in FIG. 16B, the resin frame 300 has a right side surface (side surface of the metal plate frame 100) on the right side surface (side surface of the metal plate frame 100). A contact portion 327 is formed. When the annular contact portion 327 contacts the sheet metal frame 100, the edge portion 321 of the hole 320 (the portion between the outer periphery of the hole 320 and the inner periphery of the annular contact portion 327) is lifted from the sheet metal frame 100. The height of the annular contact portion 327 is such that when the step screw 420 is tightened until the step portion 421 contacts the sheet metal frame 100, the head 423 is brought into close contact or pressure contact with the edge portion 321. The height is set such that the portion 321 does not contact the sheet metal frame 100.

  For this reason, when the stepped screw 420 is tightened, the resin frame 300 in the vicinity of the fixing portion can be moved relative to the sheet metal frame 100 as follows when the resin frame 300 is thermally expanded. That is, the resin frame 300 in the vicinity of the fixed portion receives the frictional force from the sheet metal frame 100 via the annular contact portion 327 and the frictional force from the head portion 423 of the stepped screw 420 via the edge portion 321. However, it can move relative to the sheet metal frame 100 within the range of the hole 320 having a large diameter as described above. In addition, the fixing part of the step screw 420 other than that shown in FIG. 16 is configured in substantially the same manner as that shown in FIG. 16 although the shape is slightly different.

6). As described above, in the printer 1 according to this embodiment, the reference shaft 241 is inserted into the holes 341 and 141, and the reference shaft 242 is inserted into the holes 342 and 142, respectively. The positional accuracy of the three components of the drive metal plate 200, the resin frame 300, and the metal plate frame 100 can be ensured. Therefore, the drum-side output coupling 78 is securely fitted to the drum-side input coupling 22 and the development-side output coupling 79 is securely fitted to the development-side input coupling 56, respectively, so that each part of the photosensitive drum 3 and the like can be accurately fitted. Can be driven.

  In addition, the reference shaft 241 is fitted into the holes 341 and 141 having a size that prohibits displacement of the reference shaft 241 in the radial direction, so that both the sheet metal frame 100 and the resin frame 300 regardless of thermal expansion / contraction. A reference point for positioning at a position facing each other is formed. Further, the other reference shaft 242 is inserted into the long hole-shaped holes 342 and 142, thereby ensuring the above three position accuracy with respect to the rotation direction around the reference shaft 241, and the sheet metal frame. A dimensional difference due to a difference in linear expansion coefficient between 100 and the resin frame 300 can also be absorbed.

  In addition, since the reference shaft 242 is provided at a position farthest from the reference shaft 241 in the drum drive metal plate 200, the positional accuracy in the rotational direction can be further ensured. In addition, since the resin frame 300 can be moved relative to the sheet metal frame 100 as described above even at the fixing position by the step screw 420, the dimensional difference due to the difference in the linear expansion coefficient can be absorbed better.

  Therefore, in the present embodiment, it is also preferable that the sheet metal frame 100, the resin frame 300, and the like bend at a high temperature due to the difference in linear expansion coefficient while ensuring the positional accuracy of the three parties in the rotation direction. Can be suppressed. In addition, since the reference shaft 241 is provided in the vicinity of the central photosensitive drum 3M (may be provided in the vicinity of or between the photosensitive drum 3Y), the positions of the photosensitive drums 3K, 3Y, 3M, and 3C. The color misregistration can be suppressed while maintaining the relationship as accurate as possible.

  Further, at the location fixed by the step screw 420, the step screw 420 having the step portion 421 is used in place of the general screw 430 and the annular contact portion 327 is provided. Thus, the resin frame 300 can be relatively moved. For this reason, the apparatus does not increase in size, and displacement of the step screw 420 in the insertion direction due to thermal expansion / contraction hardly occurs, so that loosening of the step screw 420 can be suppressed. Further, in the above-described embodiment, the resin frame 300 is fixed to the sheet metal frame 100 so as not to be displaced by the general screw 430 at the fixing portion closest to the holes 341 and 141 into which the reference shaft 241 is inserted. For this reason, the manufacturing cost of the printer 1 can be reduced favorably. That is, in such a fixed portion, the dimensional difference due to the difference in linear expansion coefficient is minimized, and thus the manufacturing cost can be reduced by employing such a general fixing structure.

  Moreover, since the rib 335 is formed on the receiving portion 333 at this fixed location, the stepped screw 420 is prevented from being erroneously inserted. , Dropping of the step screw 420 is suppressed. Therefore, in the present embodiment, the assembly work of the main casing 2 can be made extremely efficient.

  In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, the annular contact portion 327 may have a polygonal frame shape instead of an annular shape, and may partially have a cut.

  Further, the insertion amount regulating means is not limited to the stepped portion 421 of the stepped screw 420 as in the above embodiment, but is a screw of the generalized screw 430 or a general screw having a larger head. It may be a collar or the like fitted on the screw portion. Furthermore, the present invention can be similarly applied to monochrome printers and inkjet printers, and as a fixing tool, a so-called snap that is fixed with one touch by deformation of resin may be used.

1 is a central sectional view illustrating a configuration of a printer to which the present invention is applied. FIG. 6 is a rear left perspective view illustrating the configuration of the process cartridge of the printer. It is a left side view showing the configuration of the developing cartridge of the process cartridge (when the gear cover is mounted). FIG. 6 is a left side view illustrating the configuration of the developing cartridge (when the gear cover is detached). FIG. 6 is a rear right perspective view showing the internal configuration of the main casing with the developing cartridge removed. It is explanatory drawing showing operation | movement of the rocking | swiveling member of the main body casing. It is a disassembled perspective view showing the left frame structure of the printer. It is the perspective view and top view showing the structure and operation | movement of the linear cam for a drive attached to the flame | frame. It is a disassembled perspective view showing the connection structure of the drum drive metal plate, the resin frame, and the metal plate frame which constitute the frame. It is a perspective view showing the assembled state of the drum drive sheet metal, the resin frame, and the sheet metal frame. It is sectional drawing showing the positional relationship of the assembled drum drive sheet metal, a resin frame, and a sheet metal frame. It is a left view showing the structure of the left side resin frame. It is explanatory drawing which represents typically the mounting state to the said resin frame of the said linear cam for a drive. It is a left view showing the structure of the sheet metal frame on the left side. It is the B section enlarged view of FIG. 12, and its DD sectional drawing. It is the C section enlarged view of FIG. 12, and its EE sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Main body casing 3 ... Photosensitive drum 4 ... Scorotron type charger 5 ... LED unit 6 ... Developing roller 9 ... Transfer roller 12 ... Process cartridge 22 ... Drum side input coupling 56 ... Development side input coupling 78 ... Drum side output coupling 79 ... Development side output coupling 100 ... Sheet metal frame 101 ... Guide hole 140, 346... Screw holes 141, 142, 246, 320, 330, 341, 342... Hole 200... Drum driving sheet metal 210. Reference shaft 300 ... resin frame 321,331 ... edge 323,333 ... receiving portion 327 ... annular contact portion 335,347 ... 348 ... hook 410, 430 ... general screw 420 ... shoulder screw 421 ... stepped portions 432 and 433 ... head 430 ... general screw 432 ... threaded portion P ··· paper

Claims (6)

Image forming means for forming an image on a recording medium;
A sheet metal frame and a resin frame fixed to each other at a plurality of fixing points, and a frame for supporting the image forming means;
With
The sheet metal frame and the resin frame have reference points that are positioned at positions facing each other regardless of their thermal expansion / contraction, and insert fixtures into the holes respectively drilled in the fixing locations. Fixed to each other,
In at least one of the above fixing points,
In the hole formed in the resin frame, the fixing tool is inserted from the side opposite to the sheet metal frame, and the resin frame is moved in a direction approaching or separating from the reference point with respect to the fixing tool and the sheet metal frame. Configured to have a large diameter in at least one direction so as to allow the displacement of
The resin frame is formed with an annular abutting portion that suppresses contact between the edge of the hole and the sheet metal frame by projecting toward the sheet metal frame in an annular shape surrounding the hole and contacting the sheet metal frame. ,
The amount of insertion of the fixture into the hole is regulated to an amount of insertion in which the head of the fixture is in close contact with or pressed against the edge and the edge is not pressed against the sheet metal frame. An image forming apparatus comprising an insertion amount restricting means. At the fixed location closest to the reference point,
The image forming apparatus according to claim 1, wherein the resin frame and the sheet metal frame are fixed to each other so as not to be displaced by a fixture that does not have the insertion amount regulating means. The fixture provided with the insertion amount regulating means is configured such that the head has a larger diameter than the fixture without the insertion quantity regulating means,
At the fixed location closest to the reference point,
The insertion amount restricting means is provided on the side of the resin frame where the fixing tool is inserted, allowing the insertion of the fixing tool without interfering with the head of the fixing tool not having the insertion amount restricting means. The image forming apparatus according to claim 2, wherein an interference portion that interferes with a head of the fixing tool to prevent insertion of the fixing tool is formed. The image forming unit is configured by arranging a plurality of image forming units in series corresponding to a plurality of colors,
The image forming apparatus according to claim 1, wherein the reference point is provided at a position closer to the image forming unit at the center than the image forming unit at both ends.   5. The receiving portion for receiving the fixing member that has fallen from the hole is formed around each of the holes on the side of the resin frame where the fixing member is inserted. An image forming apparatus according to claim 1.   6. A shaft projecting from the resin frame or the sheet metal frame is fitted into a positioning hole formed in the sheet metal frame or the resin frame at the reference point. The image forming apparatus according to any one of the above.

Images