JP4186924B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art As an image forming apparatus such as a laser printer, there is known an image forming apparatus that includes a process cartridge that is detachably attached to an apparatus main body and includes a photosensitive member, a toner cartridge, and the like. In such an image forming apparatus, a cover that can be opened and closed is usually provided on the main body casing, and the process cartridge is attached and detached by opening the cover. Further, in the image forming apparatus, generally, a paper feed cassette that stores paper for performing image formation is provided so as to be drawn out from the apparatus main body.

Here, in the image forming apparatus described in Patent Document 1 below, for the convenience of the user, both the side for attaching and detaching the process cartridge and the side for drawing out the paper feed cassette are designed to be on the near side. Therefore, on the front side of the main casing, the front wall of the paper feed cassette is disposed at a position below the cover. In this case, by providing a gap between the lower end of the cover and the upper end of the front wall of the paper feed cassette so that they do not interfere with each other, the paper feed cassette can be attached / detached and the cover opened / closed smoothly. Yes.
JP 2004-157463 A

  However, in the above configuration, there is a problem in that sound inside the apparatus easily leaks to the outside through a gap between the cover and the paper feed cassette. In particular, the one in Patent Document 1 employs a so-called S-shaped path method in which the paper is reversed and conveyed so that the paper is folded around the front end of the paper feed cassette, so that the paper being conveyed is rubbed in the paper conveyance path. Sound, sound rubbed with various rollers, and sound when separating sheets one by one due to friction, etc., are likely to leak from the gap.

  Therefore, in order to suppress the above sound leakage, a method is conceivable in which an elastic member such as a sponge is attached between the lower end of the cover and the upper end of the paper feed cassette to close the gap. However, in this case, the elastic member is rubbed strongly every time the paper feed cassette is attached and detached and the cover is opened and closed, so that the elastic member is easily peeled off and the cost is increased.

  The present invention has been completed based on the above circumstances, and provides an image forming apparatus capable of suppressing sound leakage from the inside of the apparatus without using a separate member for closing the gap. For the purpose.

  As means for achieving the above object, an image forming apparatus according to the invention of claim 1 is provided with a main body casing provided with an opening on one side surface and an opening of the main body casing so as to freely open and close. An image forming apparatus comprising a cover and a lower wall provided at a position below the cover in the main body casing, wherein the cover is swung up and down with respect to the main body casing when the cover is closed Freely supporting support means, provided on at least one side of the lower end of the cover and the upper end of the lower wall, and slidably contacted with the other side in accordance with the closing operation of the cover, so that the cover is attached to the lower wall. It has a feature in that it is provided with an inclined surface that guides to a position where it rides on the upper end.

  According to a second aspect of the present invention, there is provided an image forming apparatus comprising: a main body casing provided with an opening on one side; a cover provided to open and close the opening of the main body casing; and a plurality of sheet materials. And a cassette having a lower wall disposed at a lower position of the cover, the container having a lower wall disposed in the main body casing. A support means for swinging up and down with respect to the main body casing, and provided on at least one side of the lower end of the cover and the upper end of the lower wall, and slidably contact the other side as the cassette is mounted. And an inclined surface for guiding the cover to a position where it rides on the upper end of the lower wall.

  According to a third aspect of the present invention, in the first or second aspect, the support means is provided on a support shaft provided on one side of the cover and the main body casing and on the other side. Further, the present invention is characterized in that it is provided with an elongated hole through which the support shaft can be swung up and down and rotated.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the inclined surface is formed so as to face both the lower end of the cover and the upper end of the lower wall. These two inclined surfaces are characterized in that the inclination angles are formed to be equal to each other.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the cover includes a lock unit that holds the cover in a closed state with respect to the main body casing, and the lock unit includes the cover and A claw portion provided on one side of the main casing and a locked portion that is provided on the other side and can be locked with play in the vertical direction with respect to the claw portion. It has a characteristic where it exists.

  According to a sixth aspect of the present invention, in the apparatus according to any one of the first to fifth aspects, a gap between the upper edge of the opening in the main body casing and the upper end of the cover is shielded from the inside. It is characterized in that the shielding portion to be formed is overhanging.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, at least one of the lower end of the cover and the upper end of the lower wall is formed with a horizontal plane outside the inclined surface. It has the characteristics in the place.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the cover and the lower wall are each composed of a portion in which the inclined surface is formed or a portion in contact with the inclined surface. It is characterized by being integrally molded with a resin material.

  A ninth aspect of the present invention provides the image forming apparatus according to any one of the first to eighth aspects, further comprising an image carrier that carries a visible image formed by developing the electrostatic latent image with a developer. And a housing portion for housing the process cartridge is formed in communication with the opening, and the process cartridge is detachable through the opening. Have

  The invention of claim 10 is characterized in that, in the invention according to any one of claims 1 to 9, the cover is disposed on a front surface of the main body casing.

<Invention of Claim 1>
When the cover is closed, the inclined surface provided at the lower end of the cover or the upper end of the lower wall is in sliding contact with the other side, so that the cover is guided to ride on the upper end of the lower wall. As a result, the cover and the lower wall are brought into close contact with each other, so that no gap is formed between the two, and sound leakage such as a rubbing sound from the inside of the apparatus is suppressed. Moreover, since it is not necessary to provide another member such as a sponge to close the gap, it is possible to suppress an increase in cost.

<Invention of Claim 2>
When the cassette is attached, the inclined surface provided at the lower end of the cover or the upper end of the lower wall is in sliding contact with the other side, so that the cover is guided to ride on the upper end of the lower wall. As a result, the cover and the lower wall are brought into close contact with each other, so that no gap is formed between the two, and sound leakage such as a rubbing sound from the inside of the apparatus is suppressed. Moreover, since it is not necessary to provide another member such as a sponge to close the gap, it is possible to suppress an increase in cost.

<Invention of Claim 3>
Since the support means for supporting the cover so as to be swingable up and down with respect to the main body casing is composed of the support shaft and the long hole, the support structure of the cover can be realized with a simple configuration.

<Invention of Claim 4>
Since the inclination angles of the inclined surfaces provided so as to face each other on both the cover and the lower wall are equal to each other, the inclined surfaces are in contact with each other when the cover is closed or the cassette is mounted. Therefore, sound leakage can be more effectively suppressed.

<Invention of Claim 5>
Since the cover locking means is composed of a claw portion and a locked portion that can be locked in a state where there is play in the up-down direction with respect to the claw portion, Vertical swinging can be allowed.

<Invention of Claim 6>
Since the gap between the upper end of the cover and the upper edge of the opening in the main casing is shielded by the shielding part, it is possible to prevent the inside of the apparatus from being seen from the outside through the gap and improve the appearance.

<Invention of Claim 7>
Since the horizontal surface, not the inclined surface, is formed at the outside position where the cover and the lower wall are easy to enter the eyes, the appearance can be improved.

<Invention of Claim 8>
Since the cover and the lower wall are formed integrally with the synthetic resin material at the portion where the inclined surface is formed or the portion which contacts the inclined surface, even if there is some dimensional error due to molding circumstances, When the cover is placed on the lower wall by the inclined surface, the above error is absorbed to some extent by the bending of the resin, so that the cover and the front wall can be brought into close contact with each other.

<Invention of Claim 9>
Since the housing portion for housing the process cartridge is formed in communication with the opening, the process cartridge can be replaced by opening the cover.

<Invention of Claim 10>
Since the cover is disposed on the front surface of the main body casing, operations such as opening and closing the cover and replacing the process cartridge can be easily performed.

An embodiment of the present invention will be described with reference to FIGS.
(1) Schematic Configuration of Laser Printer FIG. 1 is a perspective view showing the external appearance of a laser printer 1 (hereinafter also simply referred to as printer 1) as an image forming apparatus of the present invention, and FIG. It is a sectional side view. In the following description, the right side of FIG. 2 is the front side, and the left side is the rear side.
As shown in FIG. 1, the laser printer 1 includes a main body casing 2 having a box shape as a whole, and a feeder unit 4 for feeding a sheet 3 as a sheet material into the inside thereof. An image forming unit 5 for forming an image on the sheet 3 is provided. In addition, an opening 48 for attaching and detaching the process cartridge 17 is provided at the upper part of the front surface (one side wall) of the main casing 2, and a front cover 50 covering the opening 48 is provided so as to be openable and closable.

(2) Feeder Unit As shown in FIG. 2, the feeder unit 4 includes a paper feed cassette 6, a paper pressing plate 7 provided in the paper feed cassette 6, and an end on one end side of the paper feed cassette 6. A pickup roller 11, a paper feed roller 8 and a separation pad 9, a pinch roller 10 facing the paper feed roller 8, a paper dust removing roller 14, and a downstream side of the paper dust removing roller 14 in the conveyance direction of the paper 3. And a registration roller 12 provided in the apparatus.

  The paper feed cassette 6 is detachably mounted on the bottom of the main casing 2 and is used for stacking and storing the paper 3 therein. A front wall 65 (corresponding to the lower wall of the present invention) formed integrally with a synthetic resin material is provided at the front end of the paper feed cassette 6. The front wall 65 is formed so as to cover the lower part of the front surface of the main body casing 2 over the entire width in a state in which the paper feed cassette 6 is mounted at the regular mounting position (the state shown in FIGS. 1 and 2). 50 is disposed at a lower position. The paper feed cassette 6 is pulled out to the front side (right side in FIG. 2) of the printer 1 when the paper 3 is replenished therein. At this time, the feeder unit 4 is separated between the paper feed roller 8 and the separation pad 9, and the pinch roller 10, the separation pad 9, and the spring 13 disposed on the back side of the separation pad 9 are connected to the paper feed cassette 6. And pulled out together.

  The paper pressing plate 7 is swingably supported at the end far from the paper feed roller 8 so that the end near the paper feed roller 8 can move in the vertical direction. It is biased upward by a spring (not shown). For this reason, the sheet pressing plate 7 is swung downward against the urging force of the spring with the end far from the sheet feeding roller 8 as a fulcrum as the amount of stacked sheets 3 increases.

  The pickup roller 11 is set so as to abut on the uppermost stacked paper 3 in the paper feeding cassette 6 by the paper pressing plate 7, and is capable of transporting the paper 3 by the paper feeding roller 8 (paper feeding roller 8 And a position between the separation pad 9).

  The separation pad 9 is disposed at a position facing the paper feed roller 8. Then, it is pressed toward the paper feed roller 8 by a spring 13 disposed on the back side of the separation pad 9. In addition, the separation pad 9 has a function for preventing the plurality of sheets 3 from being supplied into the transport path in a state where they overlap each other. That is, the sheet 3 sent by the pickup roller 11 comes into contact with the sheet feeding roller 8 and the separation pad 9. At this time, since an appropriate frictional force is applied between the separation pad 9 and the sheet 3, even if a plurality of sheets 3 are sent to the separation pad 9 by the pickup roller 11, the uppermost sheet is positioned. The sheets 3 other than 3 are locked by the separation pad 9. For this reason, the paper 3 is supplied from the paper feed roller 8 one by one. The paper 3 fed by the paper feed roller 8 is reversed so as to be folded back near the front end of the paper feed cassette 6, and the paper dust is removed by the paper dust removing roller 14, and then sent to the registration roller 12. .

  The registration roller 12 conveys the toner image on the photosensitive drum 27 between the photosensitive drum 27 and the transfer roller 30 to a transfer position P where the toner image on the photosensitive drum 27 is transferred to the paper 3 after registering the paper 3.

(3) Image Forming Unit (a) Scanner Unit The image forming unit 5 includes a scanner unit 16, a process cartridge 17, a fixing unit 18, and the like.

  The scanner unit 16 is provided in the upper part of the main casing 2 and includes a laser light emitting unit (not shown), a polygon mirror 19 that is rotationally driven by a scanner motor 25, lenses 20 and 21, reflecting mirrors 22 and 23, and the like. The laser beam based on the predetermined image data emitted from the laser light emitting section passes or reflects in the order of the polygon mirror 19, the lens 20, the reflecting mirror 22, the lens 21, and the reflecting mirror 23 as shown by a one-dot chain line in FIG. Thus, the surface of the photosensitive drum 27 in the process cartridge 17 is irradiated with high-speed scanning.

(B) Process Cartridge Inside the main body casing 2, a housing part 49 communicating with the opening 48 is formed below the scanner unit 16, and the process cartridge 17 is detachably attached to the housing part 49. . The process cartridge 17 includes a developing cartridge 28 and a drum cartridge 26.

  The developing cartridge 28 includes a developing roller 31, a layer thickness regulating blade 32, a toner supply roller 33, a toner box 34, and the like. The developing cartridge 28 is detachably attached to the drum cartridge 26.

  The toner box 34 is filled with toner (developer). The toner in the toner box 34 is agitated by the rotation of the agitator 36 supported by the rotation shaft 35 provided at the center of the toner box 34 in the arrow direction (clockwise direction), and is provided in the toner box 34. The toner is discharged from the toner supply port 37.

  A toner supply roller 33 is disposed at a side position of the toner supply port 37 so as to be able to rotate counterclockwise, and the developing roller 31 faces the toner supply roller 33 in a counterclockwise direction. It is arrange | positioned so that rotation is possible. The toner supply roller 33 and the developing roller 31 are in contact with each other in a state where each of them is compressed to some extent.

  The toner supply roller 33 has a metal roller shaft covered with a roller made of a conductive foam material. The developing roller 31 has a metal roller shaft covered with a roller made of a conductive rubber material having no magnetic characteristics. More specifically, the roller part of the developing roller 31 has a urethane rubber or silicone rubber coating layer containing fluorine on the surface of a roller body made of conductive urethane rubber or silicone rubber containing carbon fine particles. It is covered. A developing bias is applied to the developing roller 31.

  In addition, a layer thickness regulating blade 32 is disposed in the vicinity of the developing roller 31. The layer thickness regulating blade 32 includes a pressing portion 40 having a semicircular cross section made of insulating silicone rubber at the tip of a blade body made of a metal leaf spring material. 28, the pressing portion 40 is configured to be pressed against the developing roller 31 by the elastic force of the blade body.

  The toner discharged from the toner supply port 37 is supplied to the developing roller 31 by the rotation of the toner supplying roller 33. At this time, the toner is positively frictionally charged between the toner supplying roller 33 and the developing roller 31, The toner supplied onto the developing roller 31 enters between the pressing portion 40 of the layer thickness regulating blade 32 and the developing roller 31 as the developing roller 31 rotates, and is further sufficiently frictionally charged here. , And is carried on the developing roller 31 as a thin layer having a constant thickness.

  The drum cartridge 26 includes a photosensitive drum 27 as an image carrier, a scorotron charger 29, a transfer roller 30, and the like.

  The photosensitive drum 27 is disposed at a side position of the developing roller 31 so as to be able to rotate in the clockwise direction so as to face the developing roller 31. The photosensitive drum 27 has a drum main body grounded and a surface portion formed of a positively chargeable photosensitive layer made of polycarbonate or the like.

  The scorotron charger 29 is disposed at a predetermined interval so as not to contact the photosensitive drum 27. The scorotron charger 29 is disposed approximately 30 degrees above the horizontal direction in the radial direction of the photosensitive drum 27. The scorotron charger 29 is a positively charged scorotron charger that generates corona discharge from a charging wire such as tungsten, and uniformly charges the surface of the photosensitive drum 27 to a positive polarity. It is configured as follows.

  The surface of the photosensitive drum 27 is first positively charged uniformly by the scorotron charger 29 as the photosensitive drum 27 rotates, and then the scanner unit 16 is based on image data input from the outside. Is exposed by high-speed scanning with turning on and off of the laser beam from the laser beam, and an electrostatic latent image based on the image data is formed.

  Next, the electrostatic charge formed on the surface of the photosensitive drum 27 when the positively charged toner carried on the developing roller 31 comes into contact with the photosensitive drum 27 by the rotation of the developing roller 31. The latent image, that is, the surface of the photosensitive drum 27 that is uniformly positively charged, is supplied to an exposed portion that is exposed to a laser beam and the potential is lowered, and is visualized by being selectively carried. Thereby, reversal development is achieved.

  The transfer roller 30 is disposed below the photosensitive drum 27 so as to face the photosensitive drum 27, and is supported by the drum cartridge 26 so as to be able to rotate counterclockwise. The transfer roller 30 is configured such that a metal roller shaft is covered with a roller made of an ion conductive rubber material, and a transfer bias (transfer forward bias) is applied during transfer. Therefore, the visible image carried on the surface of the photosensitive drum 27 is transferred to the paper 3 while the paper 3 passes between the photosensitive drum 27 and the transfer roller 30.

(C) Fixing Unit The fixing unit 18 is provided on the rear side of the process cartridge 17 and includes a heating roller 41 and a pressure roller 42.

  The heating roller 41 includes a metal tube whose surface is coated with a fluororesin, and a halogen lamp for heating in the metal tube, and is rotated by input of power from a motor (not shown). On the other hand, the pressure roller 42 is disposed opposite to the heating roller 41 so as to press the heating roller 41. The pressure roller 42 is configured by covering a metal roller shaft with a roller made of a rubber material, and is driven according to the rotational drive of the heating roller 41.

  In the fixing unit 18, the toner transferred onto the paper 3 at the transfer position is thermally fixed while the paper 3 passes between the heating roller 41 and the pressure roller 42. The sheet 3 on which the toner is fixed is conveyed to a sheet discharge path 44 extending upward. The sheet 3 conveyed to the sheet discharge path 44 is discharged onto a sheet discharge tray 46 formed on the upper surface of the main body casing 2 by a sheet discharge roller 45 provided at the upper end position.

(4) Configuration of Main Body Front The main part of the front cover 50 is formed by integral molding of a synthetic resin material, and covers the upper part of the front surface of the main body casing 2 over the entire width. The lower portion of the front cover 50 is substantially close to a vertical surface, and forms a surface that is connected to the front wall 65 of the paper feed cassette 6 almost smoothly. Further, the upper portion of the front cover 50 is curved in a substantially arcuate cross section toward an oblique rear side, and constitutes a surface that is substantially smoothly connected to the front end portion of the upper surface of the main body casing 2. A manual paper feed port 52 for feeding the paper 3 directly from the front side of the printer 1 to the position of the registration roller 12 is formed at the lower center of the front cover 50, whereby the paper is fed into the paper feed cassette 6. The sheet 3 can be supplied to the conveyance path without storing the sheet 3.

  FIG. 3 is a partially enlarged side sectional view of the vicinity of the lower end of the front cover 50 with the front cover 50 closed. As shown in the figure, a pair of left and right bearing portions 53 are provided on the rear surface of the front cover 50 so as to protrude near the lower end. Each bearing 53 is provided with an elongated hole 53A that is elongated in the vertical direction, and a support shaft 54 that protrudes from the main body casing 2 is inserted into each of the elongated holes 53A. The support shaft 54 and the long hole 53A correspond to the support means of the present invention. With these configurations, the front cover 50 can be rotated about the support shaft 54, and the closed position covers the opening 48 as shown in FIG. And an open position (see FIG. 8) that opens the opening 48 in a posture tilted about 90 degrees so that the upper end side is closer to the front than the closed position. Further, the front cover 50 is displaceable in the longitudinal direction of the long hole 53A within a range from the one end to the other end of the long hole 53A, and is supported to be swingable in the vertical direction at the closed position. Is done.

  As shown in FIG. 2, a pair of left and right lock pieces 55 for holding the front cover 50 in the closed position is provided on the upper rear surface of the front cover 50. 4A is a side sectional view showing the lock piece 55, and FIG. 4B is a plan sectional view thereof. As shown in the figure, each lock piece 55 extends horizontally from the vicinity of the side edge of the front cover 50 to the rear, and has a flat plate shape as a whole and can be elastically displaced in the left-right direction. . Further, a lock claw 56 (corresponding to a claw portion of the present invention) having a mountain-shaped cross section is formed projecting outward from each other at the tip of each lock piece 55. On the other hand, inside the main casing 2, a pair of side frames 57 are provided near the left and right ends. Each side frame 57 is formed with a rectangular engagement hole 58 at a position corresponding to the lock claw 56 of the lock piece 55. A locking projection 58A (corresponding to the locked portion of the present invention) is provided at the front edge of the locking hole 58 so as to extend in the vertical direction, and the locking claw 56 can be locked. Yes. The lock claw 56 and the locked protrusion 58A correspond to the lock means of the present invention. The locked protrusion 58A is longer than the outer dimension of the lock claw 56 in the vertical direction by a predetermined dimension, and the lock claw 56 is engaged in a state where there is play in the vertical direction with respect to the locked protrusion 58A. Stop. For this reason, the lock piece 55 and the locked protrusion 58A are configured to allow the front cover 50 to swing in the vertical direction while maintaining the locked state.

  FIG. 5 is a partially enlarged side sectional view showing the vicinity of the upper end of the front cover 50. As shown in the figure, a gap S is formed between the upper end of the front cover 50 and the upper edge 2 </ b> A of the opening 48 in the main body casing 2. In the main body casing 2, a shielding part 60 having a step shape with the upper edge part 2 </ b> A is integrally formed over the entire width of the opening 48. More specifically, the shielding portion 60 protrudes downward from the upper edge portion 2A, and further protrudes from the protruding end to the inside of the opening 48, thereby shielding the gap S. Further, the upper edge portion 2A and the shielding portion 60 are configured not to interfere with the front cover 50 so as not to prevent the front cover 50 from swinging.

  As shown in FIG. 3, a cover-side inclined surface 61 that is inclined at a predetermined angle upward from the front end is formed on the lower end surface of the front cover 50 over the entire width of the front cover 50. The cover-side inclined surface 61 has a function of guiding the riding operation of the front cover 50 as will be described in detail later. Further, a horizontal surface 62 is formed on the lower end surface of the front cover 50 in a region from the front end (upper end) of the cover-side inclined surface 61 to the front end of the front cover 50. Thus, instead of forming the cover-side inclined surface 61 up to the front end of the front cover 50, by providing the horizontal surface 62, the cover-side inclined surface 61 and the like are not easily seen from the outside, and the appearance is improved. . Further, a chamfering horizontal surface 63 is formed in a region from the rear end (lower end) of the cover-side inclined surface 61 to the rear end of the front cover 50 on the lower end surface of the front cover 50, thereby It has been dropped.

  On the other hand, on the upper end surface of the front wall 65 in the paper feed cassette 6, a cassette-side inclined surface 66 that is inclined upward toward the front end is formed across the entire width of the front wall 65 so as to face the cover inclined surface 61. The cassette-side inclined surface 66 has a function of guiding the riding operation of the front cover 50, similar to the cover-side inclined surface 61, and is formed so that the inclination angle thereof is substantially equal to the cover-side inclined surface 61. . Further, a horizontal plane 67 is formed on the upper end surface of the front wall 65 in a region from the front end (upper end) of the cassette side inclined surface 66 to the front end of the front wall 65. Thus, instead of forming the cassette-side inclined surface 66 to reach the front end of the front wall 65, by providing the horizontal surface 67, the cassette-side inclined surface 66 and the like are difficult to see from the outside, and the appearance is improved. And the corners are dropped.

(Operation and effect of this embodiment)
When image formation is performed by the printer 1, as shown in FIGS. 2 and 3, the front cover 50 is set to the closed position, and the paper feed cassette 6 is mounted to the regular mounting position. At this time, since the front cover 50 is supported so as to be swingable up and down, the front cover 50 is placed on the upper end portion of the front wall 65 of the paper feed cassette 6 by its own weight. As a result, the lower end portion of the front cover 50 and the upper end portion of the front wall 65 are in close contact with each other, and there is no gap between them, so that sound generated from the inside of the apparatus is prevented from leaking to the outside. In particular, in the present printer 1, a sound that rubs in the paper conveyance path when the paper 3 is folded near the front end of the paper feed cassette 6, a sound when the paper 3 is separated one by one by the separation pad 9, etc. Leakage is prevented. In addition, since the front cover 50 and the front wall 65 are provided with inclined surfaces 61 and 66 that are parallel to each other at positions facing the counterpart, the inclined surfaces 61 and 66 are in close contact with each other rather than with a line. As a result, sound leakage can be more effectively suppressed.

Next, an operation when the paper cassette 6 is attached / detached will be described.
When the front wall 65 is pulled forward from the state of FIG. 3 and the sheet cassette 6 is pulled out from the main casing 2, the front cover 50 is moved from its original position (indicated by a two-dot chain line) as shown in FIG. 6. The spindle 54 falls by its own weight to a position (indicated by a solid line) reaching the upper end of the long hole 53A. When the paper feed cassette 6 is inserted into the main casing 2 after the paper 3 is replenished, as shown in FIG. 7, the front wall 65 is inclined toward the cassette immediately before the paper feed cassette 6 reaches the proper mounting position. The surface 66 contacts the front end of the lower end portion of the front cover 50. Then, as the paper feed cassette 6 advances to the back side, the front cover 50 is lifted by the guidance of the cassette side inclined surface 66. When the paper feed cassette 6 is further inserted into the back side, the cassette-side inclined surface 66 comes into contact with the cover-side inclined surface 61, and the inclined surfaces 61, 66 are brought into sliding contact with each other, whereby the front cover 50 is further lifted. When the paper feed cassette 6 reaches the normal mounting position, as shown in FIG. 3, the front cover 50 also returns to the original height position. As described above, the lock claw 56 of the lock piece 55 is engaged with the engagement protrusion 58A of the side frame 57 with play in the vertical direction. Even when the cover 50 moves up and down, it is always kept in a locked state, and therefore the front cover 50 is maintained in the closed position.

Next, an operation when the front cover 50 is opened and closed will be described.
2 and 3, when the upper portion of the front cover 50 is pulled toward the front side, the front cover 50 rotates around the support shaft 54 in the clockwise direction in the drawing. Accordingly, the lock pieces 55 are elastically deformed inward from each other, and the lock claw 56 and the locked protrusion 58A are unlocked. Further, the lower end portion of the front cover 50 is separated rearward from the upper end portion of the front wall 65. Thus, when the front cover 50 is laid down to the open position shown in FIG. 8, the opening 48 is opened, and the process cartridge 17 can be exchanged through the opening 48.

  Next, when the upper portion of the front cover 50 is lifted from the state shown in FIG. 8, the front cover 50 rotates counterclockwise about the support shaft 54. When the front cover 50 approaches the closed position, the front cover 50 is lowered by its own weight as the support shaft 54 is displaced to the upper end side of the long hole 53A, and the lower end portion of the front cover 50 and the upper end portion of the front wall 65 Abut. Then, when the upper portion of the front cover 50 is further pushed inward, as shown in FIG. 9, the cover-side inclined surface 61 and the cassette-side inclined surface 66 are in sliding contact with the mating side, so that the front cover 50 is guided upward. Is done. Then, when the front cover 50 reaches the closed position, as shown in FIG. On the other hand, the front cover 50 reaches the closed position, and the lock claw 56 is locked to the locked protrusion 58A together with the elastic deformation of the lock piece 55, and the front cover 50 is locked.

  As described above, according to this embodiment, when the front cover 50 is closed or when the paper feed cassette 6 is mounted, the cover-side inclined surface 61 provided at the lower end of the front cover 50 or the upper end of the front wall 65 is provided. When the cassette-side inclined surface 66 provided in the slidable contact with the mating side, the front cover 50 is guided to ride on the upper end portion of the front wall 65. As a result, the front cover 50 and the front wall 65 are brought into close contact with each other, so that no gap is formed between them, and sound leakage such as a rubbing sound from the inside of the apparatus is suppressed. Moreover, since it is not necessary to provide another member such as a sponge to close the gap, it is possible to suppress an increase in cost.

  In addition, since the support means for supporting the front cover 50 so as to be swingable up and down with respect to the main body casing 2 is constituted by the support shaft 54 and the long hole 53A, the support structure of the front cover 50 can be simplified. realizable.

  Further, since the inclined surfaces 61 and 66 provided so as to face both the front cover 50 and the front wall 65 are equal to each other, both inclined surfaces are closed when the front cover is closed or when the paper feed cassette 6 is mounted. 61 and 66 are in contact with each other on the surface. Therefore, sound leakage can be more effectively suppressed.

  Further, since the locking means of the front cover 50 is composed of the lock claw 56 and the locked projection 58A that can be locked with play in the vertical direction with respect to the lock claw 56, the front cover 50 The front cover 50 can be allowed to swing in the up-down direction while being kept closed.

  In addition, since the gap S between the upper end of the front cover 50 and the upper edge of the opening 48 in the main casing 2 is shielded by the shielding portion 60, it is possible to prevent the inside of the apparatus from being seen from the outside through the gap S, and the appearance is good. improves.

  Moreover, since the inclined surfaces 61 and 66 are formed in the outer position where the front cover 50 and the front wall 65 are joined easily at the outside position, not the inclined surfaces 61 and 66, the appearance can be improved.

  Further, since the front cover 50 and the front wall 65 are formed integrally with synthetic resin material at the portions where the inclined surfaces 61 and 66 are formed, respectively, even if there is some dimensional error due to molding circumstances. When the front cover 50 is ridden on the front wall 65 by the inclined surfaces 61 and 66, the error is absorbed to some extent by the bending of the resin, so that the front cover 50 and the front wall 65 can be brought into close contact with each other.

  Further, since the accommodating portion 49 that accommodates the process cartridge 17 is formed in communication with the opening 48, the process cartridge 17 can be replaced by opening the front cover 50.

  Since the front cover 50 is disposed on the front surface of the main casing 2, operations such as opening / closing the front cover 50 and replacing the process cartridge 17 can be easily performed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, the lower wall is configured as a part of the paper feed cassette that can be pulled out. However, according to the present invention, the lower wall may be fixedly provided as a part of the main body casing. good.

(2) In the above embodiment, the cover is disposed on the front surface of the main body casing and is opened and closed when the process cartridge is replaced. However, according to the present invention, the cover is disposed on the side surface other than the front surface of the main body casing. In addition, for example, a manual feed tray or the like may be used other than when the process cartridge is replaced.

(3) In the above embodiment, the inclined surface is provided on both the cover and the lower wall. However, according to the present invention, the inclined surface may be provided on only one of the surfaces.
(4) In the above embodiment, each inclined surface is formed in a range smaller than the plate thickness of the cover or the lower wall. However, according to the present invention, each inclined surface is in the entire range of the plate thickness of the cover or the like. Further, an overhanging portion may be provided at the lower end of the cover or the upper end of the lower wall so that the inclined surface is formed to a range exceeding the plate thickness.

The perspective view which shows the external appearance of the laser printer which concerns on one Embodiment of this invention. Cross section of the main part of the laser printer Side sectional view showing the front cover closed (A) Side sectional view showing lock piece and locked protrusion (B) Flat sectional view Side sectional view showing the vicinity of the upper end of the front cover Side sectional view showing a state in which the paper cassette is pulled out Side sectional view showing the process of loading the paper cassette Side sectional view showing a state in which the front cover is opened Side sectional view showing the process of closing the front cover

Explanation of symbols

1. Laser printer (image forming device)
2 ... Main body casing 2A ... Open upper edge 3 ... Paper (sheet material)
6 ... Paper cassette
17 ... Process cartridge 27 ... Photosensitive drum (image carrier)
48 ... Opening part 49 ... Housing part 50 ... Front cover (cover)
53A ... Long hole (support means)
54 ... Support shaft (support means)
56 ... Lock claw (claw part, lock means)
58A: Locked protrusion (locked portion, locking means)
60 ... Shielding part 61 ... Cover side inclined surface (inclined surface)
62, 67 ... horizontal plane 65 ... front wall (lower wall)
66 ... Inclined surface on the cassette side (inclined surface)

Claims (10)

A body casing having an opening on one side;
A cover provided so as to freely open and close the opening of the main body casing;
An image forming apparatus comprising: a lower wall provided at a position below the cover in the main body casing;
Support means for supporting the cover so as to be swingable up and down with respect to the main body casing in a state in which the cover is closed;
An inclination that is provided on at least one side of the lower end of the cover and the upper end of the lower wall and guides the cover to a position where it rides on the upper end of the lower wall by slidingly contacting the other side with the closing operation of the cover And an image forming apparatus. A body casing having an opening on one side;
A cover provided so as to freely open and close the opening of the main body casing;
In an image forming apparatus comprising: a cassette having a lower wall that accommodates a plurality of sheet members and is provided so as to be freely drawn out with respect to the main body casing and disposed at a lower position of the cover.
Support means for supporting the cover so as to be swingable up and down with respect to the main body casing in a state in which the cover is closed;
An inclination that is provided on at least one side of the lower end of the cover and the upper end of the lower wall and guides the cover to a position where it rides on the upper end of the lower wall by slidingly contacting the other side with the mounting operation of the cassette. And an image forming apparatus. The support means includes a support shaft provided on one side of the cover and the main body casing, and a long hole provided on the other side, through which the support shaft can swing up and down and rotate. The image forming apparatus according to claim 1, wherein the image forming apparatus includes:. The inclined surface is formed so as to oppose each other at both a lower end of the cover and an upper end of the lower wall, and the inclined angles of both the inclined surfaces are formed to be equal to each other. The image forming apparatus according to claim 1. Lock means for holding the cover in a closed state with respect to the body casing;
The locking means includes a claw portion provided on one side of the cover and the main body casing, and a cover provided on the other side that can be locked with play in the vertical direction with respect to the claw portion. The image forming apparatus according to claim 1, wherein the image forming apparatus includes an engaging portion. The upper edge part of the said opening part in the said main body casing is protrudingly formed by the shielding part which shields the clearance gap between the upper ends of the said cover from the inside, The Claims 1-5 characterized by the above-mentioned. The image forming apparatus according to any one of the above. 7. The image forming apparatus according to claim 1, wherein a horizontal plane is formed outside the inclined surface in at least one of a lower end of the cover and an upper end of the lower wall. . 8. The cover and the lower wall, respectively, wherein the portion where the inclined surface is formed or the portion which contacts the inclined surface is integrally formed of a synthetic resin material. An image forming apparatus according to claim 1. A process cartridge having an image carrier for carrying a visible image formed by developing an electrostatic latent image with a developer;
2. A housing portion for housing the process cartridge is formed in the main body casing so as to communicate with the opening, and the process cartridge is detachable through the opening. The image forming apparatus according to claim 8. The image forming apparatus according to claim 1, wherein the cover is disposed on a front surface of the main body casing.

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