CN100474144C - Image formation apparatus and sheet conveying apparatus - Google Patents

Abstract

The invention discloses a paper conveying device, which includes: a paper feeding box detachably mounted to the main body of the device; a conveying unit that separates paper from the paper feeding box and conveys the paper; is supported swingably, and its swing positions are respectively changed between: a state where the paper feed cassette is detached from the apparatus main body, a state where the paper feed cassette is attached to the apparatus main body and paper is not conveyed, and a paper feed cassette is attached to the apparatus main body and a state that the sheet is being conveyed; and a detection unit that detects a change in the swing position.

Description

Imaging unit and paper transport unit

technical field

One aspect of the present invention relates to a sheet conveying device and an image forming device.

Background technique

Heretofore, there has been known a sheet conveying device that includes a sheet feed cassette for placing sheets thereon, and rollers for conveying the sheets one by one (see JP-A-2001-206566).

In addition to the configuration described above, the apparatus includes a paper end sensor composed of a photosensor and a driver to determine the paper conveyance timing (conveyance interval), and a sensor switch for detecting the presence or absence of a paper feed cassette.

With the above arrangement, the conveyance of each paper and the presence or absence of the paper feeding cassette are detected by a dedicated detection device. Since the number of components increases in this configuration, assembly of the components becomes complicated to a corresponding extent, and prevents cost reduction and device size reduction.

Incidentally, the image forming apparatus has an opening formed on the side of the apparatus main body casing, and it accommodates a paper feeding cassette stacked with sheets, while the paper feeding cassette can be pulled out through the opening. In the image forming operation, the paper in the paper feed cassette is sent one by one to the paper conveyance path by the paper feed roller inside the main body casing of the device, and the paper is formed with an image formed by the image forming section and discharged through the fixing unit while being conveyed by the conveyance roller. into the output tray.

Meanwhile, in such an image forming apparatus, in order to smoothly attach/detach the paper feed cassette, it is necessary to provide a gap between the opening of the apparatus main body casing and the paper feed cassette. Therefore, the noise generated when the paper being conveyed is rubbed in the paper conveyance path, or the noise generated when it rubs against various rollers, the noise generated when the paper is separated one by one by friction, and the like (hereinafter called "rustle") tends to come out of the gap.

In addition, some image forming apparatuses use the so-called "letter S path scheme", as disclosed in JP-A-2004-157463 below, to reversely feed paper so that the It folds back. The problem with this solution is, inter alia, that the rustling sound in the reverse feed tends to come from the gap between the opening and the cassette.

Here, in order to suppress these rustling noises, a method has been conceived of embedding an elastic member of a sponge or the like in the device at any portion perpendicular to each other through the gap between the opening of the device main body casing and the paper feed cassette Main body casing or paper feed tray to cover the gap. However, this clearance is provided for smooth installation/removal of the paper feed cassette. When the gap is closed with a sponge so as to cover it vertically, there occurs a problem that the elastic member rubs strongly every time attachment or detachment of the paper feed cassette is performed, so that it is torn off or worn out, so the sealing performance (noise reduction performance) is lowered, And it is impossible to install and remove the paper feed cassette smoothly.

Contents of the invention

In view of the above circumstances, an aspect of the present invention has been accomplished, and for its purpose, provides a paper conveying device capable of detecting paper conveying and the presence or absence of a paper feeding cassette, and an image forming apparatus including the paper conveying device, with a small number of components.

Another aspect of the present invention has been accomplished in view of the above circumstances, and for the purpose thereof, provides an image forming apparatus capable of suppressing rustling noise while allowing smooth attachment/detachment of a paper feed cassette.

According to an aspect of the present invention, the paper conveying device may include: a paper feeding cassette detachably attached to the device main body; a conveying unit that separates the paper from the paper feeding cassette and conveys the paper; a swing member that surrounds a shaft portion with respect to the device main body is supported swingably, and its swing position is changed in the following states respectively: a state in which the paper feed cassette is detached from the apparatus main body, a state in which the paper feed cassette is attached to the apparatus main body and paper is not conveyed, and a state in which the paper feed cassette is attached to the apparatus main body and a state that paper is being conveyed; and a detection unit that detects a change in the swing position.

According to another aspect of the present invention, the paper conveying device further includes: providing a paper conveying path between the swing member and the paper feed cassette; wherein the swing member is arranged at a position opposite to the paper feed cassette; a protruding portion on the conveying path, the protruding portion including the end portion abutting on the paper feed cassette; the swing member is swingable about the shaft portion to take a first posture, a second posture and a third posture; the swing member abuts on the paper feed in the first posture box; the swing member is rotated to take the second posture due to the collision of the conveyed paper against the protruding portion; in the third posture, when the paper feeding cassette is detached from the apparatus main body so as to release the abutment with the protruding portion, the swing member rotates in the same manner as from the first posture Rotate in a direction opposite to the direction of rotation toward the second attitude.

According to another aspect of the present invention, the swing member is arranged above the paper feeding cassette, and the tip end portion of the protruding portion is supported on the paper feeding cassette in the first posture.

According to another aspect of the present invention, the sheet conveying device further includes: an urging portion that urges the swing member in a direction from the second posture to the third posture.

According to another aspect of the present invention, the paper feed cassette is provided with a receiving portion on which the tip end of the protruding portion is supported; and at least one of the end portion of the protruding portion and the receiving portion is provided with a guide slope, When the main body is turned, the guide slope guides the end portion to the receiving portion.

According to another aspect of the present invention, the detection unit includes: a first detection unit including: a photoelectric sensor having a pair of light-emitting and light-receiving elements, and the optical axis thereof is arranged in a direction along the axial direction of the shaft portion; and a swing member A shielding portion provided in which cuts off the optical path of the detection light when the swing member is in the first posture and opens the optical path when the swing member is in any other posture, or opens the optical path of the detection light when the swing member is in the first posture and opens the optical path when the swing member is in the first posture Cutting off the optical path in any other posture; and a second detection unit that detects the presence or absence of motor drive for driving the conveyance unit, wherein the drive of the motor is prohibited when the paper feed cassette is detached from the apparatus main body.

According to another aspect of the present invention, when the swing member is in the first posture, the shielding portion has a vertical upper end to face a top wall of the cartridge accommodating portion provided in the device main body.

According to another aspect of the present invention, the paper conveying device further includes: a separation roller separating the paper; wherein the swing member is disposed on the shaft portion so as to be juxtaposed in an axial direction of the shaft portion.

According to another aspect of the present invention, the protruding portion of the swing member is protrudingly arranged on the downstream side of the position where the separation roller is placed in the conveying direction of the sheet.

According to another aspect of the present invention, the swing member is arranged at a substantially central portion in the axial direction of the shaft portion.

According to another aspect of the present invention, part of the paper conveyance path includes a paper feed cassette.

According to another aspect of the present invention, an image forming apparatus may include: an apparatus main body having a shaft portion; and a paper conveying device; wherein the paper conveying device is defined in any one of the aforementioned aspects.

According to another aspect of the present invention, an image forming apparatus includes: a cartridge accommodating a recording medium; and an apparatus main body including an opening open to the outside thereof, and a cartridge accommodating portion detachably accommodating the cartridge through the opening; wherein the apparatus main body The peripheral edge portion of the opening has a first surface at an angle with respect to the pull-out direction of the box; when the box is accommodated in the box accommodating portion, the box overlaps at least the first surface of the peripheral edge portion of the opening; the box includes a cover wall, It has a second surface facing the first surface; and at least one of the first surface and the second surface is provided with an elastic member positioned between the first surface and the second surface when the cartridge is accommodated in the cartridge accommodating portion between.

According to another aspect of the invention, the first surface and the second surface are orthogonal to the pulling-out direction of the cassette.

According to another aspect of the present invention, an opening is formed at a deeper portion having a level difference with respect to the outer surface of the device main body; at a peripheral edge portion of the opening at the deeper portion, a first surface is formed; and the elastic member is arranged at the second A surface that does not protrude over the side of the box.

According to another aspect of the present invention, the elastic member is disposed on a side of the second surface that does not protrude to the opening.

According to another aspect of the present invention, the first surface is formed at a part of the peripheral edge portion of the opening that continues to the gap between the device body and the case.

According to another aspect of the present invention, the first surface, the second surface, and the elastic member have a width greater than that of the recording medium.

According to another aspect of the present invention, the cartridge accommodating portion includes a supporting portion that supports the cartridge against a reaction force of the elastic member pressed in a state where the cartridge is accommodated in the cartridge accommodating portion.

According to another aspect of the present invention, the support unit includes: an elastic stopper protruding to the inside of the cartridge accommodating portion; Elastic stoppers engage.

According to another aspect of the present invention, one of the box accommodating portion and the box is provided with a positioning protrusion that determines the position of the box relative to the box accommodating portion, and the other is provided with a positioning recess that engages with the positioning protrusion; and when the box is held by the supporting portion When supported, the positioning protrusion and the positioning recess are positioned adjacent to each other so that the elastic member is pressed between the first surface and the second surface.

According to another aspect of the present invention, the imaging device further includes: a feeding unit arranged at a position near the opening inside the main body of the device, the feeding unit feeds a recording medium accommodated in the cassette; the conveying unit feeds the feeding unit into the The recording medium is folded back so as to be conveyed to a side opposite to the feeding unit with respect to the opening; and an image forming unit that forms an image on the recording medium conveyed by the conveying unit.

Description of drawings

The invention can be more easily explained by referring to the accompanying drawings:

1 is a side sectional view showing a main part of a laser printer according to an embodiment of the present invention;

Fig. 2 is a perspective view of a laser printer;

Figure 3 is a perspective view of the paper feed cassette;

Fig. 4 is also a perspective view of the paper feeding box;

Fig. 5 is a plan view of the paper feed cassette (only its front side is shown);

Fig. 6 is a sectional view observed along line VI-VI among Fig. 5;

Figure 7 is an enlarged view of part A in Figure 3;

8 is a sectional view showing a first attitude of the swing link;

9 is a sectional view showing a second attitude of the swing link;

10 is a cross-sectional view showing a third attitude of the swing link;

Fig. 11 is a flowchart showing the process of determining the attitude of the swing link;

Fig. 12 is a cross-sectional view of the case where the protruding portion is arranged on the upstream side of the separation roller;

Fig. 13 is a sectional view showing a modified embodiment in which the pushing portion is constituted by a torsion spring;

14 is a perspective view of a laser printer in a state where a paper feeding cassette has been pulled out according to another embodiment;

Fig. 15 is a side sectional view of the main part of the laser printer;

Fig. 16 is a partial side view showing a paper feed cassette and a part of the device main body having an upper peripheral edge portion formed with an opening;

Fig. 17 is a partial side view (I) showing a paper feeding cassette and a part of the device main body with an upper peripheral edge portion formed with an opening;

Fig. 18 is a partial side view (II) showing the paper feed cassette and a part of the device main body formed with the upper peripheral edge portion of the opening;

Figure 19 is a perspective view showing a pair of inner wall panels;

Fig. 20 is a plan view of the paper feed cassette.

Detailed ways

An embodiment of the present invention will be described with reference to FIGS. 1 to 12 .

1. The overall configuration of this embodiment

Fig. 1 is a side sectional view showing main parts of a laser printer as an image forming apparatus of the present invention. Fig. 2 is a perspective view of a laser printer, and Figs. 3 and 4 are perspective views of a paper feed cassette. By the way, in the following description, the depth direction of the laser printer will be expressed as "X direction" (the front side of the laser printer is set to +X), and its width direction will be expressed as "Z direction" (laser The right side of the printer is set to +Z), and its height direction will be set to "Y direction" (the upper side of the laser printer shown in Figure 2 is set to +Y)

The laser printer 1 includes a main body casing 2, a feeding section 4 for conveying each sheet 3 as a medium to be recorded, an image forming section 5 for conveying paper 3 on the conveyed paper 3, and the like, a feeding section 4, and the like. Form the image.

(1) Main shell

On a side wall on one side of the main body casing (corresponding to "apparatus main body" in the present invention), an attachment/detachment opening 6 for attaching/detaching a process cartridge 20 to be described later is formed. As shown in FIGS. 1 and 2 , a front cover 7 for opening or closing the attachment/detachment port 6 is arranged. The front cover 7 is rotatably supported on a cover shaft (not shown) inserted into its lower end.

Therefore, when the front cover 7 is closed with respect to the cover shaft, the installation/removal opening 6 is closed by this front cover 7 as shown in FIG. The detachment port 6 is provided, and the process cartridge 20 can be mounted to or detached from the main body casing 2 through the mounting/detachment port 6 .

Furthermore, a cartridge accommodating portion 2A opened forward is provided at the bottom of the main body casing 2 . A paper feed cassette 9 to be described below can be accommodated in the cassette accommodating portion 2A from the front (right side in FIG. 1 ), or the paper feed cassette 9 accommodated therein can be removed.

(2) Feed section

The feeding unit 4 is mainly composed of a paper feeding cassette 9 and rollers for feeding the paper 3 one by one to the paper conveyance path 56 . As shown in FIG. 3 , the paper feeding box 9 is composed of a box body 71 and a wall portion 75 , wherein the box body 71 is in the shape of a tray and stacked paper 3 is placed therein, and the wall portion 75 is arranged at the front of the box body 71 . The paper presser 15 is mounted on the front of the bottom wall 71A of the cassette body 71 . The left end of the paper pressing plate 15 is fixed to the bottom wall 71A as shown in FIG. 3, while its end on the opposite side is not fixed so that it can be bent or bent up and down.

The lever 17 is arranged between the distal end portion of the paper pressing plate 15 and the bottom wall 71A of the paper feeding cassette 9 (see FIG. 1 ). The lever 17 is adapted to rotate about a lever axis 18 . When a rotational driving force in the counterclockwise direction as shown in the figure is applied to the lever shaft 18, the lever 17 rotates around this lever shaft 18 as a fulcrum. Thus, the front end of the lever 17 lifts the front end of the paper pressure plate 15, thereby lifting the paper 3 stacked in the paper feed cassette 9, so that the paper 3 abuts against the paper feed roller 12 which will be described later.

The wall portion 75 includes a plate-like front plate 76 , and its wall surface facing the front plate 76 forms an inclined surface 77 inclined toward the box body 71 side. Above and below the central part of the width direction of the inclined surface 77, a paper powder removal roller 8 and a separation pad 11 are arranged respectively, and a guide piece 115 is arranged on the inclined surface 77 so as to be directed toward the inside of the box 9 (left side in Fig. 3 ). side) protruding. Five guide pieces 115 are arranged along the width direction of the paper feeding cassette 9 (the T direction shown in FIG. 3 and the Z direction of the device main body).

In a state where the paper dust removing roller 8 has an axis in the width direction of the paper feeding cassette 9 , both ends of the rotational axis of this roller 8 are supported by a pair of support walls 75A formed in the wall portion 75 . In addition, as shown in FIG. 6, at the portion of the inclined surface 77 of the wall portion 75 located below the paper dust removing roller 8, a recessed portion 77A is formed, and a coil spring 78 having a pad pressing plate 11A fixed to an upper end thereof is vertically accommodated in the in the recess 77A. The separation pad 11 is stuck on the upper surface of the pad holding plate 11A.

Meanwhile, as shown in FIG. 1, the feed roller 12, the separation roller 10, and the reverse roller 13 are successively disposed on the top wall front side of the cassette accommodating portion 2A, that is, at the wall portion 75 facing the paper feed cassette 9. Location. Here, the supporting structure of the roller will be briefly described. As shown in FIG. 3, the central axis (corresponding to the "shaft part" in the present invention) C1 of the separation roller 10 and the central axis C2 of the reverse roller 13 extend in the width direction of the paper feeding cassette 9, and each Both ends of each of the central shafts C1 and C2 are supported by the main body casing 2 when the axis of the central shafts is located in a direction orthogonal to the conveyance direction of the sheet. On the other hand, the feed roller 12 does not have any central axis connected to the main body casing 2 like the separation roller 10 or the reverse roller 13, but is rotatably supported on the central axis C1 by a substantially U-shaped bracket 12A. superior.

Incidentally, both of FIGS. 3 and 4 are perspective views of the paper feed cassette 9 , and the separation roller 10 , reverse roller 13 and paper feed roller 12 are elements mounted on the main body casing 2 . Therefore, the separation roller 10 and the counter roller 13 are elements that should not be shown in the figure. However, they are still shown in the figure in order to show their relationship to the paper feed cassette 9 or the rollers 8 arranged in the cassette.

Furthermore, as will be described later in detail, a swing link (corresponding to "swing member" in the present invention) 80 is outserted onto the central axis C1 and juxtaposed with the separation roller 10 . The swing link 80 is used to detect detachment of the paper feed cassette 9 from the cassette accommodating portion 2A, and to detect conveyance of paper.

As shown in FIG. 1, when the paper feed cassette 9 is accommodated in the cassette accommodating portion 2A, the front plate 76 of the paper feed cassette 9 is flush with the front wall of the main body casing 2 to close the entrance of the cassette accommodating portion 2A, and the separation roller 10 Opposite to the separation pad 11, while the paper dust removal roller 8 and the reverse roller 13 are opposite.

In this way, the sheet transport path 56 is formed by the rollers 8 , 10 , 12 , and 13 and the guide piece 115 of the wall portion 75 . Also, in this case, the urging force of the coil spring 78 causes a state where the separation pad 11 presses the separation roller 10 . In this way, an appropriate frictional force is exerted between the separation roller 19 and the conveyed paper, thereby preventing the paper 3 from being fed into the paper conveyance path 56 in a stacked state.

In addition, the letter M shown in FIG. 1 denotes a drive motor. When the motor M is driven, the driving torque of the motor M is transmitted by an unillustrated power transmission gear, thereby rotating the center shafts C1 and C2 , thereby rotating the rollers 10 , 12 and 13 . Further, as shown in FIG. 1, the paper conveying path 56 is folded back into a letter U shape and rearward from near the position of the paper dust removing roller 8 (left side as shown in the figure), and the alignment rollers constituted by a pair of sticks 14 is arranged below the process cartridge 20 . Thus, the paper 3 is conveyed along the paper conveying path 56 according to the driving of the motor M and conveyed to the side of the image forming section 5 which will be described below.

Incidentally, the motor M has a drive controlled by an unshown control device (executing electronic control of the entire device). In this embodiment, a mechanism for cutting off the power supply to the motor drive circuit by detachment of the paper feed cassette 9 is assembled in the main body casing 2 . When the sheet feeding cassette 9 is in a state of being detached from the cassette accommodating portion 2A, the driving of the motor M is stopped.

Furthermore, the rollers 8, 12, and 13 are used in the present invention as "conveyor unit".

(3) Imaging part

The image forming section 5 includes a scanner section 19, a process cartridge 20, a fixing section 21, and the like.

(a) Scanner section

The scanner section 19 is arranged at the upper part inside the main body casing 2, and it includes a laser light source not shown, a polygon mirror 22 driven to rotate, an fθ lens 23, a mirror 24, a lens 25, a mirror 26, and the like. A laser beam emitted from a laser light source and based on image data is deflected by a polygon mirror 22 and passes through an fθ lens 23 as indicated by a dotted line. Thereafter, the optical path of the laser beam is returned by the mirror 24 and further passes through the lens 25 . Thereafter, the optical path of the laser beam is further bent downward by the mirror 26 . Thus, the laser beam is projected onto the surface of the photosensitive drum 29 of the process cartridge 20 to be described below.

(b) Disposal cartridge

The process cartridge 20 is detachably mounted below the scanner portion 19 in the main body casing 2 . The process cartridge 20 includes its casing, an upper frame 27 and a lower frame 28 formed separately from the upper frame 27 and combined with the upper frame 27 . Further, the process cartridge 20 includes a photosensitive drum 29 as an image carrier, a scolotron type charger 30 as a charging unit, a developing cartridge 31 , a transfer roller 32 as a transfer unit, and a cleaning brush 33 inside a casing.

The photosensitive drum 29 has a cylindrical shape, and it includes a drum main body 34 whose outermost surface is made of a positively charged photosensitive layer made of polycarbonate or the like, and a metal drum shaft 35. 35 is a shaft extending in the longitudinal direction of the drum main body 34 at the axis of the drum main body 34 . The drum shaft 35 is supported by the upper frame 27 , and the drum main body 34 is supported so as to be rotatable relative to the drum shaft 35 , whereby the photosensitive drum 29 is rotatable about the drum shaft 35 in the upper frame 27 .

The scolotron type charger 30 is supported by the upper frame 27 , and it is placed at a predetermined interval facing the photosensitive drum 29 and at a position behind the photosensitive drum 29 and obliquely upward so as not to come into contact with the photosensitive drum 29 . The scolotron type charger 30 includes a discharge wire 37 and a grid 38, wherein the discharge wire 37 is arranged against the photosensitive drum 29 and is spaced a predetermined distance therefrom, and the grid 38 is arranged between the discharge wire 37 and the photosensitive drum 29 and used It is used to control the amount of discharge from the discharge wire 37 to the photosensitive drum 29. In the scolotron type charger 30, a bias voltage is applied to the grid 38, and a high voltage is applied to the discharge wire 37 at the same time, and the discharge wire 37 is caused to generate a corona discharge, so that the surface of the photosensitive drum 29 can be evenly charged with a positive electrode. sex.

The developing cartridge 31 includes a box-shaped housing case 60 that is open at the rear and is detachably mounted on the lower frame 28 . Inside the developing cartridge 31, a toner containing chamber 39, an toner supply roller 40, a developing roller 41, and a layer thickness regulating blade 42 are arranged.

The toner accommodating chamber 39 is formed as an internal space accommodating the front side of the housing 60 partitioned by the partition plate 43 . In the toner accommodating chamber 39, toner T of a single non-magnetic component having a positive charge property is filled as a developer. Used for the toner T is a polymer toner obtained by copolymerizing a polymerizable monomer such as styrene by suspension polymerization or the like, wherein the polymerizable monomer may be a styrene monomer such as styrene, or Acrylic monomers such as acrylic acid, alkyl (C1-C4) acrylate or alkyl (C1-C4) methacrylate. This polymer toner is substantially spherical and exhibits very good fluidity, making it possible to obtain high image quality imaging.

Incidentally, colorants such as carbon black, wax, etc. are mixed in this toner, and additives such as silica are added therein to increase fluidity. The average particle size of the toner is about 6-10 μm.

In addition, an agitator 44 supported by a centrally disposed rotary shaft 55 is located in the toner containing chamber 39 . The stirrer 44 is driven to rotate by input power from a motor not shown. When the agitator 44 is driven to rotate, the toner T in the toner accommodating chamber 39 is agitated, and is discharged toward the ink supply roller 40 from the opening 45 below the partition plate 43 at the side of the laser printer. connected in the forward and backward direction. In addition, window members (not shown) are mounted on the right side wall and left side wall regions of the housing case 60 corresponding to the toner housing chamber 39, respectively. Each window is cleaned by a wiper supported by and interlocked with an agitator 44 . Incidentally, the main body casing 2 is provided with a light emitting element (not shown) outside one window part and a light receiving element (not shown) outside the other window part. In this way, light is emitted from the light-emitting element, sensing light passing through the inside of the housing case 60 is detected by the light-receiving element, and the presence or absence of toner T can be discriminated based on the output value of the sensing light.

The ink supply roller 40 is disposed on the rear side of the opening 45 and is rotatably supported by the developing cartridge 31 . The ink supply roller 40 is constructed by covering a roller body made of a conductive foam material with a roller shaft made of metal.

The developing roller 41 is rotatably supported by the developing cartridge 31 on the rear side of the ink supply roller 40 in a state where they contact the ink supply roller 40 so as to be pressed against each other. Further, when the developing cartridge 31 is mounted on the lower frame 28 , the developing roller 41 faces and contacts the photosensitive drum 29 .

At the front end portion of the developing cartridge 31, both end portions of the roller shaft 41a protrude from the side surface of the developing cartridge 31 in the width direction (Z-axis direction) of the apparatus main body. In the developing roller 41 including the roller shaft 41a, the surface of the roller body made of carbon particle-containing urethane rubber or silicone rubber is covered with a coating of fluorine-containing urethane rubber or silicone rubber. During development, a developing bias is applied to the developing roller 41 . Further, the developing roller 41 is rotated in the same direction as that of the ink supply roller 40 by being driven by input power from a motor not shown.

The layer thickness regulating piece 42 includes a piece body 46 composed of a metal leaf spring member, and a semicircular cross-sectional pressing portion 47 arranged at a distal end portion of the piece body 46 and composed of electrically insulating silicone rubber. The layer thickness regulating blade 42 is supported above the developing roller 41 by the developing cartridge 31 , and the pressing portion 47 is supported in pressing contact with the developing roller 41 by the elastic force of the blade body 46 .

The toner T discharged from the opening 45 is supplied onto the developing roller 41 by the rotation of the toner supply roller 40 . In this case, the toner T is rubbed with positive polarity between the ink supply roller 40 and the developing roller 41 . The toner T supplied to the developing roller 41 enters between the developing roller 41 and the pressing portion 47 of the layer thickness regulating blade 42 by the rotation of the developing roller 41 so that the developing roller 41 carries the toner T in a thin layer of a predetermined thickness.

The transfer roller 32 is rotatably supported by the lower frame 28 . In a state where the upper frame 27 and the lower frame 28 are combined, the transfer roller 32 is placed in contact with the photosensitive drum 29 vertically opposed thereto with a roller gap formed between the transfer roller and the photosensitive drum 29 . The transfer roller 32 is constructed by covering a metal roller shaft 32 a with a roller body made of a conductive rubber material. A transfer bias is applied to the transfer roller 32 during transfer.

A cleaning brush 33 is mounted on the lower frame 28 . In a state where the upper frame 27 and the lower frame 28 are combined, the cleaning brush 33 is positioned so as to face and contact the photosensitive drum 29 on the rear side of the photosensitive drum 29 .

As the photosensitive drum 29 rotates, its surface is first uniformly charged with a positive polarity by a scolotron type charger 30 . Thereafter, the surface is exposed to light by high-speed scanning of a laser beam from the scanner section 19, thereby being formed with an electrostatic latent image corresponding to an image to be formed on the paper 3.

Subsequently, by the rotation of the developing roller 41, when the developing roller 41 faces the photosensitive drum 29 and contacts it, the positively charged toner carried on the developing roller 41 is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 29 , in other words, the exposed portion on the surface of the photosensitive drum 29 uniformly charged with positive polarity is exposed to light by the laser beam and the potential drops. In this way, the electrostatic latent image of the photosensitive drum 29 is visualized, and a toner image based on reversal development is carried on the surface of the photosensitive drum 29 .

Thereafter, the toner image carried on the surface of the photosensitive drum 29 is transferred onto the paper 3 by the transfer bias applied to the transfer roller 32, as shown in FIG. Pass the transfer position between the photosensitive drum 29 and the transfer roller 32. The paper 3 on which the toner image is transferred is conveyed to a fixed position 21 .

Incidentally, transfer residual toner remaining on the photosensitive drum 29 after transfer is recovered by the developing roller 41 . In addition, paper dust from the paper 3 stuck to the photosensitive drum 29 after transfer is removed by the cleaning brush 33 .

(c) fixed part

The fixing portion 21 is arranged behind the process cartridge 20 . It includes a fixed frame 48 and a heating roller 49 and a pressure roller 50 arranged in the fixed frame 48 .

The heat roller 49 consists of a metal tube whose surface is coated with a fluorine-containing resin, and a heating halogen lamp arranged in the metal tube, and it is driven to rotate by input power from a motor not shown. On the other hand, the pressure roller 50 is disposed below and opposed to the heat roller 49 so as to press the heat roller 49 . This pressure roller 50 is constructed by covering a roller shaft made of metal with a roller body made of a rubber material, and is driven by rotational driving of the heating roller 49 .

In the fixing portion 21, when the paper 3 passes between the heat roller 49 and the pressure roller 50, the toner transferred onto the paper 3 at the transfer position is heated and fixed. The paper 3 with the toner fixed thereon is conveyed to the paper discharge path 51 extending vertically toward the upper surface of the main body casing 2 . The paper 3 conveyed to the paper discharge path 51 is discharged onto a paper discharge tray 53 formed on the upper surface of the main body casing 2 by a paper discharge roller 52 arranged above the paper discharge path 51 .

2. Structure for detecting installation/removal of paper feed cassette and detection of paper conveyance

Fig. 5 is a plan view of the paper feed cassette (only its front side is shown). FIG. 6 is a sectional view taken along line VI-VI of FIG. 5 . Fig. 7 is an enlarged view of part A in Fig. 3 . 8 is a sectional view showing the first attitude of the swing link (the sectional view viewed along line VIII-VIII in FIG. 5 ), FIG. 9 is a sectional view showing the second attitude of the swing link, and FIG. 10 is a sectional view showing the third attitude of the swing link. Cutaway view of the pose. Fig. 12 is a cross-sectional view when the protruding portion is arranged on the upstream side of the separation roller.

First, the configuration of the swing link 80 will be described, and then the change in the posture of the swing link 80 according to the conveyance of the paper 3 and the detachment of the paper feed cassette 9 will be described.

As shown in FIGS. 5 and 7 , the swing link 80 includes a tubular body portion 81 . The body portion 81 includes a thin-walled small-diameter portion 81A and a thick-walled large-diameter portion 81B connected to each other, and it is installed around the center axis C1 with a certain gap therebetween so as to be able to rotate floatingly (the body portion 81 is not connected to the center axis C1). C1 rotates as a whole, but is free to rotate). Further, the small-diameter portion 81A is provided with the arm 84 , and the large-diameter portion 81B is provided with a projecting plate portion (corresponding to “protruding portion” in the present invention) 95 for the paper feed cassette 9 .

The arm 84 extends upward from the outer edge of the small-diameter portion 81A, and a shielding plate (corresponding to “shielding portion” in the present invention) 85 is formed on one end surface of the arm 84 (the one end surface on this side as shown in FIG. 7 ). At the same time, a reinforcing wall 86 is formed on an end surface on the opposite side of the arm 84 (the end surface on the back as shown in FIG. 7 ).

Above the arm 84 , a shielding plate 85 is defined in a generally rectangular flat plate shape extending in the longitudinal direction of the sheet feeding cassette 9 (the X-axis direction of the apparatus main body). On the other hand, the reinforcing wall 86 is formed substantially over the entire height of the arm 84 . The tip side of the reinforcing wall 86 has a predetermined width, and the base end side thereof is formed wider than the tip side. Further, a hook-shaped spring seat 88 is formed on the base end side of the reinforcing wall 86 and on the left front side shown in FIG. 7 .

Here, the photosensor 100 for detecting a light shielding object formed on the opposite side of the shielding plate 85 will be described. The photosensor 100 is composed of a pair of light-emitting and light-receiving elements arranged oppositely (this embodiment uses a photointerrupter of transmission type in which these photointerrupters are packaged).

The photoelectric sensor 100 is fixed at the upper end position of the swing link 80 on the top wall of the cartridge accommodating portion 2A in a posture such that its optical axis is along the central axis C1 of the separation roller 10 . The photoelectric sensor 100 is set so that in the installed state (the state in which the photoelectric sensor 100, the swing link 80, and the paper feed cassette 9 are installed and the paper 3 is not conveyed), the shielding portion 85 of the swing link 80 can be positioned between the light emitting and light receiving positions. between components.

As shown in FIG. 5 , the projecting plate portion 95 extends from the peripheral surface of the large-diameter portion 81B toward the wall portion 75 of the paper feeding cassette 9 . Regarding the width of the projecting plate portion 95 , its tip side is formed slightly narrower, while its base end side is formed over the entire width of the large diameter portion 81B. Furthermore, the end face portion of the projecting plate portion 95 on the right side in FIG. 5 extends to the reinforcement wall 86 .

Meanwhile, as shown in FIGS. 7 and 8 , at a position where the wall portion 75 is opposed to the protruding plate portion 95 , there is provided a receiving portion 79 in which the wall surface is pressed down. The bottom wall of the receiving portion 79 is configured as a flat seating surface 79A for supporting the protruding portion 95 and as a guide slope 79B for guiding the projecting plate portion 95 onto the seating surface 79A during the operation of installing the paper feed cassette 9 . In addition, as shown in the figure, the tip of the protruding plate portion 95 has a little hook shape.

Next, changes in the attitude of the swing link 80 will be described.

<first stance>

When the paper feeding cassette 9 is mounted to the cassette accommodating portion 2A, the protruding plate portion 95 enters the state shown in FIG. on 79A. In this case, the arm 84 assumes a substantially vertically standing posture, and the shielding plate 85 is in a state of cutting off the optical path of the detection light emitted from the light projecting element (hereinafter, this state will be expressed as "the state in which the sensor output is OFF") "). The posture in which the projecting plate portion 95 is supported on the seat surface 79A of the receiving portion 79 will be referred to as "the first posture of the swing link 80".

In addition, reference numeral 110 in FIG. 8 denotes a coil spring (serving as "urging portion"). One end of the coil spring 110 is held at the top wall of the cartridge accommodating portion 2A, the other end is held at the spring holder 88 of the swing link 80, and when the swing link 80 is in the first posture, the coil spring 110 moves along the direction shown in the figure. The direction S pushes the swing link 80 .

<second stance>

In the state before conveyance, the projecting plate portion 95 passes through the paper conveying path 56 so that the paper 3 can cause the projecting plate portion 95 to jump upward when the conveyance of the paper 3 starts. Thus, the swing link 80 rotates in the arrow direction (direction R) shown in FIG. 9 . Furthermore, due to the rotation, the shielding plate 85 is out of the optical path of the detection light. In this way, the photosensor 100 enters a light-receiving state (hereinafter, this state will be expressed as "the state where the sensor output is ON"). Such a posture of moving the projecting plate portion 95 upward shown in FIG. 9 will be referred to as "the second posture of the swing link 80".

Here, during conveyance of the paper 3, the swing link 80 is in a state where the lower surface of the projecting plate portion 95 is supported by the paper 3, and thus, it can maintain the second attitude. However, when the rear end of the paper 3 passes through the protruding plate portion 95, the protruding plate portion 95 correspondingly loses the support of the paper 3 (or enters a free state), so that under the pushing force of the aforementioned coil spring 110, the swing link 80 returns Original pose (first pose).

<Third Stance>

Next, when the paper feeding cassette 9 is detached from the state of FIG. 8 (moving the entire cassette to the right as shown in the figure), the state in which the projecting plate portion 95 is supported on the receiving portion 79 is released as shown in FIG. . Immediately after the release occurs, since the swing link 80 is urged by the coil spring 110, it rotates in the S direction shown in FIG. 10 . In addition, the swing link 80 is provided with a stopper (not shown), and when the stopper abuts against the end surface of the separation roller 10, the rotation is stopped. In this case, the shielding plate 85 is out of the optical path of the detection light. In this way, the photosensor 100 enters a light receiving state (ON state). This posture will be referred to as "the third posture of the swing link 80".

Incidentally, the first posture, the second posture, and the third posture of the swing link correspond to the "swing position" in the present invention.

Meanwhile, when the paper feed cassette 9 is inserted into the cassette accommodating portion 2A from the third posture at this time, the bent portion of the tip end of the projecting plate portion 95 collides with the guide slope 79B of the wall portion 75 . Thereafter, the swing link 80 is rotated against the urging force of the coil spring 110 under the guidance based on the guide slope 79B. When the paper feed cassette 9 has been accommodated in the cassette accommodating portion 2A in time, the protruding plate portion 95 climbs up the guide slope 79B so as to be supported on the seat surface 79A of the receiving portion 79, that is, the swing link 80 exhibits the position shown in FIG. first gesture.

In this way, the tip of the projecting plate portion 95 is bent, and the wall portion 75 on the opposite side is provided with a guide slope 79B, so that the projecting plate portion 95 can be smoothly guided to the seat in the process of installing the sheet feeding cassette 9 into the cassette accommodating portion 2A. Surface 79A. Therefore, the projected plate portion 95 can be prevented from being strained or damaged after colliding with the wall portion 75 .

Next, the detection of the change in the attitude of the swing link 80 and the regulation of the attitude will be described. FIG. 11 is a flowchart showing the process for determining the attitude of the swing link 80 .

In a state where paper feeding cassette 9 is installed in cassette accommodating portion 2A and paper 3 is not conveyed, swing link 80 assumes the first posture, and photoelectric sensor 100 is in a light-shielding state. Conversely, when conveyance of paper 3 or detachment of paper feed cassette 9 is performed from this state, swing link 80 changes its posture so that shielding plate 85 leaves the optical path of detection light, thereby bringing the photosensor into a light-receiving state.

Therefore, as shown in FIG. 11, it is determined in step S10 whether or not the photosensor 100 is in the light-shielding state. Therefore, it is possible to detect whether the swing link 80 is in the first posture, or whether its posture has changed from the first posture as a reference (detection of posture change).

Furthermore, if it has been determined in step S10 that the photoelectric sensor 100 is in the light-receiving state, in other words, that the attitude of the swing link 80 has changed, the process shifts to step S20 to determine whether the motor M is being driven. When any one of the following two modes of change occurs, the photoelectric sensor enters the light-receiving state: when the swing link 80 changes from the first attitude as a reference to the second attitude, and when it changes from the first attitude to the third attitude. Condition. In this regard, the second posture corresponds to conveyance of paper 3 , and the third posture corresponds to detachment of paper feed cassette 9 .

Here, the drive motor M must be driven as long as the paper 3 is being conveyed. On the contrary, as described above, the drive motor M is controlled so as to be stopped when the paper feed cassette 9 is removed. Therefore, if the motor M is being driven, it can be determined that the swing link 80 is in the second posture, in other words, the paper 3 is being conveyed, and if the motor M is in a stopped state, it can be determined that the swing link 80 is in the third posture, In other words, the paper feed cassette 9 has been pulled out (regulation of posture).

By the way, based on the light-receiving signal from the light-receiving element, the control means can determine the shading or light-receiving of the photoelectric sensor 100, and based on the pulse signal from the speed control rotary encoder (used as the second detection unit) related to the motor M, control The device is capable of determining the driving condition of the motor M.

Furthermore, when paper conveyance has been determined, the conveyance timing of the paper to be sent next is determined based on the ON/OFF state of the photosensor at that time by the point to be described below.

First, by detecting the time when the photoelectric sensor 100 switches from the OFF state (shielding light) to the ON state (receiving light in the second posture), the passing of the front end of the paper 3 can be detected. On the contrary, by detecting the time when the photosensor 100 is switched from the ON state (received light in the second posture) to the OFF state (light shielding), passage of the rear end of the paper 3 can be detected.

Here, in order to determine the transport time, there are a method of using the passage of the front end of the paper 3 as a reference, and a method of using the passage of the rear end of the paper 3 as a reference. The latter method is used in this embodiment, that is, the next sheet 3 is conveyed after it is determined that the passage of the rear end of the sheet 3 has been detected. Through such control, it is possible to prevent an erroneous operation of conveying the next sheet of paper 3 before the conveyance of the single sheet of paper 3 is completed.

Furthermore, in determining such a conveyance time of the paper 3, it is desirable to shorten the conveyance interval as much as possible in consideration of the need for high-speed printing. In this regard, in this embodiment, the coil spring 110 is arranged so as to urge the swing link 80 in the return direction (direction in which the swing link 80 returns from the second posture to the first posture) as described above. Therefore, the return time period (the time period in which the swing link 80 returns from the second posture to the first posture) is shortened to an extent comparable to the return time period in the case where no pushing portion is arranged. Therefore, the delay of the on/off time of the photosensor 100 with respect to the conveyance of the paper 3 can be shortened. Therefore, when determining the conveyance time of the paper 3 based on ON/OFF, an error corresponding to a detection delay can be eliminated, with the result that the conveyance interval can be set to the shortest period of time.

Furthermore, in order to detect the rear end of the paper 3, the swing link 80 needs to be provided so that every time the single sheet 3 passes, the swing link 80 needs to return from the second posture to the first posture. In this embodiment, therefore, the projecting plate portion 95 is arranged so as to be located on the downstream side (right side in FIG. 8 ) of the paper conveyance path 56 with respect to the separation roller 10 . As shown in FIG. 12, assuming that the projecting plate portion 130 is arranged on the upstream side with respect to the separating roller 10, where the sheets 3 have not been separated, it occurs that the sheets 3 are located under the projecting plate portion 95 in a stacked state.

In this case, even if one of the stacked sheets 3 passes, the swing link 80 does not return to the first posture, so that the rear end of the sheet 3 cannot be detected. In contrast, with the above configuration (configuration in which the projecting plate portion 95 is disposed on the downstream side of the separation roller 10 ), the swing link 80 must return to the first posture at the same time as the sheet 3 passes.

Furthermore, since the coil spring 110 is provided, in addition to the attitude change from the second attitude to the first attitude as described above, the attitude change from the first attitude to the third attitude can be accelerated. Therefore, removal of the paper feed cassette 9 can also be easily detected.

Next, the operation and advantages of this embodiment will be described.

According to this embodiment, the posture (swing position) of the swing link 80 can be changed by detaching the paper feed cassette 9 or feeding paper. Specifically, before the sheet 3 is conveyed, the swing link 80 is in a state supported on the receiving portion 79 of the sheet feeding cassette 9 (first posture). When the paper 3 is conveyed, the supporting point moves to the paper 3 from the side of the paper feeding cassette 9 . Due to the movement of the support point, the posture of the swing link 80 changes from the first posture to the second posture.

On the other hand, when the paper feed cassette 9 is detached, the support of the receiving portion 79 is released, so that the swing link 80 then enters an unsupported state. Due to the change in support, the posture of the swing link 80 changes from the first posture to the third posture. Therefore, by detecting the change in the posture of the swing link 80, both the conveyance of the paper 3 and the disassembly of the paper feeding cassette 9 can be known.

In an arrangement in which the posture changes in association with paper conveyance and paper feed cassette 9 detachment, the swing link 80 has both a function of detecting paper feed and paper feed cassette 9 detachment. Therefore, compared with the case where each function is implemented by separate components, that is, compared with the case where the detecting means for detecting the detachment of the paper feeding cassette 9 and the detecting means for detecting the paper conveyance are respectively arranged at positions spaced apart from each other, , the overall configuration of the device can be more simplified in mechanism.

In addition, the photoelectric sensor 100 and the rotary encoder are used to indicate the attitude of the swing link 80 . However, the rotary encoder is an element originally used to control the driving of the motor M, and it is not an element dedicated to determining the attitude of the swing link 80 . In this embodiment, two elements, the photoelectric sensor 100 and the swing link 80 are basically added, so that the detection of the detachment of the paper feeding cassette 9 and the detection of paper feeding can be realized. Thus, the number of components itself can be small, so this embodiment contributes to cost reduction.

Also, the swing link 80 is arranged parallel to the separation roller 10 and is arranged corresponding to the central portion of the paper feed cassette 9 in the width direction. With this configuration, the number of components can be made smaller than in the case where dedicated shafts are provided for the separation roller 10 and the swing link 80, and the center portion of the sheet 3 collides with the projecting plate portion 95 of the swing link 80, and the swing link 80 can be made more compact. Move up reliably.

In addition, part of the paper conveying path 56 is constituted by the guide plate 115 of the paper feeding cassette 9 . With this configuration, the sheet conveyance path 56 is formed with originally required components, thereby achieving simplification of the apparatus.

In addition, this embodiment is characterized in that the swing link 80 changes its posture in abutment against the paper feed cassette 9 or paper 3 (contact type). On the other hand, the detection type may well be a non-contact type in which detection light is projected directly onto the paper 3 or the paper feed cassette 9 to detect light shading, thereby detecting the presence or absence of the paper 3 or paper feed cassette 9 . However, the non-contact type has a problem in that detection cannot be performed when, for example, paper or the like is a transmissive material such as transparent. In contrast, with the contact type, detection can always be performed regardless of the material of the paper.

<Other Embodiments>

The present invention is not limited to the above-described embodiments described with reference to the drawings, for example, embodiments to be described below will be included in the technical scope of the present invention. Further, in addition to the following description, the present invention can be realized by various alternatives within the scope not departing from the object of the present invention.

(1) In the foregoing embodiments, the change in attitude of the swing link 80 is detected based on the state of the photoelectric sensor 100 and the driving of the motor M. However, for example, a proximity sensor may be positioned near the swing link 80 to detect fluctuations in the position of the swing link 80 relative to the proximity sensor (displacement of the free end of the swing link 80 with rotation). With this configuration, the posture of the swing link 80 can be determined from the displacement amount of the free end portion of the swing link 80 .

(2) In the foregoing embodiments, the photosensor 100 has been set so as to block light in the case of the first posture and receive light in the case of the other postures. However, it is entirely possible for the photoelectric sensor to receive light in the first position and to block light in the other positions. Incidentally, in this case, it is necessary to arrange a plurality of shielding portions for the swing link 80 .

(3) The foregoing embodiments have been configured so that the end of the projecting plate portion 95 abuts on the paper feed cassette 9 , but the portion abutting on the paper feeding cassette 9 may be placed separately from the projecting plate portion 95 .

(4) In the foregoing embodiments, the urging portion is constituted by the coil spring 110, but it may also be constituted by a torsion spring. In this case, the torsion spring 120 may be extrapolated onto the central axis C1 as shown in FIG. 13 .

(5) In the foregoing embodiments, in order to speed up the response of the swing link 80 to the conveyance of the paper 3 and the detachment of the paper feed cassette 9, the coil spring 110 is arranged in the cassette accommodating portion 2A. However, the coil spring 110 is not an indispensable component, and the posture of the swing link 80 can also be changed by utilizing the weight of the swing link itself.

(6) In the foregoing embodiments, the paper feed cassette 9 and the structure for accommodating the paper feed cassette 9 in the main body casing may be configured as explained in the following embodiments.

14-20 illustrate another embodiment of the present invention. In this embodiment, the paper feed cassette 9 is pulled out as shown in FIG. 14 . Hereinafter, the side of the laser printer 1 on which the front cover 7 is arranged will be referred to as "front side", and the opposite side thereof will be referred to as "rear side". In addition, the laser printer 1 from which the paper feed cassette 9 has been removed is used as the "device main body 1a".

As shown in FIG. 2 , a paper feeding cassette 9 containing unprinted paper 3 is arranged under the front cover 7 in a pull-out manner from the front side.

As shown in FIG. 15, in the state where the paper feed cassette 9 is accommodated in the cassette accommodating portion 4a, the U-shaped conveyance path 56 is partially composed of the separation pad 11 and the paper dust clearing roller 8 on the paper feed cassette 9 side, and the apparatus main body 1a. Side separating roller 10 and counter roller 13 constitute. Further, the transport path 56 extends to the gap S between the upper portion of the front side of the paper feed cassette 9 and the main body casing 2 . The gap S is used to secure a space necessary for smooth opening and closing of the front cover 7 about the cover shaft 7a. Therefore, during the conveyance of the paper 3 , the rustling sound produced by the conveyance of the paper 3 between the separation roller 10 and the separation pad 11 and between the paper dust removal roller 8 and the reverse roller 13 is emitted from the gap S especially.

Therefore in this embodiment, the sponge member 270 is arranged so as to seal the gap S. As shown in FIG. Fig. 15 is a partial side view showing the paper feed cassette 9 and that part of the main body casing 2 where the upper peripheral edge portion 273 of the opening 2a is formed. Furthermore, Figures 16 and 17 are corresponding perspective views (I and II).

Specifically, as shown in FIGS. 14 and 15, in a state where the paper feed cassette 9 is accommodated in the cassette accommodating portion 4a, the front end of the paper feed cassette 9 is integrally provided with a cover wall 9a, which extends from the front side and this peripheral edge portion. The peripheral edge portion of the opening 2a is covered over the entire periphery. The shape of the cover wall 9a is such that it substantially completely covers the left and right peripheral edge portions 271 and the lower peripheral edge portion 272 of the opening 2a from the front side (see FIG. 14). Therefore, the rustling sound is not significantly emitted from the peripheral edge portions 271 and 272 .

On the contrary, the cover wall 9a is shaped so as to cover the upper peripheral edge portion 273 of the opening 2a from the front side while leaving a gap S between the cover wall 9a and the lower end portion of the front cover 7 located above. In addition, as shown in FIGS. 14-16, the cover wall 9a is formed with an upwardly standing retaining wall 274 having a width slightly larger than the lateral width of the transport path 56 (the width of the paper 3 that can be accommodated in the paper feed cassette 9, for example, A4 format). and the width of the letter size, and is the width of the width W2 shown in FIGS. 17 and 18 (the width W1 shown in FIG. 5 ).

On the other hand, the upper peripheral edge portion 273 of the opening 2a on the rear side with respect to the front cover 7 on the side of the apparatus main body 1a similarly has a width W1 slightly larger than the lateral width W2 of the transport path 56 . Further, the lower end of the upper peripheral edge portion 273 is covered with the upper end of the retaining wall 274 from the front side in the pull-out direction of the paper feed cassette 9 (the left-right direction of the drawing paper as shown in FIG. 15 ). Here, the respective opposing surfaces 273a and 274a (corresponding to the "first surface" and "second surface" in the present invention) of the upper peripheral edge portion 273 and the holding wall 274 define surfaces perpendicular to the pull-out direction, And the sponge 270 is stuck to the entire length of the opposite surface 273a with, for example, an adhesive.

In addition, as shown in FIGS. 16-18, in a state where the paper feed cassette 9 is accommodated in the cassette accommodating portion 4a, the sponge 270 is pressed between the opposing surfaces 273a and 274a and is elastically deformed. In this way, the gap S is sealed and rustling can be prevented. Incidentally, the sponge 270 is arranged so as not to protrude below the opposing surface 273a. Actually, the sponge 270 is arranged so as not to interfere with the parts of the paper feed cassette 9 during installation/detachment of the paper feed cassette 9 .

This embodiment provides a support unit for holding the paper feed cassette 9 in the cassette housing portion 4a against the reaction force of the compressed sponge 270 when the paper feed cassette 9 is accommodated in the cassette housing portion 4a. FIG. 19 is a perspective view showing a pair of inner wall panels 280 and 280 constituting the frame inside the main body casing 2 and arranged so as to support the cartridge accommodating portion 4a in the width direction therebetween. FIG. 20 is a plan view of the paper feed cassette 9. As shown in FIG.

As shown in FIG. 7, guide grooves 281 and 281 for guiding the process cartridge 20 are formed on upper portions of opposing surfaces of a pair of inner wall panels 280 and 280 so as to extend to the mounting/demounting portion 6. Referring to FIG. In addition, at the lower portion of the opposing surfaces of the pair of inner wall panels 280 and 280, guide ribs 282 for guiding the sheet feeding cassette 9 into the cassette accommodating portion 4a (in this figure, only the drawing paper deep side inner wall panel 280 is shown). The guide ribs 282) extend along the pull-out direction. In addition, engagement stoppers 284 are respectively arranged at lower portions of the opposing surfaces of the inner wall panels 280 and 280 and closer to the rear ends of the pair of inner wall panels. Each engagement stop piece 284 is supported so as to be rotatable between a posture protruding into the box accommodating portion 4a and a posture retracted in the corresponding inner wall panel 280, and it is pushed to one of the protruding postures by the spring 83 serving as the pushing portion. side (see also Figure 20).

On the other hand, on the paper feeding cassette 9 side, engagement protrusions 285 that engage with the engagement stoppers 284 are arranged on the right and left side surfaces of the paper feeding cassette 9 , respectively. As shown in FIG. 8, each engagement protrusion 285 is conical in shape when viewed from above. In the process of loading the paper feed cassette 9 into the cassette accommodating portion 4a, each engagement protrusion 285 guides the corresponding engagement stopper 284 from the protruded posture to the retracted position by the inclined surface 85a of the engagement protrusion on its rear side. attitude.

Further, since the paper feeding cassette 9 is inserted into the deep side of the cassette accommodating portion 4a, each engaging stop piece 284 passes the tip end portion of the corresponding engaging protrusion 285 to be guided by the inclined surface 285b on the front side of the engaging protrusion 285 and is returned to the protrusion pose. Incidentally, the inclined surface 285b on the front side is a steeper inclined surface than the inclined surface 285a on the rear side. Thus, the paper feed cassette 9 is held by the device main body 1 a against the reaction force of the sponge 270 by the engagement between the engagement stopper piece 284 and the engagement protrusion 285 .

As shown in FIG. 20 , columnar positioning protrusions 286 and 286 are respectively provided on the front end side of the side surface of the paper feeding cassette 9 . On the other hand, as shown in FIG. 19, the left and right peripheral edge portions 271 of the inner wall panel 280 are respectively formed with positioning recesses 287, and the positioning recesses 287 and corresponding The positioning protrusions 286 engage. In the state where the engagement stop piece 284 is engaged with the corresponding engagement protrusion, the positioning protrusion 286 and the corresponding positioning recess 287 abut against each other and overcome the engaging force of the positioning protrusion 286 and the positioning recess 287 and the reaction force of the sponge 270 to send the paper cassette. 9 is positioned to the device body 1a.

In the configuration of this embodiment, the sponge 270 is held between the opposing surface 273a (first surface) of the upper peripheral edge portion 273 and the opposing surface 274a (second surface) of the holding wall 274, thereby having 9 planes in the pull-out direction. In this way, the sponge 270 suppresses rustling sound from being transmitted from between the opening 2a and the paper feeding cassette 9 . Also, it is possible to prevent the sponge 270 from being torn off or damaged by friction during the operation of pulling out the paper feed cassette 9 .

In addition, the opposing surface 273 a and the opposing surface 274 a are surfaces perpendicular to the direction in which the paper feeding cassette 9 is pulled out. Therefore, the supporting force between the opening 2a of the device main body 1a and the cover wall 9a of the paper feed cassette 9 can be more effectively applied to the sponge 270, and the opposite surface 273a and the opposite surface 274a have an inclination angle with respect to the pulling direction. Compared with the configuration, the sealing performance of the gap S can be improved.

The sponge 270 is disposed at an upper peripheral edge portion 273 having a level difference from the main body casing 2 in depth. Therefore, even in the state where the paper feeding cassette 9 is pulled out, it is difficult to see the sponge 270 from the outside, and deterioration of the design quality of the entire device can be avoided (see FIG. 14 ). In addition, the sponge 270 is placed on the opposite surface 273a without protruding to the side of the paper feed cassette 9, so that it can be prevented from being torn off due to contact with the paper feed cassette 9 when the paper feed cassette 9 is attached/detached.

Furthermore, due to the engagement between the engagement stopper piece 284 and the corresponding engagement protrusion 285, the paper feed cassette 9 is supported by the device main body 1a against the reaction force of the sponge 270, so that the sealing performance based on the sponge 270 is enhanced. Also, in this embodiment, the opposing surface 273a and the opposing surface 274a are surfaces perpendicular to the direction in which the paper feeding cassette 9 is pulled out. So that the support force based on the support unit can be more effectively used as the pressure on the sponge 270 compared to the configuration in which the opposite surface is inclined to the pull-out direction.

In the state where the paper feeding cassette 9 is supported by the support unit, the positioning protrusions 286 and the corresponding positioning recesses 287 abut against each other in a state where the sponge 270 is pressed, so as to adjust any further movement of the paper feeding cassette 9 to the deeper side of the cassette accommodating portion 4a. move. Therefore, during accommodating the paper feed cassette 9, it is possible to prevent the sponge 270 from being strongly pushed unnecessarily and causing its damage or the like.

Incidentally, in the above-described embodiment, the sponge 270 is disposed on the opposite surface 273a of the upper peripheral edge portion 273 as the first surface. However, this arrangement is not restrictive, and the sponge may also be disposed on the opposite surface 274a side of the holding wall 274 as the second surface, or on both the opposite surface 273a and the opposite surface 274a. In a state where the sponge is arranged on the opposing surface 274a side, it is desirable to arrange it so as not to protrude (interfere) from these opposing surfaces 274a to the device main body 1a side. Furthermore, when the sponge is disposed on both the opposing surface 273a and the opposing surface 274a, the sealing performance of the gap S can be enhanced more.

Further, in this embodiment, the opposite surface 273a and the opposite surface 274a are surfaces perpendicular to the pulling-out direction. However, this is not restrictive, and the opposing surfaces may well be inclined surfaces. Furthermore, the opposing surfaces may have the same angle or different angles with respect to the pull-out direction. Actually, the opposite surfaces may respectively have angles that can support the sponge 270 and squeeze it between them in the pulling-out direction of the paper feeding cassette 9 .

In addition, this embodiment takes the laser printer 1 of the so-called "letter S path scheme" having the U-shaped conveyance path 56 as an example. However, this is not restrictive, and the advantages of the invention can be obtained even in a solution with any other delivery path. Here, in the previous embodiments in which the paper is folded back near the gap S between the paper feed cassette 9 and the opening 2a and transported, the rustling sound comes especially from the gap S, so that the invention is particularly effective .

In this embodiment, the sponge 270 is used as the elastic member as an example. However, this is not restrictive and any elastic member of rubber, film or the like may be used.

In addition, it is also permissible to use a configuration in which an elastic member is disposed over the entire circumference of the peripheral edge portion of the opening 2a.

Claims (12)

1. An imaging device comprising: a device body having a shaft, an imaging unit, and Paper conveying device, described paper conveying device comprises: A paper feed cassette detachably mounted to the main body of the device; a conveying unit that separates paper from the paper feeding cassette and conveys it to the imaging unit, the conveying unit includes a motor; a swing member which is supported swingably around a shaft portion with respect to the apparatus main body, and whose swing positions are changed in states in which the paper feed cassette is detached from the apparatus main body, the paper feed cassette is installed to the apparatus main body and a state where paper is not conveyed, and a state where the paper feeding cassette is attached to the apparatus main body and paper is being conveyed; and A detection unit that detects the swing position of the swing member based on the detection by the sensor unit and whether the motor is driven. 2. The image forming apparatus according to claim 1, wherein the paper conveying apparatus further comprises: providing a paper conveyance path between the swing member and the paper feed cassette; Wherein, the swing member is arranged to be opposite to the paper feeding box; The swing member includes a protruding portion provided to protrude above the paper conveyance path, the protruding portion including a tip portion abutting the paper feeding cassette; The swing member can swing around the shaft to assume a first posture, a second posture and a third posture; The swing member abuts the paper feeding cassette in the first posture; the swing member is rotated to assume a second posture due to collision of the conveyed sheet against the protruding portion; and In the third posture, when the paper feed cassette is detached from the apparatus main body to release the abutment of the protruding portion, the swinging member rotates in the opposite direction from the first posture to the second posture. direction of rotation. 3. The imaging device of claim 2, wherein the swing member is arranged above the paper feeding cassette; and In the first posture, the distal end portion of the protruding portion is supported by the paper feeding cassette. 4. The image forming apparatus according to claim 2, wherein the paper conveying device further comprises: The urging portion of the swing member is pushed in a direction from the second posture to the third posture. 5. The imaging device of claim 3, wherein, the paper feeding cassette is provided with a receiving portion on which a tip end portion of the protruding portion is supported; and At least one of the end portion of the protruding portion and the receiving portion is provided with a guide slope that guides the end portion to the receiving portion when the paper feeding cassette is mounted to the apparatus main body. . 6. The imaging device of claim 2, wherein the sensor unit is a photoelectric sensor having a pair of light-emitting and light-receiving elements, and its optical axis is arranged in a direction along the axial direction of the shaft portion, and A shielding portion is provided in the swing member, which cuts off the optical path of the detection light at the first posture of the swing member and opens the optical path at any other posture, or is opened at the first posture of the swing member said detecting the optical path of light and cutting off the optical path in any other gesture; and The detection unit includes a second detection unit that detects driving of the motor of the conveyance unit, wherein the driving of the motor is prohibited when the paper feeding cassette is in a state of being detached from the apparatus main body. 7. The imaging device of claim 6, wherein the device body comprises a box receiving portion having a top wall, The shielding portion has an upright upper end so as to face the top wall when the swing member is in the first posture. 8. The image forming apparatus according to claim 6, wherein the paper conveying device further comprises: a separating roller separating the paper; The protruding portion and the shielding portion are arranged on the shaft portion so as to be juxtaposed with the separation roller in an axial direction of the shaft portion. 9. The imaging device of claim 8, Wherein, the protruding portion of the swing member protrudes so as to be arranged downstream of the position where the separation roller is placed in the conveying direction of the sheet. 10. The imaging device of claim 1 , Wherein, the swing member is arranged at a substantially center portion in the axial direction of the shaft portion. 11. The imaging device of claim 1 , A part of the paper conveyance path is included in the paper feed cassette. 12. The image forming apparatus according to claim 1, wherein the swing member includes a protruding portion that contacts the paper feed cassette at a first position and contacts the paper conveyed to the image forming unit at a second position. touch.

Images