Image forming apparatus

Abstract

To provide an image forming apparatus having improved jam processing performance.SOLUTION: A process unit including an apparatus main body including an opening portion, and an opening / closing member movable between a closed position where the opening portion is covered and an open position where the opening portion is opened, an image bearing member, a toner storage portion storing toner, and a replenishment portion communicating with the toner storage portion and configured to receive toner supplied from the outside in a state where the process unit is attached to the apparatus main body, and a sheet supporting portion configured to set and support a sheet from one side of the apparatus main body, in a plan view, with the image carrier as a reference, the replenishment portion is disposed on the same side as the one side, the opening portion is disposed on the other side opposite to the one side, and the process unit is attachable to and detachable from the apparatus main body via the opening portion when the opening / closing member is located at the opening position.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a sheet. [Background technology]

[0002] Generally, electrophotographic image forming apparatuses form images by transferring a toner image formed on the surface of a photosensitive drum onto a sheet. Developer replenishment methods include a process cartridge replacement method and a toner replenishment method. The process cartridge replacement method involves replacing a process cartridge with a new one when the developer runs out. The toner replenishment method involves replenishing a developing container with new toner when the toner runs out. For example, Patent Document 1 proposes a toner replenishment method process cartridge.

[0003] The process cartridge described in Patent Document 1 is exposed by opening the discharge tray located at the top of the image forming apparatus, and is configured so that a replenishment toner pack can be attached to a supply port provided in the process cartridge. Furthermore, the process cartridge is configured so that it can be removed upward from the device main body with the discharge tray open. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-056323 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming apparatus described in Patent Document 1, the process cartridge must be attached and detached through a narrow opening that is exposed when the discharge tray is opened, which poses a problem in terms of maintainability of the process cartridge.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus in which the ease of maintenance of the process unit is improved. [Means for solving the problem]

[0007] The present invention provides an image forming apparatus that forms an image on a sheet, the apparatus comprising: an apparatus main body having an opening, an open / close member that is movable between a closed position that closes the opening and an open position that opens the opening, and an ejection tray on which sheets with images formed thereon are stacked; a process unit that is detachably supported by the apparatus main body and is capable of forming images on sheets, the process unit having a rotatable photosensitive drum that carries a toner image, a toner storage section that stores toner, and a supply section that communicates with the toner storage section and receives toner supplied from outside while the process unit is attached to the apparatus main body; and a pair of ejection rollers that eject sheets onto the ejection tray in a ejection direction, the ejection tray being a second opening where the supply section is exposed to the outside of the image forming apparatus. and a second position covering the supply unit, the supply unit being configured to be able to attach a toner container for supplying toner to the process unit when the discharge tray is positioned at the first position, the image forming device being configured to be able to form an image with the toner container removed from the supply unit when the discharge tray is positioned at the second position, the supply unit being located closer to the downstream end of the device main body than the upstream end in the discharge direction when viewed in the direction of gravity, and the opening being upstream of the photosensitive drum in the discharge direction, and the process unit being configured to be able to be attached and detached to the device main body through the opening when the opening / closing member is positioned at the open position. The present invention also provides an image forming apparatus comprising: an apparatus main body having an opening and an opening / closing member movable between a closed position where the opening is closed and an open position where the opening is open; a process unit detachably supported by the apparatus main body and capable of forming an image on a sheet, the process unit having a rotatable photosensitive drum that carries a toner image, a toner storage section that stores toner, and a supply section that communicates with the toner storage section and receives toner supplied from outside while the process unit is attached to the apparatus main body; an output tray on which sheets that have been discharged from the apparatus main body after an image has been formed are stacked; a pair of output rollers that discharge the sheets onto the output tray in a discharge direction; a drive source that drives the photosensitive drum; and a laser beam that irradiates the photosensitive drum with laser light and rotates the photosensitive drum. and a scanner unit that forms an electrostatic latent image on the drum, wherein when viewed in the direction of gravity, the supply unit is located closer to the downstream end of the device main body than to the upstream end in the discharge direction, and the opening is located upstream of the photosensitive drum in the discharge direction, the process unit is configured to be attachable to and detachable from the device main body through the opening when the opening / closing member is located in the open position, the supply unit is configured to be able to attach a toner container for supplying toner to the process unit, and is located on the opposite side to the side where the drive source is located when the position of the scanner unit is used as a reference in the direction of the rotation axis of the photosensitive drum, and is configured to be able to form an image when the toner container is removed from the supply unit. [Effects of the Invention]

[0008] According to the present invention, the maintainability of the process unit can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic view showing an entire image forming apparatus. [Figure 2] FIG. 1 is a cross-sectional view showing a configuration of an image forming apparatus. [Figure 3] FIG. 1 is a perspective view showing an internal configuration of an image forming apparatus. [Figure 4] FIG. 3 is a block diagram illustrating the function of a power supply board. [Figure 5] FIG. 2 is a perspective view showing the image forming apparatus before a process unit is attached. [Figure 6] 1A is a rear view and an enlarged view showing the positioning configuration of the process unit by the left plate frame, and FIG. 1B is a rear view and an enlarged view showing the positioning configuration of the process unit by the right plate frame. [Figure 7] FIG. 2 is a perspective view showing the image forming apparatus with a process unit attached thereto. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] (a) is a perspective view showing an image forming apparatus with the discharge tray closed, (b) is a perspective view showing an image forming apparatus with the discharge tray open, and (c) is a perspective view showing an image forming apparatus with a supply pack attached to the supply section. [Figure 11] 1A is a perspective view showing the supply unit, FIG. 1B is a perspective view showing the supply unit and a part of the supply pack, and FIG. 1C is a perspective view showing the supply unit when the operating unit is located at the supply position. [Figure 12] FIG. 2 is a left side view showing the image forming apparatus. [Figure 13] FIG. 1 is a plan view showing an image forming apparatus 1. [Figure 14] 1A is a perspective view showing the supply pack when the pack shutter is in the closed position, and FIG. 1B is another perspective view showing the supply pack when the pack shutter is in the closed position. [Figure 15] 1A is a perspective view showing the supply pack when the pack shutter is in the open position, and FIG. 1B is another perspective view showing the supply pack when the pack shutter is in the open position. [Figure 16] FIG. 2A is an exploded perspective view showing the supply pack, and FIG. 2B is another exploded perspective view showing the supply pack. [Figure 17](a) is a perspective view showing an image forming apparatus with the rear cover closed, (b) is a perspective view showing an image forming apparatus with the rear cover open, and (c) is a perspective view showing an image forming apparatus with the transfer unit open. [Figure 18] (a) is a cross-sectional view showing the image forming apparatus with the rear cover closed, (b) is a cross-sectional view showing the image forming apparatus with the rear cover open, (c) is a cross-sectional view showing the image forming apparatus with the transfer unit open, and (d) is a cross-sectional view showing the image forming apparatus in the process of closing the rear cover. [Figure 19] (a) is a perspective view showing the image forming apparatus with the rear cover closed, (b) is a perspective view showing the image forming apparatus with the transfer unit open, (c) is a perspective view showing the start of removal of the process unit, and (d) is a perspective view showing the removal process of the process unit. [Figure 20] (a) is a cross-sectional view showing the image forming apparatus with the rear cover closed, (b) is a cross-sectional view showing the image forming apparatus with the transfer unit open, (c) is a cross-sectional view showing the start of removal of the process unit, and (d) is a cross-sectional view showing the removal process of the process unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not limited to the following embodiments.

[0011] First Embodiment Fig. 1 is a perspective view showing an image forming apparatus 1 according to a first embodiment. Fig. 2 is a cross-sectional view showing the configuration of the image forming apparatus 1. The image forming apparatus 1 is a monochrome printer that forms an image on a recording material based on image information input from an external device. The recording material includes various sheet materials of different materials, such as paper such as plain paper and cardboard, plastic film such as sheets for overhead projectors, sheets of special shapes such as envelopes and index paper, and cloth.

[0012] In the following description, the height direction of the image forming apparatus 1 (the direction opposite to the vertical direction) when the image forming apparatus 1 is installed on a horizontal surface is referred to as the Z direction. The direction that intersects with the Z direction and is parallel to the direction of the rotation axis of the photosensitive drum 11 (main scanning direction) described later is referred to as the X direction. The direction that intersects with the X and Z directions is referred to as the Y direction. The X, Y, and Z directions preferably intersect perpendicularly with each other. For convenience, the positive side in the X direction is referred to as the right side and the negative side is referred to as the left side; the positive side in the Y direction is referred to as the front side or front side and the negative side is referred to as the rear side or back side; and the positive side in the Z direction is referred to as the upper side and the negative side is referred to as the lower side.

[0013] [Overall configuration] As shown in Figures 1 and 2, the image forming apparatus 1 has an image forming section 20 that forms a toner image on a recording material, a feeding section 30 that feeds the recording material P, a fixing section 9 that fixes the toner image formed by the image forming section 20 to the recording material, and a pair of discharge rollers 10.

[0014] The image forming section 20 has a scanner unit 50, an electrophotographic process unit 40, and a transfer unit 7 including a transfer roller 7a that transfers a toner image carried on a photosensitive drum 11 of the process unit 40 onto a recording material P as a sheet. The process unit 40 has the photosensitive drum 11, a cleaning unit 13 arranged around the photosensitive drum 11, a charging roller 17, a developing roller 12, and a developing container 230 (see FIG. 8) equipped with a container 18 that contains toner. The transfer roller 7a is urged toward the photosensitive drum 11 by an urging member (not shown).

[0015] The photosensitive drum 11 serving as an image carrier is a cylindrically shaped photosensitive member. The photosensitive drum 11 of this embodiment has a photosensitive layer formed of a negatively chargeable organic photosensitive material on a drum-shaped substrate made of aluminum. The photosensitive drum 11 serving as an image carrier is driven to rotate in a predetermined direction (direction R in the figure) at a predetermined process speed by a motor.

[0016] The charging roller 17 contacts the photosensitive drum 11 with a predetermined pressure to form a charging portion. A desired charging voltage is applied from a charging high-voltage power supply, thereby uniformly charging the surface of the photosensitive drum 11 to a predetermined potential. In this embodiment, the photosensitive drum 11 is negatively charged by the charging roller 17.

[0017] The scanner unit 50 uses a polygon mirror to irradiate the photosensitive drum 11 with laser light corresponding to image information input from an external device, thereby scanning and exposing the surface of the photosensitive drum 11. This exposure forms an electrostatic latent image corresponding to the image information on the surface of the photosensitive drum 11. Note that the scanner unit 50 is not limited to a laser scanner device, and may, for example, be an LED exposure device having an LED array in which a plurality of LEDs are arranged along the longitudinal direction of the photosensitive drum 11.

[0018] 3 and 5, the apparatus main body 2 of the image forming apparatus 1 has a left side panel frame 74 and a right side panel frame 75, and a scanner holding member 76 is suspended between the left side panel frame 74 and the right side panel frame 75. The scanner holding member 76 holds the scanner unit 50. Meanwhile, a drive motor 311 serving as a drive source is attached to the right side panel frame 75, and a pinion gear connected to the drive motor 311 is provided on the positive side (right side) of the right side panel frame 75 in the X direction. The driving force of the drive motor 311 is transmitted to the feed roller 5a and the photosensitive drum 11 via this pinion gear.

[0019] 1 and 2, the developing roller 12 is rotatably supported by a storage portion 18 serving as a toner storage portion. The developing roller 12 is disposed at the opening of a developer container 230 (see FIG. 8) including the storage portion 18 so as to face the photosensitive drum 11. The storage portion 18 may be provided with a supply roller that applies toner stored in the storage portion 18 as a developer onto the surface of the developing roller 12.

[0020] The process unit 40 of this embodiment uses a contact development method. That is, a toner layer carried on the development roller 12 comes into contact with the photosensitive drum 11 in a development section (development area) where the photosensitive drum 11 and the development roller 12 face each other. A development voltage is applied to the development roller 12 by a development high-voltage power supply. Under the development voltage, the toner carried on the development roller 12 is transferred from the development roller 12 to the drum surface in accordance with the potential distribution on the surface of the photosensitive drum 11, thereby developing the electrostatic latent image into a toner image.

[0021] The toner of this embodiment does not contain a magnetic component, and is a so-called non-magnetic one-component developer in which the toner is carried on the developing roller 12 mainly by intermolecular forces and electrostatic forces (image forces). However, a one-component developer containing a magnetic component may also be used. In addition to toner particles, a one-component developer may also contain additives (e.g., wax or silica particles) for adjusting the fluidity and charging performance of the toner. A two-component developer composed of non-magnetic toner and a magnetic carrier may also be used as the developer. When a magnetic developer is used, a cylindrical developing sleeve with a magnet disposed inside is used as the developer carrier, for example.

[0022] The fixing unit 9 is a thermal fixing unit that fixes the image by heating and melting the toner on the recording material and applying pressure to it. The fixing unit 9 includes a heating roller 9a incorporating a fixing heater 9c, and a pressure roller 9b that presses against the heating roller 9a.

[0023] The feeding section 30 has a cassette 4 as a sheet support section on which the recording material P is stacked, and a pickup roller 3 as a feeding section, a feeding roller 5a, and a separation roller 5b. A front cover 70 is provided on a portion of the front end surface of the image forming apparatus 1, and the front cover 70 covers a circuit board 100. The apparatus body 2 of the image forming apparatus 1 has a housing 72. The housing 72 has the front cover 70, a discharge tray 14, a rear cover 73 (see FIG. 17(a)), and an exterior cover 71 that forms the exterior of the image forming apparatus 1 other than the front cover 70, the discharge tray 14, and the rear cover 73. The housing 72 is formed with a discharge opening 15 through which sheets pass to be discharged onto the discharge tray 14.

[0024] As shown in FIG. 2, the image forming apparatus 1 has a circuit board 100. The circuit board 100 is composed of a wiring board 101 made of an insulator and electronic components 111 and 121 soldered to the wiring board 101. Conductor wiring is provided on and inside the wiring board 101, so that the electronic components 111 and 121 are electrically connected. The circuit board 100 has the function of converting AC current supplied from outside the image forming apparatus 1 into DC current, and converting the input voltage to obtain a predetermined voltage value required for the image formation process.

[0025] The circuit board 100 is oriented such that the surface of the wiring board 101 on which the electronic components 111 and 121 are mounted intersects with the ejection direction. Furthermore, the wiring board 101 is provided between the front cover 70 and the scanner unit 50 in the ejection direction. The electronic components 111 and 121 are provided on the surface of the wiring board 101 facing the scanner unit 50.

[0026] Next, an image forming operation of the image forming apparatus 1 will be described. When an image formation command is input to the image forming apparatus 1, the image forming process is started by the image forming section 20 based on image information input from an external computer connected to the image forming apparatus 1. The scanner unit 50 irradiates the photosensitive drum 11 with laser light based on the input image information. At this time, the photosensitive drum 11 is pre-charged by the charging roller 17, and an electrostatic latent image is formed on the photosensitive drum 11 by the irradiation of the laser light. Thereafter, the electrostatic latent image is developed by the developing roller 12, and a toner image is formed on the photosensitive drum 11.

[0027] In parallel with the image forming process described above, a pickup roller 3 of a feeding unit 30 feeds a recording material P supported by a cassette 4. The recording material P fed by the pickup roller 3 is separated into individual sheets by a feeding roller 5a and a separation roller 5b, and conveyed to a conveying roller pair 5c. The recording material P is then conveyed by the conveying roller pair 5c as a conveying unit toward a transfer nip N1 formed by a transfer roller 7a and a photosensitive drum 11.

[0028] A transfer voltage is applied to the transfer roller 7a from a transfer high-voltage power supply, and the toner image carried on the photosensitive drum 11 is transferred onto the recording material P being conveyed by the conveying roller pair 5c. The recording material P with the transferred toner image is conveyed to the fixing unit 9, and the toner image is heated and pressurized as it passes through the fixing nip N2 between the heating roller 9a and pressure roller 9b of the fixing unit 9. This melts the toner particles and then solidifies them, thereby fixing the toner image to the recording material P. After passing through the fixing unit 9, the recording material P is discharged from the discharge port 15 by the discharge roller pair 10 to the outside of the image forming apparatus 1 (outside the machine) and is stacked on the discharge tray 14.

[0029] When forming images on both sides of the recording material P, the pair of discharge rollers 10 switches back the recording material P with the image formed on the first side, thereby guiding the recording material P to the double-sided conveying path 16. The recording material P guided to the double-sided conveying path 16 is conveyed again by the pair of double-sided conveying rollers 5d via the conveying path 19 toward the transfer roller 7a. After an image is formed on the second side of the recording material P by the transfer roller 7a, the recording material P is discharged outside the apparatus by the pair of discharge rollers 10. After the toner image is transferred onto the recording material P, any toner remaining on the photosensitive drum 11 is cleaned by the cleaning unit 13.

[0030] [Control Block] FIG. 4 is a block diagram illustrating the function of circuit board 100 according to this embodiment. Circuit board 100 includes low-voltage power supply unit 110 and high-voltage power supply unit 120. Low-voltage power supply unit 110 receives power from an external power source via a power supply input unit (not shown) mounted on the edge of the board and converts the AC voltage into a stable DC voltage using a rectifying and smoothing circuit including an electrolytic capacitor. Low-voltage power supply unit 110 then converts the DC voltage into a high-frequency AC voltage using switching elements such as transistors, and inputs the high-frequency AC voltage into a low-voltage power transformer. The low-voltage power transformer converts the high-frequency AC voltage, which is the input voltage, into an AC voltage (output voltage) having a desired voltage value. Low-voltage power supply unit 110 again converts the AC voltage into a DC voltage and outputs the resulting DC voltage to high-voltage power supply unit 120. Because losses in individual circuit components manifest as heat, low-voltage power supply unit 110 is provided with a heat sink (not shown) made of aluminum or iron for heat dissipation.

[0031] The high-voltage power supply unit 120 converts the voltage (for example, 24 V) supplied from the low-voltage power supply unit 110 into a high voltage required for the image formation process, such as charging, developing, and transferring. The voltage supplied from the low-voltage power supply unit 110 is converted into a charging voltage by a charging transformer and supplied to the charging roller 17. The voltage supplied from the low-voltage power supply unit 110 is converted into a developing voltage by a developing transformer 123 and supplied to the developing roller 12. The voltage supplied from the low-voltage power supply unit 110 is converted into a transferring voltage by a transferring transformer and supplied to the transfer roller 7a.

[0032] The low-voltage power supply unit 110 supplies voltage (e.g., 3.3 V or 5 V) not only to the high-voltage power supply unit 120 but also to the scanner unit 50, the drive motor 311, the engine controller 130, and the video controller 140. The engine controller 130, which serves as a control unit, plays a central role in controlling the various process components. The engine controller 130 includes a CPU (not shown), a RAM (not shown) used for calculations and temporary storage of data required to control the image forming apparatus 1, and a ROM (not shown) for storing programs and various data for controlling the image forming apparatus 1. The video controller 140 communicates with an external device such as a personal computer to receive print data and notifies the engine controller 130 of the results of analyzing the print data. The engine controller 130 and the video controller 140 may be provided on a board separate from the circuit board 100, or may be provided on the same board.

[0033] Furthermore, AC power received by the power input unit from the commercial power supply is supplied not only to the low-voltage power supply unit 110 but also to the fixing heater 9c. The rollers and other components in the fixing unit 9 are driven by a drive motor 311.

[0034] [Process unit positioning configuration] Next, the positioning configuration of the process unit 40 will be described with reference to Figures 5 to 7. Figure 5 is a perspective view showing the image forming apparatus 1 in a state before the process unit 40 is installed. Figure 6(a) is a rear view and an enlarged view showing the positioning configuration of the process unit 40 by the left side plate frame 74, and Figure 6(b) is a rear view and an enlarged view showing the positioning configuration of the process unit 40 by the right side plate frame 75.

[0035] 5, the process unit 40 has a left side surface 30L and a right side surface 30R as end surfaces in a longitudinal direction LD parallel to the direction of the arrow X. A left positioning boss 41L and a left rotation restricting boss 42L are provided on the left side surface 30L, and a right positioning boss 41R (not shown) and a right rotation restricting boss 42R (not shown) are provided on the right side surface 30R. The left positioning boss 41L and the right positioning boss 41R are located upstream of the left rotation restricting boss 42L and the right rotation restricting boss 42R, respectively, in the installation direction AD of the process unit 40.

[0036] In the present embodiment, the process unit 40 is provided with boss-shaped positioning bosses and rotation restricting bosses, but the present invention is not limited to this. That is, the process unit 40 may be provided with positioning portions and rotation restricting portions that are not boss-shaped.

[0037] The device body 2 of the image forming device 1 has a left side plate frame 74 and a right side plate frame 75 made of sheet metal members, and these left side plate frame 74 and right side plate frame 75 face each other with a gap in the longitudinal direction LD, which is the second direction.

[0038] As shown in FIGS. 5 and 6(a), the left side plate frame 74 has a first left surface 81Lf and a second left surface 82Lf extending in the installation direction AD (Y direction) and the Z direction. The second left surface 82Lf is positioned inward of the device body 2 by a distance X1 from the first left surface 81Lf in the longitudinal direction LD by drawing the first left surface 81Lf. In other words, the first left surface 81Lf and the second left surface 82Lf are not coplanar. In this embodiment, the second left surface 82Lf is configured as a surface parallel to the installation direction AD (Y direction) and the Z direction, but is not limited to this. For example, the second left surface 82Lf may be a curved surface along the installation direction AD (Y direction) and the Z direction.

[0039] The first left surface 81Lf is formed with a left positioning portion 81L with which the left positioning boss 41L can engage, and the left positioning portion 81L is a notch that is open on the upstream side in the installation direction AD. The second left surface 82Lf is formed with a left rotation restricting portion 82L with which the left rotation restricting boss 42L can engage, and the left rotation restricting portion 82L is a U-shaped notch that is open on the upstream side in the installation direction AD. Note that, because the second left surface 82Lf is formed by drawing, a slope that guides the left positioning boss 41L toward the left positioning portion 81L may be formed.

[0040] Since the first left surface 81Lf and the second left surface 82Lf are spaced apart by the distance X1 in the longitudinal direction LD, the left rotation restricting portion 82L is also spaced apart by the distance X1 in the longitudinal direction LD from the left positioning portion 81L. In other words, the left rotation restricting portion 82L is located at a different position from the left positioning portion 81L in the longitudinal direction LD.

[0041] Similarly, as shown in FIGS. 5 and 6(b), the right side plate frame 75 has a right first surface 81Rf and a right second surface 82Rf extending along the installation direction AD (Y direction) and the Z direction. The right second surface 82Rf is disposed inward of the device body 2 by a distance X2 from the right first surface 81Rf in the longitudinal direction LD by drawing the right first surface 81Rf. In other words, the right first surface 81Rf and the right second surface 82Rf are not coplanar. In this embodiment, the right first surface 81Rf and the right second surface 82Rf are configured as surfaces parallel to the installation direction AD (Y direction) and the Z direction, but are not limited thereto. For example, the right second surface 82Rf may be a curved surface along the installation direction AD (Y direction) and the Z direction.

[0042] The right first surface 81Rf is formed with a right positioning portion 81R with which the right positioning boss 41R can engage, and the right positioning portion 81R is a notch that is open on the upstream side in the installation direction AD. The right second surface 82Rf is formed with a right rotation restricting portion 82R with which the right rotation restricting boss 42R can engage, and the right rotation restricting portion 82R is a U-shaped notch that is open on the upstream side in the installation direction AD. Note that, because the right second surface 82Rf is formed by drawing, a slope that guides the right positioning boss 41R toward the right positioning portion 81R may be formed.

[0043] Since the first right surface 81Rf and the second right surface 82Rf are spaced apart by the distance X2 in the longitudinal direction LD, the right rotation restricting portion 82R is also spaced apart by the distance X2 in the longitudinal direction LD from the right positioning portion 81R. In other words, the right rotation restricting portion 82R is located at a different position from the right positioning portion 81R in the longitudinal direction LD.

[0044] 7 is a perspective view showing the image forming apparatus 1 with the process unit 40 attached. As shown in FIGS. 5 to 7, when the process unit 40 is attached to the apparatus body 2, the left positioning boss 41L and the left rotation restricting boss 42L of the process unit 40 engage with the left positioning portion 81L and the left rotation restricting portion 82L of the left side plate frame 74, respectively. Similarly, when the process unit 40 is attached to the apparatus body 2, the right positioning boss 41R and the right rotation restricting boss 42R of the process unit 40 engage with the right positioning portion 81R and the right rotation restricting portion 82R of the right side plate frame 75, respectively.

[0045] The process unit 40 is positioned in the installation direction AD by the left positioning boss 41L and the right positioning boss 41R engaging with the left positioning portion 81L and the right positioning portion 81R, respectively. Furthermore, the left rotation restriction boss 42L and the right rotation restriction boss 42R engaging with the left rotation restriction portion 82L and the right rotation restriction portion 82R, respectively, restricts rotational movement of the process unit 40 about the left positioning boss 41L and the right positioning boss 41R. In other words, the process unit 40 is positioned in the Z direction, which is the first direction.

[0046] In this state, the process unit 40 is fixed from the rear side to the front side to the left side plate frame 74 and the right side plate frame 75 by left and right fixing members 79L, 79R (see FIG. 19(b)) described later.

[0047] In this embodiment, the left positioning portion 81L and the left rotation restricting portion 82L are provided on the same sheet metal member, the left side frame plate 74. This reduces cumulative tolerances and improves the positioning accuracy of the process unit 40. Furthermore, because the left positioning portion 81L is located upstream of the left rotation restricting portion 82L in the mounting direction AD, the cutout shape of the left positioning portion 81L formed in the first left surface 81Lf can be formed with a relatively small area. By reducing the area of ​​the cutout formed in the left side frame plate 74, the rigidity of the left side frame plate 74 can be maintained. Maintaining the rigidity of the left side frame plate 74 improves the positioning accuracy of the process unit 40 relative to the device body 2. Furthermore, since the left side frame plate 74 does not need to be thick, it can be made lighter and less expensive. The same applies to the right side frame plate 75.

[0048] [Developer container] Next, the developing container 230 and its peripheral configuration will be described with reference to Figures 8 and 9. As shown in Figure 8, the developing container 230 is composed of a storage section 18 and a supply section 200 that communicates with the storage section 18 and receives toner supplied from the outside when the process unit 40 is attached to the apparatus main body 2. The supply section 200 has an operation section 201, a cylindrical toner receiving section 202, a supply path section 203 that connects the toner receiving section 202 and the storage section 18, and a main body shutter section 206 that serves as a main body shutter. A side opening 205 that connects to the supply path section 203 is formed in the inner wall of the toner receiving section 202.

[0049] As shown in Figure 9, a supply pack 210, which will be described later, is attached to the supply unit 200, and the toner discharged from the supply pack 210 is supplied to the storage unit 18 through an opening 207 in the main body shutter unit 206, a side opening 205 in the toner receiving unit 202, and the supply path unit 203.

[0050] As shown in FIG. 8 , the supply path 203 is connected to one end of the container 18 in the longitudinal direction of the developer container 230, i.e., the X direction. As shown in FIG. 9 , an agitator 60 is provided inside the container 18, rotating about a rotation shaft 60a extending in the X direction. The agitator 60 has blades 60b fixed to the rotation shaft 60a, and is driven to rotate by the drive motor 311 to agitate the toner in the container 18 and transport the toner toward the developing roller 12. Note that, in the present embodiment, the agitator 60 is composed of the rotation shaft 60a and the blades 60b, but a spiral-shaped agitator may also be used to distribute the toner throughout the entire length of the container 18.

[0051] The agitating member 60 also circulates the toner that has not been used for development and has been scraped off from the developing roller 12 within the storage section 18, thereby homogenizing the toner within the storage section 18. The agitating member 60 is not limited to a rotating type. For example, an agitating member that oscillates may also be used. Furthermore, in addition to the agitating member 60, another agitating member may also be provided.

[0052] The container 18 is also provided with a remaining amount detection unit 312 as a sensor for detecting the amount of toner in the container 18, and the remaining amount detection unit 312 has a light-emitting unit 312a and a light-receiving unit 312b. Light emitted from the light-emitting unit 312a passes through the inside of the container 18 and is received by the light-receiving unit 312b. That is, the light-emitting unit 312a and the light-receiving unit 312b form an optical path Q1 inside the container 18. The light-emitting unit 312a and the light-receiving unit 312b may have their light-emitting element and light-receiving element disposed inside the container 18, or may have their light-emitting element and light-receiving element disposed outside the container 18, with the light guide unit guiding the light between the inside and outside of the container 18.

[0053] Furthermore, light-emitting element 312a and light-receiving element 312b are provided in the central portion of storage unit 18 in the X direction. By providing light-emitting element 312a and light-receiving element 312b in the central portion of storage unit 18, it is possible to accurately detect the remaining amount of toner in storage unit 18. That is, while developer (toner) may be unevenly distributed at the ends of storage unit 18 in the X direction, the central portion of storage unit 18 has less uneven distribution of developer, making it possible to detect the actual remaining amount of toner.

[0054] In this embodiment, an LED is used for the light-emitting unit 312a, and a phototransistor that is turned on by light from the LED is used for the light-receiving unit 312b, but the present invention is not limited to this. For example, a halogen lamp or a fluorescent lamp may be used for the light-emitting unit 312a, and a photodiode or an avalanche photodiode may be used for the light-receiving unit 312b.

[0055] [Supply Department] Next, the supply unit 200 will be described with reference to FIGS. 10(a) to 11(c). The discharge tray 14 is supported so as to be able to open and close between a closed position where the recording material P can be stacked as shown in FIG. 10(a) and an open position where the discharge tray 14 is open relative to the apparatus body 2 of the image forming apparatus 1 as shown in FIG. 10(b). The discharge tray 14 covers the supply unit 200 in the closed position. When the discharge tray 14 is opened to the open position, a top surface 240 and the supply unit 200 disposed on the top surface 240 are exposed. As shown in FIG. 10(c), the supply unit 200 is configured to have a detachable supply pack 210, allowing a user or service technician to replenish toner from the outside without removing the developing container 230 from the apparatus body 2. Hereinafter, users and workers such as service technicians will be collectively referred to as users.

[0056] Furthermore, the supply unit 200 is disposed on the same side as the cassette 4 in the Y direction with respect to the photosensitive drum 11. In other words, in a plan view, the supply unit 200 is disposed on one side (the front side) of the photosensitive drum 11, which is the same side as the cassette 4, and an opening 91 (see FIG. 17(b)), which will be described later, is disposed on the other side (the rear side) of the photosensitive drum 11. This allows the supply of both toner and recording material P to be performed on the front side of the image forming apparatus 1, improving usability.

[0057] 10(b) and 10(c), the operation unit 201 is disposed on the top surface 240 and forms a supply port 204, which is an inlet for replenishing toner. The operation unit 201 is provided so as to surround the supply port 204 and has a ring portion 201a rotatably supported on the top surface 240 or the toner receiving portion 202, and a lever portion 201b integrally provided with the ring portion 201a. The operation unit 201 is a member for operating the opening and closing of the main body shutter 206 and the pack shutter 214 from the outside.

[0058] As shown in FIG. 11(a), the toner receiving portion 202 is disposed inside the main body shutter portion 206 and is provided with guide portions 247 and 248 that are integral with the toner receiving portion 202. The main body shutter portion 206 is a cylindrical member that is concentric with the toner receiving portion 202 and is provided rotatably inside the toner receiving portion 202. The main body shutter portion 206 has an opening 207 (see FIG. 11(c)), and in the closed position shown in FIG. 11(a), the opening 207 and the side opening 205 of the toner receiving portion 202 are misaligned. A seal member 243 is fixed to the main body shutter portion 206 so as to surround the periphery of the opening 207.

[0059] 11(a) is shown by a broken line because it is covered by the main body shutter 206 which is in the closed position. Therefore, the side opening 205 is blocked by the main body shutter 206, and the toner is not discharged into the supply path 203.

[0060] 11(c), the opening 207 overlaps with the side opening 205 of the toner receiving section 202. Therefore, the toner supplied from the supply pack 210 (see FIG. 11(c)) attached to the supply section 200 can be discharged to the supply path section 203 through the side opening 205 and the opening 207.

[0061] The main body shutter 206 is provided with a main body shutter drive transmission protrusion 206a, which will be described in detail later, and is used to receive drive from the supply pack 210 and rotate the main body shutter 206. When the operation unit 201 is rotated with the supply pack 210 attached to the supply unit 200, the main body shutter 206 moves between a closed position and an open position.

[0062] The operation unit 201 is provided with an operation unit drive transmission protrusion 201d that protrudes radially inward from the inner circumferential surface of the toner receiving unit 202. The operation unit drive transmission protrusion 201d is engaged with a main body shutter drive transmission protrusion 206a via a pair of drive transmission surfaces 214b (see FIG. 14(b)) of the pack shutter 214 of the supply pack 210. When the user rotates the lever portion 201b of the operation unit 201 counterclockwise by 90 degrees from the closed position shown in FIG. 11(a) to the open position shown in FIG. 11(c).

[0063] When forming an image on the recording material P, the toner is stirred in the container 18 by the stirring member 60 (see FIG. 9), and the side opening 205 needs to be closed by the main body shutter 206 to prevent the toner from leaking out from the side opening 205. Therefore, during image formation, the operation unit 201 is located in the operating position shown in FIG. 11(a) so that the main body shutter 206 is located in the closed position. On the other hand, when replenishing toner from a replenishing pack 210 (described later) to the container 18, the side opening 205 needs to be opened. Therefore, during toner replenishing, the operation unit 201 is located in the replenishing position shown in FIG. 11(c) so that the main body shutter 206 is located in the open position.

[0064] [Resupply Department Layout and Configuration] Next, a detailed description will be given of the arrangement and configuration of the supply unit 200. Figure 12 is a left side view showing the image forming apparatus 1. In Figure 12, the exterior cover 71 and the left side plate frame 74 are not shown.

[0065] As shown in Fig. 12, the supply unit 200 at least partially overlaps with the scanner unit 50 when viewed in the rotational axis direction (X direction) of the photosensitive drum 11. The portion of the scanner unit 50 that overlaps with the supply unit 200 is indicated by a dotted line in Fig. 12. Specifically, the toner receiving portion 202 and the supply path portion 203 of the supply unit 200 are arranged so as to overlap with the scanner unit 50 when viewed in the rotational axis direction of the photosensitive drum 11. Here, in the horizontal direction (Y direction), the area where the supply port 204 is provided is referred to as area R1, and the area where the scanner unit 50 is provided is referred to as area R2. In this case, area R1 overlaps with area R2 when viewed in the rotational axis direction of the photosensitive drum 11.

[0066] An imaginary plane that passes through the uppermost end portion 18b of the frame 18a of the storage unit 18 and is parallel to the horizontal plane is defined as an imaginary plane S. The imaginary plane S is indicated by a dashed line in FIG. 12 . The entire operation unit 201 of the supply unit 200, a part of the toner receiving unit 202, and a part of the supply path 203 are located above the imaginary plane S. In other words, a part of the supply unit 200 is located above the imaginary plane S. Furthermore, a part of the parts of the toner receiving unit 202 and the supply path 203 that are above the imaginary plane S overlaps with the scanner unit 50 when viewed in the direction of the rotation axis of the photosensitive drum 11.

[0067] On the other hand, a portion of the storage section 18 also overlaps with the drum frame 11a when viewed in the direction of the rotation axis of the photosensitive drum 11, as indicated by a dashed line in Fig. 12. In this way, by increasing the volume of the storage section 18, it is possible to increase the toner capacity that the storage section 18 can accommodate. The drum frame 11a rotatably supports the photosensitive drum 11, and the storage section 18 rotatably supports the developing roller 12 that carries the developer. 13 is a plan view showing the image forming apparatus 1 without showing the exterior cover 71. In the X direction, the width X3 of the supply port 204 is shorter than the width X4 of the storage section 18.

[0068] The laser light irradiated from the scanner unit 50 onto the photosensitive drum 11 spreads into a trapezoidal shape as shown in Figure 13 due to the action of a polygon mirror and a lens (neither of which are shown). Therefore, in the X direction, the width X5 of the scanner unit 50 is shorter than the width X6 of the photosensitive drum 11. As a result, a space is created between the left end of the scanner unit 50 and the left side plate frame 74, and in this embodiment, the supply unit 200 is provided in that space.

[0069] Furthermore, in the X direction, the supply unit 200 (width X3) and the scanner unit 50 (width X5) are provided side by side within the area (width X4) where the storage unit 18 is provided. This makes it possible to reduce the impact of providing the supply unit 200 on the size of the image forming apparatus 1.

[0070] Moreover, the process unit 40 is arranged so that at least a portion thereof overlaps the scanner unit 50 in a plan view. Furthermore, as shown in FIG. 20(a), the process unit 40 is arranged so that at least a portion thereof overlaps the fixing unit 9 in a plan view. This arrangement of the process unit 40, the scanner unit 50, and the fixing unit 9 makes it possible to increase the toner capacity of the storage unit 18 without increasing the size of the image forming apparatus 1. Note that the arrangement of the process unit 40, the scanner unit 50, and the fixing unit 9 is not limited to the arrangement described above.

[0071] 3, the supply unit 200 is disposed on the opposite side of the drive motor 311 in the rotational axis direction (X direction) of the photosensitive drum 11, when the position of the scanner unit 50 is used as a reference. In this embodiment, a relatively small drive motor 311 is used, and therefore, as shown in FIG. 12, the drive motor 311 and the supply unit 200 do not overlap in the Z direction. However, since the supply unit 200 is disposed on the opposite side of the scanner unit 50 as described above, the drive motor 311 can be replaced with a larger one that overlaps with the supply unit 200 in the Z direction. This improves design flexibility.

[0072] [Supply Pack] Next, the configuration of the supply pack 210 will be described with reference to Figures 14(a) to 16(b). Figures 14(a) and 14(b) are perspective views showing the supply pack when the pack shutter 214 is in the closed position. Figures 15(a) and 15(b) are perspective views showing the supply pack when the pack shutter 214 is in the open position. Figures 16(a) and 16(b) are exploded perspective views showing the supply pack.

[0073] Replenishment pack 210, which serves as a toner container, has pouch portion 211, which serves as a bag containing toner to be replenished, cylindrical insertion portion 212, which is inserted into replenishing port 204, and pack shutter portion 214, which serves as a container shutter. Insertion portion 212, which serves as a nozzle, communicates with pouch portion 211. Insertion portion 212 has opening 213, which serves as an opening through which toner in pouch portion 211 is discharged to the outside. Pouch portion 211 is made of a plastic bag that is easily deformable, but is not limited to this. For example, pouch portion 211 may be made of a resin bottle container, or a paper or vinyl container.

[0074] A pouch end 216 is formed in the pouch portion 211 at the end opposite to the insertion portion 212. The pouch portion 211 has a flattened shape toward the pouch end 216, and the pouch end 216 extends in a radial direction perpendicular to the rotation axis direction of the pack shutter portion 214.

[0075] The pack shutter 214 is a cylindrical member concentric with the insertion portion 212, and is provided radially outward of the insertion portion 212. The pack shutter 214 has an opening 214c, and by rotating relative to the insertion portion 212, it can transition between a closed position that blocks the opening 213 of the insertion portion 212 and an open position that opens the opening 213. When the opening 214c of the pack shutter 214 and the opening 213 of the insertion portion 212 overlap, toner can be replenished from the replenishment pack 210 to the replenishment portion 200.

[0076] In addition, a seal member 231 that can slide against the outer surface of the insertion portion 212 is fixed to the inner surface of the pack shutter portion 214, and the seal member 231 blocks the opening 213 of the insertion portion 212 when the pack shutter portion 214 is positioned in the closed position.

[0077] 16(a), the insertion portion 212 is formed with guided portions 232 recessed from the outer circumferential surface of the insertion portion 212, and each guided portion 232 has a pair of first guided portions 232a and second guided portions 232b. When the supply pack 210 is attached to the supply unit 200, guide portions 247, 248 integral with the toner receiving portion 202 fit into the guided portions 232. This restricts relative movement between the insertion portion 212 and the toner receiving portion 202 in the circumferential direction around the rotation axis of the pack shutter 214.

[0078] 16(b), the outer peripheral surface of the pack shutter 214 is provided with an alignment portion 217 that engages with the operating portion 201, and a drive transmission surface 214b that faces the alignment portion 217 in the circumferential direction of the outer periphery of the pack shutter 214. That is, a groove (a recess that recesses inward in the radial direction of the pack shutter 214) is formed in the outer peripheral surface of the pack shutter 214, with the alignment portion 217 serving as the groove bottom surface (recess bottom surface) and the drive transmission surface 214b serving as the groove side surface. This groove is open at the tip of the outer peripheral surface of the pack shutter 214 in the insertion direction of the insertion portion 212. The drive transmission surface 214b receives a force in the circumferential direction from the operating portion drive transmission protrusion 201d of the operating portion 201, causing the pack shutter 214 to rotate relative to the insertion portion 212.

[0079] When the pack shutter 214 is in the closed position, the insertion portion 212 is in a state in which an opening 214c provided in the pack shutter 214 and a guided portion 232 recessed from the outer circumferential surface of the insertion portion 212 overlap with each other in the circumferential rotation phase. In this state, the guide portions 247, 248 of the supply unit 200 are inserted into the guided portion 232 of the supply pack 210, and the opening 214c fits into the periphery of a seal member 243 provided on the inner circumferential surface of the main body shutter 206. When the supply pack 210 is attached to the supply unit 200, of the guided portion 232, a first guided portion 232a on the upstream side in the insertion direction engages with the guide portion 247, and a second guided portion 232b on the downstream side faces the guide portion 248. A surface extending in the circumferential direction, which is a step portion between first guided portion 232a and second guided portion 232b, engages in the insertion direction with a surface extending in the circumferential direction, which is a step portion between guide portion 247 and guide portion 248, and determines the position in the insertion direction between insertion portion 212 and operating portion 201. Opening 214c has a notched shape that widens in width toward the tip side of insertion portion 212. A pair of opposing portions that face each other in the circumferential direction and form opening 214c sandwich seal member 243 in the circumferential direction.

[0080] The drive transmission surface 214b of the pack shutter 214 engages with the operation unit drive transmission protrusion 201d of the operation unit 201 and also engages with the main body shutter drive transmission protrusion 206a of the main body shutter 206. The pack shutter 214 moves (rotates) due to the operation (operation) force of the operation unit 201, and transmits the operation force to the main body shutter 206, causing the main body shutter 206 to move as well. In other words, the drive transmission surface 214b has an area that engages and abuts with the operation unit drive transmission protrusion 201d as a force receiving area. The operation unit drive transmission protrusion 201d has a convex shape that extends radially inward from the inner circumferential surface of the operation unit 201, and the drive transmission surface 214b has an area that engages and abuts with the main body shutter drive transmission protrusion 206a as a force applying area.

[0081] [Toner replenishment procedure] Next, a procedure for replenishing toner using the replenishing pack 210 will be described with reference to Figures 10(a) to 16(b). First, as shown in Figures 10(a) to 10(c), the user removes the recording material P on the discharge tray 14 and opens the discharge tray 14 from the closed position to the open position. This exposes the replenishing unit 200. The replenishing unit 200 is provided on the upper front surface of the image forming apparatus 1, making it easy to replenishing toner.

[0082] When the discharge tray 14 is opened to the open position and the supply unit 200 is exposed, the operation unit 201 is positioned in the operating position. Then, the user aligns the operation unit drive transmission protrusion 201d (see FIG. 11(a)) provided on the supply unit 200 with the alignment notch 217 (see FIG. 16(b)) provided on the supply pack 210, and attaches the supply pack 210 to the supply unit 200. If the positions of the operation unit drive transmission protrusion 201d and the alignment notch 217 do not match, the supply pack 210 will interfere with the operation unit drive transmission protrusion 201d, and the supply pack 210 cannot be inserted.

[0083] 10(c) is a perspective view showing the state in which the supply pack 210 is attached to the supply unit 200. In this embodiment, as shown in FIG. 10(c), the supply pack 210 can be attached to the supply unit 200 when the direction of arrow D, which is the extension direction of the pouch end 216, is parallel to the X direction. When the supply pack 210 is inserted all the way into the supply unit 200, the drive transmission surface 214b forming the alignment notch 217 engages with the operation unit drive transmission protrusion 201d of the operation unit 201. In addition, the drive transmission surface 214b of the pack shutter 214 engages with the main body shutter drive transmission protrusion 206a of the main body shutter 206.

[0084] That is, the rotation of operation unit 201 is transmitted to pack shutter unit 214, and the rotation of pack shutter unit 214 is transmitted to main body shutter unit 206. As a result, main body shutter unit 206 and pack shutter unit 214 engage with each other and become integrated, and operation unit 201, pack shutter unit 214, and main body shutter unit 206 move in conjunction with each other.

[0085] 11(c), the user rotates the lever portion 201b of the operating portion 201 counterclockwise by 90 degrees. This rotates the operating portion 201 from the operating position to the replenishing position, and the pack shutter portion 214 and the main body shutter portion 206 rotate from the closed position to the open position. As a result, the opening 214c of the pack shutter portion 214, the opening 213 of the insertion portion 212 of the replenishing pack 210, the opening 207 of the main body shutter portion 206, and the side opening 205 of the toner receiving portion 202 are aligned. This causes the toner in the replenishing pack 210 to be discharged into the storage portion 18 through the replenishing path portion 203.

[0086] In other words, when the operating unit 201 is located at the replenishing position, the replenishing unit 200 is in a replenishing state in which toner can be replenished from the replenishing pack 210 to the storage unit 18. At this time, the opening 213 of the replenishing pack 210 and the side opening 205 of the toner receiving unit 202 are in communication with each other.

[0087] When the toner supply from the supply pack 210 to the storage unit 18 is complete, the user returns the operation unit 201 from the supply position to the operating position. That is, the user rotates the lever portion 201b of the operation unit 201 clockwise by 90 degrees. This causes the pack shutter portion 214 and the main body shutter portion 206 to rotate from the open position to the closed position.

[0088] In other words, when the operating unit 201 is in the operating position, the supply unit 200 is in a non-supply state where toner can be supplied from the supply pack 210 to the storage unit 18. At this time, the opening 213 of the supply pack 210 and the side opening 205 of the toner receiving unit 202 do not communicate with each other.

[0089] Then, the user removes the supply pack 210 from the supply unit 200. In this manner, when the supply pack 210 is removed from the supply unit 200, the pack shutter 214 is in the closed position, so that toner leakage from the opening 213 of the supply pack 210 can be prevented.

[0090] [Rear cover and transfer unit] Next, the peripheral configuration of the rear cover 73 and the transfer unit 7 will be described using Figures 17(a) to 18(d). As shown in Figures 17(a) to 18(d), the rear of the image forming apparatus 1 is provided with an opening 91 formed by an exterior cover 71 and a rear cover 73 that covers the opening 91. The rear cover 73, which serves as an opening / closing member, is supported so as to be openable and closable between an open position and a closed position, centered on a cover engagement portion 73d. In the closed position, the rear cover 73 covers the opening 91, the transfer unit 7, and the process unit 40, and in the open position, the rear cover 73 opens the opening 91 to expose the transfer unit 7 and the process unit 40. In addition, the transfer unit 7 is supported so as to be openable and closable, centered on a rotation shaft 7c.

[0091] An outer surface 73b of the rear cover 73, i.e., a surface that constitutes the exterior surface of the housing 72, is provided with a gripping portion 73c that can be gripped by a user when opening or closing the rear cover 73. An inner surface 73f of the rear cover 73 opposite to the outer surface 73b is provided with a plurality of (three in this embodiment) engaging claws 73a, a plurality of transport ribs 73g, and a pressing rib 73e as a pressing portion.

[0092] The rear cover 73 is held in the closed position shown in Figures 17(a) and 18(a) by the engagement of the engagement claws 73a with the exterior cover 71. Furthermore, when the rear cover 73 is in the closed position, the transfer unit 7 is retracted into the inside of the device main body 2 by a link member (not shown), and remains in the closed state until operated by the user. The transfer roller 7a, which serves as a transfer section, transfers the toner image carried on the photosensitive drum 11 onto a sheet when the transfer unit is in the closed position.

[0093] As shown in Figures 17(b) and 18(b), when the rear cover 73 is opened to the open position, the duplex conveying path 16, through which the recording material P conveyed by the duplex conveying roller pair 5d passes, is opened. The duplex conveying path 16 is formed by a plurality of conveying ribs 73g of the rear cover 73 and a plurality of conveying ribs 16a formed on the outer surface of the transfer unit 7. In other words, the conveying ribs 73g as a guide portion constitute a part of the duplex conveying path 16 as a second conveying path when the rear cover 73 is located at the closed position. That is, the rear cover 73 is movable between a closed position where it covers the duplex conveying path 16 and an open position where it exposes and opens the duplex conveying path 16 to the outside. The duplex conveying path 16 and the conveying path 19 are conveying paths through which sheets are conveyed.

[0094] Furthermore, the pressure roller 9b of the fixing unit 9 is brought into contact with or separated from the heat roller 9a by a link (not shown) in conjunction with the opening and closing of the rear cover 73. Therefore, when the rear cover 73 is in the open position and the double-sided conveying path 16 is open, the pressure roller 9b is separated from the heat roller 9a.

[0095] Next, as shown in FIGS. 17(c) and 18(c), when the transfer unit 7 is opened around the pivot shaft 7c with the rear cover 73 in the open position, the conveying path 19 is opened. The recording material P is fed by the pickup roller 3 and conveyed by the conveying roller pair 5c, the transfer nip N1, and the fixing nip N2 through the conveying path 19 as a first conveying path. That is, the transfer unit 7 is movable between a closed position as a first position that covers the conveying path 19 and an open position as a second position that exposes and opens the conveying path 19 to the outside. Note that the conveying path 19 can be opened even when the process unit 40 is attached to the apparatus main body 2 when the transfer unit 7 is in the open position.

[0096] The inner surface of the transfer unit 7 is provided with transport ribs 19a that form the transport path 19. The outer surface of the transfer unit 7 is provided with a plurality of transport ribs 16a and a grip portion 7b (see FIG. 17(b)), and the transfer unit 7 is rotated between a closed position and an open position by the user operating the grip portion 7b.

[0097] [Jam Clearance] Next, a jam clearance method will be described when a jam occurs in the double-sided conveying path 16 or the conveying path 19. When a jam of recording material P occurs during image formation operation, the user opens the rear cover 73 from the closed position to the open position, as shown in Figures 17(a) and 17(b) and 18(a) and 18(b). This opens the double-sided conveying path 16, and when a jam occurs near the double-sided conveying path 16, the jammed recording material P can be removed.

[0098] On the other hand, if a jam occurs near the transfer nip N1, the user opens the rear cover 73 and the transfer unit 7 to the open position, as shown in Figures 17(c) and 18(c). This opens the conveying path 19, allowing the user to remove the recording material P that has jammed near the conveying path 19. In this way, even if a jam occurs in the double-sided conveying path 16 or the conveying path 19, the jam can be cleared from the rear side of the image forming apparatus 1 while the process unit 40 remains attached to the apparatus main body 2. This makes jam clearance less cumbersome and improves jam clearance efficiency.

[0099] After the jam removal is complete, the user closes the rear cover 73 from the open position to the closed position while leaving the transfer unit 7 in the open position, as shown in FIG. 18(d). The rear cover 73 then rotates independently until it is closed approximately 25° from the open position. The pressing rib 73e of the rear cover 73 then comes into contact with the pressed portion 7d of the transfer unit 7. As the rear cover 73 continues to close toward the closed position, the transfer unit 7 is also pressed by the pressing rib 73e, moving from the open position to the closed position. This eliminates the need to close the transfer unit 7, improving usability. The user can also close the transfer unit 7 before closing the rear cover 73.

[0100] [Attaching and detaching the process unit] 19(a) to 20(d), a method for attaching and detaching the process unit 40, for example, when replacing or maintaining the process unit 40, will be described. When removing the process unit 40 from the apparatus main body 2, the user moves the rear cover 73 and the transfer unit 7 to the open position, as shown in FIGS. 19(a) and 19(b) and 20(a) and 20(b), in the same way as in the jam clearance described above. This exposes the process unit 40 to the outside, but in this state, the process unit 40 is fixed to the left side plate frame 74 and the right side plate frame 75 by fixing members 79L and 79R.

[0101] In this embodiment, the process unit 40 is fixed to the left plate frame 74 and the right plate frame 75 using fixing members 79L, 79R made of sheet metal and screws, but this is not limiting. For example, the process unit 40 may be held in the device body 2 by a biasing member such as a spring, or the process unit 40 may be held in the device body 2 by using the biasing force of the transfer roller 7a of the transfer unit 7 against the photosensitive drum 11.

[0102] To remove the process unit 40 from the apparatus main body 2, first remove the fixing members 79L and 79R. Then, the drive transmission between the pinion gear of the drive motor 311 and the photosensitive drum 11 is disengaged, and the process unit 40 is moved in the removal direction DD, which is opposite to the installation direction AD (see FIG. 5), as shown in FIGS. 19(c) and 20(c). This causes the left positioning boss 41L and the right positioning boss 41R to move away from the left positioning portion 81L and the right positioning portion 81R, and the left rotation restriction boss 42L and the right rotation restriction boss 42R to move away from the left rotation restriction portion 82L and the right rotation restriction portion 82R. In other words, the process unit 40 can be attached to and detached from the apparatus main body 2 through the opening 91 when the rear cover 73 is in the open position and the transfer unit 7 is in the open position. The opening 91 is located at the rear of the apparatus main body 2 and can occupy a relatively large area, which facilitates attachment and detachment of the process unit 40 and improves maintainability of the process unit 40.

[0103] In this embodiment, the fixing unit 9 is held by a fixing stay 78 suspended between the left side plate frame 74 and the right side plate frame 75. In order to reduce the size of the image forming apparatus 1, the supply unit 200, which is part of the process unit 40, overlaps with the fixing unit 9 in the X direction and the Z direction. In other words, the supply unit 200 is disposed upstream of the fixing unit 9 in the removal direction DD, and is disposed so that at least a portion of the supply unit 200 overlaps with the fixing unit 9 when viewed in the removal direction DD.

[0104] 19(d) and 20(d), the user moves the process unit 40 in the removal direction DD while rotating it about an axis parallel to the X direction in the process of pulling out the process unit 40 from the device body 2. In addition, the fixing stay 78 serving as a holding member is provided with a notch 78a, and is configured so that the supply part 200 can pass through the notch 78a when the process unit 40 is pulled out from the device body 2.

[0105] The process unit 40 may be configured so as not to overlap the fixing unit 9 in the pulling-out direction DD, so that the process unit 40 can be pulled out in the pulling-out direction DD without being rotated. Also, the process unit 40 may be configured so as not to overlap the fixing unit 9 in the Z direction, so that the process unit 40 can be pulled out in the negative Y direction, for example.

[0106] To mount the process unit 40 in the apparatus main body 2, the above-described steps for removing the process unit 40 are performed in reverse. That is, the process unit 40 is mounted in the mounting direction AD (see FIG. 5) while being rotated about the X-axis relative to the apparatus main body 2.

[0107] As described above, in the present embodiment, in the toner supply type image forming apparatus 1, jam clearance and the installation and removal of the process unit 40 are performed through the same opening 91 on the rear side of the image forming apparatus 1. This allows, for example, the area occupied by the movement path of the process unit 40 when installing or removing the process unit 40 to be reduced, thereby improving the space efficiency within the image forming apparatus 1. Furthermore, the opening 91 can have a relatively large area, improving the ease of installation and removal of the process unit 40 and the ease of jam clearance. This allows the toner capacity stored in the storage section 18 to be increased while the main body size is reduced, and jam clearance and maintenance of the process unit 40 can be improved.

[0108] <Other embodiments> In the above-described embodiment, the image forming apparatus 1 is configured to include the double-sided conveying path 16 and to be able to form images on both sides of the recording material P, but this is not limiting. For example, the image forming apparatus 1 may be configured to be able to form an image on only one side of the recording material P without including the double-sided conveying path 16. In this case, the transfer unit 7 does not need to be configured to be openable and closable, and for example, the transfer roller 7a may be rotatably supported by the rear cover 73. As a result, when the rear cover 73 is opened, the conveying path 19 is opened.

[0109] In the above embodiment, when the photosensitive drum 11 is used as a reference, the supply unit 200 and the cassette 4 are arranged on one side (the front side) and the opening 91 is arranged on the other side (the rear side) in a plan view, but this is not limiting. For example, the supply unit 200 may be arranged on the other side (the rear side) of the photosensitive drum 11. [Explanation of symbols]

[0110] 1: Image forming apparatus / 2: Device body / 4: Sheet support section (cassette) / 7: Transfer unit / 7a: Transfer section (transfer roller) / 9: Fixing section / 11: Image carrier (photosensitive drum) / 16: Conveying path, second conveying path (double-sided conveying path) / 18: Toner storage section (storage section) / 19: Conveying path, first conveying path (conveying path) / 40: Process unit / 50: Scanner unit / 73: Opening / closing member (rear cover) / 73e: Pressing section (pressing rib) / 73g: Guide section (conveying rib) / 78: Holding member (fixing stay) / 78a: Notch / 91: Opening / 200: Supply section / 311: Drive source (drive motor) / DD: Removal direction / X: Rotation axis direction

Claims

1. An image forming apparatus for forming an image on a sheet, an apparatus body including an opening, an opening / closing member movable between a closed position for closing the opening and an open position for opening the opening, and an ejection tray on which sheets having images formed thereon are stacked; a process unit detachably supported by the apparatus main body and capable of forming an image on a sheet, the process unit having a rotatable photosensitive drum that carries a toner image, a toner storage section that stores toner, and a supply section that communicates with the toner storage section and receives toner supplied from an external source while the process unit is attached to the apparatus main body; a pair of discharge rollers that discharge the sheet in a discharge direction onto the discharge tray, the discharge tray is movable between a first position where the supply unit is exposed to the outside of the image forming apparatus and a second position where the supply unit is covered; the supply unit is configured to be able to mount a toner container for supplying toner to the process unit when the discharge tray is located at the first position; the image forming apparatus is configured to be able to form an image in a state where the toner container is removed from the supply unit when the discharge tray is located at the second position, When viewed in the direction of gravity, the supply unit is located closer to a downstream end of the device main body than to an upstream end thereof in the discharge direction, and the opening is located upstream of the photosensitive drum in the discharge direction, the process unit is configured to be attachable to and detachable from the apparatus body through the opening when the opening / closing member is in the open position. An image forming apparatus characterized by:

2. The toner container attached to the supply unit restricts the discharge tray from moving from the first position to the second position.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. a scanner unit that irradiates the photosensitive drum with a laser beam to form an electrostatic latent image on the photosensitive drum; the process unit is disposed so as to overlap at least a portion of the process unit with the scanner unit when viewed in the direction of the rotation axis of the photosensitive drum; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. a drive source for driving the photosensitive drum; the supply unit is disposed on the opposite side to the side where the drive source is present when the position of the scanner unit is used as a reference in the direction of the rotation axis of the photosensitive drum; 4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

5. a fixing unit that fixes the toner image transferred onto the sheet, the process unit is disposed so as to overlap at least a portion of the process unit with the fixing unit in the direction of gravity; 5. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

6. the supply unit is disposed upstream of the fixing unit in a direction in which the process unit is removed, and is disposed so as to overlap at least a portion of the supply unit with the fixing unit when viewed in the direction in which the process unit is removed.

6. The image forming apparatus according to claim 5,

7. a holding member for holding the fixing portion, the holding member has an opening through which the supply unit passes when the process unit is removed from the apparatus body in the removal direction.

7. The image forming apparatus according to claim 6, wherein the image forming apparatus is a recording medium.

8. When the process unit is removed from the apparatus main body, the process unit is rotated around an axis parallel to the rotation axis direction of the photosensitive drum.

8. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. the opening / closing member has a guide portion that, at the closed position, forms a part of a conveying path along which a sheet is conveyed, and when positioned at the open position, opens the conveying path in a state in which the process unit is attached to the apparatus body; 9. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

10. a transfer unit movable between a third position and a fourth position, the transfer unit having a transfer portion that transfers a toner image carried on the photosensitive drum onto a sheet when the transfer unit is located at the third position; the process unit is detachable from the apparatus main body when the opening / closing member is in the open position and the transfer unit is in the fourth position.

10. The image forming apparatus according to claim 9,

11. the conveying path includes a first conveying path through which a sheet heading toward the transfer unit passes, and a second conveying path for conveying the sheet, on whose first surface an image has been transferred by the transfer unit, again toward the first conveying path; the guide portion constitutes a part of the second transport path when the opening / closing member is located at the closed position, When the transfer unit is located at the fourth position, the transfer unit opens the first transport path in a state where the process unit is attached to the apparatus main body.

11. The image forming apparatus according to claim 10.

12. the opening / closing member has a pressing portion that moves the transfer unit from the fourth position to the third position when the opening / closing member moves from the open position to the closed position.

12. The image forming apparatus according to claim 10, wherein the image forming apparatus is a recording medium.

13. an apparatus body including an opening and an opening / closing member movable between a closed position that closes the opening and an open position that opens the opening; a process unit detachably supported by the apparatus main body and capable of forming an image on a sheet, the process unit having a rotatable photosensitive drum that carries a toner image, a toner storage section that stores toner, and a supply section that communicates with the toner storage section and receives toner supplied from an external source while the process unit is attached to the apparatus main body; a discharge tray on which sheets discharged from the apparatus main body after images are formed are stacked; a pair of discharge rollers that discharge the sheet onto the discharge tray in a discharge direction; a drive source that drives the photosensitive drum; a scanner unit that irradiates the photosensitive drum with a laser beam to form an electrostatic latent image on the photosensitive drum, When viewed in the direction of gravity, the supply unit is located closer to a downstream end of the device main body than to an upstream end thereof in the discharge direction, and the opening is located upstream of the photosensitive drum in the discharge direction, the process unit is configured to be attachable to and detachable from the apparatus body through the opening when the opening / closing member is in the open position, the supply unit is configured to be able to mount a toner container for supplying toner to the process unit, and is disposed on an opposite side to a side where the drive source is present, with respect to the position of the scanner unit as a reference, in a rotation axis direction of the photosensitive drum; An image can be formed in a state where the toner container is removed from the supply unit. An image forming apparatus characterized by:

14. the process unit is disposed so as to overlap at least a portion of the process unit with the scanner unit when viewed in the direction of the rotation axis of the photosensitive drum; 14. The image forming apparatus according to claim 13.

15. a fixing unit that fixes the toner image transferred onto the sheet, the process unit is disposed so as to overlap at least a portion of the process unit with the fixing unit in the direction of gravity; 15. The image forming apparatus according to claim 13 or 14.

16. the supply unit is disposed upstream of the fixing unit in a direction in which the process unit is removed, and is disposed so as to overlap at least a portion of the supply unit with the fixing unit when viewed in the direction in which the process unit is removed.

16. The image forming apparatus according to claim 15.

17. a holding member for holding the fixing portion, the holding member has an opening through which the supply unit passes when the process unit is removed from the apparatus body in the removal direction.

17. The image forming apparatus according to claim 16.

18. When the process unit is removed from the apparatus main body, the process unit is rotated around an axis parallel to the rotation axis direction of the photosensitive drum.

18. The image forming apparatus according to claim 13, wherein the image forming apparatus is a recording medium.

19. the opening / closing member has a guide portion that, at the closed position, forms a part of a conveying path along which a sheet is conveyed, and when positioned at the open position, opens the conveying path in a state in which the process unit is attached to the apparatus body; 19. The image forming apparatus according to claim 13, wherein the image forming apparatus is a recording medium.

20. a transfer unit movable between a third position and a fourth position, the transfer unit having a transfer portion that transfers a toner image carried on the photosensitive drum onto a sheet when the transfer unit is located at the third position; the process unit is detachable from the apparatus main body when the opening / closing member is in the open position and the transfer unit is in the fourth position.

20. The image forming apparatus according to claim 19.

Images