JP2023091684A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can reduce operating force to open an opening and closing part to improve usability.SOLUTION: An image forming apparatus comprises: an apparatus body that has a rotatable image carrier; an opening and closing part that is provided between a first closed position and a first open position in an openable and closable manner; an urging part that urges the opening and closing part toward the first closed position; a lock part that is movable to a lock position and an unlock position; and a cover part that is provided between a second closed position and a second open position in an openable and closable manner, and at the second closed position, covers the opening and closing part located at the first closed position. When the cover part is located at the second closed position, the lock part is located at the lock position. The urging force of the urging part is larger than first reactive force that the opening and closing part receives from the apparatus body, and is smaller than a total sum of the first reactive force and second reactive force that the opening and closing part receives from a recording material conveyed on a conveyance path.SELECTED DRAWING: Figure 35

Description

The present invention relates to an image forming apparatus that forms an image on a recording material.

Generally, an electrophotographic image forming apparatus forms an image by transferring a toner image formed on the surface of a photosensitive drum onto a recording medium. Methods for replenishing the developer include a process cartridge replacement method and a toner replenishment method. The process cartridge replacement method is a method in which the process cartridge is replaced with a new one when the developer runs out. The toner replenishing method is a method of replenishing the developing container with new toner when the toner runs out.

By the way, Japanese Patent Application Laid-Open No. 2002-200001 proposes an image forming apparatus having a double-sided unit and a secondary transfer unit that can be opened and closed. In this image forming apparatus, when a jam occurs near the secondary transfer roller, the jammed recording medium can be accessed by opening the secondary transfer unit after opening the duplex unit. In addition, the secondary transfer unit is provided with a secondary transfer lock mechanism, and the secondary transfer lock mechanism engages with a body-side engaged portion provided in the apparatus main body, thereby locking the secondary transfer unit. can be locked in the closed state.

Japanese Patent Application Laid-Open No. 2021-021918

By the way, the secondary transfer unit forms a secondary transfer nip for transferring the toner image onto the recording medium even if it is pressed by the conveyed recording medium, and performs stable image formation. may be energized by However, if the biasing force of the biasing member is increased, the operating force required for the user to open the secondary transfer unit is increased, resulting in deterioration of usability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of improving usability by reducing the operating force required to open an opening/closing portion.

The present invention provides an image forming apparatus comprising an apparatus main body having a rotatable image carrier, and a transfer member forming a transfer nip together with the image carrier and transferring an image formed on the image carrier to a recording material. a protruding portion provided adjacent to the transfer nip at a position upstream of the transfer nip in the conveying direction of the recording material and configured to curve the recording material toward the image bearing member; an opening/closing portion provided to be openable/closable between a closed first closed position and a first open position opened with respect to the device main body; and an opening/closing portion facing the first closed position. an urging portion for biasing; a locking position provided on either one of the opening/closing portion and the device main body for locking the opening/closing portion located in the first closed position with respect to the device main body; a lock portion movable to an unlocked position where the device main body is unlocked; a second closed position where the device main body is closed; and a second open position where the device main body is opened. and a cover part that can be opened and closed between and and covers the opening and closing part positioned at the first closed position in the second closed position, and the lock part has the cover part in the second closed position is positioned at the locked position when the position is positioned at .

According to the present invention, it is possible to reduce the operating force for opening the opening/closing portion and improve usability.

1 is an overall schematic diagram showing an image forming apparatus; FIG. FIG. 2 is a cross-sectional view showing the configuration of an image forming apparatus; 2 is a perspective view showing the internal configuration of the image forming apparatus; FIG. FIG. 2 is a block diagram for explaining functions of a power supply board; FIG. 2 is a perspective view showing the image forming apparatus before the process unit is attached; (a) is a rear view and an enlarged view showing the positioning structure of the process unit by the left side plate frame, and (b) is a rear view and an enlarged view showing the positioning structure of the process unit by the right side plate frame. FIG. 2 is a perspective view showing the image forming apparatus with the process unit attached; FIG. 3 is a perspective view showing a process unit; FIG. 3 is a cross-sectional view showing a replenishing section and a developer container; (a) is a perspective view showing the image forming apparatus with the ejection tray closed, (b) is a perspective view showing the image forming apparatus with the ejection tray open, and (c) is a supply pack attached to the supply unit. FIG. 2 is a perspective view showing the image forming apparatus in a folded state; (a) is a perspective view showing the supply section, (b) is a perspective view showing the supply section and part of the supply pack, and (c) is a perspective view showing the supply section when the operation section is positioned at the supply position. FIG. 2 is a left side view of the image forming apparatus; 2 is a plan view showing the image forming apparatus; FIG. (a) is a perspective view showing the supply pack when the pack shutter is positioned at the closed position, and (b) is another perspective view showing the supply pack when the pack shutter is positioned at the closed position. (a) is a perspective view showing the replenishment pack when the pack shutter is at the open position, and (b) is another perspective view showing the replenishment pack when the pack shutter is at the open position. (a) is an exploded perspective view showing the supply pack, (b) is another exploded perspective view showing the supply pack. (a) is a perspective view showing the image forming apparatus with the back cover closed, (b) is a perspective view showing the image forming apparatus with the back cover open, and (c) is an image with the transfer unit open. The perspective view which shows a forming apparatus. 1A is a cross-sectional view showing the image forming apparatus with the back cover closed, and FIG. 1B is a cross-sectional view showing the image forming apparatus with the back cover open. (c) is a cross-sectional view showing the image forming apparatus with the transfer unit opened, and (d) is a cross-sectional view showing the image forming apparatus in the process of closing the rear cover. (a) is a perspective view showing the image forming apparatus with the back cover closed, and (b) is a perspective view showing the image forming apparatus with the transfer unit open. (c) is a perspective view showing how the process unit has started to be removed, and (d) is a perspective view showing the process of removing the process unit. (a) is a cross-sectional view showing the image forming apparatus with the back cover closed, and (b) is a cross-sectional view showing the image forming apparatus with the transfer unit open. (c) is a cross-sectional view showing how the removal of the process unit is started; (d) is a cross-sectional view showing the process of removing the process unit; FIG. 2 is a perspective view showing the image forming apparatus with the back cover opened; (a) is a perspective view showing a link and its peripheral configuration when the transfer unit is positioned at the closed position. (b) is a side view showing the link and its peripheral configuration, (c) is a perspective view showing the link, link holder and tension spring, and (d) is another perspective view showing the link, link holder and tension spring. (a) is a perspective view showing a link and its peripheral configuration when the transfer unit is positioned at the open position. (b) is a side view showing the link and its peripheral configuration, (c) is a perspective view showing the link, link holder and tension spring, and (d) is another perspective view showing the link, link holder and tension spring. (a) is a side view showing the link when the transfer unit is positioned at the open position, and (b) is a side view showing the link when the transfer unit is slightly lifted from the open position. (a) is a side view showing the link when the transfer unit is on the way to the closed position, and (b) is a side view showing the link when the transfer unit is on the way to the closed position. (a) is a side view showing the link when the transfer unit is on the way to the closed position, and (b) is a side view showing the link when the transfer unit is on the way to the closed position. (a) is a side view showing the link when the transfer unit is on the way to the closed position, and (b) is a side view showing the link when the transfer unit is positioned at the closed position. (a) is a side view showing the link when the transfer unit is positioned at the closed position, and (b) is a side view showing the link when the transfer unit is slightly opened from the closed position. (a) is a perspective view showing the lock member 99R viewed from the negative Y direction, and (b) is another perspective view showing the lock member 99R viewed from the negative Y direction. (c) is a perspective view showing how the lock member 99R is removed from the transfer unit 7, and (d) is another perspective view showing how the lock member 99R is removed from the transfer unit 7. FIG. The figure which looked at the apparatus main body from the negative Y direction. (a) is a cross-sectional view of 31AB-31AB in FIG. 30, showing the image forming apparatus when the lock member is in the unlocked position; (b) is a cross-sectional view of 31AB-31AB in FIG. 31AB sectional view. (a) is a cross-sectional view of 32AB-32AB of FIG. 30 showing the image forming apparatus when the lock member is positioned at the locked position; (b) is a cross-sectional view of 32AB-32AB of FIG. 30 showing the lock member positioned at the unlock position Cross section. FIG. 4 is a perspective view showing an unlocking pawl; (a) is a cross-sectional view showing the lock member with the rear cover closed, and (b) is a cross-sectional view showing the lock member rotated toward the unlock position by an unlocking claw. FIG. 5 is a cross-sectional view showing a reaction force acting on the transfer unit; FIG. 2 is an overall schematic diagram showing an image forming apparatus according to a second embodiment; FIG. 4 is a schematic diagram showing how the lock member is rotated from the lock position toward the unlock position by the unlock claw. FIG. 4 is a schematic diagram showing the image forming apparatus when the cover member is positioned at the open position; FIG. 4 is a schematic diagram showing the image forming apparatus when the cover member and the opening/closing member are positioned at the open position;

BEST MODE FOR CARRYING OUT THE INVENTION A mode for carrying out the present invention will be exemplarily described in detail below based on an embodiment with reference to the drawings. However, the dimensions, materials, shapes and relative arrangement of the components described in this embodiment should be appropriately changed according to the configuration of the device to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

<First Embodiment>
FIG. 1 is a perspective view showing an image forming apparatus 1 according to the first embodiment. FIG. 2 is a cross-sectional view showing the configuration of the image forming apparatus 1. As shown in FIG. 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. Recording materials include paper such as plain paper and thick paper, plastic films such as sheets for overhead projectors, special-shaped sheets such as envelopes and index paper, and various sheet materials of different materials such as cloth.

Also, 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 defined as the Z direction. A direction that intersects the Z direction and is parallel to the rotation axis direction (main scanning direction) of the photosensitive drum 11, which will be described later, is defined as the X direction. A direction crossing the X direction and the Z direction is defined as the Y direction. The X, Y and Z directions preferably intersect each other perpendicularly. For convenience, the positive side in the X direction is called the right side, and the negative side is called the left side. is called the lower side.

[overall structure]
As shown in FIGS. 1 and 2, the image forming apparatus 1 includes an image forming section 20 that forms a toner image on a recording material, a feeding section 30 that feeds the recording material P, and an image forming section 20. It has a fixing section 9 for fixing the toner image on the recording material, and a pair of discharge rollers 10 .

The image forming section 20 includes a scanner unit 50, an electrophotographic process unit 40, a transfer unit 7 including a transfer roller 7a for transferring the toner image carried on the photosensitive drum 11 of the process unit 40 onto the recording material P, have. The process unit 40 includes a photosensitive drum 11, a cleaning unit 13 arranged around the photosensitive drum 11, a charging roller 17, a developing roller 12, a supply unit 200 (see FIG. 3), and a container 18 for containing toner. and a developer container 230 (see FIG. 8). The transfer roller 7a is biased toward the photosensitive drum 11 by a biasing member (not shown).

A photosensitive drum 11 as an image bearing member is a cylindrically shaped photosensitive member. The photosensitive drum 11 of the present embodiment has a drum-shaped base made of aluminum and a photosensitive layer formed of a negatively charged organic photosensitive member on the base. Further, the photosensitive drum 11 is rotationally driven by a motor in a predetermined direction (R direction in the figure) at a predetermined process speed.

The charging roller 17 contacts the photosensitive drum 11 with a predetermined pressing force to form a charging portion. Further, the surface of the photosensitive drum 11 is uniformly charged to a predetermined potential by applying a desired charging voltage from the charging high-voltage power supply. In this embodiment, the photosensitive drum 11 is negatively charged by the charging roller 17 .

The scanner unit 50 scans and exposes the surface of the photosensitive drum 11 by irradiating the photosensitive drum 11 with laser light corresponding to image information input from an external device using a polygon mirror. By this exposure, an electrostatic latent image corresponding to image information is formed on the surface of the photosensitive drum 11 . Note that the scanner unit 50 is not limited to a laser scanner device, and for example, 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 may be employed.

As shown in FIGS. 3 and 5, the apparatus main body 2 of the image forming apparatus 1 has a left side plate frame 74 and a right side plate frame 75. The left side plate frame 74 and the right side plate frame 75 are provided with scanner holding members. 76 is suspended. The scanner unit 50 is held by the scanner holding member 76 . On the other hand, a drive motor 311 as a drive source is attached to the right side plate frame 75 , and the pinion gear connected to the drive motor 311 is provided on the X direction plus side (right side) of the right side plate frame 75 . there is The driving force of the driving motor 311 is transmitted to the feeding roller 5a and the photosensitive drum 11 via this pinion gear.

As shown in FIGS. 1 and 2, the developing roller 12 is rotatably supported by a container 18 as a toner container. Further, the developing roller 12 is arranged at the opening of a developing container 230 (see FIG. 8) including the accommodating portion 18 so as to face the photosensitive drum 11 . Note that a supply roller may be provided in the container 18 to apply the toner, which is the developer contained in the container 18 , to the surface of the developing roller 12 .

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

Further, the toner of the present 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 force or electrostatic force (mirror image force). However, a one-component developer containing a magnetic component may also be used. In addition to the toner particles, the one-component developer may contain additives (for example, wax or fine silica particles) for adjusting the fluidity and charging performance of the toner. Alternatively, a two-component developer composed of a non-magnetic toner and a magnetic carrier may be used as the developer. When a developer having magnetism is used, for example, a cylindrical developing sleeve having a magnet arranged inside is used as the developer carrier.

The fixing unit 9 is of a thermal fixing type for fixing the image by heating and melting the toner on the recording material. The fixing section 9 includes a heating film 9a containing a fixing heater 9c and a pressure roller 9b that presses against the heating film 9a.

The feeding section 30 has a cassette 4 on which recording materials P are stacked, a pickup roller 3, a feeding roller 5a, and a separating roller 5b. A front cover 70 is provided on a part of the end face on the front side of the image forming apparatus 1 , and the front cover 70 covers the 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 of the apparatus main body 2, the discharge tray 14, and an exterior cover 71 constituting the exterior of the image forming apparatus 1, and opens and closes the rear cover 73 (see FIG. 17A). support possible. A discharge port 15 through which the recording material P discharged to the discharge tray 14 passes is formed in the housing 72 .

As shown in FIG. 2, the image forming apparatus 1 has a circuit board 100. As shown in FIG. 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 . Since conductor wiring is provided on and inside the wiring board 101, the electronic components 111 and 121 are electrically connected. The circuit board 100 has a function of converting an alternating current supplied from the outside of the image forming apparatus 1 into a direct current and converting an input voltage to obtain a predetermined voltage value necessary for the image forming process.

Circuit board 100 is arranged such that the surface of wiring board 101 on which electronic components 111 and 121 are mounted intersects the discharge direction. Furthermore, the wiring board 101 is provided between the front cover 70 and the scanner unit 50 in the ejection direction. Electronic components 111 and 121 are provided on the surface of wiring board 101 facing scanner unit 50 .

Next, the image forming operation of the image forming apparatus 1 will be described. When an image forming command is input to the image forming apparatus 1 , the image forming process by the image forming section 20 is started 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 charged in advance by the charging roller 17, and an electrostatic latent image is formed on the photosensitive drum 11 by being irradiated with laser light. After that, the electrostatic latent image is developed by the developing roller 12 to form a toner image on the photosensitive drum 11 .

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

A transfer voltage is applied to the transfer roller 7a as a transfer member from a transfer high-voltage power supply, and the toner image carried on the photosensitive drum 11 is transferred onto the recording material P conveyed by the conveying roller pair 5c. The recording material P to which the toner image has been transferred is conveyed to the fixing section 9, and the toner image is heated and pressed when passing through the fixing nip N2 between the heating film 9a and the pressure roller 9b of the fixing section 9. be. As a result, the toner particles are melted and then fixed, whereby the toner image is fixed on the recording material P. As shown in FIG. After passing through the fixing section 9 , the recording material P is discharged to the outside of the image forming apparatus 1 (outside the apparatus) from a discharge port 15 by a discharge roller pair 10 and stacked on a discharge tray 14 .

When images are formed on both sides of the recording material P, the discharge roller pair 10 switches back the recording material P on which the image is formed on the first surface, 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 again conveyed toward the transfer roller 7a via the conveying path 19 by the double-sided conveying roller pair 5d. After an image is formed on the second surface of the recording material P by the transfer roller 7a, the recording material P is discharged outside the apparatus by the discharge roller pair 10. FIG. After the toner image is transferred onto the recording material P, toner remaining on the photosensitive drum 11 is cleaned by the cleaning unit 13 . Note that the image forming apparatus 1 of the present embodiment has a configuration capable of forming images on both sides of the recording material P using the double-sided conveying path 16, but is not limited to this. For example, the image forming apparatus 1 may be configured to be capable of forming an image on only one side of the recording material P without having the double-sided conveying path 16 .

[Control block]
FIG. 4 is a block diagram for explaining the functions of the circuit board 100 of this embodiment. The circuit board 100 has a low-voltage power supply section 110 and a high-voltage power supply section 120 . The low-voltage power supply unit 110 takes in power from an external power supply via a power supply input unit (not shown) mounted on the end of the substrate, and converts the AC voltage into a stable DC voltage by a rectifying and smoothing circuit including electrolytic capacitors. After that, the low-voltage power supply unit 110 converts the DC voltage into a high-frequency AC voltage using a switching element such as a transistor, and then inputs the high-frequency AC voltage to the low-voltage power transformer. A low-voltage power transformer converts a high-frequency AC voltage, which is an input voltage, into an AC voltage (output voltage) having a desired voltage value. Low-voltage power supply section 110 converts the AC voltage to DC voltage again and outputs the obtained DC voltage to high-voltage power supply section 120 . In the low-voltage power supply unit 110, since the loss of individual circuit components appears as heat, a heat sink (not shown) made of aluminum or iron is provided to dissipate the heat.

The high-voltage power supply section 120 converts the voltage (for example, 24 V) supplied from the low-voltage power supply section 110 into a high voltage necessary for image forming processes such as charging, development, and transfer. 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 section 110 is converted into a voltage for development by the transformer 123 for development and supplied to the development roller 12 . The voltage supplied from the low-voltage power supply section 110 is converted into a voltage for transfer by a transfer transformer and supplied to the transfer roller 7a.

The low-voltage power supply section 110 supplies voltage (for example, 3.3 V or 5 V) not only to the high-voltage power supply section 120 but also to the scanner unit 50 , drive motor 311 , engine controller 130 and video controller 140 . Here, the engine controller 130 plays a role of centrally controlling various process members. The engine controller 130 includes a CPU (not shown), a RAM (not shown) used for calculation and temporary storage of data necessary for controlling the image forming apparatus 1, a program for controlling the image forming apparatus 1, and various controllers. It has a ROM (not shown) and the like for storing data. The video controller 140 plays a role of communicating with an external device such as a personal computer, receiving print data, and notifying the engine controller 130 of the result of analyzing the print data. Note that the engine controller 130 and the video controller 140 may be provided on a board different from the circuit board 100, or may be provided on the same board.

Also, the AC power from the commercial power source received by the power source input section is supplied not only to the low-voltage power source section 110 but also to the fixing heater 9c. A drive motor 311 drives the rollers in the fixing section 9 .

[Process Unit Positioning Configuration]
Next, the positioning structure of the process unit 40 will be described with reference to FIGS. 5 to 7. FIG. FIG. 5 is a perspective view showing the image forming apparatus 1 before the process unit 40 is attached. 6A is a rear view and an enlarged view showing the positioning structure of the process unit 40 by the left side plate frame 74, and FIG. 6B is a rear view showing the positioning structure of the process unit 40 by the right side plate frame 75. and an enlarged view.

As shown in FIG. 5, the process unit 40 has a left side 30L and a right side 30R, which are end faces in the longitudinal direction LD parallel to the X direction. A left positioning boss 41L and a left rotation restriction boss 42L are provided on the left side surface 30L, and a right positioning boss 41R (not shown) and a right rotation restriction boss 42R (not shown) are provided on the right side surface 30R. is provided. The left positioning boss 41L and the right positioning boss 41R are arranged upstream of the left rotation restriction boss 42L and the right rotation restriction boss 42R, respectively, in the mounting direction AD of the process unit 40 .

In the present embodiment, the process unit 40 is provided with boss-shaped positioning bosses and rotation restriction 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.

The apparatus main body 2 of the image forming apparatus 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 have a gap in the longitudinal direction LD. facing each other.

As shown in FIGS. 5 and 6A, the left side plate frame 74 has a left first surface 81Lf and a left second surface 82Lf extending in the mounting direction AD (Y direction) and the Z direction. there is By drawing the left first surface 81Lf, the left second surface 82Lf is arranged inside the apparatus main body 2 by a distance X1 from the left first surface 81Lf in the longitudinal direction LD. That is, the left first surface 81Lf and the left second surface 82Lf are not on the same plane. In the present embodiment, the left second surface 82Lf is composed of surfaces parallel to the mounting direction AD (Y direction) and the Z direction, but is not limited to this. For example, the left second surface 82Lf may be a curved surface along the mounting direction AD (Y direction) and Z direction.

The left first surface 81Lf is formed with a left positioning portion 81L with which the left positioning boss 41L can be engaged, and the left positioning portion 81L is a notch whose upstream side in the mounting direction AD is open. The left second surface 82Lf is formed with a left rotation restricting portion 82L with which the left rotation restricting boss 42L can be engaged. It is missing. In addition, since the left second surface 82Lf is formed by drawing, an inclined surface that guides the left positioning boss 41L toward the left positioning portion 81L may be formed.

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

Similarly, as shown in FIGS. 5 and 6B, the right plate frame 75 has a right first surface 81Rf and a right second surface 82Rf extending along the mounting direction AD (Y direction) and the Z direction. ing. By drawing the right first surface 81Rf, the right second surface 82Rf is arranged inside the device main body 2 by a distance X2 from the right first surface 81Rf in the longitudinal direction LD. That is, the right first surface 81Rf and the right second surface 82Rf are not on the same plane. In the present embodiment, the right first surface 81Rf and the right second surface 82Rf are composed of surfaces parallel to the mounting direction AD (Y direction) and Z direction, but are not limited to this. For example, the right second surface 82Rf may be curved along the mounting direction AD (Y direction) and the Z direction.

A right positioning portion 81R with which the right positioning boss 41R can be engaged is formed on the right first surface 81Rf, and the right positioning portion 81R is a notch whose upstream side in the mounting direction AD is open. The right second surface 82Rf is formed with a right rotation restricting portion 82R with which the right rotation restricting boss 42R can be engaged. It is missing. Since the right second surface 82Rf is formed by drawing, it may be formed with an inclined surface that guides the right positioning boss 41R toward the right positioning portion 81R.

Since the right first surface 81Rf and the right second surface 82Rf are separated by the distance X2 in the longitudinal direction LD, the right rotation restricting portion 82R is also separated from the right positioning portion 81R by the distance X2 in the longitudinal direction LD. placed apart. In other words, the right rotation restricting portion 82R is arranged at a position different from that of the right positioning portion 81R in the longitudinal direction LD.

FIG. 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 main body 2, the left positioning boss 41L and the left rotation regulation boss 42L of the process unit 40 are aligned with the left positioning portion 81L of the left side plate frame 74, respectively. and the left rotation restricting portion 82L. Similarly, when the process unit 40 is attached to the apparatus main body 2, the right positioning boss 41R and the right rotation restricting boss 42R of the process unit 40 are attached to the right positioning portion 81R and the right rotation restricting portion 82R of the right plate frame 75, respectively. engage.

The process unit 40 is positioned in the mounting direction AD by engaging the left positioning boss 41L and the right positioning boss 41R with the left positioning portion 81L and the right positioning portion 81R, respectively. Further, the process unit 40 is centered around the left positioning boss 41L and the right positioning boss 41R by engaging the left rotation regulating boss 42L and the right rotation regulating boss 42R with the left rotation regulating portion 82L and the right rotation regulating portion 82R, respectively. rotational movement is restricted. That is, the process unit 40 is positioned in the Z direction.

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

In the present embodiment, the left positioning portion 81L and the left rotation restricting portion 82L are provided on the left side plate frame 74, which is the same sheet metal member. can. In addition, since the left positioning portion 81L is arranged upstream of the left rotation restricting portion 82L in the mounting direction AD, the shape of the notch forming the left positioning portion 81L formed in the left first surface 81Lf is relatively small. It takes up less area. By reducing the area of the notch formed in the left side plate frame 74 in this way, the rigidity of the left side plate frame 74 can be maintained. By maintaining the rigidity of the left side plate frame 74, the positioning accuracy of the process unit 40 with respect to the apparatus main body 2 can be improved, and since the left side plate frame 74 does not need to be formed thick, weight and cost can be reduced. can do. The same applies to the right side plate frame 75 as well.

[Development container]
Next, the developer container 230 and its peripheral configuration will be described with reference to FIGS. 8 and 9. FIG. As shown in FIG. 8, the developer container 230 communicates with the accommodating portion 18 and a replenishing portion 200 for receiving toner supplied from the outside while the process unit 40 is attached to the apparatus main body 2 . and consists of The supply unit 200 has an operation unit 201, a cylindrical toner receiving unit 202, a supply path unit 203 connecting the toner receiving unit 202 and the storage unit 18, and a main body shutter unit 206 as a main body shutter. ing. A side opening 205 leading to the supply path portion 203 is formed in the inner wall of the toner receiving portion 202 .

As shown in FIG. 9, a replenishment pack 210, which will be described later, is attached to the replenishment unit 200, and the toner discharged from the replenishment pack 210 passes through the opening 207 of the main shutter unit 206, the side opening 205 of the toner receiving unit 202, and the replenishment route. The container 18 is replenished through the portion 203 .

As shown in FIGS. 8 and 9, the replenishment path portion 203 is connected to one end side of the accommodating portion 18 in the longitudinal direction of the developer container 230, that is, the X direction. As shown in FIG. 9, a stirring member 60 that rotates around a rotating shaft 60a that extends in the X direction is provided inside the housing portion 18. As shown in FIG. The agitating member 60 has a blade portion 60b fixed to a rotating shaft 60a, and is driven by the drive motor 311 to rotate, thereby agitating the toner in the container 18 and directing the toner toward the developing roller 12. Convey the toner. In the present embodiment, the stirring member 60 is composed of the rotating shaft 60a and the blade portion 60b. may be used.

In addition, the stirring member 60 has a role of circulating the toner stripped from the developing roller 12 that is not used for development within the storage section 18 and uniformizing the toner within the storage section 18 . Note that the stirring member 60 is not limited to a rotating form. For example, a stirring member that swings may be employed. Further, in addition to the stirring member 60, another stirring member may be provided.

Further, the container 18 is provided with a remaining amount detection unit 312 for detecting the amount of toner in the container 18. The remaining amount detection unit 312 has a light emitting unit 312a and a light receiving unit 312b. are doing. Light emitted from the light emitting portion 312a passes through the interior of the housing portion 18 and is received by the light receiving portion 312b. That is, the light emitting portion 312a and the light receiving portion 312b form an optical path Q1 inside the accommodating portion 18. As shown in FIG. In addition, the light emitting unit 312a and the light receiving unit 312b may be arranged with the light emitting element and the light receiving element respectively inside the housing unit 18, or the light emitting element and the light receiving element may be arranged outside the housing unit 18, , the light may be guided in and out of the housing 18 .

Furthermore, the light-emitting portion 312a and the light-receiving portion 312b are provided in the central portion of the housing portion 18 in the X direction. By providing the light-emitting portion 312a and the light-receiving portion 312b at the central portion of the storage portion 18, the remaining amount of toner in the storage portion 18 can be detected satisfactorily. That is, although the developer (toner) may be unevenly distributed at the ends of the housing portion 18 in the X direction, the developer is less unevenly distributed in the central portion of the housing portion 18, so the actual amount of remaining toner can be detected. can do.

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

[Supply Department]
Next, the supply unit 200 will be described with reference to FIGS. 10(a) to 11(c). The discharge tray 14 has a closed position where the recording material P can be stacked as shown in FIG. It is supported so as to be openable and closable. The discharge tray 14 covers the supply section 200 in the closed position. When the discharge tray 14 is opened to the open position, the top surface portion 240 and the supply portion 200 arranged on the top surface portion 240 are exposed. As shown in FIG. 10C, a replenishment pack 210 is detachably attached to the replenishment unit 200, and a user or a service person can use the developer container 230 without removing it from the apparatus main body 2 (housing 72). Toner can be replenished from the Hereinafter, users and workers such as service personnel are generally referred to as users.

The supply unit 200 is arranged on the same side as the cassette 4 in the Y direction with respect to the photosensitive drum 11 . In other words, in plan view, the supply unit 200 is arranged on one side (front side) of the photosensitive drum 11, which is the same side as the cassette 4, and an opening 91 (see FIG. 17B), which will be described later, is a photosensitive drum. It is arranged on the other side (back side) of the drum 11 . As a result, both toner and recording material P can be replenished on the front side of the image forming apparatus 1, and usability can be improved.

As shown in FIGS. 10B and 10C, the operation unit 201 is arranged on the top surface 240 and forms a replenishment port 204 which is a receiving port for replenishing toner. Further, the operating portion 201 includes a ring portion 201a provided so as to surround the supply port 204 and rotatably supported by the top surface portion 240 or the toner receiving portion 202, and a lever portion 201b provided integrally with the ring portion 201a. ,have. The operation unit 201 is a member for operating the main body shutter unit 206 and the pack shutter unit 214 to open and close from the outside.

As shown in FIG. 11A, the toner receiving portion 202 is provided with guide portions 247 and 248 arranged inside the main body shutter portion 206 and integrated 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 rotatably provided inside the toner receiving portion 202 . The body shutter portion 206 has an opening 207 (see FIG. 11C), and the opening 207 and the side opening 205 of the toner receiving portion 202 are displaced in the closed position shown in FIG. 11A. A seal member 243 is fixed to the body shutter portion 206 so as to surround the peripheral portion of the opening 207 .

Since the side opening 205 is covered with the body shutter portion 206 positioned at the closed position, it is indicated by a dashed line in FIG. 11(a). Therefore, the side opening 205 is blocked by the main body shutter portion 206 and the toner is not discharged to the supply path portion 203 .

11C, the opening 207 overlaps the side opening 205 of the toner receiving portion 202. As shown in FIG. Therefore, the toner replenished from the replenishment pack 210 (see FIG. 10C) attached to the replenishment section 200 can be discharged to the replenishment path section 203 through the side opening 205 and the opening 207 .

The main body shutter section 206 is provided with a main body shutter section drive transmission projection 206a. Although the details will be described later, the main body shutter section drive transmission projection 206a receives a drive force from the replenishment pack 210 and rotates the main body shutter section 206. used to make By rotating the operating portion 201 with the replenishment pack 210 attached to the replenishment portion 200, the main body shutter portion 206 moves between the closed position and the open position.

The operation portion 201 is provided with an operation portion drive transmission projection 201 d that protrudes radially inward from the inner peripheral surface of the toner receiving portion 202 . The operation portion drive transmission projection 201d is engaged with the main body shutter portion drive transmission projection 206a via a pair of drive transmission surfaces 214b (see FIG. 14B) of the pack shutter portion 214 of the supply pack 210. As shown in FIG. The body shutter portion 206 moves from the closed position shown in FIG. 11A to the open position shown in FIG. do.

When an image is formed on the recording material P, the toner is agitated in the storage section 18 by the agitating member 60 (see FIG. 9), and the side opening is closed by the main body shutter section 206 so that the toner does not leak out from the side opening 205 . 205 should be shut off. Accordingly, during image formation, the operation unit 201 is positioned at the operating position shown in FIG. 11A so that the main shutter unit 206 is positioned at the closed position. On the other hand, it is necessary to open the side opening 205 when replenishing toner from a replenishment pack 210 (to be described later) to the container 18 . Accordingly, when toner is replenished, the operating portion 201 is positioned at the replenishment position shown in FIG. 11C so that the main body shutter portion 206 is positioned at the open position.

[Arrangement and composition of supply department]
Next, the arrangement and configuration of the supply section 200 will be described in detail. 12 is a left side view of the image forming apparatus 1. FIG. 12, the exterior cover 71 and the left side plate frame 74 are not shown.

As shown in FIG. 12 , at least a portion of the supply section 200 overlaps the scanner unit 50 when viewed in the rotation axis direction (X direction) of the photosensitive drum 11 . A portion of the scanner unit 50 overlapping the replenishment section 200 is indicated by a dotted line in FIG. Specifically, the toner receiving portion 202 and the supply path portion 203 of the supply portion 200 are arranged so as to overlap the scanner unit 50 when viewed in the rotation axis direction of the photosensitive drum 11 . Here, in the horizontal direction (Y direction), the area where the supply port 204 is provided is defined as area R1, and the area where the scanner unit 50 is provided is defined as area R2. In this case, the region R1 overlaps the region R2 when viewed in the rotation axis direction of the photosensitive drum 11 .

A virtual plane S is defined as a virtual plane passing through the uppermost end portion 18b of the frame 18a of the accommodating portion 18 and parallel to the horizontal plane. The virtual plane S is indicated by a dashed line in FIG. All of the operation portion 201 of the replenishment portion 200, part of the toner receiving portion 202, and part of the replenishment path portion 203 are positioned above the imaginary plane S. In other words, part of the replenishment section 200 is located above the imaginary plane S. Further, portions of the toner receiving portion 202 and the supply path portion 203 above the imaginary plane S partially overlap the scanner unit 50 when viewed in the rotation axis direction of the photosensitive drum 11 .

On the other hand, a portion of the housing portion 18 also overlaps with the drum frame 11a when viewed in the direction of the rotation axis of the photosensitive drum 11, which is indicated by a dashed line in FIG. By increasing the volume of the storage portion 18 in this manner, the amount of toner stored in the storage portion 18 can be increased. The drum frame 11a rotatably supports the photosensitive drum 11, and the container 18 rotatably supports the developing roller 12 carrying the developer.

FIG. 13 is a plan view showing the image forming apparatus 1 with the outer cover 71 not shown. In the X direction, the width X3 of the replenishment port 204 is shorter than the width X4 of the housing portion 18 . The laser beam irradiated from the scanner unit 50 to the photosensitive drum 11 spreads in a trapezoidal shape as shown in FIG. 13 by the action of a polygon mirror and a lens (both not shown). Therefore, the width X5 of the scanner unit 50 is shorter than the width X6 of the photosensitive drum 11 in the X direction. As a result, a space is created between the left end of the scanner unit 50 and the left side plate frame 74, and the supply section 200 is provided in the space in this embodiment.

Further, in the X direction, the supply section 200 (width X3) and the scanner unit 50 (width X5) are provided side by side within the area (width X4) in which the storage section 18 is provided. As a result, it is possible to reduce the effect of providing the replenishment unit 200 on the size of the image forming apparatus 1 .

In addition, the process unit 40 is arranged so that at least a portion thereof overlaps the scanner unit 50 in plan view. Furthermore, as shown in FIG. 20A, the process unit 40 is arranged so that at least a portion thereof overlaps the fixing section 9 in plan view. By arranging the process unit 40 , the scanner unit 50 and the fixing section 9 in this manner, the toner capacity of the storage section 18 can be increased without increasing the size of the image forming apparatus 1 . The arrangement of the process unit 40, the scanner unit 50, and the fixing section 9 is not limited to the arrangement described above.

As shown in FIG. 3, the replenishment unit 200 is located on the opposite side of the drive motor 311 with respect to the position of the scanner unit 50 in the rotation axis direction (X direction) of the photosensitive drum 11 . are placed in In the present embodiment, a relatively small drive motor 311 is used, so that the drive motor 311 and the replenishment section 200 do not overlap in the Z direction, as shown in FIG. However, since the supply section 200 is arranged on the opposite side of the scanner unit 50 as described above, the drive motor 311 can be replaced with a large one that overlaps the supply section 200 in the Z direction. Therefore, the degree of freedom in design can be improved.

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

A replenishment pack 210 as a toner container has a pouch portion 211 that is a bag containing toner to be replenished, a cylindrical insertion portion 212 that is inserted into the replenishment port 204, and a pack shutter portion 214 as a container shutter. are doing. An insertion portion 212 as a nozzle portion communicates with the pouch portion 211 . The insertion portion 212 is formed with an opening 213 through which the toner in the pouch portion 211 is discharged to the outside. In addition, the pouch part 211 is configured by a deformable plastic bag body, but is not limited to this. For example, the pouch part 211 may be configured from a resin bottle container, or may be configured from a paper or vinyl container.

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

The pack shutter portion 214 is a cylindrical member that is concentric with the insertion portion 212 and is provided radially outward of the insertion portion 212 . The pack shutter part 214 has an opening 214c, and by rotating with respect to the insertion part 212, the pack shutter part 214 can transition to a closed position that shields the opening 213 of the insertion part 212 or an open position that opens the opening 213. . When the opening 214c of the pack shutter portion 214 and the opening 213 of the insertion portion 212 overlap, toner can be supplied from the supply pack 210 to the supply portion 200. FIG.

A seal member 231 is fixed to the inner peripheral surface of the pack shutter portion 214 and is capable of rubbing against the outer peripheral surface of the insertion portion 212. The seal member 231 is closed when the pack shutter portion 214 is positioned at the closed position. , shield the opening 213 of the insertion portion 212 .

As shown in FIG. 16A, the insertion portion 212 is formed with guided portions 232 that are recessed from the outer peripheral surface of the insertion portion 212. The guided portions 232 each include a pair of first guided portions 232a. and a second guided portion 232b. When the supply pack 210 is attached to the supply portion 200 , the guide portions 247 and 248 integrated with the toner receiving portion 202 enter into the guided portion 232 . As a result, relative movement between the insertion portion 212 and the toner receiving portion 202 in the circumferential direction about the rotational axis of the pack shutter portion 214 is restricted.

Further, as shown in FIG. 16(b), on the outer peripheral surface of the pack shutter portion 214, a positioning portion 217 that engages with the operating portion 201 and a positioning portion 217 are arranged in the circumferential direction of the outer periphery of the pack shutter portion 214. A drive transmission surface 214b is provided that faces each other on both sides. That is, the outer peripheral surface of the pack shutter portion 214 has a groove portion (a concave portion recessed inward in the radial direction of the pack shutter portion 214) having the positioning portion 217 as the groove bottom surface (recess bottom surface) and the drive transmission surface 214b as the groove side surface. is formed. The groove is open at the distal end of the outer peripheral surface of the pack shutter portion 214 in the inserting direction of the inserting portion 212 . The pack shutter portion 214 rotates with respect to the insertion portion 212 when the drive transmission surface 214 b receives force in the circumferential direction from the operation portion drive transmission projection 201 d of the operation portion 201 .

The insertion portion 212 has an opening 214c provided in the pack shutter portion 214 and a guided portion 232 provided so as to be recessed from the outer peripheral surface of the insertion portion 212 when the pack shutter portion 214 is in the closed position. They overlap each other in the rotation phase of the direction. In this state, the guide portions 247 and 248 of the supply portion 200 are inserted into the guided portion 232 of the supply pack 210, and the opening 214c is fitted to the peripheral edge of the seal member 243 provided on the inner peripheral surface of the main body shutter portion 206. It will be in a state of matching. When the replenishment pack 210 is attached to the replenishment portion 200, the first guided portion 232a on the upstream side in the insertion direction of the guided portions 232 engages the guide portion 247, and the second guided portion 232b on the downstream side engages with the guide portion 247. It will be in a state of facing the guide portion 248 . The circumferentially extending surface that is the step between the first guided portion 232 a and the second guided portion 232 b is different from the circumferentially extending surface that is the step between the guide portions 247 and 248 . are engaged in the insertion direction, and the position in the insertion direction between the insertion portion 212 and the operation portion 201 is determined. The opening 214c has a notched shape that widens toward the distal end of the insertion portion 212 and opens. A pair of facing portions forming the opening 214c, which face each other in the circumferential direction, sandwich the sealing member 243 in the circumferential direction.

The drive transmission surface 214 b of the pack shutter portion 214 engages with the operation portion drive transmission projection 201 d of the operation portion 201 and with the main body shutter portion drive transmission projection 206 a of the main body shutter portion 206 . The pack shutter section 214 is moved (rotated) by the operating (operating) force of the operating section 201 and transmits the operating force to the main body shutter section 206 to move the main body shutter section 206 as well. That is, the drive transmission surface 214b has, as a force receiving area, an area that engages and abuts on the operating portion drive transmission projection 201d. The operating portion drive transmission projection 201d has a convex shape extending radially inward from the inner peripheral surface of the operation portion 201, and the drive transmission surface 214b serves as a force application area and engages with the main body shutter portion drive transmission projection 206a. have areas of contact.

[Toner supply procedure]
Next, a toner supply procedure using the supply pack 210 will be described with reference to FIGS. 10(a) to 16(b). First, as shown in FIGS. 10A to 10C, 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. Thereby, the replenishment part 200 is exposed. Since the replenishment unit 200 is provided on the upper front surface of the image forming apparatus 1, it is easy to replenish the toner.

When the discharge tray 14 is opened to the open position and the supply section 200 is exposed, the operation section 201 is positioned at the operating position. Then, the user operates the operation unit drive transmission projection 201d (see FIG. 11A) provided in the replenishment unit 200, the alignment notch 217 provided in the replenishment pack 210 (see FIG. 16B), are positioned, and the replenishment pack 210 is attached to the replenishment unit 200. - 特許庁If the positions of the operating portion drive transmission projection 201d and the positioning notch 217 do not match, the replenishment pack 210 interferes with the operation portion drive transmission projection 201d, and the replenishment pack 210 cannot be inserted.

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

That is, the rotation of the operation unit 201 is transmitted to the pack shutter unit 214 , and the rotation of the pack shutter unit 214 is transmitted to the main body shutter unit 206 . As a result, the main body shutter section 206 and the pack shutter section 214 are engaged with each other and integrated, and the operation section 201, the pack shutter section 214 and the main body shutter section 206 are interlocked.

Then, the user rotates the lever portion 201b of the operation portion 201 counterclockwise by 90 degrees, as shown in FIG. 11(c). As a result, the operating portion 201 rotates from the operating position to the supply 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 supply pack 210, the opening 207 of the main body shutter portion 206, and the side opening 205 of the toner receiving portion 202 overlap. As a result, the toner in the replenishment pack 210 is discharged to the storage section 18 through the replenishment path section 203 .

In other words, the replenishment unit 200 is in a replenishable state in which toner can be replenished from the replenishment pack 210 to the storage unit 18 when the operation unit 201 is positioned at the replenishment position. At this time, the opening 213 of the supply pack 210 and the side opening 205 of the toner receiving portion 202 communicate with each other.

When the toner supply from the supply pack 210 to the storage section 18 is completed, the user returns the operation section 201 from the supply position to the operating position. That is, the user rotates the lever portion 201b of the operation portion 201 clockwise by 90 degrees. As a result, the pack shutter portion 214 and the body shutter portion 206 rotate from the open position to the closed position.

In other words, the replenishment unit 200 is in a replenishment disabled state in which toner can be replenished from the replenishment pack 210 to the storage unit 18 when the operation unit 201 is positioned at the operating position. At this time, the opening 213 of the supply pack 210 and the side opening 205 of the toner receiving portion 202 do not communicate with each other.

Then, the user removes the supply pack 210 from the supply section 200 . In this way, when the supply pack 210 is removed from the supply section 200, the pack shutter section 214 is positioned at the closed position.

[Back cover and transfer unit]
Next, the configuration around the rear cover 73 and the transfer unit 7 will be described with reference to FIGS. 17(a) to 18(d). As shown in FIGS. 17A to 18D, an opening 91 formed by an exterior cover 71 and a rear cover 73 covering the opening 91 are provided on the rear surface of the image forming apparatus 1. ing. The rear cover 73 as a cover portion has a closed position as a second closed position where it is closed with respect to the device main body 2 and a second open position where it is opened with respect to the device main body 2 with the cover engaging portion 73d as the center. and the open position as . The back cover 73 covers the opening 91 , the transfer unit 7 and the process unit 40 at the closed position, and opens the opening 91 to expose the transfer unit 7 and the process unit 40 at the open position. Further, the transfer unit 7 as an opening/closing part is supported so as to be openable/closable around a rotation shaft 7c.

The outer surface 73b of the back cover 73, that is, the surface forming the exterior surface of the housing 72, is provided with a grip portion 73c that can be gripped when the back cover 73 is opened and closed by the user. An inner side surface 73f opposite to the outer side surface 73b of the rear cover 73 is provided with a plurality of (three in the present embodiment) engaging claws 73a, a plurality of conveying ribs 73g, and a pressing rib 73e. ing.

The rear cover 73 is held at the closed position shown in FIGS. When the rear cover 73 is at the closed position, the transfer unit 7 is drawn into the apparatus main body 2 by links 96L and 96R (see FIG. 21), which will be described later, and is closed until operated by the user. It is in a state where The transfer roller 7a transfers the toner image carried on the photosensitive drum 11 onto the recording material P when the transfer unit 7 is positioned at the closed position.

As shown in FIGS. 17B and 18B, when the rear cover 73 is opened to the open position, the double-sided conveying path 16 through which the recording material P conveyed by the double-sided conveying roller pair 5d passes is opened. . The double-sided transport path 16 is formed by a plurality of transport ribs 73 g of the back cover 73 and a plurality of transport ribs 16 a formed on the outer surface of the transfer unit 7 . In other words, the transport rib 73g forms part of the double-sided transport path 16 when the rear cover 73 is positioned at the closed position. That is, the rear cover 73 can move between a closed position covering the double-sided transport path 16 and an open position exposing and opening the double-sided transport path 16 to the outside. The double-sided transport path 16 and the transport path 19 are transport paths along which the recording material P is transported.

Further, the pressure roller 9b of the fixing section 9 is brought into contact with or separated from the heating film 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 at the open position and the double-sided conveying path 16 is open, the pressure roller 9b is separated from the heating film 9a.

Next, as shown in FIGS. 17C and 18C, when the transfer unit 7 is opened about the rotation shaft 7c with the rear cover 73 positioned at the open position, the transport path 19 is opened. is released. The recording material P fed by the pickup roller 3 and conveyed by the pair of conveying rollers 5c, the transfer nip N1, and the fixing nip N2 passes through the conveying path 19. FIG. That is, the transfer unit 7 has a closed position as a first closed position where the transfer path 19 is covered and closed with respect to the apparatus main body 2, and a first closed position where the transfer unit 7 is opened with respect to the apparatus main body 2 with the transfer path 19 exposed to the outside. It can be opened and closed between an open position as a first open position. The transport 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 positioned at the open position.

A conveying rib 19 a forming a conveying path 19 is provided on the inner surface of the transfer unit 7 . A plurality of conveying ribs 16a and a grip portion 7b (see FIG. 17B) are provided on the outer surface of the transfer unit 7, and the transfer unit 7 is moved to the closed position by the user operating the grip portion 7b. and the open position.

[Jam processing]
Next, a jam processing method when a jam occurs in the double-sided conveying path 16 or the conveying path 19 will be described. When the recording material P jams during the image forming operation, the user moves the rear cover 73 from the closed position to the open position as shown in FIGS. open. As a result, when the double-sided conveying path 16 is opened and a jam occurs in the vicinity of the double-sided conveying path 16, the jammed recording material P can be removed.

On the other hand, if the jam occurs near the transfer nip N1, the user opens the back cover 73 and the transfer unit 7 to the open position as shown in FIGS. 17(c) and 18(c). As a result, the transport path 19 is opened, and the jammed recording material P near the transport path 19 can be removed. In this way, even if a jam occurs in the double-sided conveying path 16 or the conveying path 19 , the jam can be removed from the rear side of the image forming apparatus 1 while the process unit 40 is attached to the apparatus main body 2 . For this reason, jam processing is not complicated, and jam processing can be improved.

After completing the jam clearance, the user closes the back cover 73 from the open position to the closed position while the transfer unit 7 remains at the open position, as shown in FIG. 18(d). Then, the back cover 73 rotates independently until the back cover 73 is closed by about 25° from the open position. After that, the pressing rib 73e of the rear cover 73 comes into contact with the pressed portion 7d of the transfer unit 7. As shown in FIG. When the rear cover 73 is closed to the closed position in this state, the transfer unit 7 is also pressed by the pressing ribs 73e and moved from the open position to the closed position. Therefore, the closing operation of the transfer unit 7 can be omitted, and the usability can be improved. Note that the user can also close the transfer unit 7 before closing the rear cover 73 .

[Attaching and removing the process unit]
Next, with reference to FIGS. 19A to 20D, a method of attaching and detaching the process unit 40 when replacing or performing maintenance on the process unit 40, for example, will be described. When removing the process unit 40 from the apparatus main body 2, the user removes the rear cover 73 and The transfer unit 7 is moved to the open position. As a result, the process unit 40 is exposed to the outside. In this state, the process unit 40 is fixed to the left side plate frame 74 and the right side plate frame 75 by the fixing members 79L and 79R.

In the present embodiment, the process unit 40 is fixed to the left side plate frame 74 and the right side plate frame 75 using the fixing members 79L and 79R made of sheet metal members and screws, but the present invention is not limited to this. For example, the process unit 40 may be held in the apparatus main body 2 by an urging member using a spring or the like, and the process unit 40 may be held in the apparatus main body 2 by using the urging force of the transfer roller 7a of the transfer unit 7 to the photosensitive drum 11. can be kept at

To remove the process unit 40 from the apparatus main body 2, the fixing members 79L and 79R are first removed. Then, the engagement between the pinion gear of the drive motor 311 and the photosensitive drum 11 is released, and the process unit 40 is moved in the mounting direction AD as shown in FIGS. 19C and 20C. (see FIG. 5) in the opposite removal direction DD. As a result, the left positioning boss 41L and the right positioning boss 41R are separated 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 are separated from the left rotation restriction portion 82L and the right rotation restriction portion 82R. move away from That is, the process unit 40 can be attached to and detached from the housing 72 of the apparatus main body 2 through the opening 91 when the rear cover 73 is at the open position and the transfer unit 7 is at the open position. . Since the opening 91 is located at the rear of the apparatus main body 2 and can occupy a relatively large area, the process unit 40 can be easily attached and detached, and maintenance of the process unit 40 can be improved.

In this embodiment, the fixing portion 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 section 200, which is part of the process unit 40, overlaps the fixing section 9 in the X direction and the Z direction. In other words, the replenishing section 200 is arranged upstream of the fixing section 9 in the removing direction DD, and is arranged so that at least a part thereof overlaps with the fixing section 9 when viewed in the removing direction DD.

Therefore, as shown in FIGS. 19(d) and 20(d), the user rotates the process unit 40 around an axis parallel to the X direction in the process of pulling out the process unit 40 from the apparatus main body 2. Move in the removal direction DD. Further, the fixing stay 78 is provided with a cutout portion 78a so that the supply section 200 can pass through the cutout portion 78a when the process unit 40 is pulled out from the apparatus main body 2 .

Alternatively, the process unit 40 may be configured so as to be pulled out in the pull-out direction DD without rotating the process unit 40 so as not to overlap the fixing section 9 in the pull-out direction DD. Further, for example, the process unit 40 may be configured so as not to overlap the fixing section 9 in the Z direction so that the process unit 40 can be pulled out in the negative Y direction.

The process unit 40 can be attached to the apparatus main body 2 by reversing the procedure for removing the process unit 40 described above. That is, the process unit 40 is mounted in the mounting direction AD (see FIG. 5) while being rotated about the X axis with respect to the apparatus main body 2 .

As described above, in the present embodiment, in the image forming apparatus 1 of the toner replenishment type, jam processing and attachment/detachment of the process unit 40 are performed through the same opening 91 on the rear side of the image forming apparatus 1 . As a result, the area occupied by the movement locus of the process unit 40 when the process unit 40 is attached or detached can be reduced, and the space efficiency in the image forming apparatus 1 can be improved. In addition, the opening 91 can occupy a relatively large area, which facilitates workability in attaching and detaching the process unit 40 and handling jams. Therefore, it is possible to reduce the size of the main body while increasing the capacity of the toner stored in the storage unit 18, and to improve the ease of handling jams and the ease of maintenance of the process unit 40. FIG.

[Link configuration]
Next, the configuration of the links 96L and 96R for stably holding the transfer unit 7 at the closed position and the open position will be described with reference to FIGS. 21 to 28(b). As shown in FIGS. 21 to 23(d), the device main body 2 is provided with links 96L and 96R, link holders 97L and 97R, and tension springs 98L and 98R as urging portions.

More specifically, a link holder 97L is fixed to the left side plate frame 74 with screws, and the link holder 97L and the transfer unit 7 are connected by a link 96L. A tension spring 98L is provided between the link 96L and the spring hooking portion 74a provided on the left side plate frame 74. As shown in FIG.

Similarly, a link holder 97R is fixed to the right side plate frame 75 with screws, and the link holder 97R and the transfer unit 7 are connected by a link 96R. A tension spring 98R is provided between the link 96R and a spring hooking portion (not shown) provided on the right side plate frame 75. As shown in FIG. The link 96R, the link holder 97R, and the tension spring 98R provided on the right side (plus X direction) of the transfer unit 7 are connected to the link 96L, the link holder 97L, and the tension spring 98R provided on the left side (minus X direction) of the transfer unit 7. It has the same configuration as the spring 98L. Therefore, the link 96L, the link holder 97L, the tension spring 98L, and their peripheral structures will be mainly described below, and the description of the link 96R, the link holder 97R, the tension spring 98R, and their peripheral structures will be omitted.

As shown in FIGS. 22(a) to 23(d), the link holder 97L fixed to the left side plate frame 74 has a projecting portion 97Lg projecting toward the rear side (minus Y direction) of the image forming apparatus 1. ing. The upper surface 97Lh of the projecting portion 97Lg extends parallel to the Y direction, and the negative Y direction surface of the projecting portion 97Lg constitutes a contact surface 97Lb. A recess 97Li is provided at the bottom of the contact surface 97Lb. A substantially triangular holding hole portion 97La extending in the X direction is provided in the projecting portion 97Lg.

The link 96L includes a rotation shaft 96La that engages with the holding hole portion 97La with a gap, a link shaft 96Lb, a link hole portion 96Lc that is provided on the opposite side of the rotation shaft 96La across the link shaft 96Lb, have. The rotating shaft 96La is sufficiently smaller than the holding hole portion 97La and is configured to be movable within the holding hole portion 97La. A tension spring 98L is engaged with the link shaft 96Lb, and the tension spring 98L biases the link shaft 96Lb toward the spring hook portion 74a. The engaging portion 7L of the transfer unit 7 is engaged with the link hole portion 96Lc. The engaging portion 7L has a shaft extending in the negative X direction from the transfer unit 7 and passing through the link hole portion 96Lc, and a rib provided at the tip of the shaft for retaining.

As shown in FIGS. 22A to 22D, when the transfer unit 7 is in the closed position, the link shaft 96Lb of the link 96L is biased toward the apparatus main body 2 along the Y direction by the tension spring 98L. be done. The transfer unit 7 is urged toward the apparatus main body 2 along the Y direction by urging the engaging portion 7L by the link hole 96Lc of the link 96L, and is stably held at the closed position.

As shown in FIGS. 23(a) to 24(a), when the transfer unit 7 is in the open position, the spring bending portion 96Lg provided in the vicinity of the rotation shaft 96La of the link 96L acts on the tension spring 98L. abutting. The tension spring 98L is bent near the spring bending portion 96Lg by being pressed by the spring bending portion 96Lg. In addition, in the present embodiment, the tension spring 98L is composed of a coil spring, but it is not limited to this. For example, the tension spring 98L may be composed of a torsion bar or the like.

At this time, the link shaft 96Lb of the link 96L is engaged with the recess 97Li provided at the bottom of the contact surface 97Lb. Further, the link shaft 96Lb of the link 96L is biased toward the rotation shaft 96La by the tension spring 98L by bending the tension spring 98L by the spring bending portion 96Lg. Since the recessed portion 97Li has a shape recessed in the direction toward the rotation shaft 96La, the link shaft 96Lb is stably held by the recessed portion 97Li. Therefore, the transfer unit 7, on which a moment is applied in the opening direction by its own weight about the rotation shaft 7c, is stably held at the open position by the engagement of the engaging portion 7L with the link hole portion 96Lc of the link 96L. is held to

Next, the action of the link 96L when closing the transfer unit 7 from the open position to the closed position will be described with reference to FIGS. 24(a) to 27(b). As shown in FIGS. 24(a) and 24(b), the lower side of the contact surface 97Lb of the link holder 97L has an arc shape centered on the rotation shaft 96La. When the user lifts the transfer unit 7 positioned at the open position toward the closed position, a moment in the closing direction is transmitted from the transfer unit 7 to the link 96L via the engaging portion 7L and the link hole portion 96Lc. Then, the link shaft 96Lb of the link 96L moves upward while rubbing against the contact surface 97Lb.

As described above, the lower side of the contact surface 97Lb has an arc shape centered on the rotation shaft 96La, and the link shaft 96Lb is biased toward the rotation shaft 96La by the tension spring 98L. there is For this reason, the biasing force acting on the link 96L from the tension spring 98L hardly acts as a turning moment in the closing direction (or opening direction) of the link 96L about the rotation shaft 96La. Therefore, when opening and closing the transfer unit 7, the user can open and close the transfer unit 7 comfortably without feeling the biasing force of the tension spring 98L.

The radius of the arc-shaped contact surface 97Lb is set to be slightly larger than the distance from the rotation shaft 96La to the link shaft 96Lb, and the rotation shaft 96La is slightly larger than the state where it hits the holding hole 97La. It is in a state of floating in the negative Y direction. Therefore, the link shaft 96Lb can reliably slide against the contact surface 97Lb when the transfer unit 7 is closed from the open position to the closed position, and the operation of the link 96L can be stabilized.

Next, as shown in FIGS. 25A and 25B, when the user further closes the transfer unit 7, only the transfer unit 7 is closed without rotating the link 96L. Here, the link hole portion 96Lc of the link 96L has an arc portion 96Lc2 centered on the rotation shaft 7c of the transfer unit 7, a first straight portion 96Lc1, and a second straight portion 96Lc3. The first linear portion 96Lc1 extends from one end of the arc portion Lc2 in a direction away from the rotation shaft 96La. The second linear portion 96Lc3 extends from the other end of the arc portion Lc2 in a direction approaching the rotation shaft 96La.

When the transfer unit 7 is closed from FIG. 24(a) to the state shown in FIG. 24(b), the engaging portion 7L of the transfer unit 7 advances in the first linear portion 96Lc1 toward the arc portion 96Lc2. Since the movement trajectory of the engaging portion 7L intersects the first linear portion 96Lc1, the link 96L also rotates in conjunction with the rotation of the transfer unit 7. As shown in FIG.

When the transfer unit 7 is closed from FIG. 25A to the state shown in FIG. move on. At this time, since the moving locus of the engaging portion 7L is along the arc portion 96Lc2, even if the transfer unit 7 rotates, the link 96L does not rotate. In addition, since the link shaft 96Lb of the link 96L is biased toward the contact surface 97Lb by the tension spring 98L, when the transfer unit 7 is closed from the position shown in FIG. can maintain its position. In the states shown in FIGS. 25(a) and 25(b), the tension spring 98L is straightened without bending due to the spring bending portion 96Lg.

24(a) to the state shown in FIG. 24(b), for example, and even if an inertial force in the closing direction is generated in the link 96L, the engaging portion 7L is not moved to the arc portion 96Lc2. No force from the transfer unit 7 acts on the link 96L while it passes through. Therefore, the inertial force in the closing direction of the link 96L can be attenuated, and it is possible to prevent the link 96L from being fully closed.

Next, as shown in FIGS. 26A and 26B, when the user further closes the transfer unit 7, the engaging portion 7L of the transfer unit 7 advances within the second linear portion 96Lc3. Since the movement trajectory of the engaging portion 7L intersects the second linear portion 96Lc3, the link 96L also rotates in conjunction with the rotation of the transfer unit 7. As shown in FIG. Here, the upper side of the contact surface 97Lb has an arc shape centered on the spring hook portion 74a, and the link shaft 96Lb is biased toward the rotation shaft 96La by the tension spring 98L. For this reason, the biasing force acting on the link 96L from the tension spring 98L hardly acts as a turning moment in the closing direction (or opening direction) of the link 96L about the rotation shaft 96La. Therefore, when opening and closing the transfer unit 7, the user can open and close the transfer unit 7 comfortably without feeling the biasing force of the tension spring 98L.

During the user's operation to close the transfer unit 7, the second linear portion 96Lc3 of the link hole 96Lc is pressed by the engaging portion 7L. occurs. On the other hand, the rotation shaft 96La receives an upward reaction force from the lower surface 97La1 of the holding hole portion 97La, so that a counterclockwise moment about the link shaft 96Lb is generated in the link 96L. These clockwise and counterclockwise moments are balanced. As the transfer unit 7 is closed by the user, the link shaft 96Lb moves upward while rubbing against the contact surface 97Lb.

Next, as shown in FIGS. 27A and 27B, when the user further closes the transfer unit 7, the link shaft 96Lb passes through the upper end of the contact surface 97Lb. As a result, the link shaft 96Lb is disengaged from the contact surface 97Lb, and the link 96L is rotated in the closing direction by the tension spring 98L. At this time, the link shaft 96Lb moves along the upper surface 97Lh toward the inside of the device main body 2, that is, toward the spring hook portion 74a. The transfer unit 7 is biased toward the closed position by the link 96L through the link hole 96Lc and the engaging portion 7L, and is stably held at the closed position.

Next, the manner in which the transfer unit 7 is opened from the state shown in FIG. 28(a) to the state shown in FIG. 28(b) will be described. As shown in FIGS. 28A and 28B, when the user opens the transfer unit 7 from the closed position, the second linear portion 96Lc3 of the link hole portion 96Lc is pressed by the engaging portion 7L. As a result, a counterclockwise moment about the link shaft 96Lb is generated in the link 96L.

On the other hand, when the rotation shaft 96La receives the reaction force in the lower left direction from the upper right surface 97La2 of the holding hole portion 97La, a clockwise moment about the link shaft 96Lb is generated in the link 96L. These counterclockwise and clockwise moments are balanced. As the transfer unit 7 is opened by the user, the link shaft 96Lb moves in the negative Y direction while rubbing against the upper surface 97Lh against the biasing force of the tension spring 98L. As a result, the transfer unit 7 and the link 96L reach the state shown in FIG. 26(b).

From here, the procedure for opening the transfer unit 7 to the open position follows the order of FIGS. Since the procedure for closing the transfer unit 7 is only reversed, the explanation is omitted. In the states shown in FIGS. 26(b)(a), 25(b)(a), and 24(b)(a), the urging force acting on the link 96L from the tension spring 98L is does not act as a rotational moment in the opening direction (closing direction) of the link 96L centered on . Therefore, when opening and closing the transfer unit 7, the user can open and close the transfer unit 7 comfortably without feeling the biasing force of the tension spring 98L.

[Lock member]
Next, as shown in FIG. 21, lock members 99L and 99R provided at both ends of the transfer unit 7 in the X direction will be described. The lock members 99L and 99R are engaged with the apparatus main body 2 when the image forming apparatus 1 forms an image, thereby restricting the transfer unit 7 from rotating from the closed position in the opening direction. Since the lock members 99L and 99R have the same configuration, the lock member 99R and its peripheral configuration will be mainly described below, and the description of the lock member 99L and its peripheral configuration will be omitted.

FIGS. 29(a) and 29(b) are perspective views showing the locking member 99R viewed from the negative Y direction. 29(c) and 29(d) are perspective views showing how the lock member 99R is removed from the transfer unit 7, respectively. As shown in FIGS. 29A to 29D, the lock member 99R is rotatably supported by a lock shaft 7aR provided in the transfer unit 7 and extending in the X direction.

The lock member 99R has a contact portion 99Ra (see FIG. 31(b)), a tip portion 99Rb, and an abutment portion 99Rc. As shown in FIGS. 29(c) and 29(d), the lock member 99R is divided into a first bearing portion 99Rd located on the plus side in the X direction and a second bearing portion 99Re located on the minus side in the X direction. ing. Although details will be described later, each of the first bearing portion 99Rd and the second bearing portion 99Re has a bearing that engages with the lock shaft 7aR. The abutting portion 99Ra corresponds to the inner region of the connecting portion that connects the first bearing portion 99Rd and the second bearing portion 99Re. Here, the inside means that it is positioned inside when viewed from the center of the lock shaft 7aR (see FIG. 31(b)). The tip portion 99Rb is provided on the first bearing portion 99Rd side, and the abutting portion 99Rc is provided on the second bearing portion 99Re side. Details of the contact portion 99Ra, the tip portion 99Rb, and the abutment portion 99Rc will be described later.

30 is a view of the apparatus main body 2 viewed from the negative Y direction, and FIG. 31(a) shows the image forming apparatus 1 when the lock member 99R is positioned at the unlock position, 31AB-31AB in FIG. It is a sectional view. FIG. 31(b) is a cross-sectional view taken along line 31AB-31AB in FIG. 30, showing the lock member 99R in the unlocked position. FIG. 32(a) is a cross-sectional view taken along line 32AB-32AB in FIG. 30, showing the image forming apparatus 1 when the lock member 99R is positioned at the lock position. FIG. 32(b) is a cross-sectional view taken along line 32AB-32AB of FIG. 30 showing the locking member 99R in the locked position.

Note that the tip portion 99Rb and the abutment portion 99Rc are arranged to be displaced from each other in the X direction, and the 31AB-31AB cross section in FIG. 30 is a cross section including the abutment portion 99Rc. The 32AB-32AB cross section in FIG. 30 is a cross section including the tip portion 99Rb.

As shown in FIGS. 31(a) and 31(b), when the rear cover 73 is positioned at the open position, the lock member 99R is biased in the arrow RD1 direction by its own weight. The lock member 99R biased in the arrow RD1 direction is held at the unlocked position by the abutting portion 99Rc abutting against the stopper portion 7bR. Although the stopper portion 7bR is provided in the transfer unit 7 in this embodiment, the present invention is not limited to this. For example, the stopper portion 7bR may be provided in the fixing portion 9 (see FIG. 2) or other portions of the apparatus main body 2. FIG.

Further, when the lock member 99R is positioned at the unlock position, the contact portion 99Ra of the lock member 99R is not engaged with the contact portion 9Ra provided in the fixing portion 9. As shown in FIG. Here, the abutted portion 9Ra is provided in a space 77 surrounded by a U-shaped member into which the locking member 99R is inserted, shown in FIGS. 29(c) and 29(d). Therefore, the transfer unit 7 provided with the lock member 99R is not locked with respect to the apparatus main body 2 including the contacted portion 9Ra, and the user can open and close the transfer unit 7. FIG.

Next, as shown in FIGS. 32(a) and 32(b), when the rear cover 73 is positioned at the closed position, the locking member 99R is positioned at the locked position. At this time, the abutting portion 99Ra of the lock member 99R engages with the abutted portion 9Ra provided in the fixing portion 9. As shown in FIG. The abutting portion 99Ra as the first engaging portion is formed in an arc shape centering on the lock shaft 7aR, and the abutted portion 9Ra as the second engaging portion tapers toward the abutting portion 99Ra. is formed to be As shown in FIG. 32(b), the abutting portion 99Ra that abuts (engages) with the abutted portion 9Ra receives a reaction force F1 as a third reaction force from the abutted portion 9Ra. The reaction force F1 is a force along the Y direction with the lock shaft 7aR as a starting point, and acts as a force in the direction of closing the transfer unit 7 toward the closed position.

Frictional force between the contacted portion 9Ra and the contact portion 99Ra resulting from the reaction force F1 and the pressed portion 99Rb1, which will be described later, are pressed by the pressing portion 73h of the rear cover 73, whereby the lock member 99R is Retained in locked position. The transfer unit 7 provided with the lock member 99R is locked with respect to the apparatus main body 2 including the contact portion 9Ra by engaging the contact portion 99Ra of the lock member 99R with the contact portion 9Ra. , held in the closed position. Further, the transfer unit 7 tends to rotate in the closing direction when the contact portion 99Ra receives the reaction force F1, so that the transfer unit 7 is more stably held at the closed position.

In the present embodiment, the abutment portion 99Ra and the abutted portion 9Ra are provided so as to abut and engage with each other when the lock member 99R is positioned at the lock position, but the present invention is not limited to this. . For example, there may be a slight gap between the contact portion 99Ra and the contacted portion 9Ra, and only when the transfer unit 7 receives a reaction force F4 shown in FIG. The contact portion 99Ra and the contacted portion 9Ra may be engaged with each other. As a result, when the transfer unit 7 receives the reaction force F4 from the recording material P, the rotation of the transfer unit 7 in the opening direction is restricted.

Further, the tip portion 99Rb of the lock member 99R has a pressed portion 99Rb1 facing the pressing portion 73h provided on the inner side surface 73f of the rear cover 73, and an inclined portion provided on the opposite side of the pressed portion 99Rb1 in the direction of the arrow RD1. and a surface 99Rb2. The inclined surface 99Rb2 is formed so as to extend downstream in the direction of the arrow RD2 toward the inner side in the radial direction of the lock member 99R.

The lock member 99R positioned at the unlock position rotates toward the lock position when the pressed portion 99Rb1 is pressed by the pressing portion 73h of the rear cover 73. As shown in FIG. That is, the lock member 99R rotates from the unlock position to the lock position in conjunction with the closing operation of the rear cover 73. As shown in FIG. Further, the pressing portion 73h as the second moving portion moves the lock member 99R from the unlock position to the lock position.

Further, as shown in FIGS. 32(b) and 33, the rear cover 73 is provided with an unlocking claw 73i. The unlocking claw 73i is arranged downstream of the pressing portion 73h in the closing direction of the rear cover 73 . In FIG. 33, only the rear cover 73 and the locking member 99 are shown for the sake of explanation.

As shown in FIGS. 34(a) and 34(b), when the back cover 73 is opened and closed between the open position and the closed position, the movement trajectory of the unlocking claw 73i follows the lock member 99R located at the unlock position. , but overlaps the lock member 99R positioned at the lock position. Therefore, for example, when the recording material P jams in the conveying path 19 (see FIG. 35) and the back cover 73 is opened from the closed position to the open position, the unlocking claw 73i provided on the back cover 73 is released by the locking member 99R. contact with the inclined surface 99Rb2. When the rear cover 73 is further opened, the unlocking claw 73i presses the inclined surface 99Rb2, and the lock member 99R rotates in the arrow RD1 direction. That is, the unlocking claw 73i as the first moving portion moves the locking member 99R from the locking position to the unlocking position.

By rotating the lock member 99R in the direction of the arrow RD1, the engagement between the contacted portion 9Ra and the contact portion 99Ra is released, and the lock member 99 is unlocked as shown in FIG. 31(b) by its own weight. Move to position. As described above, in the present embodiment, when the user simply opens the rear cover 73, the lock member 99R moves from the locked position to the unlocked position. can be improved. Further, since the inclined surface 99Rb2 is inclined with respect to the direction of the arrow RD1 centering on the lock shaft 7aR, it can smoothly contact the unlocking claw 73i.

Further, since the unlocking claw 73i does not interfere with the locking member 99R positioned at the unlocked position, when the back cover 73 is closed from the open position to the closed position, the lock member 99R positioned at the unlocked position does not interfere with the unlocking claw 73i. no contact. Then, the lock member 99R is rotated from the unlock position to the lock position by a pressing portion 73h provided on the rear cover 73. As shown in FIG. The pressing portion 73h is formed longer than the unlocking claw 73i in the Z direction. Therefore, while the unlocking claw 73i does not contact the lock member 99R located at the unlock position, the pressing portion 73h can press the lock member 99R located at the unlock position.

In the present embodiment, the locus of movement of the unlocking claw 73i does not overlap the lock member 99R positioned at the unlock position, but overlaps the lock member 99R positioned at the lock position. It is not limited to this. For example, the movement trajectory of the lock release claw 73i may overlap the lock member 99R positioned at the unlock position and the lock position. In this case, although the lock member 99R positioned at the unlock position contacts the lock release claw 73i, elastic deformation of at least one of the lock release claw 73i and the lock member 99R causes the lock release claw 73i to move toward the lock member 99R. may be configured to be able to pass through.

Next, the necessity of the locking member 99R (99L) will be explained. As described above, the links 96L and 96R hold the transfer unit 7 at the closed position by the biasing force F2 (see FIG. 28(a)) of the tension springs 98L and 98R. The biasing force F2 of the tension springs 98L and 98R is greater than the reaction force F3 that the transfer roller 7a receives from the photosensitive drum 11 (hereinafter simply referred to as the reaction force F3 of the transfer roller 7a). In other words, the reaction force F<b>3 as the first reaction force is the reaction force that the transfer unit 7 receives from the apparatus body 2 including the photosensitive drum 11 .

Here, in the present embodiment, as shown in FIG. 35, the transfer unit 7 is provided with a projecting portion 7e. The projecting portion 7e as a contact portion is provided adjacent to the transfer nip N1 at a position upstream of the transfer nip N1 in the recording material conveying direction CD. When the recording material P is conveyed through the conveying path 19, the projection 7e is pressed by the recording material P. As shown in FIG. At this time, the force that the projecting portion 7e receives from the recording material P is referred to as a reaction force F4 as a second reaction force from the recording material P. As shown in FIG. As a result, the transfer unit 7 is urged in the opening direction. The protruding portion 7e has a function of correcting the posture of the recording material P so that the recording material P is wound around the photosensitive drum 11 at a larger angle, and the image transfer at the transfer nip N1 can be stabilized. It is That is, the projecting portion 7 e bends the recording material P toward the photosensitive drum 11 .

The biasing force F2 of the tension springs 98L and 98R is set to be larger than the reaction force F3 of the transfer roller 7a, but smaller than the sum of the reaction force F3 of the transfer roller 7a and the reaction force F4 from the recording material P. In the present embodiment, the relationship F3<F2<(F3+F4) is established for a recording material having a basis weight of 60 to 90 (g/m ² ) and having greater rigidity than plain paper. For example, when A4-size cardboard with a basis weight of 91 to 199 (g/m ² ) is used as the recording material P, the relationship F3<F2<(F3+F4) is established. The biasing force F2 acts as a force in the direction of closing the transfer unit 7 toward the closed position, and the reaction forces F3 and F4 act as forces in the direction of opening the transfer unit 7 toward the open position. Therefore, when the recording material P is transported along the transport path 19, the transfer unit 7 rotates from the closed position to the open direction only by the biasing force F2 of the tension springs 98L and 98R. As a result, image formation at the transfer nip N1 and conveyance of the recording material P become unstable.

Therefore, in this embodiment, the transfer unit 7 is held at the closed position by the locking members 99L and 99R. As a result, even when the recording material P is conveyed on the conveying path 19, image formation and conveyance of the recording material P can be stably performed. Further, if the biasing force F2 of the tension springs 98L and 98R were set to be greater than the sum of the reaction force F3 of the transfer roller 7a and the reaction force F4 from the recording material P, the user would not be able to move the transfer unit 7. The operating force required to open the is increased. In other words, by providing the locking members 99L and 99R, the biasing force F2 of the tension springs 98L and 98R that biases the transfer unit 7 in the closing direction can be set small. can be reduced. This can improve usability.

Also, consider a case where the tension springs 98L and 98R are not provided, or a case where the biasing force F2 of the tension springs 98L and 98R is smaller than the reaction force F3 of the transfer roller 7a. In this case, when the rear cover 73 is opened, the transfer unit 7 is urged from the closed position toward the open position by the reaction force F3, and there is a risk that the transfer unit 7 will open vigorously to the open position. Since the transfer unit 7 is relatively heavy, if the transfer unit 7 is forcefully opened to the open position, the rotation shaft 7c and the links 96L and 96R of the transfer unit 7 may be damaged. Therefore, by setting the biasing force F2 of the tension springs 98L and 98R to be greater than the reaction force F3 of the transfer roller 7a as in the present embodiment, the transfer unit 7 is also opened when the rear cover 73 is opened. You can prevent it from being cut off. As a result, damage to the transfer unit 7 and its supporting structure can be suppressed.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the second embodiment, the present invention is applied to an image forming apparatus 300 having a configuration different from that of the image forming apparatus 1 of the first embodiment. It is. The same configuration as that of the first embodiment will be omitted from illustration or given the same reference numerals in the figure.

As shown in FIG. 36, the image forming apparatus 1 has a conveying path 319 that is a left-right reversed S shape. The image forming apparatus 1 has an image forming section 20 , a process unit 40 , a fixing section 9 , a discharge roller pair 10 , an opening/closing member 301 , a lock member 304 and a cover member 306 . The transfer roller 7 a is urged in the Z direction toward the photosensitive drum 11 by an urging member (not shown), and the process unit 40 is urged in the negative Z direction by the urging member 303 . Since the biasing force of the biasing member 303 is sufficiently larger than the biasing force (not shown) that biases the transfer roller 7a, the process unit 40 is positioned in the Z direction.

An opening/closing member 301 as an opening/closing portion is positioned between a closed position as a first closed position where it is closed with respect to the device main body 2 and a closed position as a first open position where it is opened with respect to the device main body 2. , is provided so as to be openable and closable about the rotating shaft 301a. The biasing member 303 is provided between the opening/closing member 301 and the process unit 40 . Therefore, the opening/closing member 301 is biased in the opening direction by the reaction force F5 from the biasing member 303 as the unit biasing portion. In other words, the reaction force F<b>5 as the first reaction force is the reaction force that the opening/closing member 301 receives from the apparatus main body 2 including the process unit 40 and the biasing member 303 . On the other hand, the opening/closing member 301 is biased in the closing direction by a torsion coil spring 302 as a biasing portion with a biasing force F6 larger than the reaction force from the biasing member 303 .

Here, the contact portion 301e of the opening/closing member 301 is provided upstream of the transfer nip N1 in the recording material conveying direction CD. receives a reaction force F7 as This is because the conveying roller pair 5 c conveys the recording material P faster than the photosensitive drum 11 . It is formed. The loop of the recording material P causes the recording material P to wind around the photosensitive drum 11 at a larger angle, thereby stabilizing the image transfer at the transfer nip N1.

In this embodiment, the biasing force F6 of the torsion coil spring 302 is set smaller than the sum of the reaction force F5 of the biasing member 303 and the reaction force F7 of the recording material P. FIG. The biasing force F26 acts as a force in the direction of closing the opening/closing member 301 toward the closed position, and the reaction forces F5 and F7 act as forces in the direction of opening the opening/closing member 301 toward the open position. Therefore, if the biasing force F6 of the torsion coil spring 302 alone is used, the opening/closing member 301 rotates from the closed position toward the opening direction when the recording material P is conveyed along the conveying path 319 .

Therefore, in this embodiment, the lock member 304 holds the opening/closing member 301 at the closed position. As a result, even when the recording material P is conveyed on the conveying path 319, image formation and conveyance of the recording material P can be stably performed.

The locking member 304 has a hook portion 304b that can be engaged with a contacted portion 305 fixed to the apparatus main body 2, and is supported by the opening/closing member 301 so as to be rotatable about a rotating shaft 304a. The locking member 304 is urged counterclockwise in FIGS. 36 to 39 by an urging member (not shown) or its own weight, for example, around the rotation shaft 304a. That is, the lock member 304 is biased toward the unlocked position.

A cover member 306 as a cover portion has a pressing portion 306a and an unlocking claw 306b. The cover member 306 rotates between a closed position as a second closed position where the cover member 306 is closed with respect to the apparatus main body 2 and a closed position as a second open position where the cover member 306 is opened with respect to the apparatus main body 2. It is supported so that it can be opened and closed around 306c. Also, the cover member 306 covers the opening/closing member 301 and the transport path 319 at the closed position.

When the cover member 306 is closed from the open position to the closed position, as shown in FIG. 36, the pressing portion 306a as the second moving portion provided on the cover member 306 moves the lock member 304 from the unlock position to the lock position. Rotate. When the cover member 306 is positioned at the closed position, the lock member 304 is pressed by the pressing portion 306a and held at the lock position. The lock member 34 locks the opening/closing member 301 at the closed position by engaging the hook portion 304b with the abutted portion 305 at the lock position.

As shown in FIGS. 37 and 38, when the user opens the cover member 306 from the closed position toward the open position about the pivot shaft 306c, the unlocking claw 306b as the first moving part moves the lock member 304. Rotate from the locked position to the unlocked position. When the lock member 304 is positioned at the unlocked position shown in FIG. 37, the hook portion 304b is not engaged with the abutted portion 305. As shown in FIG. Therefore, the opening/closing member 301 can be opened from the closed position to the open position about the rotating shaft 301a.

When the cover member 306 is opened to the open position shown in FIG. 38, the user can access the jammed recording material P on the conveying path 319 and clear the jam. Furthermore, as shown in FIG. 39, when the user opens the opening/closing member 301 from the closed position to the open position about the pivot shaft 301a, the user can remove the process unit 40 and replace it. That is, the process unit 40 is detachable from the apparatus main body 2 .

As described above, in the present embodiment, the lock member 304 holds the opening/closing member 301 at the closed position. As a result, even when the recording material P is conveyed on the conveying path 319, image formation and conveyance of the recording material P can be stably performed. Further, if the biasing force F6 of the torsion coil spring 302 is set to be greater than the sum of the reaction force F5 of the biasing member 303 and the reaction force F7 of the recording material P, when the user opens the opening/closing member 301 operation force required for That is, by providing the lock member 304, the biasing force of the torsion coil spring 302 that biases the opening/closing member 301 in the closing direction can be set small, and the operating force required to open the opening/closing member 301 can be reduced. This can improve usability.

<Other embodiments>
In addition, in the first embodiment, the contact portion 99Ra has an arc shape centering on the lock shaft 7aR, but the shape is not limited to this. For example, the contact portion 99Ra may be formed in an arc shape such that the radius between the contact portion 99Ra and the lock shaft 7aR decreases toward the downstream in the arrow RD2 direction. As a result, the contact portion 99Ra and the contacted portion 9Ra of the lock member 99R are engaged with each other with a stronger force at the lock position, and the transfer unit 7 can be reliably locked at the closed position.

Further, in the first embodiment, the transfer unit 7 is provided with the projecting portion 7e, but the present invention is not limited to this. For example, the protruding portion 7 e may be provided in a transport guide that is opposed to the transfer unit 7 and that constitutes the transport path 19 .

Further, although the torsion coil spring 302 is used in the second embodiment, the present invention is not limited to this. For example, instead of the torsion coil spring 302, other springs such as leaf springs and torsion bars may be applied.

Further, although the lock members 99L and 99R of the first embodiment are provided in the transfer unit 7, the present invention is not limited to this. For example, the locking members 99L and 99R may be provided in the apparatus main body 2 instead of the transfer unit 7. That is, the lock members 99L and 99R as lock portions may be provided on either the transfer unit 7 or the apparatus main body 2 . In any case, the lock members 99L and 99R need only be able to lock the transfer unit 7 positioned at the closed position to the apparatus main body 2 when the rear cover 73 is positioned at the closed position.

Further, although the locking member 304 in the second embodiment is provided on the opening/closing member 301, the present invention is not limited to this. For example, the locking member 304 may be provided on the device main body 2 instead of the opening/closing member 301 . That is, the locking member 304 as a locking portion may be provided on either one of the opening/closing member 301 and the device main body 2 . In any case, the lock member 304 should be able to lock the opening/closing member 301 positioned at the closed position to the apparatus main body 2 when the cover member 306 is positioned at the closed position.

In addition, although the electrophotographic image forming apparatus 1, 300 has been used in each of the above-described embodiments, the present invention is not limited to this. For example, the present invention can also be applied to an inkjet image forming apparatus that forms an image on a recording material by ejecting ink liquid from nozzles.

The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or storage medium, and one or more processors in the computer of the system or device read and execute the program. processing is also feasible. It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

1,300: Image forming apparatus/2: Apparatus main body/5c: Conveyance section (conveyance roller pair)/7: Opening/closing section, transfer unit/7a: Transfer member (transfer roller)/7e: Protruding section/9Ra: Second engagement Joint portion (abutted portion)/11: image carrier (photosensitive drum)/18: toner storage portion (storage portion)/19, 319: transport path/40: process unit/72: housing/73: cover portion (Rear cover)/73h, 306a: Second moving part (pressing part)/73i, 306b: First moving part (unlock claw)/98L, 98R: Biasing part (tension spring)/99L, 99R, 304: Lock portion (locking member)/99Ra: first engaging portion (contact portion)/303: unit biasing portion (biasing member)/200: supply portion/301: opening/closing portion (opening/closing member)/302: biasing Part (torsion coil spring)/306: Cover part (cover member)/CD: Recording material conveying direction/F1: Third reaction force (reaction force)/F2, F6: Biasing force/F3, F5: First reaction force (reaction force) force)/F4, F7: second reaction force (reaction force)/P: recording material/N1: transfer nip

Claims (14)

an apparatus main body having a rotatable image carrier;
a transfer member that forms a transfer nip together with the image carrier and transfers an image formed on the image carrier to a recording material;
a protruding portion provided adjacent to the transfer nip at a position upstream of the transfer nip in the conveying direction of the recording material, and for curving the recording material toward the image carrier;
an opening/closing portion provided to be openable/closable between a first closed position closed with respect to the device main body and a first open position opened with respect to the device main body;
a biasing portion that biases the opening/closing portion toward the first closed position;
a lock position provided on either one of the opening/closing portion and the device main body to lock the opening/closing portion located in the first closed position with respect to the device main body, and releasing the lock of the opening/closing portion from the device main body a unlocked position, a lock portion movable to;
provided to be openable and closable between a second closed position closed with respect to the device main body and a second open position opened with respect to the device main body, and the first closed position at the second closed position a cover portion that covers the opening and closing portion located in
wherein the lock portion is positioned at the lock position when the cover portion is positioned at the second closed position;
An image forming apparatus characterized by: The urging force of the urging portion is greater than the first reaction force that the opening/closing portion receives from the apparatus body, and the second reaction force that the opening/closing portion receives from the recording material conveyed in the conveying direction and the first reaction force that the opening/closing portion receives from the recording material conveyed in the conveying direction. less than the sum with the reaction force,
2. The image forming apparatus according to claim 1, wherein: The first reaction force and the second reaction force act as forces in the direction of opening the opening/closing portion toward the first open position,
3. The image forming apparatus according to claim 2, wherein: The protruding portion is provided in the opening/closing portion and configured to contact the recording material conveyed in the conveying direction and receive the second reaction force.
4. The image forming apparatus according to claim 2, wherein: The lock portion is urged toward the unlocked position and positioned at the unlocked position when the cover portion is positioned at the second open position.
5. The image forming apparatus according to claim 2, wherein: The cover portion has a first moving portion that moves the lock portion from the lock position to the unlock position when the cover portion is opened from the second closed position to the second open position.
6. The image forming apparatus according to claim 5, wherein: The cover portion has a second moving portion that moves the locking portion from the unlocking position to the locking position when the cover portion is closed from the second open position to the second closed position.
7. The image forming apparatus according to claim 6, wherein: The apparatus main body includes a process unit having the image carrier and a toner storage section that stores toner,
The opening/closing portion is a transfer unit having the transfer member that forms the transfer nip together with the image carrier when positioned at the first closed position,
The first reaction force is a reaction force that the transfer member receives from the image carrier.
8. The image forming apparatus according to claim 2, wherein: the lock portion has a first engagement portion and is provided in the transfer unit;
The device main body has a second engagement portion that can be engaged with the first engagement portion when the transfer unit is positioned at the first closed position and the lock portion is positioned at the lock position.
9. The image forming apparatus according to claim 8, wherein: the lock portion is rotatable about a rotation shaft between the lock position and the unlock position;
The first engaging portion is formed in an arc shape centering on the rotation shaft, and receives a third reaction force from the second engaging portion by engaging the second engaging portion,
The third reaction force acts as a force in the direction of closing the opening/closing portion toward the first closed position,
10. The image forming apparatus according to claim 9, wherein: The process unit has a replenishment part that communicates with the toner storage part and receives toner supplied from the outside while the process unit is attached to the apparatus main body.
11. The image forming apparatus according to any one of claims 8 to 10, characterized by: the apparatus main body includes a process unit including the image bearing member and a toner storage unit that stores toner;
a unit biasing section provided between the process unit and the opening/closing section positioned at the first closed position, the unit biasing section biasing the image carrier toward the transfer member provided in the apparatus main body; prepared,
The first reaction force is a reaction force that the opening/closing portion receives from the unit biasing portion.
8. The image forming apparatus according to claim 2, wherein: wherein the locking portion is provided in the opening/closing portion;
13. The image forming apparatus according to claim 12, wherein: The process unit is attachable to and detachable from a housing of the apparatus main body when the cover portion is positioned at the second open position and the opening/closing portion is positioned at the first open position.
14. The image forming apparatus according to any one of claims 8 to 13, characterized by:

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