JP2003084564A - Image forming device - Google Patents

Abstract

(57) Abstract: A photosensitive drum 1000a and a developing device 1100 for supplying a developer (toner) to the photosensitive drum with a developing sleeve 1100a to visualize a latent image formed on the photosensitive drum.
In the image forming apparatus, the developing device is efficiently pressed against the photosensitive drum according to the setting spring of the pressing spring. A shaft is formed in the developing device on the side of the developing sleeve from the center of gravity, and one of the shafts is supported by a substantially U-shaped bearing so as to be movable in a substantially vertical and rotational direction.
A pressure is applied in a substantially upward direction from almost immediately below the developing sleeve to abut the developing sleeve side against the photosensitive drum side,
The angle between the pressure direction and the line connecting the center of the photosensitive drum and the center of the spindle supported by the substantially U-shaped bearing is substantially 90 degrees.
The angle between the line connecting the center of the photosensitive drum and the center of the support shaft supported by the substantially U-shaped bearing and the allowable movement direction of the substantially U-shaped bearing with respect to the support shaft is substantially 90 °.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor,
An image carrier such as an electrostatic recording dielectric / magnetic recording magnetic material and a developing device for visualizing a latent image formed on the image carrier are provided.
The present invention relates to an image forming apparatus such as a copying machine, a printer and an image display machine.

More specifically, the present invention relates to improvement of a pressure urging means of a developing device with respect to the image carrier side.

[0003]

2. Description of the Related Art FIG. 18 is a schematic view of an image forming portion of an image forming apparatus as a conventional example. This image forming apparatus is a laser beam printer using an electrophotographic process.

Reference numeral 1000a denotes a rotary drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) as an image bearing member, which is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed.

During the rotation process of the photosensitive drum 1000a,
A time series electric digital pixel signal of image information is uniformly charged to a predetermined polarity and potential by a charging roller 1000b as a charging unit, and the uniformly charged surface is output from a laser scanner 701 as an image exposing unit. By being scanned and exposed by the correspondingly modulated laser light L,
An electrostatic latent image corresponding to the scanning exposure image information is formed on the surface of the photosensitive drum.

The electrostatic latent image is a developing device (developing device) 110.
0 is developed (visualized) as a toner image, and at a transfer nip portion that is a contact portion between the photosensitive drum 1000a and a transfer roller 703 as a transfer unit, a predetermined paper feed mechanism portion (not shown) is connected to the transfer nip portion. And is transferred to the recording paper P fed at the control timing.

The recording paper on which the toner image has been transferred through the transfer nip portion is separated from the surface of the photosensitive drum 1000a and introduced into a fixing means (not shown) to undergo a toner image fixing process and discharged to a paper discharging portion. To be paper.

Further, the photosensitive drum 1000 after the recording paper is separated
Contamination such as residual toner after transfer and paper dust that are slightly left on the surface a are removed and cleaned by the cleaning device 1000c, and are repeatedly used for image formation.

The developing device 1100 comprises a developing sleeve 1100a as a developing member, a developing blade 1100e, toner stirring blades 1100b and 1100c, a toner replenishing container (toner cartridge) 1200 and the like.
The toner filled in the toner replenishing container 1200 is sequentially sent out from within the container by the rotational driving of the toner stirring blade 1200a in the container, which is further moved to the developing sleeve 1100a side by the rotational driving of the toner stirring blades 1100b and 1100c. Sequentially sent developing sleeve 1100
is supplied to a. FIG. 19 is a partially cutaway perspective view of the developing device 1100.

A spacer roller 1100f having an outer diameter larger than the outer diameter of the developing sleeve is provided concentrically with the developing sleeve on both ends of the developing sleeve 1100a, and a developing device for the photosensitive drum 1000a as an image carrier is provided. By moving and urging the developing device 1100 toward the photosensitive drum 1000a side by the developing and pressing unit 1500 which is a pressing and urging means, the spacer roller 1100f is moved to the photosensitive drum 10.
00a is kept pressed and abutted on both end surfaces of the photosensitive drum 00a with a predetermined pressing force, and the developing sleeve 1100a is fixed to the photosensitive drum 1
000a is maintained in a state where a predetermined constant distance (about 300 μm) is secured.

The developing sleeve 1100a is rotationally driven in the counterclockwise direction indicated by an arrow at a predetermined peripheral speed, and the toner supplied as described above is coated on the surface of the developing sleeve as a thin layer having a constant film thickness by the developing blade 1100e. . A predetermined developing bias is applied to the developing sleeve 1100a from a developing bias applying power source (not shown), and the toner coated on the surface of the developing sleeve is selectively transferred to the electrostatic latent image on the surface of the photosensitive drum 1000a to be electrostatically charged. The latent image is developed as a toner image (reverse development or regular development).

Reference numeral 1150 denotes a front wall portion of the exterior of the developing device, which also serves as a recording material guide plate introduced into the transfer nip portion.

As shown in FIG. 20, the developing device 1100 is detachable from the printer body 1 by opening the front cover 900 of the printer body 1 and opening 902 provided in the side frame 3001 of the printer body.

Developing device 1100 for printer body 1
The mounting operation of the front cover 900 of the printer body 1
Then, the pressure handle 1510 disposed on the outer surface side of the printer main body side frame 3001 is tilted laterally rightward around the pressure shaft 1502 as shown in FIG. By this operation, the developing and pressurizing unit 1500, which is integrally provided on the pressurizing shaft 1502, is set in the standing posture as shown in FIG. The standing posture of the developing pressure unit 1500 is the pressure releasing posture. The developing device 1100 is inserted into the printer main body from the opening 902 of the side frame 3001 of the printer main body with the back side of the developing device 1100 first, and is fully inserted until the insertion of the developing device is regulated by a regulation member (not shown). It is inserted in parallel with the axis of the photosensitive drum 1000a. During this insertion process, the developing device 1100 does not interfere with the photosensitive drum 1000a or the developing pressure unit 1500 in the upright position.
FIG. 21 shows the insertion end state. In this inserted state, the developing device 1100 is mounted on the printer main body side frame 3000, and the frame 3000
The upper part can be slid in a direction D perpendicular to the axis of the photosensitive drum 1000a.

Next, the pressing handle 1510 is rotated counterclockwise from the tilted state in the right lateral direction in FIG. As a result of this operation,
As shown in the figure, the player turns to the left sideways. The developing device pressing unit 1500 is in the left sideways tilted position in the developing device pressing position. The developing device pressing unit 1500 elastically presses the rear surface wall of the developing device exterior, and the developing device 1100 exposes the frame 3000 on the frame 3000. The spacer roller 1100f is slid in the direction perpendicular to the axis of the drum 1000a toward the photosensitive drum 1000a, and the spacer rollers 1100f are held in pressure contact with both end surfaces of the photosensitive drum 1000a with a predetermined pressing force. That is, the developing device 1100 side is held in a state of being pressed to the photosensitive drum 1000a side by a predetermined amount. In this state, the printer body 1 side and the developing device 1100 side are mechanically and electrically connected to each other in a predetermined state.

The developing pressurizing unit 1500 includes a pressurizing shaft 1502 having a U-shaped cross section, a pressurizing member 1503 movably supported by the pressurizing shaft 1502, and a pressurizing member 1503 on the pressurizing shaft 1502. It is composed of a pressure spring 1501 and the like for applying a pressure in a direction away from it. Pressure shaft 150
2 is rotatably supported via a bearing member between the front and rear body side frames of the printer body. The pressure handle 15 is provided at the front end of the pressure shaft 1502.
10 (FIG. 20) is fixed. As shown in FIG. 18, when the developing device 1100 is pressed down, the developing device 1100 is tilted to the left lateral direction so that the pressing member 1503 compresses the pressing spring 1501 and abuts against the rear wall of the developing device 1100. Developing device 1100 by the compression reaction force of the pressing spring 1501.
Is elastically pressed.

After the developing device 1100 is pressurized as described above, the front cover 900 is closed in the printer body 1 to complete the mounting of the developing device 1100 to the printer body 1.

The developing device 1100 mounted on the printer body 1 is taken out in the reverse order of the above.

Further, the toner in the developing device 1100 attached to the printer body 1 is successively consumed, the toner is exhausted in the toner supply container 1200, and the amount of toner remaining in the developing device reaches a predetermined lower limit amount. When it is detected by a detection means (not shown), the operation unit 5 of the printer body 1
Is displayed on the display 501 (FIG. 20). Based on this warning display, the toner supply container 1200 of the developing device 1100 is replaced.

To replace the toner supply container 1200, when the front cover 900 of the printer body 1 is opened, the developing device 110 attached to the printer body 1 is opened through the opening 902 provided in the side frame 3001 of the printer body.
The front end face of 0 is exposed. A toner supply container insertion / removal opening 1100g (see FIG. 19) is provided on the front end surface of the developing device 1100.
(FIG. 20) is provided, and an empty toner replenishing container 1200 is grasped from the opening 1100g by gripping the knob portion 1200b and pulled out according to a predetermined procedure to perform a new toner replenishing container 1200 filled with toner. Opening 1100
g from inside the developing device 1100 and a knob portion 1200b
Grasp and perform the opening and mounting operation according to the prescribed procedure. Next, the front cover 900 is closed in the printer main body 1 so that the toner supply container 1200 for the developing device 1100 is provided.
End the old and new exchange operations.

[0021]

In the above-mentioned conventional example, when the developing device 1100 is mounted on the printer main body 1, it is mounted on the printer main body side frame member 3000 so as to be slidable in the direction D in FIG. 18 is a system in which pressure is applied in the left direction by a pressure member 1503 of the developing pressure unit 1500 from the right in FIG.
200, the weight of the developing device 1100 including the toner contained inside is the developing device 1100 and the frame member 30 on the printer body side.
00 acting on both contact portions A to generate a frictional resistance, it is easy to hinder the sliding movement of the developing device 1100 in the D direction.
In some cases, the set spring pressure of No. is not actually pressed as set, or in order to improve this, the set spring pressure of the pressurizing spring 1501 may have to be set higher considering the friction resistance. When rotating the pressurizing handle 1510, the frictional resistance may cause a heavy rotational load and deteriorate operability.

In view of the above problems, it is an object of the present invention to improve the operability of the pressure urging means of the developing device for the image carrier in this type of image forming apparatus.

Specifically, in accordance with the image forming apparatus of the above example, the purpose is as follows.

[0024]. The developing device 1100 efficiently presses the photosensitive drum 1000a according to the set spring pressure of the pressing spring 1501 of the developing pressurizing unit 1500.

[0025]. It is not necessary to set the spring pressure of the pressure spring 1501 to a high value in consideration of the frictional resistance between the developing device 1100 and the main body frame member 3000.

.. When the pressure handle 1510 is rotationally operated, the frictional resistance prevents the rotational load from becoming heavy and impairs the operability.

[0027]

The present invention is an image forming apparatus having the following configuration.

(1) An image forming apparatus having an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member. The developing device is supported on the carrier so as to be swingable about a supporting portion, and in this case, in the free state of the developing device,
The supporting portion of the developing device is moved so that the developing member side of the developing device swings toward and abuts on the image carrier side due to the rotation moment of the developing device around its supporting portion due to its own weight. The developing device is set at a position deviated from the center of gravity, and the contact / reception state of the developing device with respect to the image carrier is suppressed by further pressing the image carrier to the developing device and releasing the pressure suppression. An image forming apparatus comprising a developing device pressurizing means that can be switched.

(2) In the image forming apparatus having an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member, A supporting shaft is formed in the device at a position closer to the developing member than the center of gravity of the developing device and near both ends of the developing member in the longitudinal direction.
Further, at least one of the two support shafts is supported so as to be movable in a substantially vertical direction and a rotation direction, and the other one is supported so as to be movable in a rotation direction, and a pressure is applied in a substantially upward direction from directly below a developing member to develop. The member side is abutted against the image carrier side, and the angle formed by the pressing direction and the line connecting the center of the image carrier and the center of the one support shaft is about 90 °, and the image carrier center and the one of the one side are An image forming apparatus, wherein an angle formed by a line connecting the centers of the support shafts and an allowable movement direction with respect to the one support shaft is approximately 90 °.

(3) A drum cartridge which has a photosensitive drum for forming a latent image by irradiating scanning light of image data on its surface, and which is detachable in a substantially horizontal direction with respect to the main body of the image forming apparatus, A developing device that has a developing sleeve for supplying toner to the photosensitive drum to visualize the latent image on the photosensitive drum, is rotatably supported by the image forming apparatus main body, and is detachable in a substantially horizontal direction. In the image forming apparatus having the above-mentioned, a supporting shaft is formed on the developing device at a position closer to the developing sleeve than the center of gravity of the developing device and near both end portions in the longitudinal direction of the developing sleeve, and at least one of the both supporting shafts is provided. The developing sleeve is supported by a substantially U-shaped bearing so as to be movable in the vertical direction and the rotating direction, and the other one is supported so as to be movable in the rotating direction. Abutting against the photosensitive drum side, an angle formed by the line connecting the pressing direction and the center of the support shaft supported by the substantially U-shaped bearing with the photosensitive drum center is approximately 90 °, and the photosensitive drum center and the An image forming apparatus, wherein an angle formed by a line connecting the centers of support shafts supported by the substantially U-shaped bearing and an allowable movement direction of the substantially U-shaped bearing with respect to the support shaft is approximately 90 °.

(4) The image forming apparatus according to claim 4, wherein the drum cartridge and the developing device are respectively attachable to and detachable from the image forming apparatus main body in a direction substantially perpendicular to the axis of the photosensitive drum.

(5) An image forming apparatus having an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member. A supporting shaft is formed at a position closer to the developing member than the center of gravity of the developing device and near both ends in the longitudinal direction of the developing member, and at least one of the supporting shafts is movable in a substantially vertical direction and in a rotational direction. While supporting the other one so as to be movable in the rotation direction, pressurizing the developing member side in a substantially upward direction from directly below the developing member and abutting the developing member side against the image carrier side, and the pressing direction, An angle formed by a line connecting the center of the image carrier and the center of the one support shaft is approximately 90 °, and an allowable movement direction with respect to the one support shaft is an arc shape concentric with the image carrier. Image forming apparatus.

(6) A drum cartridge which has a photosensitive drum for forming a latent image by irradiating scanning light of image data on the surface thereof and which is detachable in a substantially horizontal direction with respect to the main body of the image forming apparatus, A developing device that has a developing sleeve for supplying toner to the photosensitive drum to visualize the latent image on the photosensitive drum, is rotatably supported by the image forming apparatus main body, and is detachable in a substantially horizontal direction. In the image forming apparatus having the above-mentioned, a supporting shaft is formed on the developing device at a position closer to the developing sleeve than the center of gravity of the developing device and near both end portions in the longitudinal direction of the developing sleeve, and at least one of the both supporting shafts is provided. The developing sleeve is supported by a substantially U-shaped bearing so as to be movable in the vertical direction and the rotating direction, and the other one is supported so as to be movable in the rotating direction. Abutting against the photosensitive drum side, an angle formed by the line connecting the pressing direction and the center of the spindle supported by the photosensitive drum center and the substantially U-shaped bearing is approximately 90 °, and the substantially U-shaped An image forming apparatus, wherein an allowable movement direction of the bearing with respect to the support shaft is an arc shape concentric with the photosensitive drum.

(7) The image forming apparatus according to (6), characterized in that the drum cartridge and the developing device can be attached to and detached from the image forming apparatus main body in a direction substantially perpendicular to the axis of the photosensitive drum.

(8) An image forming apparatus having an image bearing means having an image bearing member and a developing means for developing a latent image formed on the image bearing member with a developer carried by a developer bearing member. In the developing means, the image carrier is centered on a supporting portion provided at a position different from the center of gravity of the developing means so that the developing means comes into contact with the image carrying means by a rotation moment due to its own weight. The image forming apparatus includes a pressing unit that is swingable with respect to the developing unit and pressurizes the developing unit against the image carrying unit so that the developing operation can be performed by the developing unit. .

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) An image forming apparatus according to the present embodiment is also a laser beam printer using an electrophotographic process similar to the image forming apparatus according to the conventional example described above. The same components and parts as those of the image forming apparatus of the conventional example described above are designated by the same reference numerals, and the repetitive description will be omitted.

FIG. 1 is an external perspective view of the image forming apparatus of this embodiment. Reference numeral 4 denotes a laser printer section (image forming section) having a recording and discharging section (in-cylinder discharge stacking section) 12 having an in-cylinder discharge configuration, and 3 and 5 are original document reader sections arranged above the laser printer section 4. An operation unit 6 is a cassette paper feeding unit which is arranged below the laser printer unit 4 in a vertically stacked manner.

The document reader unit 3 places a document on the platen glass, sets it over the document pressure plate 301, and photoelectrically reads the image information of the set document. Original plate 30
Instead of 1, the document feeder (DF) may be arranged on the platen glass of the document reader unit 3 to automatically convey the document onto the platen glass.

Reference numeral 900 denotes a front cover arranged on the front side of the laser printer unit 4, which can be opened and closed as shown in FIG. Reference numeral 212 denotes a cartridge cover which is provided on the left side surface of the laser printer unit 4 and is detachably attached in the direction of arrow N. When the cartridge cover 212 is removed, as shown in FIG. 2, the opening 901 is exposed on the left side surface of the laser printer unit 4 and the inside of the laser printer unit is opened. In this embodiment, the opening 90 is formed as shown in FIG.
From 1 to the laser printer unit 4, the drum cartridge 1000 and the developing device 1100 are attached / detached in a substantially horizontal direction in a direction substantially perpendicular to the axis of the photosensitive drum.

FIG. 4 is a schematic view of a main part when the drum unit 1000 and the developing device 1100 are mounted on the laser printer unit 4, and FIG. 5 is a partially enlarged view thereof.
Since the image forming operation itself of the laser printer unit 4 is the same as that of the image forming apparatus of the above-mentioned conventional example, the repetitive description is omitted.

Drum cartridge 10 in this embodiment
Reference numeral 00 designates a photosensitive drum 1000a as an image bearing member, a charging roller 1000b, and a cleaning device 1000c which are integrally made into a cartridge which can be attached to and detached from the laser printer unit 4. FIG. Perspective view of the notch, FIG. 7 is a cross-sectional view,
FIG. 8 is a plan view. 1001 is a drum cartridge 1
It is a knob part for handling that is provided in the 000.

FIG. 7 is a perspective view of a notch in the middle of the developing device 1100. The structure of the developing device 1100 is substantially the same as the developing device of the image forming apparatus of the above-mentioned conventional example, but in the developing device 1100 of the present embodiment, the support shafts 1120 and 1121 are provided at the end portions on the back side and the front side of the apparatus. Is coaxially provided integrally with the developing device main body. This spindle 1120
And 1121 are provided closer to the developing sleeve 1100a than the center of gravity of the developing device (W is the load of the developing device), which is represented by the point ω shown in FIG.

When neither the drum cartridge 1000 nor the developing device 1100 is installed in the laser printer unit 4, the drum cartridge 1000 and the developing device 1100 are installed in the laser printer unit 4 in the following manner.

The detachable cartridge cover 212 disposed on the left side surface of the laser printer section 4 is removed, and an opening 90 is formed on the left side surface of the laser printer section 4 as shown in FIG.
1 is exposed and the inside of the laser printer is opened. The transfer roller 703 is disposed inside the cartridge cover 212 and is removed from the laser printer unit 4 together with the cartridge cover 212.

Further, the front cover 900 arranged on the front side of the laser printer unit 4 is opened as shown in FIG. When the front cover 900 is opened, the front frame 3001 of the laser printer unit 4 is exposed. The front frame 3001 has an opening 9 for inserting and removing the toner supply container.
10, round hole-shaped bearing 2002 described later (Figs. 10 and 16)
Is provided with a bearing fitting hole portion 3001a.
A pressure handle 1350 of a developing pressure unit 1300, which will be described later, is provided on the outer surface side of the front frame 3001. The pressure handle 1350 is tilted laterally rightward about the pressure shaft 1302 to operate. This operation causes the developing pressure unit 1300 to release the pressure (see FIGS. 11 and 12).
13).

Opening 9 on the left side of the laser printer unit 4
From 01, as shown in FIG. 3, first, the developing device 1100 is inserted and mounted in the laser printer unit 4, and then the drum cartridge 1000 is inserted and mounted in the laser printer unit 4.

The developing device 1100 includes a toner supply container 120.
Laser printer unit 4 from opening 901 with the 0 side first
Is inserted substantially horizontally in the direction substantially perpendicular to the axis of the photosensitive drum.

Inside the laser printer unit 4, FIG.
As shown in FIG.
A U-shaped bearing 2001 is arranged on the inner surface of 002, and a round hole-shaped bearing fitting hole 3001 is formed in the front frame 3001.
a is formed. The U-shaped bearing 2001 and the round hole-shaped bearing fitting hole 3001a are on the same axis. Reference numeral 2002 denotes a round hole-shaped bearing fitting hole portion 3 from the outer surface side of the front frame 3001.
This is a round hole-shaped bearing that is attached to and detached from 001a.

The support shaft 1120 at the rear end of the developing device 1100, which is inserted into the laser printer unit 4 from the opening 901 with the toner supply container 1200 side first, is engaged and supported by the U-shaped bearing 2001. , Support shaft 11 at the front end
21 is positioned corresponding to the round hole-shaped bearing fitting hole portion 3001a, and the round hole-shaped bearing 2002 is inserted from the outer surface side of the front side frame 3001 into the round hole-shaped bearing fitting hole portion 3001a to support the spindle 1121. Support. The round hole bearing 2002 is prevented from coming off. As a result, the developing device 1100 is configured so that the rear side frame 3002 and the front side frame 3 of the laser printer unit 4 are
During 001, the support shaft 1120 has the U-shaped bearing 200
1, the support shaft 1121 is rotatably supported in a substantially vertical direction and a rotation direction, and the support shaft 1121 is rotatably supported by a round hole bearing 2002.

The above-mentioned support shaft 1120 of the developing device 1100.
As described above, since 1121 is provided on the developing sleeve 1100a side from the center of gravity of the developing device represented by the point ω shown in FIG. 4, the support shafts 1120 and 1121 are U-shaped as described above.
When the developing device 1100 is released after being supported by the character-shaped bearing 2001 and the round hole-shaped bearing 2002, the support shafts 1120.
It rotates in the clockwise direction around 21 by a turning moment due to its own weight. This rotation is prevented by a slight rotation so that the bottom portion of the developing device 1100 on the toner supply container 1200 side hits the frame 3000 of the laser printer unit 4 and is received as shown in FIG.

As described above, the developing device pressurizing unit 1300 is operated by tilting the pressurizing handle 1350 (FIG. 3) laterally to the right around the pressing shaft 1302 and releasing the lateral pressurizing to the right as shown in FIG. It is held in the posture and does not interfere with the developing device 1100 inserted as described above.

Next, the drum cartridge 1000 is inserted by grasping the knob portion 1100 from the opening portion 901 and guiding it to the laser printer portion 4 substantially horizontally in a direction substantially perpendicular to the axis of the photosensitive drum by a guide member (not shown) ( (Fig. 12).
During the insertion, the outer peripheral portions (non-image forming portions) of both ends of the photosensitive drum 1000a in the drum cartridge 1000
Contact the front slopes of the mountain-shaped cam portions (not shown) provided on the rear side and the front side of the front wall of the developing device 1100. When the drum cartridge 1000 is further pushed in, the chevron-shaped cam portion is pushed down by the pushing force, and the developing device 1100 is supported by the spindle 1.
120.1121 rotates counterclockwise about the spindle 1120.1121 against the clockwise turning moment due to its own weight, and the outer peripheral portions of both ends of the photosensitive drum 1000a in the drum cartridge 1000 have the above-mentioned chevron shape. After overcoming the cam portion, the mountain-shaped cam portion moves to the rear slope side and is positioned at a predetermined mounting position.

In this state, the developing device 1100 rotates clockwise about the support shafts 1120 and 1121 by a clockwise rotating moment due to its own weight about the support shafts 1120 and 1121, and the spacer rollers on both ends of the developing sleeve 1100a. 1100f naturally comes into pressure contact with both end surfaces of the photosensitive drum 1000a in the drum cartridge 1000 by the above-described developing device rotation moment, and the developing sleeve 1100a has a predetermined constant distance ( They are facing each other at about 300 μm). FIG. 13 shows this state. In this state, the front end surface of the toner replenishing container 1200 of the developing device 1100 has the opening 910 for inserting and removing the toner replenishing container of the front frame 3001 of the laser printer unit 4 as shown in FIG.
In response to the above, the state of facing the opening 910 is achieved.

Next, the pressing handle 1350 on the outer surface side of the front side frame 3001 of the laser printer section 4 is rotated from the right sideways posture of FIG. 3 in the pressure releasing posture to the vertical posture which is the pressing posture of FIG. To do. By this operation, the developing / pressurizing unit 1300 is brought into a vertical posture as shown in FIGS. 4 and 5, and is brought into pressure contact with the pressed portion 1130 of the developing device 1100, whereby the photosensitive drum 1000a of the developing device 1100 described above is pressed.
The pressure contact state with respect to is stably maintained.

Next, the cartridge cover 212 is mounted in the opening 901 and the front cover 900 is closed to complete the mounting of the drum cartridge 1000 and the developing device 1100 in the laser printer unit 4 (FIG. 1).

Removal of the drum cartridge 1000 and the developing device 1100 from the laser printer unit 4 is performed in the reverse order of the above.

Toner supply container 12 in the developing device 1100
For the old and new replacement of 00, open the front cover 900 (Fig. 1
2), the front side frame 30 of the laser printer unit 4
01, the empty toner supply container 1200 is grasped by the grip portion 1200b from the toner supply container insertion / removal opening 910, and the operation is performed by pulling out the toner supply container 1200 according to a predetermined procedure to open the new toner supply container 1200 filled with toner with the opening 910. From the above, it is inserted into the developing device 1100, the knob portion 1200b is grasped, and the opening / mounting operation is performed in a predetermined procedure. Then front cover 9
By closing 00 into the laser printer unit 4, the old and new replacement operation of the toner supply container 1200 for the developing device 1100 is completed. FIG. 16 is a perspective view of the toner supply container 1200.

A pressed portion 1130 for receiving a developing pressure is integrally formed with the developing device 1100 just below the developing sleeve of the developing device 1100. This pressurized part 1
A developing device pressurizing unit 1300 is disposed inside the laser printer unit 4 so as to oppose to it.

As shown in FIG. 5, the developing pressure unit 1300 includes a pressure shaft 1302 having a U-shaped cross section, and a pressure member 1303 movably supported by the pressure shaft 1302.
And a pressing spring 1501 for pressing the pressing member 1303 in a direction away from the pressing shaft 1502.
As shown in FIG. 15, the pressure shaft 1302 has a bearing 1 on the back side floor surface of the main body frame 3000 of the laser printer unit 4.
The rear end portion by 360 and the front end portion by the bearing 1361 on the front frame 3001 are respectively the central axis store X.
It is rotatably supported in the arrow Y direction around a point (FIGS. 11 to 14).

At the front end of the pressure shaft 1302, the pressure handle 135 is provided outside the front frame 3001 of the laser printer unit 4 as shown in FIGS.
0 is fixed, and the user of the device can use the front cover 9
00 is opened, the pressure handle 1350 is rotated in the direction of arrow Y around the point X to develop the developing device 1100.
It is possible to apply pressure to and release pressure from the photosensitive drum 1000a.

When the pressure handle 1350 is rotated counterclockwise about the point X, the pressure member 1303 of the developing pressure unit 1300 causes the pressure-applied portion 113 on the developing device 1100 side.
Since 0 is pressed in a substantially upward direction, the developing device 1100 is rotationally biased in the M direction shown in FIG. 4 about the support shafts 1120 and 1121, and the spacer rollers 1100f on both ends of the developing sleeve 1100a are exposed to light in the drum cartridge 1000. The state in which the developing sleeve 1100a is pressed against both end surfaces of the drum 1000a and faces the photosensitive drum 1000a at a predetermined constant distance is stably maintained. F in FIG. 4 is an abutting force that the photosensitive drum 1000a receives from the spacer roller 1100f.

At this time, the rear support shaft 11 of the developing device 1100
20 is a U formed on the surface of the inner frame 3002 of the main body frame 3000 of the laser printer unit 4 as described above.
It is supported by a U-shaped bearing 2001 so as to be movable in a substantially vertical direction and a rotational direction, and only the rear side of the developing device 1100 can be moved in the substantially vertical direction. Further, the rear side support shaft 1120 and the U-shaped bearing 2001 have bottoms. Since the space Z is secured as shown in FIG. 5, the photosensitive drum 1000a and the developing sleeve 11 are
It is possible to absorb the misalignment such as the parallelism of 00a, and the photosensitive drum 1000a and the developing sleeve 1
The spacer roller 1100f of 100a can obtain a predetermined butting force.

As described above, the developing device 1100 has the developing device 11 with respect to the center of gravity of the developing device represented by the point ω shown in FIG.
00, the toner cartridge 1200, and the weight W of the toner contained in both of them, acts on the support shaft 11 by the load W even if the developing device 1100 is not pressurized by the developing pressure unit 1300.
Since a moment is generated in the M direction in FIG. 4 about 20.1121, the set spring pressure of the pressure spring 1301 can be set lower by that amount.

Further, in the above-mentioned conventional example, frictional resistance is generated at the contact portions of both the developing device 1100 and the main body side frame member 3000, and the sliding movement of the developing device 1100 in the D direction (FIG. 21) is likely to be obstructed. In the example, since there is a local line contact between the developing device 1100 and the main body side bearings 2001 and 2002, and there is a rotational movement instead of a horizontal movement, the frictional resistance thereof is hardly a problem. Therefore, when the user of the apparatus rotates the pressing handle 1350, it is possible to prevent the friction load from causing a heavy rotation load and deteriorating the operability.

In this embodiment, the pressure handle 1350 is used.
When the pressing member 1303 of the developing pressurizing unit 1300 is pressed against the pressed portion 1130 on the developing device 1100 side by rotating counterclockwise about the X point (FIG. 5). Direction, center of photosensitive drum 1000a, and rear support shaft 1
An angle θ1 formed by a line connecting the centers of 120 is set to about 90 °. In addition, the center of the photosensitive drum 1000a and the rear support shaft 1
The angle θ2 formed by the line connecting the centers of 120 and the allowable movement direction of the U-shaped bearing 2001 is also set to approximately 90 °.
Therefore, the developing pressure direction by the developing pressure unit 1300 and the allowable movement direction of the U-shaped bearing 2001 are substantially parallel.

By setting these angles, the photosensitive drum 100
0a and the developing sleeve 1100a cause misalignment such as parallelism, and the rear side support shaft 1120 has a U-shaped bearing 20.
Even if the inside of 01 is slightly moved in the θ2 direction, if the amount of movement is small, the movement of the developing device 1100 as a whole is almost equal to the circular movement about the photosensitive drum 1000a.

Therefore, the distance R (FIG. 5) between the tip of the paper guide 1150 and the photosensitive drum 1000a for smoothly guiding the recording paper P to the nip portion between the photosensitive drum 1000a and the transfer roller 703 is kept substantially constant. The recording paper P is smoothly guided to the nip portion between the photosensitive drum 1000a and the transfer roller 703, and the toner image on the photosensitive drum 1000a is also transferred onto the recording paper P without any problem, and high image quality can be realized.

As in the embodiment described above, the developing device 11
4, support shafts 1120 and 1121 are formed on the developing sleeve 1100a side from the center of gravity (W is the load of the developing device) of the developing device represented by the point ω shown in FIG.
120 is supported by a U-shaped bearing 2001 so as to be movable in a substantially vertical direction and a rotational direction, and the developing sleeve 11
00a, the developing and pressing unit 1300 applies developing and pressing, and an angle θ1 formed by a line connecting the pressing direction and the center of the photosensitive drum and the center of the back side support shaft 1120 is approximately 9 °.
0 °, an angle θ2 formed by the line connecting the center of the photosensitive drum and the center of the back support shaft 1120 and the allowable movement direction of the U-shaped bearing 2001 is set to about 90 °, and the developing pressure direction and the U-shaped bearing 20 are set.
By making the allowable movement direction of 01 substantially parallel, the following effects can be obtained.

1) It is possible to absorb misalignment such as parallelism between the photosensitive drum 1000a and the developing sleeve 1100a, and the spacer roller 1100f of the photosensitive drum 1000a and the developing sleeve 1100a can obtain a predetermined abutting force.

2) The spring pressure of the pressure spring 1301 can efficiently act as the developing pressure, and the pressure spring 1301
The set spring pressure of 1 can be set lower than the conventional example.

3) The user of the apparatus uses the pressure handle 1350.
It is possible to prevent the operability from deteriorating due to a heavy rotation load due to the frictional resistance when rotating the.

4) The recording paper P is smoothly guided to the nip portion between the photosensitive drum 1000a and the transfer roller 703, and the toner image on the photosensitive drum 1000a does not have any problem.
High quality can be achieved by being transferred on top.

(Second Embodiment) FIG. 17 is an explanatory diagram of the second embodiment. In this embodiment, when the pressing handle 1350 is rotated counterclockwise around the point X to press the pressing member 1303 of the developing pressing unit 1300 against the pressed portion 1130 on the developing device 1100 side. Further, an angle θ1 formed by a line connecting the pressing direction and the center of the photosensitive drum 1000a and the center of the back side support shaft 1120 is set to about 90 °. The allowable movement direction of the U-shaped bearing 2001 is the photosensitive drum 10
It forms an arc R1 that is concentric with 00a. The rest of the device configuration is the same as that of the device of the first embodiment, so a repetitive description will be omitted.

By setting these angles, the photosensitive drum 100
0a and the developing sleeve 1100a cause misalignment such as parallelism, and the rear side support shaft 1120 has a U-shaped bearing 20.
Even when the inside of 01 is slightly moved in the θ2 direction, the developing device 1
The movement of 100 as a whole is completely equal to the circular movement centered on the photosensitive drum 1000a.

Therefore, the interval R between the tip of the paper guide 1150 and the photosensitive drum 1000a for smoothly guiding the recording paper P to the nip portion between the photosensitive drum 1000a and the transfer roller 703 is more strict than in the case of the first embodiment. Therefore, the recording paper P is smoothly guided to the nip portion between the photosensitive drum 1000a and the transfer roller 703, and the toner image on the photosensitive drum 1000a is also transferred onto the recording paper P without any problem, and high image quality is realized. it can.

As in the second embodiment described above, the developing device 1100 has spindles on the developing sleeve 1100a side from the center of gravity (W is the load of the developing device) of the developing device represented by the point ω shown in FIG. 1120 and 1121 are formed, and the back side support shaft 1120 is supported by a U-shaped bearing 2001 so as to be movable in a substantially vertical direction and a rotation direction, and a developing pressure unit 1300 applies a developing force from directly below the developing sleeve 1100a. The angle θ1 formed by the line connecting the center of the photosensitive drum and the center of the back side support shaft 1120 is approximately 90 °, and the allowable movement direction of the U-shaped bearing 2001 is concentric with the photosensitive drum 1000a. By forming a certain arc R1, the following effects can be obtained.

1) It is possible to absorb misalignment such as parallelism between the photosensitive drum 1000a and the developing sleeve 1100a, and the spacer roller 1100f of the photosensitive drum 1000a and the developing sleeve 1100a can obtain a predetermined abutting force. .

2) The spring pressure of the pressure spring 1301 can be efficiently applied as a developing pressure, and the pressure spring 130
The set spring pressure of 1 can be set lower than the conventional example.

3) The user of the apparatus uses the pressure handle 1350.
It is possible to prevent the operability from deteriorating due to a heavy rotation load due to the frictional resistance when rotating the.

4) The recording paper P is smoothly guided to the nip portion between the photosensitive drum 1000a and the transfer roller 703, and the toner image on the photosensitive drum 1000a also has no problem.
High quality can be achieved by being transferred on top.

(Others) The image forming apparatus of the above embodiments is a laser beam printer using an electrophotographic photosensitive drum as an image carrier, but the image forming principle and process of the image forming apparatus of the present invention are not limited to this. Of course, it is not something. For example, an image forming device such as a copying machine, a printer, or an image display device having an image carrier such as an electrostatic recording dielectric / magnetic recording magnetic material and a developing device for visualizing a latent image formed on the image carrier. It may be a device or the like.

Needless to say, the configurations of the drum cartridge and the developing device are not limited to those of the embodiment.

The supporting portion for swingably supporting the developing device on the main body of the image forming apparatus may be configured such that at least one supporting shaft is on the main body side of the image forming apparatus and its corresponding bearing portion is on the developing device side.

[0084]

As described above, according to the present invention, the image carrier and the developing device for developing the latent image formed on the image carrier by supplying the developer to the image carrier by the developing member. In the image forming apparatus having the above-mentioned structure, the pressure urging means of the developing device with respect to the image carrier can be improved so that the developing device can be efficiently pressed against the image carrier according to the set pressure of the pressure urging means. It became so. It has been possible to eliminate the need to set the set pressure of the pressurizing means to a higher value in consideration of the frictional resistance between the developing device and the frame member of the image forming apparatus main body. It was possible to prevent the operability from being deteriorated due to the rotation load becoming heavy due to the frictional resistance when the operation member (pressure handle) of the pressure urging means is rotated.

[Brief description of drawings]

FIG. 1 is an external perspective view of an image forming apparatus according to a first embodiment.

FIG. 2 is an external perspective view of the image forming apparatus with the front cover open and the cartridge cover removed.

FIG. 3 is an explanatory diagram of how to attach and detach the drum cartridge and the developing device to and from the laser printer unit

FIG. 4 is a schematic diagram of a main part of a laser printer unit.

5 is a partially enlarged view of FIG.

FIG. 6 is a perspective view of a drum cartridge with a notched part in the middle.

FIG. 7 is a schematic cross-sectional view of a drum cartridge.

FIG. 8 is a schematic plan view of a drum cartridge.

FIG. 9 is a perspective view of the developing device with a cutaway portion in the middle thereof.

FIG. 10 is an exploded perspective view of bearing portions on a rear side and a front side of a laser printer portion that supports a developing device.

FIG. 11 is a schematic view of a state in which a developing device is inserted into a laser printer unit and supported by bearings.

FIG. 12 is a schematic view of a process in which the drum cartridge is then inserted into the laser printer unit.

FIG. 13 is a schematic diagram of a state in which the drum cartridge is pushed all the way to the insertion end point.

FIG. 14 is a schematic view of a state in which the developing pressure unit is switched to a pressure position.

FIG. 15 is a schematic vertical sectional view of the developing and pressing unit portion when the developing and pressing unit is switched to a pressing posture.

FIG. 16 is a perspective view of a toner supply container.

FIG. 17 is a schematic diagram of a main part of a laser printer unit of the image forming apparatus according to the second embodiment.

FIG. 18 is a schematic diagram of a main part of an image forming apparatus of a conventional example.

FIG. 19 is a perspective view of the developing device with a cutaway portion in the middle thereof.

FIG. 20 is an explanatory diagram of how to attach and detach the developing device to and from the image forming apparatus main body.

FIG. 21 is a schematic view of the developing device inserted in the main body of the image forming apparatus in a state before pressure is applied.

[Explanation of symbols]

1000. ． ． Drum cartridge 1000a ... Photosensitive drum 1100. ． ． Development device 1100a ... Development sleeve 1300 ... Development pressure unit 1301 ... Development pressure spring 1302 ... Development pressure shaft 1303 ... Developing pressure member 1130 ... Pressurized portion 1120 ... Development spindle 1121 ... Development spindle 2001 ... U-shaped bearing 2002 ... Bearing for supporting developing device 1150 ... Paper guide 1350 ... Pressure handle

Claims (8)

[Claims] 1. An image forming apparatus having an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member. The developing device is supported on a body so as to be swingable about a supporting portion, and in a free state of the developing device, a developing member of the developing device is caused by a rotation moment of the developing device about the supporting portion due to its own weight. The supporting portion of the developing device is set at a position displaced from the center of gravity of the developing device so that the side of the developing device swings to the side of the image bearing member and is received and abutted against the image carrier. An image forming apparatus, comprising: a developing device pressurizing means for switching a contact / reception state between a state in which the developing device is further pressed against the image carrier to be suppressed and a state in which the pressurization is released. 2. An image forming apparatus having an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member. A supporting shaft is formed at a position closer to the developing member than the center of gravity of the developing device and near both ends in the longitudinal direction of the developing member, and at least one of the supporting shafts is movable in a substantially vertical direction and in a rotational direction. While supporting the other one so as to be movable in the rotation direction, pressurizing the developing member side in a substantially upward direction from directly below the developing member and abutting the developing member side against the image carrier side, and the pressing direction, The angle formed by the line connecting the center of the image bearing member and the center of the one supporting shaft is approximately 90 °, and the line connecting the center of the image bearing member and the center of the one supporting shaft and the allowable movement direction with respect to the one supporting shaft. The angle formed is almost 9
An image forming apparatus characterized in that the angle is 0 °. 3. A drum cartridge, which has a photosensitive drum for forming a latent image by irradiating scanning light of image data on its surface, and which is detachable in a substantially horizontal direction with respect to the main body of the image forming apparatus. A developing device that has a developing sleeve for supplying toner to the photosensitive drum to visualize the latent image on the photosensitive drum, is rotatably supported by the image forming apparatus main body, and is detachable in a substantially horizontal direction. In the image forming apparatus, a supporting shaft is formed on the developing device at a position closer to the developing sleeve than the center of gravity of the developing device and near both end portions in the longitudinal direction of the developing sleeve, and at least one of the both supporting shafts is substantially formed. A U-shaped bearing movably supports in the up-down direction and the rotational direction, and one of them is rotatably supported in the rotational direction. While abutting against the optical drum side, the angle formed by the line connecting the pressing direction and the center of the supporting shaft supported by the U-shaped bearing with the center of the photosensitive drum is approximately 90 °,
Further, the angle formed by the line connecting the center of the photosensitive drum and the center of the support shaft supported by the substantially U-shaped bearing and the allowable movement direction of the substantially U-shaped bearing with respect to the support shaft is approximately 90 °. Image forming apparatus. 4. The image forming apparatus according to claim 3, wherein the drum cartridge and the developing device are respectively attachable to and detachable from the image forming apparatus main body in a direction substantially perpendicular to the axis of the photosensitive drum. 5. An image forming apparatus comprising: an image carrier and a developing device for developing a latent image formed on the image carrier by supplying a developer to the image carrier by a developing member. A supporting shaft is formed at a position closer to the developing member than the center of gravity of the developing device and near both ends in the longitudinal direction of the developing member, and at least one of the supporting shafts is supported so as to be movable in a substantially vertical direction and in a rotational direction. The other one is movably supported in the rotation direction, and pressure is applied in a substantially upward direction from directly below the developing member to abut the developing member side against the image carrier side, and An angle formed by a line connecting the center of the carrier and the center of the one support shaft is about 90 °, and an allowable movement direction with respect to the one support shaft is an arc shape concentric with the image carrier. Image forming apparatus. 6. A drum cartridge, which has a photosensitive drum for forming a latent image by irradiating scanning light of image data on its surface, and is detachable in a substantially horizontal direction with respect to the main body of the image forming apparatus, A developing device that has a developing sleeve for supplying toner to the photosensitive drum to visualize the latent image on the photosensitive drum, is rotatably supported by the image forming apparatus main body, and is detachable in a substantially horizontal direction. In the image forming apparatus, a supporting shaft is formed on the developing device at a position closer to the developing sleeve than the center of gravity of the developing device and near both end portions in the longitudinal direction of the developing sleeve, and at least one of the both supporting shafts is substantially formed. A U-shaped bearing movably supports in the up-down direction and the rotational direction, and one of them is rotatably supported in the rotational direction. While abutting against the optical drum side, an angle formed by the line connecting the pressing direction and the center of the support shaft supported by the center of the photosensitive drum and the substantially U-shaped bearing is approximately 90.
The image forming apparatus is characterized in that the allowable movement direction of the substantially U-shaped bearing with respect to the support shaft is an arc shape concentric with the photosensitive drum. 7. The image forming apparatus according to claim 6, wherein the drum cartridge and the developing device can be attached to and detached from the image forming apparatus main body in a direction substantially perpendicular to the axis of the photosensitive drum. 8. An image forming apparatus comprising: an image bearing unit having an image bearing member; and a developing unit for developing a latent image formed on the image bearing member with a developer carried by a developer bearing member. The developing means has a supporting portion provided at a position different from the center of gravity of the developing means so that the developing means comes into contact with the image carrying means by a rotation moment due to its own weight. It is swingable with respect to, so that the developing operation by the developing means can be executed,
An image forming apparatus comprising: a pressing unit that presses the developing unit against the image carrying unit.