JP2001154564A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of easily performing the attaching/detaching operations of an image carrier to/from a device main body without relative displacement in a rotating direction between the image carrier and an image carrier supporting shaft at the time of mounting. SOLUTION: A compression spring 33 is provided inside a drum fixing member 28 capable of being engaged with the open side tip part of a drum shaft 22 through a centering plate 23 and a drum flange 24. The drum flange 24 is pressed to the drum shaft 22 by the stretching force of the compression spring 33 and the pin 27 of the drum shaft 22 is engaged with the chevron shaped groove part 26 of the drum flange 24 so as to be positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile, etc., which forms an image by using an electrophotographic process system.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic process system, a full-color image forming apparatus has been put to practical use. Further, in order to realize full-color image formation at high speed, a tandem type image forming apparatus in which a plurality of image forming units are arranged in a transfer material conveying direction is widely used.

The image forming apparatus having the above-described structure includes an electrophotographic photosensitive drum serving as an image carrier for each color image forming unit, an exposing unit, a developing unit, a cleaning unit, a charging unit, and the like in order to ensure maintainability. As an image forming unit, those which are configured to be detachable from an apparatus main body are generally used.

On the other hand, a transfer material is conveyed by a transfer belt, passes through image forming sections for each color, and a full-color image is sequentially transferred.

[0005] In the case of a color image forming apparatus, there is a problem of "color misregistration" as one of the factors determining the image quality.
This occurs when the image forming position of each color is shifted in the sub-scanning direction, which is the transfer direction of the transfer material, or in the main scanning direction, which is orthogonal thereto, or is not relatively parallel.

In a tandem type full-color image forming apparatus, unlike a one-drum type full-color image forming apparatus in which only one electrophotographic photosensitive drum serving as an image carrier is provided in the image forming apparatus, a plurality of image forming sections for each color are provided. Since they are arranged independently, color misregistration easily occurs.

When attention is paid to the color shift in the sub-scanning direction, the cause of the shift is, for example, a shift in the separation distance between the photosensitive drums or a shift in the exposure position as a static cause.
Dynamic causes include fluctuations in the rotational speed of the photosensitive drum, transfer belt, and the like.

[0008] Of the above-mentioned color misregistration causes, static causes can be corrected by, for example, electrically adjusting the exposure timing. However, it is difficult to correct the dynamic cause, and it is necessary to minimize fluctuations in the rotation speed of the photosensitive drum and the transfer belt.

Therefore, regarding the photosensitive drum, first,
It is essential that the fluctuation of the rotation speed of the drum shaft that rotatably supports the photosensitive drum is sufficiently small.

Further, in the tandem type image forming apparatus, since the transfer material passes through each photosensitive drum while being adsorbed to the transfer belt, the rotation of the photosensitive drum is caused to rotate by the impact when the transfer material enters or exits. The disturbance acts.

The transfer material during image formation may be pushed by a transfer roller or the like disposed upstream of the image formation position in the transfer material transfer direction, or may be disposed downstream of the image formation position in the transfer material transfer direction. The rotation of the photoconductor drum is affected by a disturbance in the rotation direction even when the photoconductor drum enters the fixed device.

Accordingly, even if the drum shaft rotatably supporting the photosensitive drum is rotating at a constant angular speed, if the restraining force between the photosensitive drum and the drum shaft is not sufficient, an angular speed variation occurs on the photosensitive drum.

As described above, the method of fixing the photosensitive drum to the drum shaft has a great effect on the rotational speed fluctuation of the photosensitive drum. However, when the photosensitive drum is configured to be able to be pulled out of the apparatus body in order to maintain maintainability, the photosensitive drum and the drum shaft must be separable and firmly fixed during the image forming operation. In the past, various techniques have been proposed for both fixing means.

A fixing means for fixing a photosensitive drum and a drum shaft, which has been conventionally put into practical use, will be described with reference to FIGS. FIG. 12 is a schematic perspective view showing a configuration of a tandem type full-color image forming apparatus, FIG. 13 is a cross-sectional explanatory view showing a state in which a photosensitive drum and a drum shaft of a conventional example are fixed, FIG.
14A is an exploded perspective view of a conventional structure for fixing a photosensitive drum and a drum shaft, and FIG. 14B is a cross-sectional view of the drum flange taken along line AA in FIG. 14A.

FIG. 15 is an explanatory sectional view showing the structure of the disassembled drum flange and drum shaft. FIG. 16 is an exploded drum flange and drum viewed in a state rotated by 90 ° about the drum shaft of FIG. Sectional explanatory view showing the configuration of the shaft, FIG.
FIG. 17A is an exploded perspective view of another conventional example of a fixing structure of a photosensitive drum and a drum shaft, and FIG. 17B is a cross-sectional view of the drum flange taken along line AA in FIG.

In the tandem type image forming apparatus shown in FIG. 12, it is necessary to position the image forming unit 101 including the photosensitive drum 102 and the drum shaft 103 with high precision. In general, the position on the front side of the drum shaft 103 that rotatably supports the drum 102 is supported and regulated by a single centering plate 104.

In FIGS. 13 to 17, reference numeral 105 denotes a pin which is press-fitted into the drum shaft 103 and protrudes from the outer peripheral surface of the drum shaft 103. A groove 103a is formed.

A guide portion 108 is provided on an inner side surface of a drum flange 106 fixed to both ends of the photosensitive drum 102 and extends along the drum shaft 103 toward the inside of the photosensitive drum 102. Thus, two V-shaped grooves 107 are formed. Then, the pin 105 of the drum shaft 103 is engaged with the V-shaped groove 107, and the positioning of the drum flange 106 and the drum shaft 103 in the rotation axis direction and the rotation direction is performed.

The inner peripheral surface of the drum flange 106 has
A plurality of projections 106a are formed, and the projections 106a can be loosely fitted into the slot-shaped grooves 103a formed on the drum shaft 103, respectively.

Reference numeral 109 denotes a screw hole 103 formed at the center of the drum shaft 103 inside the slot-like groove 103a of the drum shaft 103.
A drum fixing screw that can be screwed onto or fastened to or removed from b.

Then, as shown in FIG.
The drum shaft 103 is inserted into a bearing member 110 provided on a centering plate 104 fixed to the apparatus main body while the protrusion 106a of the 106 is loosely fitted in the slot-shaped groove 103a of the drum shaft 103, and a pressing member
The drum fixing screw 109 is screwed and fastened to the screw hole 103b of the drum shaft 103 in a state where the projection 111b of the 111 is loosely fitted in the groove 103a of the drum shaft 103.

At this time, the end surface of the projection 111b of the pressing member 111 on the drum flange 106 side is in contact with the projection 10b of the drum flange 106.
6a, the pin 105 of the drum shaft 103
The V-shaped groove 107 of the photosensitive drum 106 is engaged with and locked by pressing the drum flange 106 against the drum shaft 103.
Rotation direction between 2 and drum shaft 103 is centering plate 104 without play
It is rotatably attached to.

The drum fixing screw 109 is rotatably inserted into the pressing member 111, and the claw 111 a of the pressing member 111 rotates in a locking groove 109 a provided on the outer peripheral surface of the drum fixing screw 109 at a predetermined length position. It is locked freely.

As shown in FIG. 14, when the drum shaft 103 is inserted into the drum flange 106, two projections 106a provided on the inner peripheral surface of the drum flange 106 are opposed to the slot-shaped groove 103a of the drum shaft 103. Therefore, if the phase in the rotation direction is not appropriate, it cannot be inserted.

Therefore, the guide portion 108 of the drum flange 106
The drum flange 106 rotates relative to the drum shaft 103 while the cam-shaped tapered surface 108a provided on the drum shaft slides against the pin 105 protruding from the outer peripheral surface of the drum shaft 103.
Before the leading end 103c of the drum 103 reaches the protrusion 106a of the drum flange 106, the protrusion 106a and the groove 103 of the drum shaft 103 are separated.
Alignment with a.

Then, the drum flange 106 is connected to the drum shaft 103.
The transmission of the force pressing against the drum flange 106 and the pressing member 111
Is performed in a region that does not protrude from the outer peripheral surface of the drum shaft 103. As a result, the photosensitive drum 102 and the drum shaft 103 from outside the bearing member 110 provided on the centering plate 104
Can be attached and detached.

The photosensitive drum 102 and the drum shaft are
In order to attach / detach the drum flange 106 to / from the drum shaft 103 while maintaining the position of the drum 103 with high accuracy, a configuration in which the drum flange 106 and the drum shaft 103 are pressed against each other in a region not protruding from the outer peripheral surface of the drum shaft 103 is advantageous. In addition, with the above-described configuration, the photosensitive drum 102 and the drum shaft 103 are detachable, and the fastening between the photosensitive drum 102 and the drum shaft 103 can be firmly performed during the image forming operation.

[0028]

However, in the above-mentioned conventional example, the drum is screwed into a screw hole 103b formed at the center of the drum shaft 103, and a detachable drum fixing screw 109 is fastened. Since the flange 106 and the drum shaft 103 are pressed against each other, a tool such as a screwdriver for turning the drum fixing screw 109 is required when attaching or detaching the photosensitive drum 102 to or from the apparatus main body. Difficult, image forming unit 101 and photosensitive drum 1
It was common for service personnel to replace 02.

In recent years, in order to reduce the running cost, there is a configuration in which the image forming unit 101 is formed into a cartridge so that the user can replace the cartridge. For example, as shown in FIG. 17 (a), a knob 109b is provided at the end of the drum fixing screw 109 to eliminate the need for tools. To perform the operation, pull knob 109b to fix the drum
Even when 109 was screwed, the attachment / detachment work was troublesome.

The present invention solves the above problems,
An object of the present invention is to provide an image forming apparatus in which the image carrier can be easily attached to and detached from the apparatus main body, and there is no relative displacement in the rotation direction between the image carrier and the image carrier support shaft when the image carrier is mounted. It is something you want to do.

[0031]

A typical configuration of an image forming apparatus according to the present invention for achieving the above object is an image forming apparatus in which an image carrier is detachably provided to an apparatus main body. An image carrier support shaft capable of rotatably supporting the image carrier, a flange portion provided at an end of the image carrier, and the image carrier support shaft being inserted therethrough, with the flange portion interposed therebetween A pressure contact member capable of engaging with the image carrier support shaft, wherein the image carrier support shaft and the flange portion are provided on a first groove provided on one of the two, and on the other; The flange portion and the image carrier support shaft are engaged by a first protrusion, and the urging means provided on the pressure contact member in a state where the pressure contact member is engaged with the image carrier support shaft. The flange portion and the image carrier support are pressed against each other in the axial direction of the image carrier support shaft. Characterized by restraining the rotational direction of the relative displacement between.

In the present invention, as described above, the flange portion and the image carrier support shaft are moved by the urging means provided on the image carrier in a state where the press member is engaged with the image carrier support shaft. Since the relative displacement of the flange portion and the image carrier support shaft in the rotational direction can be restrained by being pressed against the image carrier support shaft direction, the device body can be fixed without any tools or troublesome fastening operations. The image carrier can be easily attached and detached.

When the image carrier is mounted, the image carrier support shaft and the flange are engaged by the first groove provided on one of the two and the first projection provided on the other. In this state, the flange portion and the image carrier support shaft are pressed in the direction of the image carrier support shaft, so that a sufficient restraining force is secured between the image carrier fixed to the flange portion and the image carrier support shaft. There is no relative displacement in the rotation direction between the image carrier and the image carrier support shaft, and there is no possibility that an angular velocity fluctuation occurs on the image carrier, thereby preventing image displacement and the like. I can do it.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a tandem-type full-color copying machine employing an electrophotographic system as an example of an image forming apparatus according to the present invention will be specifically described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view showing the configuration of a first embodiment of the image forming apparatus according to the present invention, FIG. 2 is a schematic perspective view showing the configuration of the first embodiment of the image forming apparatus according to the present invention, and FIG.
FIG. 3 is an explanatory cross-sectional view illustrating a configuration of an image forming unit.

FIG. 4 is an explanatory sectional view showing a state in which the image carrier and the image carrier support shaft are fixed, and FIG. 5A is an exploded view of a fixing structure between the image carrier and the image carrier support shaft. Perspective view, FIG. 5
FIG. 5B is a cross-sectional view of the flange portion taken along line AA in FIG.

FIG. 6 is an explanatory sectional view showing the structure of the disassembled flange portion and the image carrier support shaft. FIG. 7 is an exploded view of the image carrier support shaft shown in FIG. FIG. 7 is an explanatory cross-sectional view showing a configuration of a formed flange portion and an image carrier support shaft.

FIG. 8 is an exploded sectional view showing the structure of the press-contact member, FIG. 9 is a cross-sectional explanatory view showing the structure of the press-contact member in a state where the press-contact member and the image carrier support shaft are not engaged. Figure
FIG. 10 is a front view showing the configuration of the press-contact member viewed from the direction of arrow B in FIG.

1 and 2, reference numeral 1 denotes a main body of an image forming apparatus constituting a color electrophotographic copying machine for forming an image by superimposing toners of four colors of cyan, magenta, yellow and black. The image forming units 2c, 2m, 2y, and 2k (hereinafter, simply referred to as "image forming units 2") of respective colors are arranged as a so-called tandem type image forming apparatus.

Each image forming unit 2 is mounted on the apparatus main body 1.
The image forming unit 2 can be detached after the user pulls out each image forming unit 2 to the front side of the apparatus main body 1 at the time of replenishment and maintenance of each color toner.

A transfer material transport belt 3 serving as a transfer material carrier for electrostatically adsorbing and transporting a transfer material made of paper, synthetic resin, or the like, to a position facing all over each image forming unit 2.
The transfer material transport belt 3 is rotated by a motor 6 connected to the drive roller 4. The transfer roller 3 is stretched by a drive roller 4 and driven rollers 5 a and 5 b.

On the other hand, the transfer material accommodated in the sheet cassettes 7a and 7b is selectively fed out by the pick-up rollers 8a and 8b as appropriate, and then the pair of retard rollers 9a and 9b.
, And are conveyed to the registration roller pair 11 by the conveyance roller pair 10.

After the skew of the transfer material that has arrived at the registration roller pair 11 is corrected, the electrophotographic photosensitive drums 12c, 12m, 12y, and 12k (hereinafter, simply referred to as "photosensitive drums") serving as image carriers.
12 ”) at a suitable timing in synchronization with the rotation of the transfer material conveying belt 3.

The transfer material transport belt 3 is made of an insulating resin sheet material. The transfer chargers 13c, 13m, 13y, 13k (hereinafter simply referred to as "transfer") are arranged on the inner peripheral side of the transfer material transport belt 3. The surface of the transfer material transport belt 3 is charged by the charger 13 ").

The transfer material sent out by the registration roller pair 11 is electrostatically attracted and carried on the charged transfer material transport belt 3 while passing under the image forming unit 2 of each color by the transfer material transport belt 3. Conveyed.

On the other hand, inside each image forming unit 2, as shown in FIGS. 1 and 3, primary chargers 14c, 14m, 14y and 14k (hereinafter simply referred to as "primary chargers 14") are provided on the outer periphery of the photosensitive drum 12. ), Developing units 15c, 15m, 15y, 15k (hereinafter simply referred to as "developing units 15"), cleaners 16c, 16m,
16y and 16k (hereinafter, simply referred to as "cleaner 16") are arranged respectively.

Then, the photosensitive drum is driven by the primary charger 14.
After uniformly charging the surface of the LED 12, each LED (light emitting diode) array 17c, 17m, 17
y, 17k (hereinafter simply referred to as "LED array 17") to perform an exposure scan in accordance with an image information signal sent from an output device such as a document reading device or a computer (not shown), so that the surface of each photosensitive drum 12 is scanned. An electrostatic latent image corresponding to each color is formed.

The electrostatic latent images formed on the surfaces of the respective photosensitive drums 12 are supplied with toners of respective colors from the developing device 15 and are visualized as toner images.

The transfer material transport belt 3 and the photosensitive drum 12 are placed on the transfer material transported by the transfer material transport belt 3.
The toner images of the respective colors are sequentially transferred by the transfer charger 13 in each of the transfer portions adjacent to each other.

The transfer material on which the transfer of the toner images of the four colors is completed is peeled off from the transfer material transport belt 3 by a separation charger 18 disposed opposite to the drive roller 4 via the transfer material transport belt 3 and fixed. The sheet is conveyed to a fixing device including a roller 19a and a pressure roller 19b.

The fixing roller 19a is heated by a heater (not shown).
a and the pressure roller 19b, after being hot-melted while being conveyed while being pressed and held, and then pressed and permanently fixed on the transfer material,
It is discharged onto a discharge tray 20 provided outside the machine.

The image forming unit 2 is supported by a rail 21 on the front side of the apparatus main body 1 so as to be able to be pulled out. The image forming unit 2 is connected to a drive source (not shown) on the back side of the apparatus main body 1 so that the photosensitive drum 12 can rotate. Open ends of the drum shafts 22c, 22m, 22y, and 22k (hereinafter, simply referred to as "drum shafts 22") serving as image bearing member support shafts that can be supported are positioned on the front side of the apparatus main body 1 with positioning members fixed to the apparatus main body frame. Is rotatably positioned by a single centering plate 23.

4 to 7, a drum flange 24 serving as a flange portion through which the drum shaft 22 is inserted is fixed to the end of the photosensitive drum 12 by press-fitting. Is formed with a projection 24a serving as a second projection provided to project inward from the outer peripheral surface of the drum shaft 22 inserted into the drum flange 24.

A guide portion 25 extending inward of the photosensitive drum 12 along the drum shaft 22 is provided on an inner side surface portion of the drum flange 24. The guide portion 25 defines two first grooves. A V-shaped groove 26 is formed. This V
As shown in FIG. 5B, a V-shaped tapered portion 26a is formed at the end of the U-shaped groove 26.

On the other hand, the open end of the drum shaft 22 is formed by penetrating from the tip end 22d of the drum shaft 22 toward the inside in the axial direction of the drum shaft 22 so as to enter the inside of the outer peripheral surface of the drum shaft 22. A slot-shaped groove 22a serving as a second groove is formed so that a projection 24a serving as a second projection provided on the drum flange 24 can be loosely fitted into the slot-shaped groove 22a. Has become.

A first projection is positioned at a position on the inner side of the drum shaft 22 relative to the slot-like groove 22a and is positioned by engaging with a V-shaped groove 26 as a first groove provided on the drum flange 24. A cylindrical pin 27 is press-fitted, and both ends of the pin 27 project from the outer peripheral surface of the drum shaft 22 by a predetermined amount.

As shown in FIG. 5, when the drum shaft 22 is inserted into the drum flange 24, two projections 24a provided on the inner peripheral surface of the drum flange 24, and a slot-like groove 22a of the drum shaft 22 are provided. If the phase in the rotation direction is not appropriate, it cannot be inserted.

Therefore, the cam-shaped tapered surface 25a provided on the guide portion 25 of the drum flange 24 comes into contact with a pin 27 projecting from the outer peripheral surface of the drum shaft 22 while sliding.
Rotates with respect to the drum shaft 22 so that the tip of the drum shaft 22
Before the protrusion 22d reaches the protrusion 24a of the drum flange 24, the protrusion 24a and the slot-like groove 22a of the drum shaft 22 are aligned in the rotational direction.

The pressing member 36 of the drum fixing member 28, which will be described later in detail, serves as a pressing member.
The transmission of the force that presses the drum flange 22 to the drum shaft 22
This is performed in a region that does not protrude from the outer peripheral surface of the drum shaft 22 using the drum fixing member 28.

Thus, the photosensitive drum is positioned from outside the bearing member 34 provided on the centering plate 23 serving as a positioning member for positioning the rotation center of the open end of the drum shaft 22.
The attachment / detachment operation between the drum shaft 12 and the drum shaft 22 can be performed.

In order to carry out the attachment / detachment operation of the drum flange 24 and the drum shaft 22 while maintaining the rotation center position of the photosensitive drum 12 and the drum shaft 22 with high precision by the centering plate 23, the protrusion from the outer peripheral surface of the drum shaft 22 The structure in which the drum flange 24 and the drum shaft 22 are pressed against each other in an area where the drum flange 24 is not pressed is advantageous.
The photosensitive drum 12 and the drum shaft 22 are detachable, and the fastening between the photosensitive drum 12 and the drum shaft 22 can be firmly performed during the image forming operation.

Reference numeral 28 denotes a bearing member 34 provided on the centering plate 23.
And a drum fixing member that engages with the open end side of the drum shaft 22 via the drum flange 24 and presses the drum flange 24 against the drum shaft 22. As shown in FIGS. The pressing shaft 30 is inserted inside, and a pin 31 is press-fitted into an end of the pressing shaft 30.

A compression spring 33 serving as urging means is inserted between the pin 31 and the knob cover 32 locked by the knob 29, and the claw portion of the knob cover 32 is inserted into a hole 29e of the knob 29 shown in FIG.
After the insertion of the knob 32a, the claw 32a is locked to the side wall surface 29f of the knob 29, and the knob 29, the pressing shaft 30, the compression spring 33, and the knob cover 32 are integrally formed.

On the other hand, a bearing member 34 is mounted at a predetermined position which coincides with the axis of the drum shaft 22 of the centering plate 23, and rotatably supports the drum shaft 22 inserted through the bearing member 34.

In a state where the drum fixing member 28 is not engaged with the drum shaft 22, as shown in FIG.
The pin 31 press-fitted into the pressing shaft 30 is pressed against the inner wall surface 29 a of the knob 29 by a compression spring 33 housed inside the knob 28.

FIG. 10 is a view of the knob 29 as viewed from the direction of arrow B in FIG. 9. As shown in FIG. 10, the knob 29 has a symmetrical shape about the axis, and as shown in FIG. When the pin 31 pressed by 33 moves in the axial direction of the pressing shaft 30,
The cam-shaped guide surfaces 29b and 29c for guiding the 31 are formed so that the guide surface 29c is continuously formed at a height close to the knob cover 32 side with respect to the guide surface 29b.

When the drum fixing member 28 is not engaged with the drum shaft 22, as shown in FIGS. 9 and 10, the pressing force of the compression spring 33 moves the pin 31 into the groove 29d continuous with the guide surface 29b. In this state, relative rotation between the knob 29 and the pressing shaft 30 connected to the pin 31 is restricted.

When the photosensitive drum 12 is mounted on the apparatus main body 1, first, a drum flange 24 fixed to both ends of the photosensitive drum 12 is inserted from the open end of the drum shaft 22 to the photosensitive drum. The drum 12 is fitted on the drum shaft 22.

At this time, the cam-shaped tapered surface 25 a provided on the guide portion 25 of the drum flange 24 comes into contact with the pin 27 protruding from the outer peripheral surface of the drum shaft 22 while sliding.
Rotates with respect to the drum shaft 22 so that the tip of the drum shaft 22
Before the protrusion 22d reaches the protrusion 24a of the drum flange 24, the rotation of the protrusion 24a and the slit groove 22a of the drum shaft 22 are aligned.

Then, the drum shaft 22 is inserted into the bearing member 34 of the centering plate 23 so that the tip of the drum shaft 22 projects outside the bearing member 34 as shown in FIG. A state in which the knob 29 of 28 is pinched and the protrusion 36a of the pressing member 36 provided at the distal end of the pressing shaft 30 and the slot-like groove 22a provided at the distal end of the drum shaft 22 are aligned in the rotational direction. Then, the drum fixing member 28 is pushed in the direction of arrow B in FIG.

The pressing member 36 is connected to the projection 24 of the drum flange 24.
When the drum fixing member 28 is further pushed in the direction of arrow B in FIG. 9 from this state, the compression spring 33 accommodated inside the drum fixing member 28 starts to contract, and the pressing shaft 30
The movement of the inside of 29 starts to the left in FIG.

As shown in FIG. 9, the tip of the knob 29 on the drum shaft 22 side projects from the outer peripheral surface of the drum shaft 22 to the inside, and has a width smaller than the width of the slot-shaped groove 22a of the drum shaft 22. There are provided two projections 29g serving as third projections having the following. The projections 29g are circumferentially attached to the distal end of the drum shaft 22 inserted through a bearing member 34 provided on the centering plate 23. The pin 31 provided on the pressing shaft 30 moves to the position shown in FIG. 4 when reaching the position of the groove 22b which becomes the third groove formed in FIG.

In this state, the knob 29 can be rotated clockwise in FIG. 10 with respect to the pressing shaft 30 due to the height relationship between the guide surfaces 29b and 29c for guiding the pin 31 described above. Then, when the knob 29 is rotated clockwise in FIG. 10, the protrusion 29 g at the tip of the knob 29 engages with and is engaged with the groove 22 b formed at the tip of the drum shaft 22.

In this state, the pressing shaft 30 itself does not rotate with respect to the drum shaft 22 because the groove 22a of the drum shaft 22 is loosely fitted. When the knob 29 is further rotated in the clockwise direction in FIG. 10, the pin 31 of the pressing shaft 30 comes into contact with the step between the guide surface 29b and the guide surface 29c in the knob 29, and can be further rotated. Disappears.

In this state, the pin 31 and the pressing shaft are pushed by the extension force of the compression spring 33 housed inside the drum fixing member 28.
30, the drum flange 24 is connected to the apparatus main body 1 via the pressing member 36.
It is urged to the back side of.

Since the drum flange 24 is engaged with the pin 27 of the drum shaft 22 at the V-shaped groove 26, the drum flange 24 and the drum shaft 22 are separated by the urging force of the compression spring 33.
In this direction, the drum flange 24 and the drum shaft 22 are firmly fixed without any backlash in the rotation direction by restricting the relative displacement of the drum flange 24 and the drum shaft 22 in the rotation direction.

Next, when removing the drum fixing member 28,
When the knob 29 is rotated in the counterclockwise direction in FIG. 10 and the protrusion 29g at the tip of the knob 29 reaches the slot-like groove 22a of the drum shaft 22, the knob 29 It moves to the left in FIG.

With the compression spring 33 fully extended, the protrusion 29g of the knob 29 is disengaged from the slot-like groove 22a of the drum shaft 22, but as described above, the protrusion 29g is provided on the pressing shaft 30 in this state. The pin 31 is restrained at the position of the groove 29d in the knob 29, and the pressing shaft 30 and the knob 29 do not rotate relatively.

In the drum fixing member 28 serving as the pressure contact member, the protrusion 29g of the knob 29 whose rotational direction of the drum shaft 22 has a predetermined phase with respect to the drum shaft 22 does not coincide with the slot-like groove 22a of the drum shaft 22. The engagement with the drum shaft 22 is released when the projection 29g of the knob 29 which is engaged with the drum shaft 22 at other times coincides with the slot-like groove 22a of the drum shaft 22. I have.

According to the above configuration, when the photosensitive drum 12 is mounted, the photosensitive drum 12 is engaged with the drum shaft 22 via the centering plate 23 fixed to the apparatus main body 1 and the drum flange 24 fixed to the photosensitive drum 12. The drum flange 24 and the drum shaft 22 are pressed against the drum shaft 22 by a compression spring 33 provided on the obtained drum fixing member 28, and the pin 27 of the drum shaft 22 engages with the V-shaped groove 26 of the drum flange 24. And locked, the photosensitive drum
Since a sufficient restraining force can be secured between the drum shaft 12 and the drum shaft 22 and the relative displacement of the drum flange 24 and the drum shaft 22 in the rotation direction can be restrained, the photosensitive drum 12 and the drum shaft There is no relative displacement in the rotational direction between the photosensitive drum 12 and the angular velocity fluctuation on the photosensitive drum 12.

Accordingly, the operation of attaching and detaching the photosensitive drum 12 to and from the apparatus main body 1 can be easily performed without the need for a tool or a troublesome tightening operation as in the conventional example, and it is possible to prevent image displacement and the like. .

Further, the photosensitive drum 12 and the drum shaft 22 are attached and detached in front of a centering plate 23 serving as a positioning member for regulating the rotation center position of the drum shaft 22 provided on the front side of the apparatus main body 1. It is excellent in operability because it can do.

Since the axial pressurization of the drum flange 24 and the drum shaft 22 can be performed in a region that does not protrude from the outer peripheral surface of the drum shaft 22, a normal bearing is used for positioning the drum shaft 22 on the front side of the apparatus main body 1. The member 34 can be used, and the rotational center position of the drum shaft 22 can be regulated with high accuracy.

Further, in the case of a so-called tandem type image forming apparatus having a plurality of drum shafts 22, the above-mentioned effects become more remarkable.

Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 11 is a schematic explanatory view showing the configuration of the second embodiment of the image forming apparatus according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the first embodiment, the toner images formed on the photosensitive drums 12 serving as a plurality of image carriers are transferred to a transfer material carried on a transfer material transport belt 3 serving as a transfer material carrier. However, in the present embodiment, as shown in FIG. 11, after the toner images formed on the photosensitive drums 12 serving as a plurality of image carriers are transferred to an intermediate transfer belt 41 serving as an intermediate transfer body, This is similarly applied to an image forming apparatus configured to transfer a toner image carried on a transfer belt 41 to a transfer material.

In FIG. 11, the image forming apparatus 1 according to the present embodiment is configured by an intermediate transfer system equipped with an intermediate transfer belt 41 serving as an intermediate transfer body, and the intermediate transfer belt 41 is mounted on four photosensitive drums 12. Opposite drive roller 42, driven roller
It is stretched by the transfer roller 43 and the transfer roller 44, and is driven to rotate in the direction of arrow a in FIG.

Then, four-color image forming units 2y, 2m, 2c, 2 each having photosensitive drums 12y, 12m, 12c, 12k on the intermediate transfer belt 41 along the moving direction.
k, the toner images of the respective colors formed by the image forming units 2 of the respective colors are superimposedly transferred onto the intermediate transfer belt 41, and then the toner images of the respective colors are collectively transferred onto the transfer material.

The structure for supporting the photosensitive drum 12 of each image forming unit 2 is the same as that of the first embodiment. The photosensitive drum is driven by an image information signal sent from an original reading device (not shown) or an output device such as a computer.
An electrostatic latent image corresponding to each color is formed on each of the toner images 12, and toner images of each color developed by the developing device (not shown) are sequentially superimposed on the intermediate transfer belt 41 by the transfer charger 13. The image is transferred, and a full-color image is formed on the intermediate transfer belt 41.

On the other hand, the skew of the transfer material is corrected by the registration roller pair 11, and the intermediate transfer belt 41 and the transfer charger 45 where the transfer roller 44 is located at a predetermined timing in synchronization with the image forming process. To the transfer section.

The four color toner images on the intermediate transfer belt 41 are collectively transferred onto the transfer material by the action of the transfer roller 44 inside the intermediate transfer belt 41 and the transfer charger 45 outside. The transfer material onto which the four color toner images have been transferred is transported by a transport belt 46, and a fixing roller 19a having a built-in heater.
Further, the toner of each color is heated and pressurized while being nipped and conveyed by the pressing roller 19b pressed against the fixing roller 19a, and is melted by heat, and is fixed on the transfer material to complete a full-color image. The transfer material on which the toner image has been fixed is discharged outside the apparatus.

Also in this embodiment, as in the first embodiment, since a plurality of image forming units 2 are arranged independently, color misregistration is likely to occur. Therefore, as in the first embodiment, it is necessary to minimize fluctuations in the rotation speed of the drive source of the photosensitive drum 12 and to firmly fix the photosensitive drum 12 to the drum shaft 22.

On the other hand, the necessity of making the image forming unit 2 detachable easily is the same as in the first embodiment.

Therefore, the present invention can be effectively applied to an image forming apparatus using an intermediate transfer member as in the present embodiment.

[0094]

Since the present invention has the above-described structure and operation, the flange member and the image bearing member are biased by the urging means provided on the image contact member while the pressure member is engaged with the image carrier support shaft. The body support shaft can be pressed against the image carrier support shaft in the direction of the image carrier support shaft to restrain the relative displacement of the flange portion and the image carrier support shaft in the rotation direction, so that a tool or a troublesome fastening operation is required. The operation of attaching and detaching the image carrier to and from the apparatus main body can be easily performed with a single touch.

Therefore, the user who does not have a special tool can be entrusted with the replacement and maintenance work of the image forming unit including the image carrier and the like, so that the running cost can be reduced.

Further, when the image carrier is mounted, the image carrier support shaft and the flange are engaged with the first groove provided on one of the two and the first projection provided on the other. In this state, the flange portion and the image carrier support shaft are pressed in the direction of the image carrier support shaft, so that a sufficient restraining force is secured between the image carrier fixed to the flange portion and the image carrier support shaft. There is no relative displacement in the rotation direction between the image carrier and the image carrier support shaft, and there is no possibility that an angular velocity fluctuation occurs on the image carrier, thereby preventing image displacement and the like. I can do it.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view illustrating a configuration of a first embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic perspective view showing a configuration of a first embodiment of the image forming apparatus according to the present invention.

FIG. 3 is an explanatory cross-sectional view illustrating a configuration of an image forming unit.

FIG. 4 is an explanatory sectional view showing a state in which the image carrier and the image carrier support shaft are fixed.

FIG. 5A is an exploded perspective view of a fixing structure of an image carrier and an image carrier support shaft, and FIG. 5B is an A- view of a flange portion in FIG.
It is A sectional drawing.

FIG. 6 is an explanatory sectional view showing a configuration of a disassembled flange portion and an image carrier support shaft.

7 is an explanatory cross-sectional view showing a configuration of a disassembled flange portion and an image carrier supporting shaft as viewed in a state rotated by 90 ° about the image carrier supporting shaft of FIG. 6;

FIG. 8 is an exploded cross-sectional view showing the structure of the press contact member.

FIG. 9 is an explanatory cross-sectional view showing the structure of the pressing member in a state where the pressing member and the image carrier support shaft are not engaged.

10 is a front view showing the configuration of the press-contact member viewed from the direction of arrow B in FIG. 9;

FIG. 11 is a schematic explanatory view illustrating a configuration of an image forming apparatus according to a second embodiment of the invention.

FIG. 12 is a diagram illustrating a conventional example.

FIG. 13 is a diagram illustrating a conventional example.

FIG. 14 is a diagram illustrating a conventional example.

FIG. 15 is a diagram illustrating a conventional example.

FIG. 16 is a diagram illustrating a conventional example.

FIG. 17 is a diagram illustrating a conventional example.

[Explanation of symbols]

1. Image forming apparatus main body, 2, 2c, 2m, 2y, 2k
Image forming unit, 3: transfer material conveying belt, 4: drive roller, 5a, 5b: driven roller, 6: motor, 7a, 7
b: sheet cassette, 8a, 8b: pickup roller, 9a, 9b: retard roller pair, 10: transport roller pair, 11: registration roller pair, 12, 12c, 12m, 12y, 12
k: photoconductor drum, 13, 13c, 13m, 13y, 13k: transfer charger, 14, 14c, 14m, 14y, 14k: primary charger, 1
5, 15c, 15m, 15y, 15k ... developing unit, 16, 16c, 16
m, 16y, 16k ... cleaner, 17, 17c, 17m, 17y, 17
k: LED array, 18: separation charger, 19a: fixing roller, 19b: pressure roller, 20: discharge tray, 21: rail,
22, 22c, 22m, 22y, 22k: drum shaft, 22a: slotted groove, 22b: groove, 22d: tip, 23: centering plate, 24:
Drum flange, 24a ... Projection, 25 ... Guide, 25a ...
Tapered surface, 26: V-shaped groove portion, 26a: Tapered portion, 27: Pin, 28: Drum fixing member, 29: Knob, 29a: Inner wall surface, 29
b, 29c: guide surface, 29d: groove, 29e: hole, 29f: side wall, 29g: protrusion, 30: pressing shaft, 31: pin, 32: knob cover, 32a: claw, 33: compression spring, 34 ... Bearing members,
36 ... Pressing member, 36a ... Protrusion, 41 ... Intermediate transfer belt, 42
… Drive roller, 43… follower roller, 44… transfer roller, 45…
Transfer charger, 46 ... Conveyer belt

Claims (7)

[Claims] 1. An image forming apparatus in which an image carrier is detachably provided to an apparatus main body, an image carrier support shaft capable of rotatably supporting the image carrier, and an end of the image carrier. And a press-contact member that can be engaged with the image carrier support shaft with the flange portion interposed therebetween, and the image carrier support shaft is provided. A first groove provided in one of the two, and a first groove provided in the other.
When the pressing member is engaged with the image carrier supporting shaft, the flange portion and the image carrier supporting shaft are moved by the urging means provided on the pressing member. An image forming apparatus, wherein a relative displacement in a rotation direction between the flange portion and the image carrier support shaft is restrained by being pressed against a carrier support shaft direction. 2. The image-pressing member engages with the image carrier support shaft when the phase in the rotation direction of the image carrier support shaft with respect to the image carrier support shaft is a predetermined phase, and when the phase is at any other phase. The image forming apparatus according to claim 1, wherein the engagement with the image carrier support shaft is released. 3. A second projection provided on an inner peripheral surface of the flange portion so as to protrude inward from an outer peripheral surface of the image bearing member support shaft.
A projection portion extending from the tip of the image carrier support shaft toward the inside in the axial direction of the image carrier support shaft so as to penetrate the inner side of the outer peripheral surface of the image carrier support shaft, and And a second groove portion in which the projection portion is loosely fitted. The pressing member presses the second projection portion of the flange portion through the second groove portion of the image carrier support shaft. 4. The image forming apparatus according to claim 1, wherein the flange portion and the image carrier supporting shaft are pressed against each other in a direction of the image carrier supporting shaft to restrain a relative displacement of the flange portion and the image carrier supporting shaft in a rotational direction. The image forming apparatus according to claim 1. 4. A third circumferential groove provided at an end of the image carrier support shaft, wherein the press-contact member is provided at a third circumferential groove provided at an end of the image carrier support shaft. The image forming apparatus according to any one of claims 1 to 3, further comprising a third protrusion protruding inward from an outer peripheral surface of the image carrier supporting shaft that can be engaged. apparatus. 5. The image forming apparatus according to claim 1, comprising a plurality of said image carriers. 6. The image forming apparatus according to claim 5, wherein the toner images formed on the plurality of image carriers are transferred to a transfer material carried on a transfer material carrier. 7. The method according to claim 5, wherein the toner images formed on the plurality of image carriers are transferred to an intermediate transfer member, and then the toner images carried on the intermediate transfer member are transferred to a transfer material. An image forming apparatus according to claim 1.