JP2003122078A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus with which an image of high quality can be obtained by effectively keeping down the vibration of an image carrier, to provide an image forming apparatus which can be easily assembled and also to provide an image forming apparatus provided with fewer number of parts. SOLUTION: In the apparatus, a reference member 200 fixed to the apparatus main body, an image carrier (1U) on which an electrostatic latent image is formed and an image carrier positioning mechanism 110 carrying out positioning of the image carrier to the reference member are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system such as a copying machine, a printer, a facsimile and a composite machine of these,
The present invention relates to an image forming apparatus using an electrostatic recording method, and more particularly, to a vibration isolation technique for an image carrier of the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer utilizing an electrophotographic method (electrostatic transfer method) has been widely known. In these image forming apparatuses, in order to obtain a high quality image, it is necessary to avoid vibration of the image carrier during image formation as much as possible. For example, if the photoconductor drum vibrates while the toner image is being transferred from the photoconductor drum (image carrier) to the intermediate transfer belt, the transferred toner image is disturbed in a band shape, and an image quality defect called so-called banding occurs. Will occur.

Further, the vibration of the image carrier during image formation is caused by, for example, when a rotary type developing device is adopted.
It occurs by the following mechanism. That is, in an image forming apparatus that employs a rotary type developing device, three developing devices corresponding to each color of yellow, magenta, and cyan, or a black developing device for these, is provided in the vicinity of one photosensitive drum (image bearing member). A developing device for holding a developing device of a desired color is arranged by arranging a developing device in which four developing devices including a developing device are held along the circumferential direction of a rotating body, and the rotating developing device is rotationally driven. To the development position opposite
The electrostatic latent images of a predetermined color sequentially formed on the photoconductor drum are developed with the toner of the corresponding color to form a color image.

When a predetermined developing device moves to a developing position facing the photoconductor drum, a tracking roll which comes into contact with the photoconductor drum and keeps a constant gap between the photoconductor drum and the developing roll of the developing device is provided. , At both ends of the developing roll of each developing device.

Therefore, if the tracking roll of the developing device for developing the image of the next color comes into contact with the photosensitive drum while the rear end of the toner image of the previous color is being transferred onto the intermediate transfer member, Vibration may be applied to the photoconductor drum to cause the above banding.

Conventionally, in response to such technical problems,
Various proposals have been made. For example, JP 2000-7
In Japanese Patent No. 5591 and Japanese Patent Laid-Open No. 2001-183902, the mounting position of the tracking roll is adjusted to reduce the impact when the tracking roll comes into contact with the image carrier and suppress the vibration of the image carrier. Techniques for preventing image defects due to banding have been proposed.

[0007]

However, Japanese Patent Laid-Open No. 2000-2000
In any of the cases disclosed in JP-A-75591 and JP-A-2001-183902, the tracking roll is in direct contact with the image bearing member, so it is difficult to sufficiently suppress the vibration of the image bearing member, resulting in a high image quality. There was a limit to image quality. Further, since it is necessary to finely adjust the contact start position between the tracking roll and the image carrier, the man-hours for assembling the image carrier and the developing device increase, which is disadvantageous in terms of cost, and a special part for adjusting the contact position. Is required.

The present invention has been made in view of such technical problems, and a first object thereof is to effectively suppress the vibration of the image carrier and obtain a higher quality image. An object is to provide an image forming apparatus. A second object is to provide an image forming apparatus that can be easily assembled. A third object is to provide an image forming apparatus having a smaller number of parts.

[0009]

According to the present invention, a reference member fixed to a main body of an apparatus, an image carrier on which an electrostatic latent image is formed, and the image carrier is positioned with respect to the reference member. An image forming apparatus having an image carrier positioning mechanism. By configuring the image forming apparatus in this way, the movable member comes into direct contact with the image carrier as compared with the conventional case where other movable members (for example, rotary developing devices) are positioned with the image carrier as a reference. Therefore, the vibration of the image carrier can be significantly suppressed.

Here, the reference member can be fixed to a frame forming a skeleton of the image forming apparatus. Further, the image carrier positioning mechanism includes an image carrier holding unit that holds the image carrier so as to be close to and away from an image carrier side surface of the reference member, and the image carrier is an image carrier of the reference member. An image carrier pressing means for pressing in a direction approaching the body side surface,
The reference member may be configured to have an image carrier gap regulating means for regulating the gap between the image carrier side face of the reference member and the image carrier. The image carrier pressing means may directly press the image carrier, or may indirectly press the image carrier by pressing the image carrier holding means. Further, the image carrier spacing control means may be provided on the image carrier and directly control the spacing between the image carrier side surface of the reference member and the image carrier, or provided on the image carrier holding means. The distance between the image carrier side surface of the reference member and the image carrier may be indirectly controlled by controlling the distance between the image carrier side surface of the reference member and the image carrier holding means.

In addition to these constitutions, the present invention also provides a developer carrier for carrying a developer for developing an electrostatic latent image on the image carrier, and the developer carrier for the reference member. And a developer carrier positioning mechanism for positioning. By configuring the image forming apparatus in this way, the image carrier and the reference member and the developer carrier and the reference member are positioned without applying vibration to the image carrier, and as a result, the image carrier is carried out. Positioning of the body and the developer carrying body is performed.

Here, the developer carrying member positioning mechanism holds the developer carrying member in the developing position so as to be capable of approaching and separating from the developer carrying member side surface of the reference member. And a developer carrier pressing means for pressing the developer carrier in a direction approaching the developer carrier side surface of the reference member, and a gap between the developer carrier side surface of the reference member and the developer carrier. It may be configured to have a developer carrier spacing regulating means for regulating. The developer carrying member pressing means may directly press the developer carrying member, or may indirectly press the developer carrying member by pressing the developer carrying member holding means. Further, the developer carrier spacing control means may be provided on the developer carrier to directly regulate the distance between the developer carrier side surface of the reference member and the developer carrier, or the developer carrier. The distance between the image carrier side surface of the reference member and the developer carrier holding means is regulated by indirectly controlling the distance between the image carrier side surface of the reference member and the developer carrier. It may be one.

In the image forming apparatus including the image carrier, the image carrier positioning mechanism, the developer carrier and the developer carrier positioning mechanism, the image carrier positioning mechanism contacts the developer carrier. Without doing so, the developer carrying member positioning mechanism is configured so as not to come into contact with the image carrying member, and vibration of the image carrying member during image formation and image defects caused by the vibration can be prevented. In particular, when the image forming apparatus includes a rotary developing device, that is, a plurality of the developer carriers are held along the circumferential direction, and a desired developer carrier moves to a developing position facing the image carrier. In the case of having such a rotating developing device, the vibration of the image carrier tends to be large in general, so that the effect of the present invention is remarkably exhibited.

According to the present invention, the image carrier positioning mechanism includes an image carrier holding means for holding the image carrier so as to be close to and away from the side of the reference member of the image carrier, and the image carrier. An image carrier pressing unit for pressing the reference member in a direction of approaching the image carrier side face of the reference member, and an image carrier space regulating unit for regulating a distance between the image carrier side face of the reference member and the image carrier. The developer carrying member positioning mechanism holds the developer carrying member at the developing position so as to be able to approach and separate from the developer carrying member side surface of the reference member. A developer carrying member pressing means for pressing the agent carrying member in a direction of approaching the developer carrying member side surface of the reference member, and a developer for regulating a distance between the developer carrying member side surface of the reference member and the developer carrying member. The carrier spacing regulation means The image bearing member side surface of the reference member and the developer carrying member side may be one in the front and back of each other. By configuring the image forming apparatus in this way, the image carrier and the developer carrier can be more reliably positioned.

When a rotary developing device is used as the developing device of the image forming apparatus, the positioning may be performed as follows. In other words, a plurality of the developer carrying members are held along the circumferential direction thereof, and a rotary developing device that rotates so as to move the desired developer carrying member to a developing position where the desired developer carrying member faces the image carrying member is provided. The developer carrying member positioning mechanism can perform positioning of the desired developer carrying member with respect to the reference member when the desired developer carrying member moves to a developing position facing the image carrying member.

As a more specific structure of the developer carrying member positioning mechanism, a developer carrying member holding means for holding each of the developer carrying members so as to be movable in a substantially radial direction of the rotary developing device, Developer carrier pressing means for pressing each developer carrier to the outside in the substantially radial direction of the rotary developing device,
A developer carrier spacing regulation that regulates a distance between the developer carrier side surface of the reference member and the desired developer carrier when the desired developer carrier reaches a developing position facing the image carrier. It is possible to employ those having respective means and.

Further, as a more specific structure of the developer carrying member spacing regulating means, the developer carrying member is provided on one or both ends of the respective developer carrying members coaxially, and is in contact with the side surface of the developer carrying member of the reference member. A possible ring-shaped tracking member can be adopted. When the tracking member is provided at one end of the developer carrier, the rotational driving force is transmitted from the non-driving side, that is, the developer carrier from the first end side thereof. The tracking member may be formed at the second end (the end opposite to the first end) of the developer carrier.

In the developer carrying member positioning mechanism, when the rotary developing device rotates and the desired developer carrying member moves to the developing position, the tracking member carries the developer carrying member of the reference member. It is also possible to have a cushioning member that comes into contact with the tracking member before coming into contact with the body side surface. With this configuration, the impact when the tracking member comes into contact (collision) with the reference member can be alleviated, and the vibration of the image carrier can be further reduced. Further, when the buffer member has a guide shape that guides the tracking member to the reference member along the trajectory of the tracking member when the rotary developing device rotates, the tracking member contacts the reference member ( The impact at the time of collision) can be further reduced, and the vibration of the image carrier is further reduced. The buffer member may be formed separately from the reference member or may be integrally formed.

Further, the image carrier holding means is an image carrier unit for rotatably holding the image carrier, and the image carrier spacing regulating means is (integrally or fixedly) attached to the image carrier unit. Is a convex member that is provided on the side of the image carrier of the reference member, and the convex member and the tracking member of the developer carrier that has reached the developing position face each other with the reference member interposed therebetween. Can be configured to. At least one of the convex member, the reference member, and the tracking member may be elastically deformable by contact with the reference member. Further, the reference member may be configured such that the portion attached to the apparatus main body has higher rigidity than the portion in contact with the convex member and / or the tracking member.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a full-color printer as an image forming apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a photosensitive drum as an image carrier, and the photosensitive drum 1 is rotationally driven at a predetermined speed in the direction of arrow 2 by a driving means (not shown). The surface of the photoconductor drum 1 is uniformly charged to a predetermined potential by a charging roll 3 as a charger, and then ROS (Raster Output Scan).
In the case of forming a full-color image by the exposure device 4 including a color image forming device, a four-color image of yellow (Y), magenta (M), cyan (C), and black (K) is sequentially exposed, and each color is exposed. An electrostatic latent image corresponding to is formed.

The electrostatic latent image of a predetermined color formed on the surface of the photosensitive drum 1 is developed by the developing devices 5Y, 5M, 5C and 5K of the corresponding color of the rotary developing device 5 to obtain a predetermined color. Toner image. Since the rotary developing device 5 performs full-color development, four-color developing devices 5Y of yellow (Y), magenta (M), cyan (C), and black (K),
It is equipped with 5M, 5C, 5K, and each developing device 5Y, 5M,
5C and 5K develop the latent image on the photosensitive drum 1 with yellow, magenta, cyan, and black toners, respectively.

When developing the toner of each color, the rotary developing device 5 is rotated in the direction of arrow R (clockwise direction) by a motor (not shown) to develop the developing devices 5Y, 5Y of the corresponding color.
M, 5C, and 5K are positioned at the developing position facing the photoconductor drum 1. In addition, on the photosensitive drum 1,
In the process control mode, a test chart is formed, and the density of this test chart is the density sensor 6
To be detected by. The toner image of each color developed on the photosensitive drum 1 is transferred by the primary transfer roll 7 to the intermediate transfer belt 9 as an intermediate transfer member.
The toner images of the four colors are superposed one on top of the other and superimposed on one another. The intermediate transfer belt 9 is rotatably stretched around a drive roll 10, an idle roll 11, a backup roll 12, and an idle roll 13. The drive roll 10 is driven by a drive motor (not shown) having an excellent constant speed, and rotationally drives the intermediate transfer belt 9 at a predetermined speed.

The four-color toner images transferred in multiple layers on the intermediate transfer belt 9 are pressed against the backup paper 12 and the intermediate transfer belt 9 on the recording paper P as a recording medium. Are transcribed collectively by. The recording paper P is fed by a paper feed roll 18 or 19 from one of two paper feed cassettes 16 and 17 provided in the lower part of the printer main body, and a plurality of conveyance roll pairs 20, 21. It is conveyed to the pair of registration rolls 22 through and is temporarily stopped.

Thereafter, the recording paper P is backed up by the registration roll pair 22 which starts rotating in synchronization with the toner image transferred onto the intermediate transfer belt 9.
The secondary transfer roller 14 and the secondary transfer roller 14 are conveyed to the secondary transfer position where they are pressed against each other via the intermediate transfer belt 9. Then, after the toner images of four colors are collectively transferred from the intermediate transfer belt 9 onto the recording paper P at the secondary transfer position,
The recording paper P is subjected to fixing processing by heat and pressure in the fixing device 23, and is switched and discharged by a switching gate (not shown) onto the discharge tray 24 on the side surface of the apparatus body or the discharge tray 25 provided on the upper side of the apparatus body. It

After the transfer process of the toner image is completed, the residual toner is removed from the photosensitive drum 1 by the cleaning device 8 including a cleaning blade or the like to prepare for the next image forming process. The intermediate transfer belt 9 after the toner image transfer process is completed is
The residual toner is removed by the belt cleaner 15 which faces the belt cleaner 15 to prepare for the next image forming step. The belt cleaner 15 is usually separated from the surface of the intermediate transfer belt 9.

The photosensitive drum 1 or the intermediate transfer belt 9
The waste toner scraped off by the cleaning device 8 and the belt cleaner 15 is collected in the waste toner collecting container 26. In particular, the waste toner collected from the belt cleaner 15 is transported to the waste toner recovery container 26 in the transport pipe 27 by a transporting means including an auger and a transport screw.

2 and 3 are views for explaining the positioning of the photoconductor unit (image carrier holding means) 1U and the rotary developing device 5 of the full color printer device.

The photoconductor unit 1U rotatably holds the photoconductor drum 10 therein. This photoconductor unit 1U is shown in FIG.
It is constructed so that it can be pulled out in the Y direction and can be finely moved in the XX direction in the drawing, and is biased (pressed) in the -X direction in the drawing. On the other hand, each developing device 5 of the rotary developing device 5
Each of Y to K is configured to be finely movable in the radial direction of the rotary developing device 5, and each of the developing devices Y to K is biased (pressed) outward in the radial direction. Therefore, for example, the developing device 5Y existing at the developing position in FIG. 2 is biased in the X direction in the drawing.

A positioning plate (reference member) 200 is provided between the photoconductor unit 1U and the rotary developing device 5 (developing device 5Y). The positioning plate 200 includes a mounting member (reference member) 201.
Is fixed to the frame of the full-color printer device via. A side (image carrier side surface) 200a and B surface (developer carrier side surface) 200b of this positioning plate 200
And the projections (convex members, image carrier spacing control means, image carrier positioning mechanism) 110 of the photoconductor unit 1U are in contact with the A surface 200a.
A tracking roll (tracking member, developer carrier spacing control means, developer carrier positioning mechanism: described later) 6 of the developing device 5Y is provided on the side B (developer carrier side surface) 200b.
0Y is in contact. Then, when the developing device 5Y reaches the developing position, the protrusion 110 and the tracking roll 60Y face each other with the positioning plate 200 interposed therebetween. The positioning plate 200
Is made of steel and is more easily elastically deformed than the mounting member 201.

Next, the structure and operation of the photoconductor unit 1U will be described with reference to FIGS.

FIG. 4 illustrates the frame of this full-color printer, in which the photoconductor unit 1U is not mounted. The frame 100 constitutes the skeleton of the full-color printer device, and is made of metal such as steel to ensure sufficient rigidity. This frame 1
Positioning pins 101 and 102 are provided on the front surface of the apparatus No. 00, that is, the surface in the Y direction in the drawing, aligned in the substantially XX direction. On the other hand, FIG. 5 and FIG. 6 both illustrate a state in which the photoconductor unit 1U is attached to and detached from the frame 100. Positioning holes 103 and 104 corresponding to the positioning pins 101 and 102 are formed inside the photosensitive unit 1U (see FIG. 6). The positioning holes 103 and 104 are provided with the positioning pins 101 and 10, respectively.
It is formed slightly larger than the diameter of 2 in the XX direction in the drawing. Therefore, in the mounted state, the photoconductor unit 1
U is slightly movable with respect to the frame 100 in the XX direction in the drawing. A leaf spring (image bearing member pressing means) 105 is provided on the side surface of the positioning hole 103.

When mounting the photoconductor unit 1U on the printer, the photoconductor unit 1U is pushed in the -Y direction in FIGS. 5 and 6, and the positioning pins 101 and 102 are inserted into the positioning holes 103 and 104. To wear. At this time, since the positioning pin 101 is pressed by the leaf spring 105,
The reaction force urges the photoconductor unit 1U toward the -X side in the figure. As a result, when the photoconductor unit 1U is attached, the photoconductor drum 1 and the positioning plate 200 are
The distance from (A surface 200a of) is kept constant.

Next, the structure and operation of the rotary developing device 5 will be described with reference to FIGS. 7, 8 and 9.

FIG. 7 is a sectional view showing a specific example of the rotary developing device 5. As shown in FIG. 7, this rotary developing device 5 has a rotary shaft 32 located at the center as a center,
The rotating body 30 is provided which is rotatable in the clockwise direction. The rotating body 30 has a central portion 33 formed in a substantially square shape.
And extending substantially radially from the central portion 33,
And four arms 31 provided so as to form an angle of degrees. As will be described later, the arm 31 of the rotating body 30 has four developing devices (developer carrier holding means) 5Y, 5M for yellow (Y), magenta (M), cyan (C), and black (K). 5C and 5K are installed.

These developing devices 5Y, 5M, 5C, 5K
Have the same configuration, the yellow (Y) developing device 5Y will be described here as an example. The yellow (Y) developing device 5Y is roughly divided into the developing device main body 40 and the developing device main body 40. It is composed of an agent cartridge 50.

Inside the developing device main body 40, a developing roll (developer carrying member) 41 which is long in a direction perpendicular to the paper surface, and which is located on the back side of the developing roll 41,
Two spiral augers 42 and 43 extending in parallel with are arranged. Here, when the developing roll 41 rotates,
The spiral auger 42 conveys the developer 44 contained in the developing device 40 while stirring the developer 44 in one direction perpendicular to the paper surface. On the other hand, the spiral auger 43 conveys the developer 44 while stirring the developer 44 in a direction opposite to the conveying direction of the spiral auger 42, and supplies the developer 44 to the developing roll 41 evenly.

The developing roll 41 attracts carriers contained in the developer 44 with a magnetic force by a magnet roll (not shown) provided inside, and forms a magnetic brush of the developer 44 on the surface of the developing roll 41. The toner adsorbed on the carrier is conveyed to the developing area facing the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is visualized by the magnetic brush of the developer 44 formed of the carrier and toner formed on the surface of the developing roller 41.

The developer cartridge 50 is composed of a cylindrical container elongated in the direction perpendicular to the paper surface. Inside the developer cartridge 50, there are a new developer storage chamber and a deteriorated developer recovery chamber. It is divided into. A supply port (not shown) is provided in the new developer storage chamber, and the supply port communicates with a substantially cylindrical casing 51 for guiding the new developer to the developing device main body 40. The cylindrical casing 51 is provided on the upper portion on the back side of the developing device main body 40. A spiral auger 52 is arranged in the casing 51, and the developer 44 supplied from the developer cartridge 50 is supplied by the spiral auger 52 to the upper surface on the back side of the developing device main body 40. It is guided to the port 53 and supplied into the developing device main body 40. At the outlet located at the lower end of the supply port 53 of the developing device main body 40, a flap 54 is provided so as to be openable and closable, and is opened when the developing device 5Y is at the developing position D in FIG. On the other hand, the flap 54 is closed by its own weight when the developing device 5Y is at the position F or the position G in FIG.

A circulating recovery passage 56 is provided in the deteriorated developer recovery chamber 55 of the developer cartridge 50.
In the recovery passage 56, the discharge pipe 5 bent into a substantially L-shape.
7 is connected. The discharge pipe 57 is connected to the developing device main body 4
The recovery port 58 is disposed in the upper part of substantially the center of 0 and is located at the tip of the discharge pipe 57 (lower end in FIG. 7) is located in the developing device main body 40. The recovery port 58 is located on the front side of the new developer supply port 53, and is opened in the ceiling wall portion of the developing device main body 40. And
The new developer 44 supplied from the supply port 53 is agitated and conveyed by the spiral augers 42 and 43, and is supplied to the developing roller 41 while circulating in the developing device main body 40 and contributes to the development. The old developer 44 that has contributed to the developing process while circulating in the developing device body 40 is collected by the recovery port 58 when the developing device body 40 is at position E or position F in FIG. 50 is recovered in the deteriorated developer recovery chamber 55 through a recovery passage 56.

In the rotary developing device 5 having the developing devices 5M, 5C and 5K configured similarly to the developing device 5Y configured as described above, the developing device main body 40 is at the developing position where the developing device main body 40 faces the photosensitive drum 1. When it comes to the D position, the flap 54
The supply port 53 is opened by its own weight, and the spiral auger 5
By rotating 2 the new developer 4 as needed
4 is replenished in the developing device main body 40. Then, the development of the electrostatic latent image on the photoconductor drum 1 by the developing device main body 40 is completed, the rotating body 30 rotates in the clockwise direction, and the developing device main body 40 moves from the position D to the lower right position E. Then, as shown in the figure, the flap 54 is half opened and the recovery port 5
8 faces upward, and the old developer conveyed by the discharge pipe 57 flows toward the recovery passage 56 without backflowing into the developing device main body 40. The deteriorated developer C is collected in the recovery passage 56 from the F position of the lower left of the developing device main body to the G position of the upper left.
And is recovered into the deteriorated developer recovery chamber 55. By thus providing the circulating recovery passage 56, it is possible to prevent the recovered developer C from flowing back into the developing device main body 40.

On the other hand, while the developing device main body 40 is moving from the G position at the upper left to the D position which is the developing position at the upper right, the new developer 44 is provided by the action of an agitator (not shown) provided in the developer cartridge 50. Is sent to the casing 51 and guided to the supply port 53 by the spiral auger 52 in the casing 51. At this time, flap 5
No. 4 has opened the supply port 53 again, the new developer 4
4 is supplied into the developing device main body 40 through the supply port 53.

The rotary developing device 5 is shown in FIGS.
As shown in, a plurality of developing devices 5C, 5M, 5Y, 5K are held along the circumferential direction, and desired developing devices 5C, 5M, 5Y,
It has a rotating body 30 that rotates so that 5K moves to a developing position facing the photosensitive drum 1. The rotating body 30 is provided with four arms 31 in a substantially cross shape, and these four arms 31 include yellow (Y), magenta (M), cyan (C), and black (BK). Developing device 5 for each color
C, 5M, 5Y and 5K are attached. Rotating body 3
The developing roll (developer carrying member) 41 of each of the developing devices 5C, 5M, 5Y, and 5K is exposed on the outer peripheral surface of 0. Ring-shaped tracking roll (tracking member, developer carrier spacing regulation means) with an outer diameter slightly larger than
60 is provided coaxially.

As the tracking roll 60, for example, one made of synthetic resin is used, but in this embodiment, the tracking roll 60 is formed of a member such as elastically deformable rubber. Tracking roll 6
As 0, for example, a rubber material having a rubber hardness of 60 to 80 degrees is used. As described above, by using the tracking roll 60 made of an elastically deformable material, the impact force when the tracking roll 60 contacts the B surface of the positioning plate 200 can be significantly reduced. Each of the developing devices 5C, 5M,
The 5Y and 5K tracking rolls 60 contact the surface B of the positioning plate 200 at the developing position, and hold the gap between the developing roll 41 and the positioning plate 200 at a predetermined value.

In the rotary developing device 5, as shown in FIG. 8, the rotary knob 62 fastened to the shaft portion 32 of the rotary body 30.
It is rotatably attached to the front panel 63 of the printer device via. A front panel 63 of the printer device is provided with an outlet 64 for attaching and detaching the toner cartridge 50. The rotary knob 62 is gripped and the rotating body 33 is manually rotated, so that an arbitrary developing device 5C,
It is possible to move 5M, 5Y, and 5K to the exit 64.

As shown in FIG. 9, a guide plate 65 is attached to the front surface of each of the developing devices 5C, 5M, 5Y and 5K.
It is movably held in a substantially radial direction of the rotating body 30 via the guide plate 65. The developing devices 5C,
As shown in FIG. 9, 5M, 5Y, and 5K are coil springs (developer-carrying member pressing means) S and pins (developer-carrying member pressing means) arranged at the center of the rotating body 30 when moved to the developing position. Means) P and the tracking roll 60 is pressed by a predetermined pressure to the B surface 2 of the positioning plate 200.
00b. As a result, when the desired developing device, for example, the developing device 5Y reaches the developing position, the developing roll 41Y and the positioning plate 200
The distance from (B surface 200b of) is kept constant.

As described above, in the full-color printer device according to the present embodiment, on the other hand, when the photoconductor unit 1U is attached, the photoconductor drum 1 and the positioning plate 200 are attached.
The distance between the developing roll 41 and the positioning plate 200 (the B surface 200b thereof) is constant when the desired developing device 5 reaches the developing position. As a result, during development, the distance between the photosensitive drum 1 and the desired developing roll 41 is kept constant.

Further, when the rotary developing device 5 rotates during the formation of the full-color image and the next developing devices 5Y to 5K reach the developing position D, the tracking roll 60 thereof contacts (collides) with the positioning plate 200. The photosensitive drum 1 does not come into direct contact with the photosensitive drum 1 and
The vibration of can be greatly reduced. As a result, image defects such as banding can be effectively suppressed.

Modified Example This modified example relates to an improvement of the full-color printer device according to the embodiment.

FIG. 10 is a view for explaining the positioning of the photoconductor unit (image carrier holding means) 1U and the rotary developing device 5 of this full color printer. In this printer device, the rotary developing device 5 rotates and the desired developing device 5
When Y to K move to the developing position D, the tracking roll 60 moves the B side 20 of the positioning plate 200.
It has a cushioning member 210 that comes into contact with the tracking roll 60 before coming into contact with 0b.

The developing device side surface 210 of this buffer member 210
The reference character b forms a guide shape that is integral with the positioning plate 200 along the circular locus of the tracking roll 60 when the rotary developing device 5 rotates, and guides the tracking roll 60 to the positioning plate 200. By providing such a cushioning member 210, the tracking roll 6
It is possible to mitigate the shock when 0 comes into contact (collision) with the positioning plate 200 and further reduce the vibration of the image carrier.

[0052]

As described in detail above, according to the present invention, first, it is possible to provide an image forming apparatus capable of effectively suppressing the vibration of the image carrier and obtaining a higher quality image. You can Secondly, it is possible to provide an image forming apparatus that can be easily assembled. Thirdly, it is possible to provide an image forming apparatus having a smaller number of parts.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a full-color printer device according to an embodiment.

FIG. 2 is a cross-sectional view illustrating a positioning state of a photoconductor unit and a rotary developing device of the full-color printer device shown in FIG.

FIG. 3 is a perspective view illustrating a positioning state of a photoconductor unit and a rotary developing device of the full color printer device shown in FIG.

FIG. 4 illustrates a frame structure of the full-color printer device shown in FIG.

FIG. 5 is a perspective view from one direction for explaining attachment / detachment of a photoconductor unit to / from the full-color printer device shown in FIG. 1.

FIG. 6 is a perspective view from another direction for explaining attachment / detachment of a photoconductor unit to / from the full-color printer device shown in FIG. 1.

7 is a cross-sectional view of one of the rotary developing devices of the full color printer device shown in FIG.

FIG. 8 is a perspective view of a rotary developing device of the full-color printer device shown in FIG.

9 is another cross-sectional view of the rotary developing device of the full-color printer device shown in FIG.

FIG. 10 is a cross-sectional view illustrating a positioning state of a photoconductor unit and a rotary developing device of a full-color printer device according to a modified example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoconductor drum (image carrier), 1U ... Photoconductor unit (image carrier holding means), 100 ... Frame, 101, 1
02 ... positioning pin, 103, 104 ... positioning hole, 1
05 ... Leaf spring (image bearing member pressing means), 110 ... Projection portion (image bearing member spacing regulating means), 5 ... Rotating developing device, 5Y
-K ... Developing device (developer carrying member holding means), 41 ... Developing roll (developer carrying member), 200 ... Positioning plate (reference member), 60 ... Tracking roll (developer carrying member spacing regulating means), S ... Spring (Means for pressing developer carrier)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noriyoshi Nagamine             Fujize, 3-7-1, Fuchu, Iwatsuki City, Saitama Prefecture             Rocks Co., Ltd. Iwatsuki Office (72) Inventor Keiji Sasaki             Fujize, 3-7-1, Fuchu, Iwatsuki City, Saitama Prefecture             Rocks Co., Ltd. Iwatsuki Office (72) Inventor Masatomo Yamada             Fujize, 3-7-1, Fuchu, Iwatsuki City, Saitama Prefecture             Rocks Co., Ltd. Iwatsuki Office F-term (reference) 2H030 BB24 BB33                 2H071 BA16 BA29 CA02 CA05 DA08                       DA15 EA14 EA18                 2H077 AD02 AD06 BA01 BA07 GA13

Claims (16)

[Claims] 1. A reference member fixed to the apparatus main body, an image carrier on which an electrostatic latent image is formed, and an image carrier positioning mechanism for positioning the image carrier with respect to the reference member. Image forming apparatus. 2. The image carrier positioning mechanism includes an image carrier holding unit that holds the image carrier so as to be able to approach and separate from the side of the image carrier of the reference member, and the image carrier as a reference. The image carrier pressing means for pressing the member in a direction approaching the side surface of the image carrier, and the image carrier spacing restricting means for restricting a distance between the side surface of the image carrier of the reference member and the image carrier. The image forming apparatus according to item 1. 3. A developer carrying body carrying a developer for developing an electrostatic latent image on the image carrying body, and a developer carrying body positioning mechanism for positioning the developer carrying body with respect to the reference member. The image forming apparatus according to claim 1, further comprising: 4. A developer carrying member holding means for holding the developer carrying member in a developing position so as to be capable of approaching and separating from the developer carrying member side surface of the reference member. A developer carrier pressing means for pressing the developer carrier in a direction approaching the developer carrier side surface of the reference member, and a distance between the developer carrier side surface of the reference member and the developer carrier body is regulated. 4. The image forming apparatus according to claim 3, further comprising a developer carrier spacing control unit. 5. The image forming apparatus according to claim 3, wherein the image carrier positioning mechanism does not contact the developer carrier, and the developer carrier positioning mechanism does not contact the image carrier. 6. A rotary developing device which holds a plurality of the developer carriers along the circumferential direction thereof and rotates so as to move a desired developer carrier to a developing position where the desired developer carrier faces the image carrier. The image forming apparatus according to claim 3. 7. The image bearing member positioning mechanism holds an image bearing member that holds the image bearing member so that the image bearing member can approach and separate from the side of the image bearing member of the reference member, and the image bearing member as the reference. An image carrier pressing means for pressing the member in a direction approaching the image carrier side surface, and an image carrier space restricting means for restricting a distance between the image carrier side surface of the reference member and the image carrier, The developer carrying member positioning mechanism, at the developing position,
A developer carrier holding means for holding the developer carrier so as to be able to approach and separate from the side face of the reference member, which is closer to the side face of the reference member. And a developer carrier pressing means for pressing in the direction of the reference member, and a developer carrier spacing restricting means for restricting the distance between the developer carrier side surface of the reference member and the developer carrier, and the image of the reference member. 7. The image forming apparatus according to claim 3, wherein the side surface of the carrier and the side surface of the developer carrier are in a front-back relationship with each other. 8. A rotary developing device which holds a plurality of the developer carriers along the circumferential direction thereof and rotates so as to move a desired developer carrier to a developing position where the desired developer carrier faces the image carrier. The developer carrying member positioning mechanism positions the desired developer carrying member with respect to the reference member when the desired developer carrying member moves to a developing position where the desired developer carrying member faces the image carrying member. Item 7. The image forming apparatus according to any one of Items 3 to 7. 9. The developer carrier positioning mechanism, which holds the developer carriers so as to be movable in a substantially radial direction of the rotary developing device, and the developer carriers. And a developer carrying member pressing means for pressing the developing device substantially outward in the radial direction of the rotary developing device, and the developer carrying member of the reference member when the desired developer carrying member reaches a developing position where the desired developer carrying member faces the image carrying member. 9. The image forming apparatus according to claim 8, further comprising a developer carrier spacing control unit that regulates a space between the body side surface and the desired developer carrier. 10. The developer-carrying member spacing regulating means is provided on one or both ends of the respective developer-carrying members coaxially, and is a ring-shaped tracking capable of contacting with the side surface of the developer-carrying member of the reference member. The image forming apparatus according to claim 9, which is a member. 11. The developer carrier according to claim 10, wherein a rotational driving force is transmitted from a first end side of the developer carrier, and the tracking member is formed on a second end of the developer carrier. Image forming device. 12. The developer carrying member positioning mechanism, wherein the tracking member carries the developer carrying member of the reference member when the rotary developing device rotates and a desired developer carrying member moves to the developing position. The image forming apparatus according to claim 10, further comprising a cushioning member that comes into contact with the tracking member before coming into contact with a body side surface. 13. The image forming apparatus according to claim 12, wherein the buffer member has a guide shape that guides the tracking member to the reference member along a trajectory of the tracking member when the rotary developing device rotates. apparatus. 14. The image carrier holding means is an image carrier unit that rotatably holds the image carrier, and the image carrier space regulation means is provided in the image carrier unit and is provided on the reference member. 14. A convex member that can be brought into contact with a side surface of an image carrier, and the convex member and a tracking member of the developer carrier that has reached a developing position face each other with the reference member interposed therebetween. An image forming apparatus according to claim 2. 15. The image forming apparatus according to claim 14, wherein at least one of the convex member, the reference member, and the tracking member is elastically deformable by contact with the reference member. 16. The reference member is the convex member and / or
16. The image forming apparatus according to claim 14, wherein a portion attached to the apparatus main body has a higher rigidity than a portion with which the tracking member contacts.