JP2000066467A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of miniaturizing the device whole body, improving assemblability and reducing its cost. SOLUTION: This image forming device is provided with an exposing means for forming an electrostatic latent image on the image carrier, a developing means for forming a toner image by developing the electrostatic latent image, a transferring means for transferring the toner image to transfer material fed separatedly for every sheet by paper feeding means, a fixing means for fixing the toner image transferred to the transfer material on the transfer material, and a transporting means for transporting the transfer material to the fixing means. In the device frames as the device whole body is constituted by constituting the exposing means, the developing means, the paper feed/transporting means or the like as respectively independent paper feed/transporting unit K, the optical unit H and the rotary unit R, providing the frames on the respective unit K, H and R mutually connectable by positioning, and mutually connecting the respective unit K, H and R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Conventionally, in a relatively large image forming apparatus such as a copying machine or a color laser beam printer, as shown in FIG. 10, the entire apparatus is composed of a bottom plate 60, a main left side plate 61, a main right side plate 62, an optical After the frame is composed of the stay 63, the paper feed stay 64, the other stays 65, etc., the developing unit 66, the scanner unit 67, etc. are inserted into a gap provided above or on the side of the frame to position them on the frame. Was attached. In addition, a configuration in which various individual parts are directly attached to a frame is often adopted.

[0003]

However, in the above-described conventional image forming apparatus, a large main body frame is first formed, and then a developing unit switching unit, a paper feed unit, a transport unit, a transfer unit, and the like are formed through a gap between the main body frames. Since various units and parts must be inserted and assembled, a space for inserting each unit is required in the frame structure of the device main body, and a space larger than the size of each unit is required, and the entire device However, there have been basic problems such as an increase in size and poor assemblability and poor mass productivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an image forming apparatus capable of reducing the size of the entire apparatus, improving the assemblability, and reducing the cost. .

[0005]

According to one aspect of the present invention, there is provided an exposure apparatus for forming an electrostatic latent image on an image carrier, and a toner for developing the electrostatic latent image. Developing means for forming an image; transfer means for transferring the toner image to a transfer material separated and fed one by one by a sheet feeding means;
In an image forming apparatus having a fixing unit for fixing the toner image transferred to the transfer material to the transfer material, and a conveying unit for conveying the transfer material to the fixing unit, the exposing unit, the developing unit, the sheet feeding / conveying unit And the like are configured as independent units, each unit is provided with a frame that can be positioned and connected to each other, and each unit is connected to each other to form a frame as the entire apparatus.

According to a second aspect of the present invention, in the first aspect of the invention, the developing means has four color developing units of yellow, magenta, cyan and black.

According to a third aspect of the present invention, in the second aspect of the present invention, the exposing means has four exposing means respectively corresponding to the four color components.

According to a fourth aspect of the present invention, in the second aspect of the present invention, there is provided a developing device switching means for switching the four color developing devices to form toner images corresponding to the respective colors on the image carrier. It is characterized by having.

According to a fifth aspect of the present invention, there is provided an electrophotographic full-color image forming apparatus using an intermediate transfer member according to the fourth aspect of the present invention, wherein the image carrier is provided on the intermediate transfer member. The image carrier and the intermediate transfer member are detachably provided substantially parallel to the transfer material transport direction, and the developing units for the four colors are detachably provided from the upper surface of the apparatus.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the optical unit having the exposing means and the transfer means is positioned and connected to an upper part of a paper feeding / conveying unit including the transfer material stacking means, After the optical unit and the developing unit switching means are positioned at the rotation center axes at both ends of the image carrier, the developing unit switching means is positioned and connected to the sheet feeding / conveying unit.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the rotation center axis of the image carrier also serves as a drive transmission mechanism for transmitting a rotational driving force to the image carrier itself. I do.

According to an eighth aspect of the present invention, in the first aspect of the present invention, each of the units has an electric board having a driver for driving various actuators, sensors and the like provided in each unit. Features.

According to a ninth aspect of the present invention, in the first aspect of the present invention, an air duct is formed between the developing means and the fixing means.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a four-color full-color laser beam printer as an image forming apparatus according to the present invention.

Here, the image forming operation of the full-color laser beam printer shown in FIG. 1 will be outlined.

The photosensitive drum 1 is rotated in the direction of the arrow in FIG. 1 (counterclockwise) in synchronization with the rotation of the intermediate transfer belt 5a.
The surface of the photosensitive drum 1 is uniformly charged by a charging device 2 and a scanner unit 3 serving as an exposure unit.
The photosensitive drum 1 is irradiated with light of a yellow image by
A yellow electrostatic latent image is formed on the photosensitive drum 1. Simultaneously with the formation of the electrostatic latent image, the developing device 4 is driven to dispose the yellow developing device 4Y at the developing position, so that the yellow toner adheres to the electrostatic latent image on the photosensitive drum 1.
A voltage having the same polarity and substantially the same potential as the charging polarity is applied to the developing device 4Y to cause the yellow toner to adhere to the electrostatic latent image, thereby developing the electrostatic latent image as a yellow toner image. Thereafter, a voltage having a polarity opposite to that of the toner is applied to a pressing roller (primary transfer roller) 5j of the intermediate transfer body 5, and the yellow toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 5a.

When the primary transfer of the yellow toner image onto the intermediate transfer belt 5a is completed as described above, the next magenta developing device 4M is rotated and positioned at the developing position opposed to the photosensitive drum 1, and As in the case of yellow, the magenta electrostatic latent image formed on the photosensitive drum 1 is developed as a magenta toner image by the developing device 4M, and this magenta toner image is primarily transferred onto the intermediate transfer belt 5a. Hereinafter, similarly, the formation, development and primary transfer of the electrostatic latent image are sequentially performed for each of the colors of cyan and black, and the toner images of four colors of yellow, magenta, cyan and black are superimposed on the intermediate transfer belt 5a. .

During this time, the cam 18 changes from the state shown in FIG.
The secondary transfer roller 11 is in a state of being rotated by 80 ° and is not in contact with the intermediate transfer belt 5a. At this time, the charging roller 5f of the cleaning unit 5e is not in contact with the intermediate transfer belt 5a.

The transfer material S is separated and fed one by one by a pickup roller 7e, a retard roller 7g, and a feed roller 7f from a cassette 14, which is a transfer material stacking means, in synchronization with the rotation of the intermediate transfer belt 5a. Material S
Are waiting at a predetermined position near the registration roller pair 7d.

Thus, as described above, the intermediate transfer belt 5a
When four color toner images are formed thereon, the secondary transfer roller 1
1 is pressed against the intermediate transfer belt 5a as shown in FIG. 1, and the transfer material S, which has been waiting at a predetermined position near the registration roller pair 7d, is moved to the nip portion between the intermediate transfer belt 5a and the secondary transfer roller 11. Will be sent to Immediately before the registration roller pair 7d, there is provided a pre-registration sensor that detects the leading end of the transfer material S, shuts off the rotational driving force of the registration roller pair 7d, and waits the transfer material S at a predetermined position.

Incidentally, a voltage having a polarity opposite to that of the toner is applied to the secondary transfer roller 11 so that the intermediate transfer belt 5 a
The upper toner image is collectively secondarily transferred onto the surface of the transferred transfer material S.

The transfer material S on which the toner image is secondarily transferred in this manner reaches the fixing device 8 via the transport belt unit 12, and after the fixing device 8 has fixed the toner images of a plurality of colors, The paper is conveyed along the paper discharge unit 15 by the paper discharge roller pairs 13 and 16 and is discharged to the paper discharge tray 10 above the image forming apparatus A by the paper discharge roller pair 9, where image formation is completed.

Next, the frame structure of the apparatus body and each unit will be described with reference to FIGS.

FIG. 2 is a perspective view showing a frame structure of the apparatus main body of the color laser beam printer. As shown in FIG. 2, the frame of the apparatus main body of the present color laser beam printer includes the cassette 7a and the intermediate transfer member 5. Holding the transfer material S
Separating and transporting each sheet, and transporting this to the fixing device 8
An optical unit H having a transport unit K, a scanner unit 3 and holding a photosensitive drum cartridge B, and a developing device as a rotary unit holding and switching between the four color developing units 4Y, 4M, 4C and 4Bk 4 and the transfer material S discharged from the fixing device 8
It is composed of three frame units K, H, R of a rotary unit R composed of a paper discharge unit 15 that carries the paper to zero, and these frame units K, H, R constitute a frame of the entire apparatus. Here, the sheet feeding / conveying unit K constitutes the lower half of the apparatus main body, and details of the constitution are shown in FIG. Further, the optical unit H constitutes a front surface on the upper side of the apparatus, and details of the constitution are shown in FIG. Further, the rotary unit R constitutes a rear surface on the upper side of the apparatus, and details of the constitution are shown in FIG.

As shown in FIG. 3, in the sheet feeding / transporting unit K, a sheet feeding left side plate 22 and a sheet feeding right side plate 23 are positioned on a bottom plate 21, and these are fixed by screws or caulking. ing. Then, the sheet feeding left side plate 22 and the sheet feeding right side plate 23 are positioned and fixed by the sheet feeding section stay 24 and the fixing stay 25, and constitute a frame of the sheet feeding / transporting unit K.

A left sheet reinforcing plate 26 is fixed between the bottom plate 21 and the left sheet side plate 22. The paper feed / transport unit K is further provided with a pickup roller 7e, a feed roller 7f, a pair of registration rollers 7d, a transport belt unit 12, and the like. A drive gear train and a drive source (not shown) for rotating these are provided. It is provided on the side surface of the sheet feeding left side plate 22. An electric board 27 having an IC driver for driving a driving source for driving a sheet feeding device, a conveying device, and the like is provided on a side surface of the sheet feeding left side plate 22. Further, positioning long holes 22a and 23a used for positioning in the height direction when the rotary unit R is mounted are formed in the left sheet feeding plate 22 and the right sheet feeding plate 23. Are formed with holes 24a, 24b, 24c, 24d for positioning the rotary unit R and the optical unit H.

A notch 26a for positioning the optical unit H is formed on the left paper reinforcing plate 26, and a projection 24e for positioning the optical unit H is also formed on the paper stay 24. ing.

On the other hand, as shown in FIG.
In, the scanner unit 3 as the exposure means is positioned on a frame constituted by the left optical plate 31, the right optical plate 32, and the optical stay 30.

The optical left side plate 31 and the optical right side plate 32 have holes 31 for positioning the rotary unit R.
a and 32c are formed respectively. Further, the optical unit H is provided on the optical left side plate 31 with the sheet feeding / transporting unit K.
The optical right side plate 32 is provided with a groove 32a.

In FIG. 4, reference numeral 3d denotes an electric board for driving the scanner, and 33 denotes an electric board for the DC controller.

As shown in FIG. 5, in the rotary unit R constituting the upper rear portion of the apparatus main body, the developing device 4 is provided in a frame constituted by a rotary left side plate 41, a rotary right side plate 42 and a rotary stay 43. Is provided on the rotary right side plate 42 for driving the developing device 4 and the sleeve 4a in each of the developing devices 4Y, 4M, 4C, and 4Bk.
A driving device 45 for rotationally driving (see FIG. 1) is provided,
The electric board 44 for driving these is also the rotary right side plate 42.
Is provided in the vicinity.

A paper discharge unit 15 is provided on the rear side of the rotary stay 43. In the paper discharge unit 15, an air layer is formed between the developing device 4 and the fixing device 8, and An air duct 15a for preventing heat from being transmitted to the developing device 4 is connected. Note that it is also possible to let air flow through the paper discharge unit 15 with a fan.

Further, cut-and-raised portions 46 and 47 are provided below the rotary stay 43, and these cut-and-raised portions 46 and 47 have positioning pins 46a and 47a used for positioning with the sheet feeding / transporting unit K. Are provided respectively.

Next, the procedure for assembling the apparatus body will be described.

The entire frame of the apparatus main body is constructed by assembling three main units of a paper feeding / conveying unit K, an optical unit H and a rotary unit R.

That is, as shown in FIG. 6, first, the optical unit H is attached to the sheet feeding / conveying unit K by lowering it from above. At this time, the projection 3 for positioning the optical unit H
1c and the groove 32a are fitted into the positioning notch 26a and the projection 24e of the sheet feeding / transporting unit K, respectively.

Then, both side plates 31 and 3 of the optical unit H are provided.
2, the bottoms 31d and 32b and the bottom of the groove 32a
The optical unit H is lowered until it hits the butting portions 26b, 24e and 23b of the transport unit K, and then the two units H and K are fastened with screws or the like.

Next, as shown in FIG. 2, while sliding the rotary unit R from the left side to the right side of the apparatus, the positioning pins 4 provided at the lower part of the rotary unit R are used.
6a and 47a are inserted into the long holes 22a and 22
3a and fitted. Then, the rotary unit R is slid until the cut-and-raised portions 46 and 47 at the bottom thereof abut against the left and right feeding plates 22 and 23 of the feeding and conveying unit K, respectively. The hole 41a thus formed is aligned with the hole 31a formed in the optical left side plate 31, and the photosensitive drum non-drive side bearing 51 is inserted. The outer diameter of the photosensitive drum non-drive-side bearing 51 and the diameter of the hole 41a formed in the rotary left side plate 41 and the diameter of the hole 31a formed in the optical left side plate 31 are the bearing 51 and the hole 41.
a and 31a are set to dimensions that fit each other.

A hole 42a formed in the opposite rotary right plate 42 is also a hole 32c formed in the optical right plate 32.
And the photosensitive drum drive side bearing 52 and the intermediate transfer body drive bearing 53 provided in the drum / intermediate transfer body drive unit M are inserted into the holes 32c and 32d, respectively. The outer diameter of the photosensitive drum drive side bearing 52 and the rotary right side plate 42
The diameter of the hole 42a formed in the hole 52a and the diameter of the hole 32c formed in the optical right side plate 32 are set to dimensions such that the bearing 52 fits the holes 42a and 32c. Further, the outer diameter of the intermediate transfer member driving-side bearing 53 and the diameter of the hole 32d formed in the optical right side plate 32 are also set to a size in which the bearing 53 and the hole 32d fit.

In the above, the sheet feeding / conveying unit K, the optical unit H and the rotary unit R are in a state where they are positioned with respect to each other.
The vicinity of the positioning fitting portion between H and R is fastened by screws or the like.

In FIG. 2, reference numeral 50 denotes a non-driving side bearing of the intermediate transfer body 5, which is inserted into the hole 31b of the left optical plate 31 and fastened with a screw similarly to other bearings.

As described above, the entire frame of the color laser beam printer as shown in FIG. 2 is constituted by positioning and fastening the sheet feeding / conveying unit K, the optical unit H and the rotary unit R, respectively. You.

Thereafter, as shown in FIG. 7, the fixing unit 8 is slid from above the fixing unit 25 of the sheet feeding / conveying unit K into the fixing unit 25, and the fixing unit 8 is positioned and fixed.

Further, the high-voltage power supply unit HV is inserted from the right side of the apparatus until it comes into contact with the right side plate 23, and the high-voltage power supply unit HV is positioned and fixed below the drum / intermediate transfer body drive unit M. Further, the low-voltage power supply unit LV is also inserted from the right side of the device and fixed next to the high-voltage power supply unit HV. Then, the controller box F is fixed above the low-voltage power supply unit LV.

FIG. 8 shows the photosensitive drum cartridge B
And the direction in which the intermediate transfer member 5 and the developing devices 4Y, 4M, 4C, and 4K are attached and detached. FIG. 9 shows a state before assembling the sheet feeding / conveying unit K, the optical unit H, and the rotary unit R.

[0047]

As is apparent from the above description, according to the present invention, an exposure means for forming an electrostatic latent image on an image carrier,
Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image to a transfer material separated and fed one by one by a paper feeding means; and transfer means for transferring the toner image to the transfer material. In an image forming apparatus having a fixing unit for fixing a toner image to a transfer material and a conveying unit for conveying the transfer material to the fixing unit, the exposing unit, the developing unit,
Conveying means etc. are configured as independent units,
Each unit is provided with a frame that can be positioned and connected to each other, and the units are connected to each other to form a frame as the entire apparatus. Therefore, the size of the entire apparatus is reduced, the assemblability is improved, and the cost is reduced. The effect that it can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus (full color laser beam printer) according to the present invention.

FIG. 2 is a perspective view illustrating a frame configuration of the image forming apparatus according to the present invention.

FIG. 3 is a perspective view of a sheet feeding / conveying unit of the image forming apparatus according to the present invention.

FIG. 4 is a perspective view of an optical unit of the image forming apparatus according to the present invention.

FIG. 5 is a perspective view of a rotary unit of the image forming apparatus according to the present invention.

FIG. 6 is a perspective view showing a state in which a sheet feeding / conveying unit and an optical unit of the image forming apparatus according to the present invention are assembled.

FIG. 7 is a perspective view of the entire apparatus in a state where another unit of the image forming apparatus according to the present invention is attached.

FIG. 8 is a perspective view showing a mounting direction of a photosensitive drum cartridge, an intermediate transfer member, and a developing device of the image forming apparatus according to the present invention.

FIG. 9 is a perspective view showing a state before assembling a sheet feeding / conveying unit, an optical unit, and a rotary unit of the image forming apparatus according to the present invention.

FIG. 10 is a perspective view showing a conventional frame configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum (image carrier) 3 Scanner unit (exposure means) 4 Developing device (developing means) 4Y, 4M, 4C, 4Bk Developing device 5 Intermediate transfer body 8 Fixing device (fixing means) 11 Secondary transfer roller (transfer means) 12) Conveying belt unit (conveying means) 14 Cassette (transfer material loading means) 15 Discharge unit 15a Air duct 27 Electric board K Paper feeding and conveying unit H Optical unit R Rotary unit S Transfer material

Claims (9)

[Claims] An exposure unit for forming an electrostatic latent image on an image carrier; a developing unit for developing the electrostatic latent image to form a toner image; An image forming apparatus including a transfer unit that transfers the toner image onto the transfer material, a fixing unit that fixes the toner image transferred onto the transfer material to the transfer material, and a conveyance unit that conveys the transfer material to the fixing unit. In the above, the exposure unit, the developing unit, the sheet feeding / conveying unit, and the like are configured as independent units, each unit is provided with a frame that can be positioned and connected to each other, and the units are connected to each other to form the entire apparatus. An image forming apparatus comprising: a frame; 2. The image forming apparatus according to claim 1, wherein said developing means includes yellow, magenta,
2. The image forming apparatus according to claim 1, further comprising four color developing units for cyan and black. 3. The image forming apparatus according to claim 2, wherein the exposure unit has four exposure units corresponding to the four color components, respectively. 4. The image forming apparatus according to claim 2, further comprising: a developing device switching unit configured to form a toner image corresponding to each color on the image carrier by switching the developing devices of the four colors. . 5. An electrophotographic full-color image forming apparatus using an intermediate transfer member, wherein said image bearing member is disposed above said intermediate transfer member, and said image bearing member and said intermediate transfer member are arranged in a same manner. 5. The image forming apparatus according to claim 4, wherein the developing devices of the four colors are detachably provided substantially parallel to a transfer material transport direction, and the developing units of the four colors are detachably provided from an upper surface of the apparatus. 6. An optical unit having an exposure unit and a transfer unit is positioned and connected to an upper portion of a sheet feeding / transporting unit including a transfer material stacking unit, and the optical unit and the developing unit switching unit are connected to the image carrier. 5. The image forming apparatus according to claim 4, wherein the developing device switching unit is positioned and connected to the sheet feeding / conveying unit after the positioning at the rotation center shafts at both ends. 7. The image forming apparatus according to claim 6, wherein the rotation center axis of the image carrier also functions as a drive transmission mechanism for transmitting a rotational driving force to the image carrier itself. 8. The image forming apparatus according to claim 1, wherein each unit has an electric board having a driver for driving various actuators, sensors, and the like provided in each unit. 9. An image forming apparatus according to claim 1, wherein an air duct is provided between said developing means and said fixing means.