JPH01195470A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To prevent developing devices from being erroneously loaded just with covers by forming the covers of the developing devices in shapes different from one another. CONSTITUTION:In a cover body 440b, a pin 462 is made to be extended in a horizontal direction on both side ends of the front edge part 461 thereof and a hook part 463 is provided in the center of a rear edge part thereof. And a container main body 440a and the cover body 440b can be firmly combined by providing a recess groove 464 having a width with which the pin 462 can be firmly fitted and a hook 465 with which the hook part 463 can be easily deformed and engaged with the elasticity of stock material in the container main body 440a. In such a case, the shape and the size of the container main body 440a are common in all the developing devices 43-45 but the shape and the length of the front edge part 461 of the cover body 440b are made different from one another. Namely, the circular arc and the length of the front edge part 461 are the largest in the developing device 43 in the uppermost stage and they are made smaller as you go from said device 45 to the developing devices 44 and 45 in the middle stage and in the lowest stage. Thus, the developing device can be prevented from being erroneously loaded without cost-up since only cover is changed.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electrophotographic multicolor image forming apparatus, and particularly to a method for preventing developing devices containing toners of different colors from being placed in the wrong position for each color. The present invention relates to a multicolor image forming apparatus.

[Conventional technology]

Generally, an electrophotographic multicolor image forming apparatus includes a photoreceptor drum at its center, and around it a charger and a plurality of developing devices containing toners of different colors. This developing device is removable for toner replenishment or maintenance, inspection and repair, and its position when returning after escape is clearly determined. In other words, the one-rotation opening of the photosensitive drum, which starts rotating in response to a signal from the document reading unit, is colored in the first color (for example, red).
The developing device containing toner of the second color is operated, the developing device containing the second color (for example, blue) toner is operated for the second time, and the third color (for example, black) toner is stored for the third time. However, if these developing units containing toner of different colors could be installed in any position, the latent image corresponding to red could be converted to blue or black. There was a possibility that the toner would be used to develop the image, and the colors would become disjointed.

Therefore, in order to prevent multiple developing units from being placed in the wrong position for each color, a protrusion of a different shape is provided for each developing unit, and a recess into which only the protrusion can fit is provided in the main body of the copying machine. In many cases, the developing device is provided on the side and can be installed only in a position where the protrusion and the recess can fit together, or the cross-sectional shape of the developing device is made different.

[Problem that the invention seeks to solve]

However, if the protrusions provided on the developing device or the cross-sectional shape of the developing device itself are different, it is not possible to standardize the mold, and
The shape of the receiver on the copying machine main body side had to match the shape of the developing device, which resulted in an increase in cost.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a multicolor image forming apparatus that can prevent incorrect loading of a developing device without increasing costs.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a multicolor image forming apparatus in which a plurality of developing units are removably installed around a photosensitive drum, in which a lid of the developing units is closed. They are molded into different shapes and configured to prevent incorrect loading of the developing device (fool proof) by changing only the lid.

〔Example〕

Next, the present invention will be explained based on drawings of an image forming apparatus capable of forming color images.

In FIG. 1, A is a document reading section, and B is a part of the printer. The document reading section A illuminates a document 2 placed on a platen glass 1 provided on the top surface of the housing with a fluorescent lamp 5 provided on a carriage 4 moving on a slide rail 3, and passes the reflected light through a slit 6. The light can be taken out by the first mirror 7 and led out to the lens reading unit 20 via the mirror 9.9' provided in the movable mirror unit 8.

The carriage 3 and the movable mirror unit 8 are driven by pulleys 11, 12, 13, and 14 connected to a stepping motor 10 via a wire 15. In this case, the movable mirror unit 8 moves on the slide rail 3 at 1/2 the speed of the carriage 4 in the same direction. Reference numerals 16 and 17 denote standard white plates provided on the lower surface of both ends of the platen glass 1, and the standard white plates 16 and 17 are used to obtain standard white signals before and after the start and end of document reading scanning.

The lens reading unit 20 has a lens 2 as shown in the second figure.
1. Prism 22, first reading board 24, red channel (hereinafter referred to as R-ch) CCD 25, second reading board 2
6. Cyan channel (hereinafter referred to as C-ch) CCD2
It consists of 7. The original light image transmitted by the first mirror 7 and the mirrors 9 and 9' is focused by the lens 21 and separated into an R-ch image and a C-ch image by the dichroic mirror 23 built into the prism 22. and R-ch CCD 25 provided on the first reading board 24,
and C-c hCCD 27 provided on the second reading board 26
The image is formed on each light-receiving surface. This R-chCCD
The image signals outputted from the CCD 25 and the C-ch CCD 27 are subjected to signal processing in a signal processing section 28, and a color signal separated according to the color of the toner is outputted to a writing unit 29 provided in the printer B.

As shown in the third diagram, the writing unit 29 includes a semiconductor laser 31, a polygon mirror 32 that is rotated by a drive motor 3o to rotate and scan the laser beam generated by the semiconductor laser 31, an fθ lens 33, and cylindrical lenses 35 and 36. We are prepared. The laser beam generated by the semiconductor laser 31 passes through the cylindrical lens 35 and is rotated and scanned by the polygon mirror 32, passes through the fθ lens 33, the cylindrical lens 36, and the reflecting mirror 37, and is projected onto the surface of the photosensitive drum 400, forming a bright line 39. Form. Reference numeral 34 denotes an index sensor that detects the start of beam scanning, and detects the start of scanning by the laser beam via a reflecting mirror 38.

When the index sensor 34 detects the start of scanning, the first color signal output from the signal processing section 28 is input to the writing unit 29, and modulation of the beam by the color signal is started. The modulated beam is applied to the photosensitive drum 4 which is uniformly charged in advance by a charger 41.
Scan over 0. Main scanning by this beam and the drum 40
A latent image corresponding to the first color is formed on the drum surface by the sub-scanning caused by the rotation of the drum, and the latent image is developed by a developing device 43 loaded with, for example, red toner. After this red toner image is formed, the drum surface is charged again by the charger 41 in the next copy cycle. In this case, the cleaning blade 47 of the cleaning device 46 is separated from the photosensitive drum 40 to prevent the red toner image from being scraped off.

Next, the second color signal output from the signal processing section 28 is input to the writing unit 29, and the second color signal is input to the writing unit 29.
Similarly to the above, a latent image corresponding to the second color is formed on the surface. The latent image is then developed by a developing device 44 loaded with, for example, blue toner. That is, the blue toner image is formed on top of the already formed red toner image.

Next, based on the control signal generated by the signal processing section 28, a black toner image is formed on the surface of the photosensitive drum 40 by the developing device 45 loaded with black toner by the same operation as described above.

The developing units 44 to 45 have a container main body 440 as shown in the fourth figure.
A developing sleeve 441 with a magnet embedded in its outer periphery and a developer 442 are contained in a housing consisting of a and a lid 440b.
a main stirring member 443, a first conveying means 444 that conveys the developer in one direction from one end side to the other end side in the development width direction;
A second conveying means 445 for conveying the developer in the opposite direction to the first conveying means 444 is provided.

An alternating current and direct current bias is applied to the developing sleeve 441, and a jumping phenomenon is performed by the toner of the two-component developer, so that development is performed without contacting the grounded photoreceptor drum 40. .

Reference numeral 446 denotes a doctor blade that adheres the developer in the form of a thin film to the surface of the developing sleeve 441, and 447 denotes a developer that adheres to the developing sleeve and is carried to the front of the photoreceptor drum 40, where the toner content has been reduced by being used for development. This is a scraper for scraping off (mainly carrier) from the surface of the developing sleeve 441. The tired developer scraped off by the scraper 447 is well stirred and mixed while being circulated by the first conveying means 444 and the second conveying means 445 around both ends of the partition wall 448 as shown by the arrow, and is reactivated. turned into
It is attached to the developing tube IJ-tub 441 by the main stirring member 443 .

In order to keep the distance between the developing sleeve 441 and the photosensitive drum 40 constant, the developing units 44 to 45 have an abutment roller 450 with a slightly larger diameter attached to the shaft 44F of the developing sleeve 441 so as to be rotatable. , the abutment roller 4
A means (not shown) is provided for pressing the developing device toward the photosensitive drum 400 so that the developing device 50 abuts the surface of the photosensitive drum 400.

Further, the developing units 43 to 45 can be pulled out in the axial direction (in the direction of the arrow) of the photosensitive drum 4o for toner replenishment or maintenance, inspection and repair. When the developing device is stored, the developing sleeve 441 is connected to a shaft 451 through a gear train 453 through a coupling 451 fixed to the shaft end of the shaft 441' and a drive motor 452 provided on the main body side, as shown in FIG.
It is coupled to a coupling 454 fixed to the shaft end of the drive motor 452, and receives drive transmission from a drive motor 452.

The lid 440b has a front edge 461 as shown in FIG.
Bins 462 extend horizontally from both ends (only one is shown in the drawing), and a hook 463 is provided at the center of the rear edge. Further, the container body 440a has a groove 464 having a width that allows the pin 462 to fit snugly therein, and a hook portion 46.
3 is provided with a hook 465 that can be easily deformed and engaged due to the elasticity of the material, so that the container main body 440a and the lid body 440b can be firmly connected. In this case, the shape and size of the container body 440a are common to all of the developing devices 43 to 45, but the shape and length of the front edge 461 of the lid body 440b are different. That is, the developing devices 43 to 4
5, when the developing sleeves are installed horizontally at a constant interval around the photosensitive drum 40, the upper surface space of the developing sleeve 441 differs depending on the position. As shown in FIG. 4, if the developing device 44 installed on the center line a of the drum is the standard, the upper surface space is wider for the upper developing device 43 and narrower for the lower developing device 45. The shape and length of the front edge 461 of the lid 440b are determined in accordance with this space. That is, the arc and length of the front edge portion 461 are maximum in the uppermost developing device 43, and decrease toward the middle and lowermost developing devices 44 and 45. In this case, the lowermost developing device 45 can be loaded into the middle and top tiers, which have larger spaces, and the middle developing device 44 can be loaded into the uppermost tier, but the uppermost developing device 43 can be loaded into the middle and top tiers, which are narrower. It cannot be loaded into the bottom row.

Therefore, even if the lower stage is successfully loaded into the middle stage, and the middle stage is successfully loaded into the upper stage, there is no room for loading the upper stage, and eventually, at this point, the mistake is noticed.

The three-color toner images developed as described above are separated one by one by the paper feed belt 52 of the paper feed unit 50 in the transfer unit 51, and are timed by the paper feed roller 53 and placed on the guide plate 5.
The images are transferred all at once onto the recording paper 55 that has been sent through the process.

After that, the recording paper is transferred to the photosensitive drum 4 by the separation electrode 56.
0, placed on a conveyor belt 57, and transferred to a fixing device 5.
8, and is fixed by heat and pressure with fixing rollers 58a and 58b, and then transferred to output roller 5 as a color hard copy.
It is held between 9a and 59b and discharged outside the machine.

After the transfer is completed, unnecessary toner remaining on the photosensitive drum 40 is scraped off by bringing the blade 47 of the cleaning device 46 into contact with it. A cleaning roller 48 provided on the downstream side of the cleaning device 46 completely removes the small amount of toner left behind between the drum surface and the blade when the blade 47 separates from the drum 40 for the next exposure and development after cleaning. It is used for removal and rotates in the opposite direction to the drum.

Although not explained in the above embodiments, it is also possible to color code the lid of the developing device depending on the material itself, or to use a pasted mark, etc., and by doing so,
It has a foolproof function and is even more robust, further improving workability to prevent erroneous operations.

〔Effect of the invention〕

As described above, the present invention provides a multicolor image forming apparatus in which a plurality of developing units are removably installed around a photosensitive drum.
Since the lids of the developing devices are molded into different shapes, it is possible to prevent incorrect loading of the developing device without increasing costs by changing only the lids, which is an excellent effect. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a hydrophilic sectional view of the copying machine of the present application, Fig. 2 is an enlarged view of the lens reading unit, Fig. 3 is a plan view of the writing unit, and Fig. 4. 5 is an explanatory diagram of the drive system of the developing sleeve, and FIG. 6 is an exploded perspective view of the developing device. A--Document reading section B--Printer part 40--Photosensitive drums 43 to 45--Developer 440a-Container body 440 tl--Lid 461--Front edge 462- Pin 463...Hook portion 464--Concave groove 465-...Hook patent applicant Konica Co., Ltd. Figure 2, Figure 5, Figure 4-2

Claims (2)

[Claims] (1) A multicolor image forming apparatus including a plurality of removably attached developing devices around a photosensitive drum, characterized in that the lids of the developing devices are molded into mutually different shapes. . (2) The multicolor image forming apparatus according to claim 1, wherein the lid body is formed to match the size of the space on the upper surface of the developing sleeve facing the photosensitive drum.