JPS6343170A - Multiplex image forming device - Google Patents

Abstract

PURPOSE:To easily execute maintenance work and jam processing by constituting an image carrier, a developing means and image carrier cleaning means in a lower case body and making it possible to separate these members from a transfer position of a transfer material supporting body to the lower case body. CONSTITUTION:An electrostatic charger, a developing device, a cleaning device an image forming process group are arranged around a photosensitive belt in a lower half formed through an X-X line as a border, a transfer material carrying part is arranged in the upper half and both the halve can be separated. Thereby, paper processing such as paper jam or maintenance can be easily executed. Since both the halves can separated, function-separated assembling and check can be executed. Thus, jam paper near the transfer position of a transfer drum can be easily extracted by separating an image formation process group from the transfer drum 4. Since the drum 4 is drawn out, glit timing with the drum 4 is sheared and always stable paper carrying can be attained.

Description

Detailed Description of the Invention (Industrial Application Field of the Invention) The present invention has a plurality of developing devices, develops a latent image formed on an endlessly moving image carrier, and transfers the toner image to a transfer material. The present invention relates to a multicolor image forming apparatus that obtains an image by overlapping transfer on the top.

(Prior Art) Recently, the demand for color copying has increased rapidly not only in special fields but also in general office fields, and there is a desire for a color copying machine that can be used not only by professionals but by anyone. Currently, full-color electrophotographic copying machines that utilize electrophotographic technology are widely used as color copying machines.

Considering the conveyance path of the transfer material in such a conventional color image forming apparatus, the transfer of the photosensitive drum located roughly in the center of the apparatus! It is necessary to guide the transfer material up to the i position, and when handling a jam, etc., it is necessary to take out the transfer drum for gripping and rotating the transfer material from the apparatus.

Generally, image forming process units such as a charger, developer, and cleaning device are concentrated near the photosensitive drum, and each is configured to be detachable from the main body for maintenance reasons, which weakens the structure at the center of the device. There is a problem.

Furthermore, since the process units concentrated around the photosensitive drum are arranged so as not to interfere with each other, it becomes difficult to sufficiently expand the functions.

(Problems to be Solved by the Invention) The present invention provides a multiplex image forming apparatus having a plurality of developing devices, which is equipped with a simple developing device with good development stability, and by distributing image forming process units around the image carrier. The present invention provides a novel multi-image forming apparatus that is easy to install by providing flexibility in the configuration and broadly separating the image forming process unit group and transfer material conveyance path.

(Embodiment) Next, an embodiment of the multicolor image forming apparatus according to the present invention will be described in detail with reference to the drawings.

The image forming apparatus according to the present invention is applied to a monochrome image forming apparatus such as a two-color copying machine, a full-color copying machine, a printer, etc., but in this embodiment, an electrophotographic full-color printer applying the Carlson process will be described. do.

FIG. 1 is a schematic sectional view of a full color printer based on the present invention. In the figure, a photosensitive belt 1 is an endless belt placed over a belt pulley 2 and a belt pulley 3, and is rotating in the direction of the arrow in the figure. A cleaning device 5 and a charging device 6 are arranged in the order of the direction, and furthermore, in the direction of the advancing force of the belt, it is located between the belt pulley 3 and the belt pulley 2, and in the lower straight part of the photoreceptor belt.
From the right: yellow developer 7 (Y), magenta developer 7 (
M), cyan developer 7 (C), black developer 7 (B
k) is located.

Reference numeral 8 denotes a scanner device, which includes a semiconductor laser that converts an electrical signal into an optical signal, a rotating polygon mirror that scans in the horizontal direction, etc., and the laser beam changes its optical path by a reflecting mirror 9 according to the image signal. , a latent image is formed on the photosensitive belt l at a position approximately below the belt pulley 3.

On the other hand, the transfer material is stored in a cassette 10, and after being fed from the cassette in response to a paper feed signal, the transfer material is conveyed to the transfer drum 4, where the leading edge of the transfer material is sandwiched between the grippers 11 and wrapped around it.

The transfer drum 4 has a cycle with the photosensitive belt and is driven at the same circumferential speed.The transfer drum 4 is charged based on the cycle of the position of the transfer material on the transfer drum 4 and the position of the developed image on the photosensitive belt 1. A device 12 transfers the toner image on the photosensitive belt 1 onto a transfer material.

The transfer material wound around the transfer drum 4 can be transferred multiple times, and after being transferred a required number of times, it is separated from the transfer drum by a separating claw 14 while being neutralized by a static eliminator 13 and conveyed by a conveyor belt 15. After the image is fixed on the transfer material by the fixing device 16, the transfer material is discharged onto the tray 17.

When obtaining a full-color image, first, a latent image formed on the photosensitive belt l by a yellow image signal is transferred to the Y developing device 7.
(Y), and the yellow image is transferred to the transfer material. Next, at the same time as the transfer material rotates to the transfer position, a magenta image is formed on the photosensitive belt, the magenta image is transferred, and then a cyan image and a black image are transferred in the same manner, resulting in a full color image. An image is obtained. Therefore, the transfer drum passes through the transfer position at least four times with the transfer material wrapped around it.

FIG. 2 shows the relationship between the photosensitive belt and the developing devices, and the developing devices for the four colors have the same shape. Although it is possible to use a one-component developer or a two-component developer as the developer, an example in which a two-component developer composed of a carrier and a toner is used will be described.

During non-development, the developing device is as shown in FIG. is an eccentric cam for moving the developer container up and down from the non-developing state (shown in Figure 3) to the developing position (shown in Figure 2).By rotating the cam 81 half a turn in the direction of the arrow from the state in Figure 3, , is maintained in the state shown in Fig. 2.The developing device is pressed against the photoreceptor belt with a constant force by a plate spring 73.The developing gap D required during development is
2 is ensured by pressing rollers (not shown) coaxially and rotatably supported at both ends of the developing sleeve 78 against the photoreceptor belt l. At this time, the backup member 21 prevents the belt from shifting due to the belt being pressed.

Each developing device has the configuration shown in FIGS. 2 and 3. For example, when developing Y color, only the Y developing device is kept in the state shown in FIG. 2, and the other M, C, and Bk developing devices are connected to the cam 81. By operating and maintaining the state shown in Fig. 3, development without color mixture can be achieved. The driving force during development is generated by driving a drive gear disposed on the main body side (not shown) and an input gear on the developing unit side so that they mesh as shown in Figure 2, and the developing unit is driven as shown in Figure 3. As a result, the drive gear and input gear become disengaged. Therefore, by selectively bringing any developing device to the state shown in FIG. 2, development of the required color can be performed.

The driving force of the developing device to which the drive is input is distributed by a gear arrangement (not shown), and the screws 76 and 77 and the developing sleeve 7
8 rotates in the direction of the arrow shown in the second figure.

The screws 76 and 77 reciprocate and circulate the developer in the container 71 while stirring it, thereby making the developer in the container uniform. A fixed magnet is provided inside the developing sleeve, and the magnet is placed in the direction of rotation of the sleeve from the NI pole (looking up and S).
, the amount of developer coated is regulated by the pole and the doctor blade 80, and developed by the N2 pole, and then S2 and 8
It falls from above the sleeve due to the repulsive magnetic field composed of three poles.

As mentioned above, all the developing devices can develop in the same shape and in the same manner on the straight portion of the photosensitive belt, so that stable development can be performed.

As is clear from Figure 1, the lower half of the X-X line contains the photoreceptor belt, charger, developer, cleaning device, and image forming process unit group, and the upper half contains the transfer material transport section. Can be separated. Therefore, it is easy to handle paper jams and the like, and to perform maintenance. Furthermore, since the upper and lower parts can be separated, assembly and checking can be performed with separate functions. Figure 4 shows photosensitive belt 1. Developing device7. Cleaning device 5. −
Next, the charger 6 is used as an integrated process structure 30 to form a pan tag.

It shows a state in which the image is divided into upper and lower parts with the transfer position as a boundary by means of a vertical elevating means 31 such as a rough. Furthermore, this process structure 30
It is also possible to pull it out using the guide rail.

Furthermore, from the process structure 30, the individual developers 7.degree. cleaning devices 5. - It is also possible to configure the secondary charger 6 and the photosensitive belt to be detachable from the main unit.

By separating the image forming process group from the transfer drum 4 in this way, it is possible to easily remove jammed paper near the transfer position of the transfer drum. Furthermore, since the transfer drum does not have to be pulled out, the grip timing on the transfer drum does not lag or shift, allowing stable paper feeding at all times.

Further, as shown in FIG. 5, a part of the right side surface can be structured as a door 30 to take out jammed paper. Furthermore, maintenance of the screen and sheet provided on the transfer drum for adsorbing the transfer material onto the transfer drum can be performed at the same time, and furthermore, the transfer drum 4 can be replaced while the door 30 in FIG. 5 is open. Can be configured.

Next, as another example, an example in which a solid-state scanner 8 is used will be described in FIG. 6.

The solid-state scanner 8 is an image writing device using a liquid crystal shutter array or an LED array, and can be made more compact than the scanner using a rotating polygon mirror shown in FIG. Then, centering around the photosensitive belt 1, ■Charging (-charger 6) ■Exposure (solid-state scanner 8)
■Developing (developing unit 7) ■Cleaning (cleaning unit 5)
) and image forming process unit group A except for the transfer process.
form.

The image forming process unit group A is swingably supported around the center of rotation of the belt pulley 2, and is configured to be able to be attached to the transfer drum 1 at the transfer position. In this way, it is also possible to make the lower half of the apparatus a complete image forming process unit group including the image writing means, and to separate the upper half into a transfer material transport system including transfer fixing.

The examples shown in FIGS. 7 and 8 are explanatory diagrams in which the photoreceptor is formed into a drum shape, and the same members as in the above embodiment are given the same reference numerals. FIG. 8 shows a state in which the upper casing X and the lower casing Y are opened with the support axis Z as the center. In this case, each developing device that is not used may be one that approaches and separates from the photoreceptor, and an LED element array is used as the optical means.

(Effects of the Invention) As explained above, the present invention provides the following effects.

(1) Stable full color development without scattering can be performed.

(2) Since the process unit group can be completely separated from the transfer material conveying device, maintenance and jam removal are easy.

(3) Since the paper transport path is fixed, stable paper transport is possible at all times.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus showing an embodiment of the present invention, FIGS.
The figure is a sectional view of a device showing an embodiment of the present invention. In the figure, 1... Photoreceptor 4... Transfer drum 5... Cleaning device 6... Charger 7... Developing device X... Upper housing Y... Lower part Housing Z...Rotation center support shaft

Claims (2)

[Claims] (1) An endlessly movable image carrier, a latent image forming means for forming a latent image on the image carrier, and a plurality of color developing means for developing the latent image on the image carrier; In a multiple image forming apparatus having an endlessly movable transfer material support capable of transferring a developed image on the image carrier onto a transfer material multiple times, cleaning the image carrier, the developing means, and the image carrier. A multiplex image forming apparatus characterized in that the means is constructed in a lower housing and is separable from the lower housing from the transfer position of the transfer material support. (2) In the image forming apparatus, the image carrier, a charging means for uniformly charging the image carrier, an exposure means for writing a latent image on the belt-like image carrier, and the belt-like image a developing means for visualizing the latent image on the carrier;
A cleaning means for cleaning the belt-like image carrier is integrally supported to form an image forming process unit group, and the image process unit group is configured to be separable from the transfer material support. A multiple image forming apparatus according to claim (1).