JPH03249765A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the splashing of toner and color mixture occurring at the time of loading/unloading a process cartridge and to obtain a multicolor image whose quality is good by allowing the process cartridge to be loaded in and unloaded from an image forming device in a posture that a developer storing part is positioned below with respect to a developer carrier. CONSTITUTION:A cartridge loading/unloading guiding member is disposed in the image forming device main body so that the posture of the process cartridge 18 provided with plural developing devices 4-7 having colors different from one another in the case that the process cartridge is loaded in and unloaded from the image forming device main body is made such a posture that the developer storing parts 24 in the developing devices 4-7 are positioned below with respect to the developer carrier 22, that means, such a positional relation that the toner in a developer container does not apply pressure to the developer carrier side may be kept between them. Then, the cartridge 18 is loaded/ unloaded along the guiding member. Thus, the toner in the developing device is prevented from splashing to the outside of the developing device and the color mixture is prevented even in the case that impact is given to the device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming apparatus such as an electrophotographic copying machine, an electrostatic recording device, a laser beam printer, etc., and more specifically to an image forming apparatus with a removable process cartridge type. The present invention relates to an image forming apparatus capable of forming multicolor images.

[Conventional example]

Image forming apparatuses with removable process cartridges require specific equipment out of all the process equipment for image formation, such as image carriers (electrophotographic photoreceptors, electrostatic recording dielectrics, etc.), chargers, developing devices, and cleaning devices. In this device, these components are assembled into a common housing (frame) as a unit that can be freely attached to and detached from the main body of the image forming apparatus in a predetermined mutual positional relationship.

Regarding the image bearing member, developing device, etc. contained in the process cartridge, if the image bearing member reaches the end of its durability (repetitive use life), or if the developing device contains a predetermined amount of developer (
When the toner (toner) is used up or malfunction occurs due to malfunction, etc., the user should remove the process cartridge that has reached the end of its useful life or has malfunctioned from the image forming apparatus, and install a new process cartridge. The image forming apparatus is installed and used interchangeably, and there is no need to rely on service personnel with specialized knowledge, improving the maintainability and serviceability of the image forming apparatus. Furthermore, by equipping a plurality of process cartridges with different functions such as developing color and installing the process cartridge for a desired device into the main body of the image forming apparatus, a uniform image forming apparatus can be used for multiple functions. This method has advantages such as being able to perform the following operations, and has already been put into practical use as one of the configuration methods for, for example, a personal type compact and lightweight image forming apparatus.

[Problem that the invention is trying to solve]

Nowadays, electrophotographic printers are often used as printers for terminal devices of information equipment such as computers, facsimiles, and CAD.

These printers use laser beams or LEDs to transmit information signals.
- A recorded image is obtained through the process of writing on a photosensitive drum as an image carrier using an LCD, etc., making it visible using a developing device, and transferring and fixing the visible image onto transfer paper, but with conventional printers, The recorded image was, for example, in one color, black only.

However, in recent years, recorded images have become clearer and information has become easier to understand, so for example, the color of the format and the color of the calculated value or data value are expressed in different colors, or It is desired that the drawings be distinguished using two or more colors, such as outputting a part of a drawing in a different color.

FIG. 5 is a schematic diagram of an example of a multicolor recording type electrophotographic printer. As an image carrier, a drum-shaped photoreceptor (hereinafter referred to as a photoreceptor drum) 101 formed by coating a photoconductive layer on a conductive substrate is rotatably provided.
is uniformly charged using a charger 102, and exposed to a first information signal (a signal consisting of information components of a first color) 103 using a light emitting element (not shown) as an information writing means such as a laser. Forms an electrostatic latent image and produces a first color (e.g. yellow)
The image is visualized using the developing device 104. Next, the charger 102 recharges the electricity and exposes the second information signal (signal consisting of information components of the second color) 103 to form a second electrostatic latent image.
For example, the image is visualized using a developing device 105 (magenta). Furthermore, the same process is performed for a third color (for example, cyan), and the third color is visualized by the third color developing device 106. Next, photosensitive drum 1
The recorded image of the three color components formed on the transfer device 110
7, the images are transferred onto the transfer paper P at once and fixed by the fixing device 108. This results in a multicolor print.

Further, the developer that has not been transferred to the transfer paper P on the photosensitive drum 101 is removed by a cleaning device 109, and the photosensitive drum 101 is repeatedly used for image formation. In such a multicolor recording printer, in addition to the three color developing devices 104, 105, and 106, there is usually a black developing device 11.
0, and without composing black information with yellow, magenta, and cyan, the black developing device W can be used directly.
110.

In the case of the multicolor image forming apparatus as described above, the photosensitive drum 10
1. The above-mentioned advantages can be obtained by collectively constructing a process cartridge in which the developing device 104, 105, 106, 110, charger 102, cleaning device 109, etc. are removably attached to the main body of the image forming apparatus. can. However, when the process cartridge is configured as described above, a strong impact may be applied when the process cartridge is installed in the main body of the image forming apparatus. This impact may cause the toner in the developing device to scatter from the developing container and may even adhere to the developing device or developing sleeve of another color below it, resulting in so-called color mixing, which is a serious problem in color image forming apparatuses. This results in poor image quality.

Therefore, an object of the present invention is to provide an image forming apparatus that can obtain multicolor images of high quality by preventing toner from scattering from each developing unit and preventing color mixing when a process cartridge is attached or removed. It is to provide.

[Means for Solving the Problem] That is, the present invention provides a method for removing and removing a process cartridge including a plurality of developing devices of mutually different colors from a developer carrier such as a developing sleeve of the developing device. The toner filling section, which is a developer storage section in the developing device, is maintained in a downward position relative to the position. This is intended to prevent toner from scattering due to toner being blown out from the developing device even in the event of impact when the process cartridge is attached or detached. In particular, in a process cartridge that includes multiple color developing devices such as a multicolor image forming apparatus, toner scattered from the developing device located on the upper side of the cartridge may be stored in the container of the lower developing device or If the toner falls onto the developer carrier, a problem of so-called color mixing occurs, so it is more effective to prevent toner scattering due to impact by maintaining the attitude of the process cartridge when it is attached or detached as described above.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 and FIG. 2 are diagrams showing a first embodiment of the present invention, which will be explained in order below.

In FIG. 2, reference numeral 1 denotes a drum-shaped image carrier whose surface is coated with a photoconductor such as organic semiconductor (OPC) or amorphous silicon, and the image carrier 1 is uniformly charged by a charger 2. Next, the laser beam 3 from the laser unit 3' is transmitted to the image carrier 1 by an electric signal according to the yellow image component.
After the electrostatic latent image is irradiated onto the image carrier 1 and an electrostatic latent image is formed on the image carrier 1, it is developed with a yellow developer 4. At this time, other developing devices 5.6.
7 takes measures such as applying a sufficient reverse voltage to the image carrier 1 so as to retreat or stop toner supply. The yellow toner image on the image carrier l is transferred onto the recording paper fed from the recording paper cassette 8, which is electrostatically wound around the transfer rotary member 10. This transfer rotating body 10 has a resistance value of 109 to 103 on the outer periphery of the metal cylinder.
A resin sheet of about Ω/cm is wrapped around it, and if necessary, a gripper or suction means can be installed to hold the leading edge of the recording paper, or the sheet can be held using commonly known electrostatic adsorption. An insulating material such as a polyester sheet may be placed to prevent the damage from occurring.

A voltage of 1 to 5 kV with a polarity opposite to that of the toner is applied to the transfer rotating body 10 from an external power source (not shown), and the width of the recording paper 2
In the case of 10 mm and a basis weight of 89 gr/rd, a yellow visible image can be obtained on the recording paper by selecting a transfer current of about 1 to 1.5 μA. Next, the toner remaining after transfer on the image carrier 1 is cleaned and collected by a cleaning means 12 such as a blade or a fur brush.

The image carrier 1 is charged again by the charger 2, subjected to magenta image exposure, and magenta development 5 to visualize the magenta toner image, which is superimposed and transferred with the yellow toner on the recording paper. Similarly, the cyan developing device 6 and the black developing device 7 perform overlapping transfer, and then the recording paper is separated from the transfer rotating body 10 by separating means such as a separating claw 13, and the toner on the recording paper is fixed by the fixing device 14. , and is placed on the tray 16 via the paper discharge rollers 15.

If this recording process is repeated over a long period of time, the image carrier 1, toner, etc. will deteriorate, resulting in a decrease in image quality. Therefore, it is necessary to replace it periodically. When replacing the image bearing member 1 and developer, the transfer rotary member 11 and the image bearing member 1 may be damaged, or the cleaning device 12 must be evacuated from the image bearing member 1 during the above-mentioned replacement. Since there is a drawback that toner scatters and stains the inside of the apparatus body, in this embodiment, the above-mentioned yellow, magenta, cyan, and black developing units, image carrier 1, charger 2,
The cleaning device 12 is housed in one process cartridge container 17, and each process cartridge 18 is replaced when toner runs out. By using a process cartridge type as described above, anyone can easily replace the cartridge.

Next, a procedure for replacing the process cartridge 18 will be explained.

When attaching or detaching the cartridge 18, the cover 19 of the main body of the image forming apparatus is rotated around the fulcrum 21 as shown in FIG.

Thereafter, a new process cartridge is inserted in the reverse order, and the opening/closing cover 19 is closed. Cart refrigeration 18 at this time
The configuration of the developing device 4.5.6.7 will be explained. In FIG. 2, the yellow developing device 4 includes a developing sleeve 22 as a developer carrier and a coating roller 23 in its container 24.
The sealing member 25 is a member that prevents toner from coming out to the applicator roller 23 side when it is new (unused), and when in use, the sealing member 25 is filled with toner. The member 25 is removed and used. Also,
The toner filling section 24 , which is a developer storage section, is provided with a means such as a belt for conveying the toner to the application roller 23 side, so that the application roller 23 is always supplied with toner and the outer circumferential surface of the developing sleeve 22 is further supplied with toner. supplies toner. This configuration is the same for the other developing devices 5.6.7.

In a developing device with this structure, it is natural to apply a seal to the end of the developing sleeve to prevent toner scattering, but a perfect seal cannot be achieved between the eaves 24a of the developing container and the developing sleeve 22. extremely difficult. Also, as a matter of course, since there is a toner layer on the surface of the developing sleeve, scattering occurs from this area. This toner scattering is a serious problem because magnetic sealing means cannot be applied to non-magnetic toner that does not contain a magnetic substance. In particular, if a strong impact is applied to the developer container, toner inside the developer container or on the outer peripheral surface of the developer sleeve will be scattered. Furthermore, this toner scattering is caused by, for example, when the developing device is configured with a plurality of chromatic toners as shown in this embodiment, yellow toner falls onto the developing sleeve of the magenta developing device below, and is mixed. This causes the problem of color mixing, which is a very troublesome problem when producing color images.

Referring to FIG. 1, mounting of the cartridge 18 will be described in detail. The cartridge 18 is installed by opening the opening/closing cover 19 as described above.At this time, install the cartridge 18 so that the developer side of the cartridge 18 is first and the filled toner container side is downward with respect to the developing sleeve. Since the position of the developer is taken into consideration, toner will not scatter outside the developer container even if a shock is applied during installation.

In addition, in FIG. 1, the transfer rotor 10 is supported by a transfer rotor support plate 27, and a spring 2 is attached around the fulcrum 26.
8, it is possible to obtain the effect of alleviating the impact between the image carrier 1 and the transfer rotating body 10 when the opening/closing cover 19 is closed, and the effect of ensuring pressure contact between the two. Incidentally, when the cartridge is attached or detached, the image carrier and the transfer rotating body are separated from each other, as shown in FIG.

[Other Examples]

FIG. 3 shows a second embodiment of the invention.

In FIG. 3, numeral 31 is the main body of the image forming apparatus that forms images in the same process as the image forming apparatus explained in FIG. It is printed and fixed using an electrophotographic process, etc., and is stacked on the paper discharge tray 33. In FIG. 3, when the cartridge 35 is to be attached or detached, the cartridge 35 is attached or detached after opening the opening/closing cover 32 and the cartridge housing [30]. At this time, the cartridge accommodating portion 30 is tilted about the opening/closing center 30a as a fulcrum as shown in FIG. It is installed and removed while being tilted due to its lower position.

Therefore, when the cartridge is attached or detached, the shock is applied to the cartridge 35.
Even if the toner is added to the developer container, the toner in the toner storage section will not be scattered outside the developer container. That is, the problem of color mixing as described above does not occur.

In addition, in the embodiment explained in FIGS. 1, 2, and 3, the case was explained in which the cartridge includes means such as a developer, a length of 1 m, a cleaner, a photosensitive drum, a charger, etc. It goes without saying that the present invention is effective even in the case of a cartridge that is only a container. Furthermore, even if the cartridge is inserted into the main body of the apparatus with the positional relationship between the developing sleeve and the toner storage portion in each developing unit as described above, and then only the cartridge is rotated or moved to a predetermined position. The present invention is effective.

FIG. 4 shows an example in which a process cartridge that can be used in the image forming apparatus of the present invention is provided with a carrying handle. Since the developer accommodating portion 24 is disposed downward, it is possible to prevent toner from scattering from the developer even when subjected to impact during transportation. This carrying handle is not limited to the shape shown in FIG.
It may be attached to the surface 5a, and furthermore, it may have a concave or convex shape so that you can know where to hold it by hand, even if it does not have a so-called handle shape.

〔Effect of the invention〕

As explained above, at least when a process cartridge having a plurality of developing devices of different colors is attached to and removed from the main body of an image forming apparatus, the attitude of the process cartridge is determined relative to the developer carrier of each developing device. A cartridge attachment/detachment guide member is disposed within the image forming apparatus main body so as to maintain a position in which the developer accommodating portion is located downward, that is, a positional relationship in which the toner in the developer container does not apply pressure to the developer carrier side. By attaching and detaching the cartridge along this guide member, the toner in the developing device will not be scattered outside the developing device even if an impact is applied, and color mixing can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing attachment and detachment of a process cartridge according to a first embodiment of the present invention, FIG. 2 is a schematic sectional view of an image forming apparatus according to a first embodiment of the present invention, and FIG. FIG. 4 is a perspective view of an image forming apparatus according to a second embodiment, FIG. 4 is a schematic diagram of a process cartridge in which the present invention can be implemented, and FIG. 5 is a schematic diagram showing a conventional example. 1... Image carrier 4.5.6.7... Developing device 10... Transfer rotating body 18... Process cartridge 22... Developer carrier 24... Developer storage section/ ρ7

Claims (2)

[Claims] (1) An image forming apparatus in which a process cartridge including a plurality of developing devices for mutually different colors each having at least a developer carrier and a developer accommodating portion is removably attachable to the developer carrier. An image forming apparatus characterized in that the process cartridge can be attached to and removed from the image forming apparatus in an attitude in which a developer storage section is positioned downward. (2) The process cartridge has an image carrier, and in a state where the image carrier is separated from a transfer rotary member that rotates in contact with the image carrier at least during transfer, the process cartridge is connected to the image forming apparatus. The image forming apparatus according to claim 1, which is attached to and detached from the image forming apparatus.