JPH0310261A - Color image forming device - Google Patents

Abstract

PURPOSE:To easily guarantee and maintain the quality of a color image and to facilitate jam processing and the replacement of parts by attaching/detaching a cartridge from a front surface at the time of opening a door provided in front of a device main body. CONSTITUTION:Around an image carrier drum 30, an electrifier 9, plural develop ing unit 36-39 separated into yellow Y, magenta M, cyan C and black BK or integrally united, a cleaning device 40, as necessity requires, a waste toner recovering container 47, etc., are contained in a process cartridge 3, which is removably provided in the device main body. In addition, the upper case 1 is opened upuward through an opening member, for instance, a hinge, provided on the back surface perpendicular to the image carrier drum axis of a device main body 2, the process cartridge 3 is pulled out forward by opening a door H provided in front surface to be replaced. Therefore, attaching/detaching of the process cartridge, the replacement of other parts, jam processing, etc., can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus such as a color printer or a color copying machine, and more particularly to a color image forming apparatus employing a color process cartridge.

[Conventional technology]

In conventional electrophotographic copying machines and the like, image forming materials involved in image formation wear out and deteriorate as they are used, and eventually reach their usage limit. Generally, on the user side, it is difficult to judge the usage limit of the image forming equipment, and therefore, unreasonable copying operations exceeding the limit are performed. As a result, the copy quality is always unstable, the service work on the manufacturer's side becomes complicated, and it becomes difficult to maintain quality assurance. Furthermore, there are also disadvantages such as a shortened lifespan due to overuse of copying machines and the like.

Therefore, the image forming equipment that wears out and deteriorates, such as an image carrier, a developing device, a cleaning device, etc., is configured as a process car 1-ridge, and the cartridge is removably inserted into the main body of the device, and the amount of developer in the developing device is A device for pulling out the cartridge and making it disposable is disclosed in, for example, JP-A-58-202459 and JP-A-59-3454.
This method is well known and is described in Japanese Patent Application Laid-open No. 8, No. 58721.59, and the like. Also, the above-mentioned Japanese Patent Application Laid-Open No. 58-7215
No. 9 also discloses a color copying machine having a color process cartridge including an image carrier drum, a charger, a plurality of developing devices for 2J color, a cleaning device, and the like.

[Problem to be solved by the invention]

By the way, the devices described in each of the above-mentioned publications have a clamshell structure, and after the upper case is opened upward relative to the main body of the device, if the process cartridge is installed in the upper case, it is pulled down diagonally downward. If the process cartridge is installed in the lower housing, it is removed by being pulled up diagonally upward.

The upper casing is opened and closed via a hinge provided on one side edge of the apparatus main body parallel to the image carrier drum axis, and the process cartridge is opened and closed between the other side edge of the apparatus main body and the open end of the upper casing. It is inserted and removed diagonally through the space. Therefore, it is difficult to insert and remove the process cartridge, and when the upper case is opened, the space near the hinge is narrow, making it difficult to replace parts in the vicinity, especially clearing jams.

Furthermore, in the devices disclosed in each of the above-mentioned publications, the transfer paper conveyance and transfer means are located below the process cartridge, so they are easily contaminated by leaked toner from the developing device and the Kling device, especially when the process cartridge is inserted or removed. When the transfer paper transport path becomes contaminated, the image quality deteriorates. Furthermore, in the color process cartridge described in Japanese Patent Application Laid-Open No. 5872159, since a plurality of thin developing devices are stacked horizontally, toner leakage is likely to occur, resulting in color mixing of various color toners. This method has disadvantages such as a tendency to cause color turbidity in color images and a decrease in resolution.

[Means to solve the problem]

(Object of the Invention) The present invention has been proposed in view of the above-mentioned circumstances, and its purpose is to provide a compact, easy-to-maintain color image quality guarantee and easy to maintain, as well as easy jam removal, parts replacement, etc. The object of the present invention is to provide a light-weight color image forming apparatus.

(Structure and operation of the invention) The object is to provide a color image forming apparatus having a charger, a plurality of developing devices, a cleaning device, and a transfer means on the periphery of the image carrier drum, in which the image carrier drum, the charger,
A process cartridge containing a cleaning device and a plurality of developing units disposed below the image carrier tram is removably inserted into the apparatus main body, and is provided on a back surface of the apparatus main body perpendicular to the image carrier drum axis. Through the opening and closing section,
The upper housing including the transfer means is configured to be openable to the apparatus main body, and a door is provided in the front of the apparatus main body,
This is achieved by a color image forming apparatus characterized in that the cartridge can be inserted and removed from the front when the door is opened.

The color image forming apparatus of the present invention has an image bearing drum as a center, a charger, yellow (Y), and magenta (M).

A plurality of individually separated or integrally unitized developing units of black (C) and black (BK), a clinging device, and if necessary a waste toner collection container are included in the process cartridge. can be inserted into and removed from the main body of the device. In addition, the process cartridge has an opening provided on the back side perpendicular to the image carrier drum axis of the main body of the apparatus. For example, after opening the upper case upward via a hinge, open the front door provided on the front side toward you. When opened, it is pulled forward and replaced.

With such a configuration, advantages such as easy insertion and removal of the process cartridge, replacement of other parts, jam removal, etc. can be obtained.

Further, the plurality of developing devices included in the process cartridge are arranged vertically below the image bearing drum so as to surround the bottom surface of the drum, with the openings facing upward, thereby preventing toner leakage, color mixing, etc. The structure is designed to prevent this from occurring. As the transfer means, a transfer belt with stable performance and high transfer efficiency is disposed in the upper housing. In the present invention, it is preferable to use the method described in JP-A-50-76766, in which toner images of each color are formed in a superimposed manner on an image bearing drum, and the toner images are transferred and fixed all at once onto a transfer paper to form a color image. In this case, the transfer belt is particularly advantageous because the transfer efficiency is uneven.

Next, in order to ensure a long usage period until the process cartridge is replaced, a toner replenishment device is installed on the main body of the apparatus, and the toner is continuously replenished to the developing device in the cartridge. preferable.

Further, it is preferable that a container for collecting waste toner scraped and collected from the image bearing drum after transfer by a cleaning device is provided in the process cartridge.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto.

1 to 5 are diagrams for explaining this embodiment, and the first
The figure is a sectional view of the printer of this embodiment, and FIG. 2 is a perspective view of the printer. The illustrated printer has a Talamusiel-type structure divided into an upper housing 1 and a main body 2, and the upper housing 1 is opened at a predetermined angle (60°) about a hinge IA connected to the main body 2. When the lid is closed, it is locked integrally with the device main body 2 by a stopper (not shown).

Image carrier drum 30, charger 35, Y, M, C, B
K developing device, pre-transfer charger 9, cleaning device 40
A guide member 4 is provided on the bottom of the process cartridge 3 that integrally houses various equipment such as a toner collection container 47 and the like.
It is removably attached to the inside of the device main body 2 via 6.

To insert/remove the process cartridge into/from the main body 2 of the apparatus, as shown in FIG.
After opening the front door H upward using the hinge IB as a fulcrum, grasp the knob M and open it forward as indicated by H', then hold the handle provided on the front and pull the cartridge 3 forward. The drawer main body 2 is also detached.

To attach the cartridge 3 to the main body 2 of the device, it is enough to perform the reverse operation when removing it. After installing the IJ cartridge 3, close the front door H, and then close the upper case 1. Then, the image forming state is established.

In this way, it becomes possible to insert and remove process cartridges and other image forming equipment, clear jams, etc. all from the front, resulting in excellent ergonomic operability.

In particular, there are advantages in that it is easy to insert and remove the process cartridge, and it is also easy to handle jams in all paper transport paths. Note that a jam on the paper conveyance path on the side of the apparatus main body 2 is handled by opening the side cover (left side in the drawing) 5 outward with the hinge IC as a fulcrum. Further, a jam near the paper ejection port is cleared by opening the side cover (on the right side of the drawing) 6 outward with the hinge ID as a fulcrum.

Next, the Y, IV[, C, and BK developing devices are integrated so that the adjacent developing devices share the wall surface of the housing, and are arranged so as to wrap around the lower surface of the image bearing drum 30, and the developing roller ( 36a, 37a, 38a, 39a
) is arranged vertically with the opening facing upward. Therefore, the stirring rolls (36b, 36c, 37b) in each developing device are
, 37c.

381), 38c, 39b, 39c), the agitation and frictional charging efficiency of the developer is high, resulting in excellent developability, as well as less leakage of the developer, which prevents negative effects such as environmental pollution and color mixing. There are also advantages such as being Furthermore, the apparatus has the advantage that it can be packed compactly, the center of gravity is located relatively downward, and the apparatus can be stabilized during image formation.

In the printer of this embodiment, the laser writing system unit B is disposed in a space on the side of the process cartridge 3, and the transfer material conveyance surface is disposed in a portion spanning both the upper housing 1 and the main body 2 of the apparatus. The image carrier drum 30 is subjected to laser scanning by the laser writing unit B from diagonally downward, and a color toner image formed on the circumferential surface thereof is transferred to the lower surface of the transfer material. There is.

In this way, the transfer paper is conveyed horizontally above the process cartridge 3, and since the surface to be transferred faces downward, there is an advantage that the problem of screen contamination due to toner scattering from the cleaning device 40 or the like is extremely small. occurs.

Next, the image forming process of the printer of FIG. 1 in this example was carried out as follows.

That is, when the video signal A consisting of each color signal outputted from an image reading device separate from the printer is input to the laser writing system unit B, the semiconductor laser 100 in the laser writing system unit L-H The generated laser beam is rotated and scanned by a polygon mirror 32 rotated by a drive motor 31, and is scanned by an f-θ lens 33.
The light path is bent by three mirrors 34A, 34B, and 34c, and the light is projected onto the circumferential surface of the image carrier drum 30, to which a charge of 1,700 V is applied in advance by the charger 35.

On the other hand, when heam scanning is started, the laser beam is detected by the index sensor, modulation of the laser beam by the first color signal is started, and the modulated laser beam is scanned over the circumferential surface of the image carrier drum 30. Ta. Here, by main scanning by the laser beam and sub-scanning by the rotation of the image carrier drum 30, a latent image of the first color is formed on the circumferential surface during the first rotation of the drum 30. This latent image was developed by the Y developing device 36, and a Y toner image was formed on the circumferential surface of the image carrier drum 30. The obtained Y toner image, while being held on the circumferential surface of the image carrier drum 30, passes under a cleaning device 40 that is spaced apart from the circumferential surface of the drum 30, and is transferred to image formation using the next color signal. .

That is, in the second rotation of the image carrier drum 30, the drum 30 is charged again by the charger 35, and the second rotation is performed.
The color signal is input to the writing system unit B, and the image carrier drum 3
Writing was performed on the zero peripheral surface and a latent image was formed. This latent image was developed by the M developing device 37. This M l-toner image was formed on top of the previously formed Y toner image.

Next, in the third and fourth rotations of the image bearing drum 30, CI-
toner image and BK) toner image is the Y toner image and M
A color toner image was formed by superimposing the color toner image on the h toner image.

Note that each developing device has a DC component of -600V and a DC component of 3K.
A developing bias consisting of an alternating current component of 500 Hz was applied, and development was carried out using a two-component developer using a non-contact reversal development method.

In this way, the color toner image formed on the circumferential surface of the image carrier drum 30 is transferred to the paper feed cassette and the cartridge C in the transfer section.
The image was transferred onto the lower surface of the transfer paper fed through the paper feed roller 12 and the paper feed guide.

That is, after this color toner image is charged by the pre-transfer charger 9 to be easily transferred, the transfer belt 50 used as a transfer means, which has been rotating since the start of transfer, is brought into contact with the image carrier drum 30 and fed. The image was transferred to a transfer paper supplied from the paper cassette C via the paper feed roller 12 and the timing roller 13 in synchronization with the image formation.

The transfer paper belt 50 is stretched between a roller 59 and a roller 60, and the image carrier drum 3 is rotated by the rotation of the roller 60.
It is rotated in synchronization with the circumferential speed of 0, and the roller 58
By moving up and down, the drum 30 is separated from or brought into contact with the drum 30.

The roller 58 is attached to a lever 57 that can swing around the axis of the roller 60 as a fulcrum.
The image carrier drum 30 is held in the upper position shown by the solid line by an elastic member that urges the image carrier drum 30, but the transfer belt 50 is held in the lower position shown by the dashed line 2 by the power of a renoid or the like that operates at the timing of transfer. was moved to a position where it came into pressure contact with the circumferential surface of the

The structure of the transfer belt 50 used as the transfer means is as follows: (a) A rubber belt or a similar belt-like member is used as a base, and (b) An elastic layer of silicone rubber or polyurethane with a thickness of about 0.5 to 5 mm is provided around the base. Place conductive rubber such as rubber or butyl rubber.

The resistivity of the conductive rubber is preferably 10 10 Ω·Cm or less, more preferably 10 7 Ω·Cm or less. Hardness is 2
It is desirable that the angle be 0 to 80 degrees JIS standard (K 6301/A type). In addition, in order to prevent the applied bias voltage from leaking from scratches on the image forming body drum 30 and widening the scratches, and from being unable to generate a sufficient electric field in the transfer section, it is necessary to ) On top of that, the thickness is 10~
It is desirable to provide a dielectric layer with a thickness of about 100 μm or a high resistance layer with a resistance of 10”Ω·cm or more. In either case, in order to maintain good adhesion with the image bearing drum 30, the surface roughness should be set at 20 μm. It is desirable that the distance be less than /1m.

The transfer belt 50 was charged by the transfer device 51, and a transfer charge having an inverse ai property to that of the toner was applied to perform the transfer. Note that in order to remove toner adhering to the surface of the transfer belt 50, if necessary, a cleaning device exclusively for the transfer belt 50 may be provided and a blade may be brought into pressure contact with the belt surface to perform cleaning.

The transfer paper, onto which the color toner image has been transferred, is separated from the circumferential surface of the image carrier drum 30 and conveyed to a fixing section, where the toner is melted and fixed by a fixing roller 80 that rotates at a speed synchronized with the conveyance speed. Thereafter, it was discharged to the outside of the machine via the paper discharge roller 90.

The image carrier drum 30 from which the transfer material was separated was cleaned and removed of residual toner by a cleaning device 1401.

FIG. 4 shows a charger 35, developing devices 36, 37, 38, and 39, and a cleaning device 40, which constitute the image forming section of the color process cartridge 3 shown in FIG.
3 shows the positional relationship of each piece of equipment, such as the blade 40A, with respect to the image carrier drum 30.

The image carrier drum 30 is assumed to rotate clockwise in the figure, and the phase of the rotation at which the cleaning action has been completed is set as the reference position S, and the clockwise direction of the rotation is sequentially moved to positions facing the circumferential surface at the angular intervals shown in the figure. Each image forming equipment was placed at

In this case, the processes of charging, latent image formation, toner image formation, transfer, and cleaning of residual toner will proceed according to the time chart 1- shown in FIG. One cycle of image copying was completed after the cleaning operation was completed.

In the cleaning device 40, the image carrier drum 3
The waste toner that has been removed from the cartridge 0 and collected in the collection section is transferred to a waste toner conveying pipe 41 installed on the front surface of the process cartridge 3.
The waste toner is then collected in a waste toner collection box 47 attached to the process cartridge 3.

The waste toner transport pipe 41 has a built-in flexible waste toner transport screw 42 which is rotated by the power system of the apparatus main body 2 or the upper housing 1, and the waste toner is transported by the propulsive force generated by the rotation of the flexible waste toner transport screw 42. is transported.

Note that, for the waste toner conveying pipe 41, a pipe section molded from a synthetic resin material with excellent mold releasability was used so as not to provide resistance to the operation of the waste toner conveying screw 42.

Note that when installing the process cartridge 3 into the apparatus main body 2, the connection terminal for the electrical system provided on the outside of the back surface in the rear direction of the process cartridge 3, the rotating shaft of the image carrier drum 30 and the developing unit 36 that protrude from the back surface of the process cartridge 3 are connected. A rotating shaft for transmitting power to 39, etc. is connected to a connecting terminal provided on the device main body 2 and a power shaft.

In addition, as shown in FIG. 5, by operating the keys on the upper panel of the printer, the CPU accesses the program memory in which image forming programs such as monochrome, 2-color, 3-color, and 4-color are stored.
The imaging process may be selectively controlled via.

Further, the structure of the developing device will be described in detail below.
6, 37, 38, and 39 are distributed to the left and right with respect to the center line of the image bearing drum 30, that is, the developing units 36 and 37 are on the right side, and the developing unit 38 is on the right side with respect to the axis of the drum 30. 39 are arranged at symmetrical positions on the left side, and furthermore, the developing sleeves of the developing units 36 and 37 arranged on the right side are arranged clockwise, and the developing sleeves of the developing units 38 and 39 arranged on the left side are arranged clockwise. Each image is developed by rotating the sleeve counterclockwise.

By arranging the developing device group in this manner and also by rotating the developing sleeve in the opposite direction, the process cartridge 3 has a well-balanced left and right balance in terms of weight and power transmission, making it easy to handle. The occurrence of harmful vibrations is also prevented.

Also, each developing device 36, 3738 placed at a symmetrical position on the left and right.
．． 39 can have the same structure, and the toner is scraped off from the developing sleeve after the developing action is completed very efficiently due to the action of gravity, so that a fresh and appropriate amount of 1. It has the advantage of being able to supply energy.

Further, each of the developing units is provided with toner replenishment hoppers 61, 62, 63, and 64 at the back rear of the apparatus main body 2, and a toner replenishing pipe (not shown) connects the process cartridge 3 and each of the developing units in the car 1 to the cartridge. connected to the developing chamber.

In this embodiment, when the process cartridge 3 (7) is installed, it is connected to the toner supply pipe, and when the cartridge 3 is removed, the toner supply pipe is disconnected, and at the same time its opening is closed.

Although a color printer is illustrated in this embodiment, a color copying machine may also be used by integrally combining a color scanner.

〔Effect of the invention〕

As is clear from the above description, according to the color image forming apparatus of the present invention, quality assurance of color images is ensured by employing a color process cartridge, maintenance is easy, and proper arrangement and suitability of image forming equipment are achieved. Adoption of a Ramun-El structure made it easier to clear jams and replace parts, and the device was made more compact.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of the printer of the embodiment;
The figure shows the image forming timer 1, Figure 4 shows an example of the arrangement of each equipment in the process nozzle cartridge for the nozzle, and Figure 5
The figure is an image forming program control diagram. 1... Upper casing l A, l B, I C5l D... Hinge 2... Device main body H (H')... Front door 3... Flossing unit for color 4... Guide Element
9... Pre-transfer charger 30... Image carrier drum 3
6, 37, 38, 39...Developer 40/Cleaning device 40A...Blade old...I/Toner transport tube 47...Toner collection box 50...Transfer belt 51-1 Transfer device 80... Fixing roller B Laser writing system unit C...Paper feed force cera 1~

Claims (1)

[Claims] In a color image forming apparatus having a charger, a plurality of developing devices, a cleaning device, and a transfer device on the periphery of an image carrier drum, the image carrier drum, the charger, the cleaning device, and the image carrier drum are arranged below the image carrier drum. A process cartridge containing a plurality of developing devices is installed in the main body of the apparatus in a freely insertable and removable manner, and the upper casing containing the transfer means is opened via an opening/closing member provided on the back surface of the main body perpendicular to the axis of the image carrier drum. A color image forming apparatus characterized in that a body is configured to be openable to the apparatus main body, a door is provided on the front of the apparatus main body, and the cartridge can be inserted and removed from the front when the door is opened.