JPH0746937Y2 - Electrophotographic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electrophotographic apparatus provided with means suitable for maintenance and replacement of an electrostatic latent image carrier and members arranged in the vicinity thereof. .

[Conventional technology]

In an electrophotographic apparatus, a photosensitive member, which is an electrostatic latent image carrier, is arranged in the center of the main body of the apparatus, and a charger for applying an electric charge, an optical system for giving an original image, and an electrostatic latent image are developed around the photosensitive member. There is provided a developing device for performing the above operation, a transfer portion for transferring the toner image developed by the developing device onto a transfer sheet, a cleaning cartridge for removing the residual toner on the photoconductor, and the like.

As described above, the photoconductor and each of the constituent members arranged around the photoconductor include a consumable item having a predetermined life. The replacement, this replacement, and the adjustment of the positions between the members based on the [-] replacement are required.

For this reason, Japanese Patent Laid-Open No. 51-2433 discloses a means in which a photoreceptor, a developing device, and a cleaning cartridge are integrally incorporated into a single housing and can be attached to and detached from the apparatus main body.

[Problems to be solved by the device]

In the prior art as described above, since the photosensitive member and the main members in the vicinity thereof are integrally replaced and replaced, among the members having different lifespans, the member having the shortest lifespan is replaced and replaced as a reference. The running cost per copy increases. Further, among these members, since the capacity of the waste toner of the cleaning cartridge is small, if it is attempted to match the life required for exchanging other members, the waste toner container of the cleaning cartridge must be increased in size. For this reason, the entire unit to be replaced becomes large, the weight increases, and the operability for the user deteriorates.

The present invention aims to eliminate the above-mentioned conventional drawbacks,
An object of the present invention is to provide a structure suitable for exchanging a constituent member that matches the life of the photosensitive member together with the photosensitive member in an electrophotographic apparatus while maintaining a predetermined positional relationship. It is an object of the present invention to provide means with good operability that can easily maintain the positioning of each component between the cartridges, and particularly, to accurately position the photosensitive member and the developing roller, and between the developing roller and the toner supply roller. Keeps the image quality constant and is compact, copy 1
It provides a means for reducing the running cost per sheet.

[Means for Solving the Problems]

In order to achieve the above object, the present invention supplies a developer to a developer carrying member, forms a constant developer layer on the developer carrying member, and forms a static latent image on the electrostatic latent image carrying member. An electrophotographic apparatus for developing an electrostatic latent image with the developer carrying member, transferring the toner image on the electrostatic latent image carrying member to a transfer material, and cleaning the toner remaining on the electrostatic latent image carrying member. The first cartridge supporting the electrostatic latent image carrier, the developer carrier, and the developer layer forming member that regulates the developer layer of the developer carrier in a predetermined positional relationship is attached to and detached from the apparatus main body. A second cartridge supporting an agitating member and a toner supply member composed of an elastic surface layer for accommodating a predetermined amount of toner in the first cartridge and supplying the toner to the developer carrying member is detachable. Attached and the first cartridge Positioning means for supporting the second cartridge, in that a pressurizing means for pressing the toner supply member of the second cartridge to the side of the developer carrying member, wherein the.

[Action]

With the configuration of the present invention, an electrostatic latent image carrier, a developer carrier,
The three developer layer forming members that are in contact with the developer carrying member are integrally positioned and supported by the first cartridge, and the first cartridge is attached to and detached from the apparatus main body.
Can be exchanged, the electrostatic latent image carrier and the developer carrier,
The developer carrier and the developer layer forming member are integrated with each other at the minimum required accuracy of position, and by having the same life, maintenance and replacement operability by the user is improved, and the apparatus is improved. Helps reduce overall size and cost.

Then, a second cartridge having a toner supply roller and containing a toner that is frequently exchanged is detachably attached to the first cartridge, and when the second cartridge is attached to the first cartridge, a developer carrier The toner supply roller can be accurately positioned with respect to.

〔Example〕

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

FIG. 1 shows a sectional view of an image forming portion of a laser printer as an example of an electrophotographic apparatus. Around the photosensitive drum 1 serving as an electrostatic latent image carrier, a charger 2 and a writing unit 3 capable of writing image information composed of laser light on the surface of the charged photosensitive drum 1 are written by the writing unit 3. A developing unit 4 for developing the latent image, a transfer unit (not shown) for transferring the toner image formed by the developing unit 4 onto a transfer sheet, and a cleaning cartridge 5 for cleaning the toner remaining on the surface of the photosensitive drum 1 after the transfer. Are arranged.

The developing unit 4 supplies toner to the surface of the photoconductor drum 1, and contacts the surface of the photoconductor drum 1 with a developing roller 6 as a developer carrying member positioned with a minute gap, and the toner in the toner cartridge 7. A toner supply roller 8 made of an elastic material such as polyurethane foam and supplied to the developing roller 6, and a developer layer for frictionally charging the toner supplied to the developing roller 6 to form a uniform thin layer. The forming blade 9 is composed of a toner cartridge 7 having an agitator 10 which is always slowly rotating so as to prevent toner blocking in order to replenish toner.

In the cleaning cartridge 5, a blade 11 pressed against the surface of the photosensitive drum 1 is held by a holder 12 via a spindle 12.
The toner remaining on the surface of the photoconductor drum 1, which is supported by 13, can be scraped off and the removed toner can be stored.

In the electrophotographic apparatus of the present invention, the image forming portion shown in FIG. 1 which is detachable from the apparatus main body is shown in FIG. 2 in a separated state.

The machine frame portion 14 which is the first cartridge that integrally houses the photosensitive drum 1 and a part of the developing portion 4 and the cleaning cartridge 5 are independently attached to and detached from the apparatus main body. On the other hand, the toner cartridge as the second cartridge is attached and detached.

The configuration of the machine frame portion 14 corresponding to the first cartridge that is attached to and detached from the apparatus body will be described. The photosensitive drum 1 is rotatably supported by the machine frame portion 14, and the developing roller 6 is rotatably supported by providing a contact or a minute gap with the surface of the photosensitive drum 1. In addition, the developing roller 6
The developer layer forming blade 9 pressed against the roller is supported by the pressure spring 15 and the sealing material 16 provided in the recess 14a formed in the machine frame 14 while being biased toward the developing roller 6 side. There is. It should be noted that the machine frame portion 14 has openings formed at portions corresponding to the transfer portion and the cleaning portion of the photosensitive drum 1, and the charger 2 is provided at a position corresponding to the photosensitive drum 1.

The machine frame portion 14 (FIG. 2 (A)) having such a configuration has a second
As shown in FIG. 2B, a toner cartridge 7 corresponding to a second cartridge that supports a toner supply roller 8 that rotates in the direction of the arrow and that is equipped with an agitator 10 and that can replenish toner is detachably supported.

Therefore, a toner cartridge mounting portion 14b is formed at the rear of the machine frame portion 14, and the toner cartridge mounting portion 14b is formed.
In addition, a sealing material 17 having high elasticity is attached to the inner surface thereof, and the detachable toner cartridge 7 can be elastically held. The toner supply roller 8 provided in the toner cartridge 7 is attached to the toner cartridge 7 so as to scrape off the toner remaining on the developing roller 6 and supply the toner in the toner cartridge 7.

Further, FIG. 3 shows a positioning means for the toner cartridge 7 supported by the toner cartridge mounting portion 14b of the machine frame portion 14.

This positioning means is provided in the shaft 8a of the toner supply roller 8 located below the toner cartridge 7 side, the positioning pin 18 provided above the toner cartridge 7, and the toner cartridge mounting portion 14b of the machine frame portion 14. The positioning guide members 19a and 19b are made of an elastic material and have a concave locking portion so as to support the shaft 8a of the toner supply roller 8 and the positioning pin 18. It has a different shape. Therefore, by mounting the toner cartridge 7 on the toner cartridge mounting portion 14b from above, the toner cartridge 7 is mounted at a predetermined position in the machine frame portion 14.

When the toner cartridge 7 is mounted in the toner cartridge mounting portion 14b, the pressure spring 20 as a pressing member that presses the toner supply roller 8 provided in the toner cartridge 7 toward the developing roller 6 is
It is provided on the side wall of 14b. 21 is a developing roller gear, 22
Is an idle gear, and 23 is a toner supply roller gear, and the idle supply gear 22 and the toner supply roller gear 23 driven by the developing roller gear 21 can accurately mesh with each other to drive the toner supply roller gear 23.

In such an embodiment of the present invention, the machine frame portion 14 as the first cartridge is provided with the photoconductor drum 1, the developing roller 6, and the developer layer forming blade 9 in a predetermined positional relationship, and has a long life. It is easy to replace these members having the same structure, and even when they are mounted, the machine frame portion 14 in which the positional relationship of the three members is regulated in advance is simply attached to the apparatus main body, and the operability for maintenance and replacement by the user is good.

As the number of copies (the number of prints) increases, the photoconductor drum deteriorates in electrostatic characteristics and the charging potential decreases, and the developing roller wears on the surface and filming of toner on the surface due to heat or pressure occurs. The agent layer forming blade is not able to form a uniform developer layer on the surface of the developing roller due to abrasion and toner sticking. Normally, these durable sheets are 6 ~
The configuration of the present invention is useful because it has a level of 200,000 sheets and can be used for a much longer period than the practical replacement time of the cleaning cartridge and toner cartridge.

Then, the toner cartridge can be arranged at a predetermined position by the positioning member and the pressure member with respect to the machine frame portion 14 provided with the photosensitive drum 1, the developing roller 6, and the developer layer forming blade 9. The toner supply roller provided can be positioned and arranged with respect to the developing roller.

In the embodiment shown in FIGS. 4 and 5, there is shown a means for always maintaining a uniform contact state between the developing roller and the toner supply roller when the toner cartridge 7 is attached to or detached from the machine frame portion 14.

FIG. 4 is a top view showing the positioning means between the developing roller 6 and the toner supply roller 8 when the toner cartridge 7 is attached to the machine frame portion 14, and FIG. FIG. 6 is a partial state diagram of the toner supply roller 8 before mounting.

The difference from the embodiment shown in FIG. 3 is that spacer rollers are provided at both ends of the rotary shaft 24 of the toner supply roller 8 made of an elastic material.
25, 25 are rotatably supported on the rotary shaft 24,
In this case, the outer diameter d ₁ of the spacer rollers 25, 25 is set to be smaller than the outer diameter d ₂ of the toner supply roller 8 (the fifth).
Figure).

When the toner cartridge 7 having such a toner supply roller 8 is attached to the machine frame portion 14, the toner cartridge 7
Presses the toner supply roller 8 against the developing roller 6 by the pressure spring 20. At this time, the spacer rollers 25, 2
The outer peripheral surface of 5 is set at a position where it contacts the outer peripheral surface of the developing roller 6. In this case, the amount of the toner supply roller 8 biting into the developing roller 6 is (d _2-
It can be set to d ₁ ) / 2.

A predetermined amount of toner is hermetically sealed in the toner cartridge 7, and when the toner runs out, the toner cartridge 7 is removed from the machine frame portion 14, and a new toner cartridge 7 is attached to the machine frame portion 14, At this time, the spacer roller comes into contact with the developing roller by the positioning by the positioning means and the pressing of the pressing member. In this way, the machine frame
When the toner cartridge 7 is attached to 14, the toner supply roller can be attached in a state where the toner supply roller is accurately set to the developing roller.

In this way, the contact state between the developing roller and the toner supply roller is maintained and the contact pressure is non-uniform in the longitudinal direction of the shaft regardless of whether the first cartridge is replaced or the second cartridge is replaced with the first cartridge. In addition, the contact pressure can always be maintained uniformly without causing torque increase due to excessive bite amount, the occurrence of jitter due to this can be prevented, and stable toner supply and charging can be achieved. Uniform image quality can be obtained in the non-magnetic one-component developing system.

FIGS. 6 to 8 are provided with means for bringing the photosensitive drum into contact with the developing roller uniformly and with high precision in the structure of the embodiment shown in FIGS. 4 and 5, and between the two cartridges. The means for smoothly attaching and detaching is shown.

In this embodiment, the developing roller has a JI
Using rubber material such as NBR and urethane with SA hardness of 30-40 degrees,
The developing roller 6 is driven at a speed twice the linear speed of the photosensitive drum 1.

The developing roller 6 has a shaft portion at both ends thereof axially supported by a bearing portion 26 provided on the machine frame portion 14, and the both end shaft portions are provided with a second spacer roller 27, which is rotatable with respect to the shaft portion. 27 are provided. The second spacer rollers 27, 27 have an outer diameter D ₁ smaller than the outer diameter D ₂ of the developing roller 6 before being mounted on the machine frame portion 14 (FIG. 8). As described above, the shaft of the toner supply roller 8 is supported by the toner cartridge 7, and the shaft of the toner supply roller 8 has an outer diameter d ₂ of the toner supply roller 8.
First spacer roller 25,25 with smaller outer diameter d ₁
Are provided (FIG. 5).

When the toner cartridge 7 is mounted on the machine frame 14, the pressure spring 20 presses the first spacer rollers 25, 25 against the second spacer rollers 27, 27 so that the developing roller 6 and the toner supply roller 8 come into contact with each other. Maintained in a state.

Further, the shaft portion 28 of the photosensitive drum 1 is rotatably supported by a bearing portion 29, and the bearing portion 29 is provided in the elongated hole 30 formed in the machine frame portion 14 by a pressure spring 31 so as to develop the developing roller 6.
Therefore, the photosensitive drum 1 is positioned with respect to the developing roller 6 so that its surface contacts the second spacer rollers 27, 27 of the developing roller 6.
In this case, the developing roller 6 having elasticity is the photosensitive drum 1
On the other hand, the bite amount of (D ₂ -D ₁ ) / 2 is set accurately.

Since the developing roller 6 and the toner supply roller 8 are spacer rollers each having a diameter smaller than that of the elastic surface, the biting amount is (D ₂ -D ₁ ) / 2 + (d ₂ -d ₁ ) / 2 in the meantime. Can be set accurately.

As described above, in the embodiment of the present invention, when the toner cartridge which is frequently replaced is attached to and detached from the machine frame portion which is provided with the photosensitive drum and the developing roller which are less frequently replaced, Positioning can be performed between the roller and between the developing roller and the toner supply roller. Therefore, even when the machine frame, which is the first cartridge, or the toner cartridge, which is the second cartridge, is repeatedly replaced with respect to the machine frame, the development between the photosensitive drum and the developing roller is performed. A uniform contact can always be maintained between the roller and the toner supply roller, and a high-quality image can be obtained.

In addition, the photosensitive drum and the toner cartridge are respectively pressed around the developing roller, and the photosensitive drum is attached to the developing roller and the machine frame portion in which the developer layer forming blade is arranged at a predetermined position with respect to the developing roller. By movably supporting, the positional relationship among the photosensitive drum, the developing roller, and the developer layer forming blade in the first cartridge can be easily secured.

Further, since spacer rollers provided at both ends of the shaft portion of the developing roller and both ends of the toner supply roller are rotatably arranged with respect to the rotating shaft portion, the photosensitive drum, the developing roller, and the toner supply Even if the rotation speeds of the rollers are different, the two spacer rollers rotate at a constant speed through the spacer rollers that contact the photoconductor drum, improving the wear resistance of the contact area and maintaining a constant bite amount over a long period of time. Can be maintained.

[Effect of device]

With the configuration of the present invention, in the electrophotographic apparatus, a member that makes the time required for replacement and replacement approximately the same is positioned and attached to a single cartridge, and is separate from the toner cartridge and the cleaning cartridge that have different replacement and replacement times. In addition, the toner of the present invention has the effects of reducing the size of the entire apparatus, facilitating maintenance and replacement, lowering the running cost per copy, and frequently replacing toner in the cartridge including the photosensitive drum and the developing roller. This has an effect that the cartridge can be easily attached and detached and the positioning between the respective members can be accurately attached.

[Brief description of drawings]

FIG. 1 is a sectional view of an image forming portion of an electrophotographic apparatus to which the present invention is applied, and FIGS. 2 (a), (b) and (c) show the image forming portion of FIG. 1 separated for each removable component. Sectional views, FIGS. 3 (a) and 3 (b) are separated sectional views showing the positioning means between the two cartridges of the present invention, and FIG. 4 shows the positioning means between the developing roller and the toner supply roller of the present invention. Top view, FIG. 5 is a partial sectional view of the toner supply roller used in FIG. 4, and FIGS. 6A and 6B are separate sectional views showing other positioning means between two cartridges of the present invention. FIG. 7 is a top view showing the positioning means between the photosensitive drum, the developing roller and the toner supplying roller of the present invention, and FIG. 8 is a partial sectional view of the developing roller used in FIG. 1 ... Photosensitive drum, 6 ... Developing roller, 7 ... Toner cartridge (second cartridge), 8 ... Toner supply roller, 9 ... Developer layer forming blade, 14 ... Machine frame (first cartridge) ), 17 …… Seal material on the inner surface of the machine frame,
20: Pressure spring, 25: Spacer roller provided on the shaft of the toner supply roller, 27 ... Spacer roller provided on the shaft of the developing roller.

Claims (4)

[Scope of utility model registration request] 1. A developer carrier is supplied with a developer, a constant developer layer is formed on the developer carrier, and the electrostatic latent image formed on the electrostatic latent image carrier is carried by the developer carrier. In the electrophotographic apparatus, the toner image on the electrostatic latent image carrier is transferred to a transfer material while being developed by the body, and the toner remaining on the electrostatic latent image carrier is cleaned. A first cartridge that removably supports the developer carrier and a developer layer forming member that regulates a developer layer of the developer carrier in a predetermined positional relationship is provided in the apparatus main body; The cartridge stores a certain amount of toner,
Positioning means for detachably mounting a second cartridge supporting a toner supply member composed of an elastic surface layer for supplying toner to the developer carrying member and an agitating member, and supporting the second cartridge in the first cartridge. And an applying unit for pressing the toner supply member of the second cartridge to the developer carrying member side. 2. A spacer roller having a diameter smaller than the outer diameter of the toner supply member, which is in contact with both ends of the outer peripheral surface of the developer carrying member, is provided at both ends of the shaft portion of the toner supply member. The described electrophotographic apparatus. 3. A spacer roller having a diameter smaller than the outer diameter of the developer bearing member, which is in contact with both ends of the outer peripheral surface of the electrostatic latent image bearing member, is provided at both ends of the shaft portion of the developer bearing member. The electrophotographic apparatus according to claim 1. 4. The electrophotographic apparatus according to claim 2, wherein the spacer roller is rotatable with respect to a rotary shaft portion.