JP2662528B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an electrostatic storage device such as an electrophotographic copying machine.

BACKGROUND OF THE INVENTION

Generally, in an electrostatic recording apparatus such as an electrophotographic copying machine, a rotating drum type photoreceptor having a photoconductive photosensitive layer on an outer peripheral surface is used, and after the photoreceptor is charged, image exposure is performed while rotating. An electrostatic latent image of a document image is formed on the photosensitive layer, developed with toner, and the obtained toner image is transferred to a recording paper or the like to obtain a target recorded material. As shown in FIG. 8, the developing device in the electrostatic recording device such as the electrophotographic copying machine has a fixed magnet built in a housing 2 facing the photosensitive drum 1 so as to be in close proximity to the photosensitive drum 1. The developing sleeve 3 is provided. While the developer mixed and stirred in the housing 2 is conveyed on the peripheral surface of the developing sleeve 3, the toner in the developer is electrostatically attracted to the electrostatic latent image formed on the surface of the photosensitive drum 1. Let it. That is, the electrostatic latent image is developed and visualized by the toner. The distance d between the developing sleeve 3 and the photosensitive drum 1 was kept constant. If the distance d is different, the generated electric field is not uniform, which affects the developability. Therefore, conventionally, in order to determine the interval d,
At the shaft end of the developing sleeve 3, there is provided a roller 4 having a diameter increased by a dimension corresponding to the distance d, and a means such as a spring (not shown) so as to apply the roller 4 to the surface of the photosensitive drum 1. The housing 2 was pressed toward the photosensitive drum 1 as shown by an arrow.

[Problems to be solved by the invention]

However, in the case of the above-mentioned developing device, the processing accuracy of the roller 4 is required, and since the roller 4 and the photosensitive drum 1 are always in contact and rotation, there are disadvantages such as damage to the drum surface being accelerated. In recent years, there is a type in which the entire image forming unit including the photosensitive drum and the developing device is unitized, and the unit is replaced for each color of toner so that a color copy can be easily made. To perform such a unitization, the photosensitive drum and the entire developing device are installed in the same housing, but only the developing sleeve is directed toward the photosensitive drum independently of the developer stirring plate and the like. It was not possible to take a configuration of pressing.

[Means for solving the problems]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and a photosensitive drum moving type developing device capable of maintaining an interval between a photosensitive drum and a developing sleeve without using a roller. It is intended to provide. The object is to provide a photoconductor drum rotatably supported and having a photoconductive layer on the outer peripheral surface, and to transport a developer to the outer peripheral surface of the photoconductor drum to visualize an electrostatic latent image. A developing sleeve provided opposite to the outer peripheral surface, a bearing member for pivotally supporting the photosensitive drum in the direction of the developing sleeve, and a residual toner by rubbing the outer peripheral surface of the photosensitive drum. A cleaning member to be removed, wherein the cleaning member applies a pressing force for pressing and moving the photosensitive drum in the direction of the developing sleeve. is there.

【Example】

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 10 denotes an image forming unit of a copying machine.
In the image forming unit 10, a charging unit 12, a developing unit 13, and a cleaning unit
14 are arranged. The transfer section is provided so as to correspond to the lower surface of the photoconductor drum 11, and this unit 10
Is not arranged. The developing section 13 includes a developing sleeve 15, a main stirring plate 16, and an auxiliary stirring plate 17. The developing sleeve 15 is disposed close to the photosensitive drum 11, and functions to electrostatically adsorb the toner in the developer to the drum surface and develop the electrostatic latent image as a toner image. The main stirring plate 16 has a rotating shaft 16
The developer (carrier and toner) is fixed at an angle to a (not shown in the figure), and the developer (carrier and toner) is stirred and mixed. Direction).
Further, the auxiliary stirring plate 17 mixes the toner supplied from the toner supply unit 18 with the developer circulating in the developing unit 13,
This is for feeding the main stirring plate 16 toward the installation site. Reference numeral 19 denotes a developer regulating blade fixed to the image forming unit, which regulates the thickness h of the developer layer D adhered to the surface of the developing sleeve 15 as shown in FIG. The toner replenishing section 18 includes a toner retaining chamber 21 in which the cartridge 20 is replaceably provided, and a toner replenishing chamber 23 communicating with an upper part of the toner retaining chamber 21 through an opening 22. A ladder chain 24 is installed, and the operation of the ladder chain 24 transfers the toner in the stagnant chamber 21 to the transport plate 24.
The toner is scooped up at a, so that the toner can be supplied from the upper opening 22 into the toner supply chamber 23. Then, the toner supply chamber 23
Is provided with a supply roller 25. By the rotation of the supply roller 25, toner can be supplied into the developing section through a gap between the supply roller 25 and a tongue 27 of an opening groove 26 provided on the lower surface of the supply chamber. In the present invention, the shaft support members 59 and 60 having a long hole having a long diameter in the horizontal direction are provided. The photoreceptor drum 11 has shafts 50, 50 protruding from both side end surfaces thereof, movably supported by the shaft support members 59, 60. As shown in FIGS. 3 and 4, the photosensitive drum 11 is provided on both side plates of the image forming unit 10.
The above-mentioned horizontal direction fixed to 10b, 10c is a long hole 59a, 60a with a long diameter.
Are movably supported to the developing sleeve 15 side via bearing members (not shown) such as bearings. Thus, a pressing force for pressing the photosensitive drum 11 against the developer layer D on the developing sleeve 15 as shown by an arrow a in FIG. 2 is applied by the cleaning blade 52 of the cleaning unit 14. That is, the cleaning blade 52 is supported on the front end side of the support member 53, and the rear end side is pressed by the spring 54 so that the hinge connecting portion 55
Is rotated in a counterclockwise direction around the photosensitive drum, and the biasing force makes sliding contact with the surface of the photoreceptor drum. Even if it escapes to the side, the sliding contact force of the cleaning blade 52 does not weaken. Here, the developer forming the developer layer D is a two-component developer composed of a mixture of a carrier and a toner. As shown in FIG. A repulsive force as shown by an arrow b is generated in response to the pressing. Therefore, as long as the thickness h of the developer layer D is kept constant on the developing sleeve 15 by the regulating blade 19, the developing sleeve 15
The distance d between the photosensitive drum 11 and the photosensitive drum 11 can maintain a dimension (0.3 to 0.5 mm) close to the regulated thickness h. Note that the moving range of the long hole of the photosensitive drum 11 in the major axis direction is about 0.4 mm at the maximum, and is within the range of the depth of focus of the lens used in the optical system. Never be. When the photosensitive drum 11 is driven to rotate from the drive gear 58 to the drum gear 57 formed on the outer periphery of one end of the drum as shown in FIGS. 3 to 6, the drive gear on the main body side is used. With the meshing rotation of the drum gear 57 on the photosensitive drum side with the engagement of the drum gear 57, an acting force acting to separate the drum gear 57 side of the photosensitive drum from the drive gear 58, that is, a so-called "playing force F" acts, The left and right sides of the body drum 11 tend to tilt. Therefore, in the embodiment of the present invention, a pressing member for pressing the photoconductor drum 11 is provided, and the pressing member presses one of the shaft ends of the photoconductor drum 11 to cancel the action of the above-mentioned "floating force F". Like that. In the first embodiment shown in FIG.
A pressing member is provided on the shaft support portion on the side not having 57 so as to be able to be pushed out with the same force in the same direction as the action direction of the "playing force F" so as to negate the action of the "playing force F". . That is, the lever 61 and the tension spring 62 are provided on the shaft supporting member 60 of the photosensitive drum 11 on the side where the drum gear 57 is not provided, and the same acting force as the above-mentioned "fraying force F" is added. The configuration is such that the effect of the acting force of "F" is negated. In the second embodiment shown in FIGS. 5 to 7,
A pressing member is provided on the shaft supporting portion having the drum gear 57 so as to press in the direction opposite to the direction of action of the "playing force F" to cancel the action of the "playing force F". FIG. 5 is a perspective view of the vicinity of a portion for transmitting a rotational driving force to the photosensitive drum, FIG. 6 is a plan view of the pressing member installation portion viewed from the photosensitive drum side (inside), and FIG. FIG. 3 is a sectional view of a portion, in which the same members as those in the first embodiment are denoted by the same reference numerals. Also in the second embodiment, the horizontal direction is a long hole 65 having a long diameter.
A shaft support member 65 provided with a was provided. The photosensitive drum 11
The shaft 66 protruding from the side surface is movably supported by the shaft support member 65. As shown in FIG. 7, the photosensitive drum 11 is moved toward the developing sleeve 15 by the shaft support member 65 having a long hole 65a having a long diameter in the horizontal direction fixed to the side plate 10b of the image forming unit 10. It is supported as much as possible. A pressing pin 64 and a tension spring 63 are provided on a shaft support member 65 of the photosensitive drum 11 on the side having the drum gear 57, and an acting force equivalent to the "fraying force F" is applied in the opposite direction. The structure was designed to negate the effect of the "force F". Although the present invention has been described with reference to the embodiment of the two-component developer, it goes without saying that a one-component developer can also be used. Further, it is needless to say that the above embodiments can be variously modified based on the technical idea of the present invention.

【The invention's effect】

As described above, the present invention is characterized in that the photosensitive drum is movably supported on the developing sleeve side, and the photosensitive drum is pressed against the developer on the developing sleeve with a uniform and constant force. This eliminates the need for abutting rollers to maintain the distance between the photoconductor drum and the developing sleeve, and eliminates the need for processing to increase the accuracy of the rollers, further reducing production costs. Was. Also,
The surface of the photoreceptor drum is not damaged by the roller, which can contribute to the improvement of the service life. Furthermore, according to the present invention, the distance between the photosensitive drum and the developing sleeve can be maintained by moving the photosensitive drum, so that the adjustment when the photosensitive drum and the developing sleeve are simultaneously installed in the same unit becomes easy, and the image forming unit Various excellent effects such as simplification of the whole configuration can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming unit in a copying machine provided with a developing device of the present invention, FIG. 2 is an explanatory diagram showing a relationship between regulation of the thickness of a developer layer on a developing sleeve and a photosensitive drum, and FIG. 3 is a plan cross-sectional view showing a state of supporting the photosensitive drum, FIG. 4 is a side view showing a first embodiment of the present invention, FIG. 5 is a perspective view showing a second embodiment of the present invention, and FIG. FIG. 7 is a plan view of the shaft supporting portion of the embodiment as viewed from the photosensitive drum side, FIG. 7 is a side sectional view of the shaft supporting portion, and FIG. 8 is an explanatory diagram of a conventional device. 10 image forming unit 11 photosensitive drum 13 developing section 15 developing sleeve 19 developer regulating blade 50, 66 rotating shaft of photosensitive drum 52 cleaning blade 53 blade support Member 57: Drum gear (driven gear) 58: Driving gear 59, 60, 65: Shaft support member 59a, 60a, 65a: Slot 61: Lever (pressing member) 62, 63: Tension spring 64 … Pressing pin D …… Developer layer

Claims (4)

(57) [Claims] 1. A photosensitive drum rotatably supported and having a photoconductive layer on an outer peripheral surface thereof, and a developer transported to an outer peripheral surface of the photosensitive drum to visualize an electrostatic latent image. A developing sleeve provided so as to face the outer peripheral surface, a bearing member for supporting the photosensitive drum movably in the direction of the developing sleeve, and a residual toner by rubbing the outer peripheral surface of the photosensitive drum. A cleaning member for removing the toner, and applying a pressing force for the cleaning member to press and move the photosensitive drum in the direction of the developing sleeve. 2. An electrostatic recording apparatus according to claim 1, wherein said photosensitive drum and said developing sleeve are provided in the same unit. 3. A drum gear that rotates while meshing with a drive gear on the main body side is provided on one end side of the photosensitive drum, and meshes with the drive gear and the drum gear on a side where the drum gear is not provided. The electrostatic recording apparatus according to claim 1, further comprising a pressing member that presses the photosensitive drum in a separating direction with an operating force equivalent to a separating operating force generated by rotation. 4. A drum gear that rotates while meshing with a drive gear on a main body side is provided at one end of the photosensitive drum, and meshes with the drive gear and the drum gear on a side where the drum gear is provided. The electrostatic recording apparatus according to claim 1, further comprising a pressing member that presses the photosensitive drum in a direction opposite to the separation direction with an operation force equivalent to the separation operation force generated by rotation.