JPH0695487A - Developer - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a developing device of a printing apparatus using various electrophotographic systems, etc., in which the layer thickness of the developer of the developer carrier supplied to the photosensitive drum is always constant. It is intended to improve the image quality of paper. A developing device including a developer, a developer carrier 11 for supplying the developer to the photosensitive drum 1, and a developer layer thickness regulating member 12 for regulating the layer thickness of the developer 2 while charging the developer 2. In the above, in addition to forming a charging layer 11a having a small surface energy and being charged on the outer peripheral surface of the developer carrying member 11,
A polymer layer 12-1a having a small surface energy is formed on the contact surface of the developer layer thickness regulating member 12 with the developer carrying member 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device of a printing apparatus using various electrophotographic systems. Recently, electrophotographic devices such as laser printers, laser facsimiles, and copiers can print various information at high speed with little noise and are widely used in offices. Therefore, in order to improve the quality of electrophotographic printing. It is necessary that the image fixed on the paper does not have uneven density.

However, although the developer layer thickness regulating member is brought into contact with the outer peripheral surface of the developer carrying member facing the photosensitive drum to make the supply amount of the developer constant by rotation, the outer peripheral surface of the developer carrying member is The developer layer thickness regulating member vibrates due to friction with the developer layer thickness regulating member, and the thickness of the developer deposited on the outer peripheral surface of the developer carrier fluctuates and is transferred / fixed by the photosensitive drum. Since light and shade are generated in the image on the paper, a developing device for a new printing device that can improve the image quality of the paper by keeping the layer thickness of the developer of the developer carrier supplied to the photosensitive drum always constant is required. Has been done.

[0003]

2. Description of the Related Art A developing device for an electrophotographic printing apparatus, which has been widely used in the past, is a developer made of a non-magnetic and insulating resin contained in a container by rotating in a direction of an arrow as shown in FIG. 2 to convey a developer carrying member 3-1 made of urethane or the like for developing an electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 1 to a position facing the photosensitive drum 1 at a minute interval in the direction of arrow A. A reset member 3-3 is provided so as to rotate in the direction of arrow A while being pivotally supported so as to rotate in the direction of arrow A, and for resetting the layer thickness of the developer 2 formed on the outer peripheral surface of the developer carrier 3-1. In addition, a paddle 3-4 and an agitator 3-5 for transporting the developer 2 toward the developer carrying member 3-1 are axially supported in parallel.

Further, one end side is biased with a constant pressure by the pressure spring 3-2b and rotates about the support shaft, so that the developer 2 on the developer carrier 3-1 has a constant layer thickness. The tip edge of the blade 3-2a fixed to the other end of the developer layer thickness regulating member 3-2 that regulates the developer 2 and charges the developer 2
It is arranged in a state of being brought into contact with the outer peripheral surface of the developer carrier 3-1.

In the electrophotographic apparatus equipped with the developing device having the above-described structure, as shown in FIG. 5, the photosensitive drum 1 rotating in the direction of the arrow is surrounded by a charging device 4-1, an exposing device 4-2, and the above-mentioned device. A developing device 3, a transfer device 4-3, a discharge lamp 4-4, and a cleaner 4-5 are arranged. For example, when an organic photoconductor is used, the entire surface of the photosensitive drum 1 is generally covered by the charger 4-1. It is negatively charged. Next, when the exposure device 4-2 irradiates the surface of the photosensitive drum 1 with light in accordance with a predetermined pattern, the charge of the exposed portion is reduced and an electrostatic latent image is formed. When this electrostatic region passes through the developing device 3, the developer 2 negatively charged by the developer layer thickness regulating member adheres to the electrostatic latent image to form a toner image on the outer peripheral surface of the photosensitive drum 1. .

On the other hand, the paper 5 on which the image is printed is supplied one by one to the position where it comes into contact with the toner image formed on the photosensitive drum 1. The transfer unit 4-3 is installed below the photosensitive drum 1 with the paper 5 interposed therebetween, and is configured to give a positive charge to the paper 5. Therefore, the toner image formed on the surface of the photosensitive drum 1 is attracted to the positive charge of the sheet 5 and transferred. The sheet 5 carrying the toner image is sandwiched between the heat roller 4-6a which constitutes the fixing device 4-6 and the rubber roller 4-6b which is pressed and rotated by the heat roller 4-6a, and the toner image is formed on the sheet 5 by heat and pressure. It is fixed and discharged to a stacker (not shown) outside the apparatus.

Photosensitive drum 1 having a toner image transferred onto a sheet 5
The surface of the toner is completely discharged by the discharging lamp 4-4, and the residual developer 2 is cleaned by the cleaner 4-5 to return to the initial state, and the above cycle is repeated again.

Although the above is the process of negative charging, the process of positive charging is the same.

[0009]

The problem with the conventional developing device described above is that the developer carrier 3-1 for supplying the developer 2 to the photosensitive drum 1 has a friction coefficient of about 1.0 to 1.5. A developer for controlling the layer pressure of the developer 2 supplied to the photosensitive drum 1 in contact with the outer peripheral surface of the developer carrier 3-1 because it is formed of a solid rubber roller made of urethane or the like having Friction between the layer thickness regulating member 3-2 and the blade 3-2a is large.

Therefore, when the developer carrying member 3-1 is rotated, the developer layer thickness regulating member 3-2 is rotated together with the blade 3-2a to a certain angle, and the developer carrying member 3-1 and the blade are When the friction coefficient of 3-2a is exceeded, the blade 3-2a slips and returns to its original position, and so-called Stip-Sli
The developer layer thickness regulating member 3-2 vibrates due to the phenomenon of p (adhesion slip).

The developer carrying member is used by using an OD meter capable of measuring the density of the influence of this vibration by the light reflectance.
When the density of the developer 2 attached to 3-1 was measured, the light and shade were generated at intervals of about 0.5 mm as shown by the white circle line in FIG. 2, and as shown in FIG. Since the thin and thick layers of the developer 2 attached to the outer peripheral surface of the developer 2 are formed at intervals of about 0.5 mm in the direction of the axis of rotation, the image on the paper transferred and fixed from the photosensitive drum 1 is fixed. There is a problem that uneven density occurs at the pitch.

In view of the above problems, the present invention is a new printing apparatus capable of constantly improving the image quality of a sheet by keeping the layer thickness of the developer of the developer carrier supplied to the photosensitive drum constant. The purpose of the present invention is to provide a developing device.

[0013]

According to the present invention, as shown in FIG. 1, a developer, a developer carrier 11 for supplying the developer to the photosensitive drum 1, and a layer for charging the developer 2 are provided. In a developing device including a developer layer thickness regulating member 12 for regulating the thickness, a charging layer 11a having a small surface energy and being charged is formed on the outer peripheral surface of the developer carrying member 11, and the developer layer thickness regulating member is formed. A polymer layer 12-1a having a small surface energy is formed on the contact surface of 12 with the developer carrying member 11.

[0014]

In the present invention, the charging layer 11a having a small surface energy and being charged is formed on the entire outer peripheral surface of the developer carrying member 11 for supplying the developer to the photosensitive drum 1, and the outer peripheral surface of the developer carrying member 11 is formed. The polymer layer 12-1a having a small surface energy is also applied to the blade 12-1 of the developer layer thickness regulating member 12 which regulates the layer pressure of the developer supplied in contact with the surface of the developer 2. Since the layer thickness is regulated through the low energy polymer material, friction between the outer peripheral surface of the developer carrier 11 and the blade 12-1 of the developer layer thickness regulating member 12 that regulates the layer pressure of the developer. Becomes smaller.

Therefore, even when the developer carrying member 11 is rotated, the blade 12-1 is always in sliding contact with the developer to regulate the layer pressure of the developer, so that the Stip-Slip phenomenon of the developer layer thickness regulating member 12 is caused. The image quality can be improved by eliminating the problem and making the layer thickness of the developer uniform.

[0016]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing a developing device of a printing apparatus according to this embodiment, and FIG. 2 is a diagram for explaining the effects of this embodiment. In the figure, the same members as those in FIG. Attached.

The developing device of this embodiment is a non-magnetic device housed in a container by rotating in the direction of the arrow as shown in FIG.
The developer made of an insulating resin is conveyed to the photosensitive drum 1
Table 1 is formed on the entire outer circumference of a conventional roller formed of urethane or the like for developing the electrostatic latent image formed on the outer circumference of the roller.
At a surface energy of 35 to 50 erg / cm ² and charged, for example, a developer carrier 11 having a charging layer 11a formed by coating nylon with a thickness of about 1 mm and facing the photosensitive drum 1 at a minute interval. A reset member (not shown), which is rotatably supported so as to be rotatable in the direction of arrow A, keeps the layer thickness of the developer adhered to the outer peripheral surface of the developer carrier 11 constant, and the developer is the above-mentioned A paddle and an agitator which are conveyed toward the agent carrier 11 are axially supported in parallel as in the conventional case.

[0018]

[Table 1]

Further, one end side is biased with a constant pressure by the pressure spring 3-2b to rotate about the support shaft, so that the developer 2 attached to the developer carrier 11 has a constant layer thickness. The blade 12-1 fixed to the other end of the developer layer thickness regulating member 12 that regulates the developer 2 and charges the developer 2 is arranged in a state of being brought into contact with the outer peripheral surface of the developer carrier 11. Set up.

Surface energy is applied to the contact surface of the blade 12-1 of the developer layer thickness regulating member 12 that regulates the developer adhered by abutting on the outer peripheral surface of the developer carrier 11 to a constant layer thickness. A small layer, for example nylon, is coated to a thickness of about 0.1 mm to form the polymer layer 12-1a, and one end is a pressure spring.
The contact surface of the blade 12-1 is disposed in a state of being in contact with the outer peripheral surface of the developer carrying member 11 by being biased by a constant pressure by 3-2b and rotating about a support shaft. ing.

The printing apparatus using the developing device as described above, like the conventional example shown in FIG. 5, has a charger 4-1, around the photosensitive drum 1 rotating in the direction of the arrow as shown in FIG. Exposure unit 4-2, developing unit 3, transfer unit 4-3, static elimination lamp 4-4
, Cleaners 4-5 are arranged. For example, when an organic photosensitive member is used, the entire surface of the photosensitive drum 1 is generally negatively charged by the charger 4-1. Next, when the exposure device 4-2 irradiates the surface of the photosensitive drum 1 with light in accordance with a predetermined pattern, the charge of the exposed portion is reduced and an electrostatic latent image is formed. When this electrostatic region passes the developing device 3, the developer 2 negatively charged by the developer layer thickness regulating member 12 adheres to the electrostatic latent image to form a toner image on the outer peripheral surface of the photosensitive drum 1. Is configured as follows.

As a result, the friction coefficient between the outer peripheral surface of the developer carrying member 11 and the blade 12-1 of the developer layer thickness regulating member 12 is
Nylon is smaller than 0.15 or less compared to conventional rubber and metal 1.0 to 1.5, so that the vibration of the developer layer thickness regulating member 12 is eliminated and adheres to the outer peripheral surface of the developer carrier 11. By making the layer thickness of the developer 2 uniform as shown by the black circle line in FIG. 2, it is possible to improve the image quality of the sheet transferred / fixed on the photosensitive drum 1.

The above description is based on the illustrated embodiments, but the present invention is not limited to the embodiments described above,
For example, the charging layer 11a made of a polymer material may be formed only on the outer peripheral surface of the developer carrier 11, and in order to charge the developer 2 to the positive side, the charging layer 11a of the developer carrier 11 and the blade may be formed. The polymer layer 12-1a of 12-1 may be coated with a polymer resin such as silicone, fluorine resin, polyethylene, or Teflon shown in Table 1. Alternatively, the entire developer carrier 11 may be formed of a polymer material having a small surface energy.

[0024]

As is apparent from the above description, according to the present invention, since the vibration of the developer layer thickness regulating member is eliminated with the extremely simple structure, the layer of the developer adhered to the outer peripheral surface of the developer carrying member is eliminated. It is possible to provide a developing device for a printing apparatus, which has the advantages that the thickness is uniform and the image quality of the paper can be improved, and the effect of remarkable economic improvement and reliability improvement can be expected.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a developing device of a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a chart for explaining the effect of the present embodiment.

FIG. 3 is a schematic cross-sectional view showing a conventional developing device.

FIG. 4 is a schematic diagram for explaining a problem.

FIG. 5 is a schematic cross-sectional view showing an electrophotographic printing apparatus.

[Explanation of symbols]

1 is a photosensitive drum, 3-2b is a pressure spring, 11 is a developer carrier,
11a is a charging layer, 12 is a developer layer thickness regulating member, 12-1 is a blade, 12-1a is a polymer layer,

Claims (1)

[Claims] 1. A developer (2), a developer carrying member (11) for supplying the developer (2) to the electrostatic latent image carrier (1), and a charge for the developer (2). In a developing device provided with a developer layer thickness regulating means (12) for regulating the layer thickness, the developer (2) is characterized in that the layer thickness is regulated through a polymer material having a small surface energy. vessel.