JPS59214864A - Sealing device of photosensitive body development part of electrostatic copying machine - Google Patents

Abstract

PURPOSE:To prevent toner from being scattered and a copy from being stained by specifying the contact angle that the tangent where a seal member contacts a photosensitive body and a seal member holding part contain at the upstream side of the photosensitive body. CONSTITUTION:The contact angle theta that the tangent where the seal member 5 arranged at the upstream side of the development part 6 of the photosensitive body 1 contacts the photosensitive body 1 and the seal member holding part 5a contain at the upstream side of the photosensitive body 1 is set to <=70 deg.C. Consequently, toner hardly sticks to the seal member and is therefore prevented from appearing on a copy as stains in addition to preventing the scatter of the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a sealing device for an electrostatic copying apparatus having a sealing member disposed outside a photoreceptor and in contact with the photoreceptor.

(Prior art) There are various methods for cleaning the residual toner on the photoreceptor after it has been transferred to transfer paper, but due to space, performance, cost, etc. considerations, the blade method shown in Figure 1 is common. . 1 is a photoreceptor drum, and a charger (
DC ■) 2° in-slump 8. Exposure section 4. Seal member 5° developing section 6. Pre-transfer static elimination charger 7, transfer charger 8 (DC) 1 separation charger 9. Conveyor belt 102
Separation claw 11. Cleaning deletion charger 12 (D
C■), cleaning brush 18, blade 14. Static elimination lamps 15 are sequentially arranged. The sealing member 5 is used to prevent the toner from scattering in the developing section 6, and is brought into contact with the surface of the photoreceptor 1 with a bristle brush or a Teflon brush so as not to disturb the latent image.

FIG. 2 shows a state in which the blade 14 of FIG. 1 is cleaning the residual toner on the photoconductor l, but as shown in FIG. When contacting the photoreceptor 1, the length R from the pressure fulcrum 16 of the blade 14 to the blade edge 14α
is slightly shorter than during the cleaning shown in FIG. 2, so the blade edge 14α comes into contact with the toner 17 on the photoreceptor 1 that remains at the blade edge 14α position before the blade is released, and pressurizes. As a result, a small amount of toner 17α in the upper portion is left unwiped and transported downstream. This toner is charged by the pre-cleaning static elimination charger 12, and since the sealing member 4 is Teflon-based and has a polarity of ◯, the toner 17α adheres to the sealing portion U hand. The adhered toner 17a is reversely developed on the background area (low potential area) when a latent image pattern of a halftone dot or a caterpillar image of appropriate roughness comes, and the toner 17a (Z is charged to ■, so the developing section 6 It remains as it is without being scavenged, and appears as dirt on the copy.This phenomenon occurs only on the first copy after the blade is turned on and off, and does not occur on the second and subsequent copies.

(Purpose) The present invention prevents toner remaining on the photoreceptor and transferred due to poor cleaning from adhering to the sealing member and appearing as dirt on the copy, and at the same time, the sealing member prevents the toner from scattering. The purpose is to fulfill the role of

(Structure) The structure of the present invention will be described below based on one embodiment. FIG. 4 shows an embodiment of the present invention, in which a tangent line at a position where the seal member 5 disposed upstream of the developing section 6 of the photoreceptor 1 contacts the photoreceptor 1, and a seal member holding portion 5a. Assuming that the contact angle on the upstream side of the photoconductor l is θ, the experimental results show that the smaller the contact angle θ is, as shown in FIG. At the same time,
It has been found that toner scattering from the developing section 6 can be prevented.

Therefore, by setting the contact angle θ to 70 degrees or less, stains on the copy can be tolerated.

In the above embodiment, the sealing member is used to prevent toner from scattering from the image area, but the sealing member is not limited to this, and may be used to prevent toner from scattering from the cleaning area.

(Effects) According to the present invention, when the sealing member is attached to the same predetermined position outside the photoreceptor, simply by controlling the contact angle, toner is difficult to adhere to the sealing member, thus preventing toner from appearing as dirt on the copy. At the same time, it can also serve to prevent toner scattering.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of the area around the photoreceptor of an electrostatic copying apparatus embodying the present invention, FIG. 2 is a front view of the main part of FIG. 1 during cleaning, and FIG. 8 is a view when the blade is in contact with the photoreceptor. 4 is a front view of the main part of an embodiment of the present invention, and FIG. 5 is a front view of the main part of the embodiment of the present invention.
2 is a graph showing the inclination angle of the seal portion shown in the figure and the dirt state on the copy. ■...Le light body, 5...Seal member, 5a...N-
Le member holding part, θ...Contact angle. Patent applicant Rico Co., Ltd. −

Claims (1)

[Claims] The angle of contact between the tangent at the position where the sealing member disposed on the outside of the rotating and moving photoconductor contacts the photoconductor and the sealing member holder on the upstream side of the photoconductor is 70 degrees or less. A sealing device for the photoconductor developing section of a copying machine.