JPS6183565A - Ppc type developing device - Google Patents

Abstract

PURPOSE:To transport uniformly a magnetic toner and to simplify the constitution of the permanent magnet shaft in a non-magnetic cylindrical sleeve by providing freely rotatably said sleeve around the permanent magnet shaft and providing a permanent magnet layer magnetized to multiple poles to the outside or inside peripheral surface of the cylindrical sleeve. CONSTITUTION:The permanent magnet shaft 12 having a magnetic pole for development facing always a photosensitive drum 6 is fixedly provided and the non-magnetic cylindrical sleeve 10 is freely rotatably provided around the shaft 12. The permanent magnet layer 11 magnetized to multiple poles is provided to the outside or inside peripheral surface of the sleeve 10. The magnetic pole width of the multipolar permanent magnet layer 11 is set at 1-6.5mm and the ratio of the moving speed of the latent image on the drum 6 with respect to the peripheral speed of the layer 11 is set at 0.2-0.36.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to electrostatic copying, etc., which is used in PPCPP type developing apparatuses, especially PPC using R3 toner. Concerning mold developing equipment.

(Prior Art) FIG. 6 shows the configuration of a conventional PPC type developing device of this type. In this figure, a permanent magnet shaft 2 is disposed concentrically within a non-magnetic cylindrical sleeve 1 made of non-magnetic material such as stainless steel or aluminum to form a PPCPP type developing device. In most cases, the permanent magnet shaft 2 is made up of two alternating permanent magnets 3 having opposite magnetic poles. Mainly, magnetic toner as a developer is provided in the toner bomb system 5 . The non-magnetic cylindrical sleeve 1 and the permanent magnet shaft 2 are placed close to the photoreceptor drums 1 and 6 of an i-sized electrophotographic copying machine. Reference numeral 8 denotes a regulating charging plate for regulating the amount of magnetic toner adhering to the outer periphery of the sleeve 1.

In the above configuration, the permanent magnet shaft 2 is fixed and 111
f non-magnetic circle π) attract magnetic toner to the magnetic cylindrical sleeve 1- by rotating the sleeve 1 or by rotating both the permanent magnet shaft 2 and the non-magnetic cylindrical sleeve 1;
The toner is then fed, and the electrostatic charge on the photoreceptor drum 6 is removed.

Problems trying to decide whether 1' completion or 1Y) By the way, r
If the configuration is as shown in the iSe diagram, the magnetic toner cannot be conveyed unless some kind of liquid is provided between the magnetized/I raw circular box sleeve 1 and the magnetic toner. It is necessary to create slight irregularities on the surface of the cylindrical sleeve 1.

In addition, the permanent drawer 2 is built into the non-magnetic cylindrical sleeve 1 to magnetically restrain the magnetic toner on the surface of the sleeve 1.
-71D plane L C8A flux density 5oo~', 10()
, the distribution of Ll'ES must be given a magnetic flux, and due to the presence of a gap between the permanent magnet shaft 2 and the surface of the non-magnetic cylindrical sleeve 1, the built-in permanent magnet ÷ I! ! A force of about 1j is generated for a magnetic pole number of 2. Usually 20 to 60 ;+
Considering the magnetic flux density mentioned above, the -λ number of the magnet shaft 2 is within the Okawa range of - to 20I.

Also, a permanent magnet to make 7jC magnet 2 +7:
), it is necessary to use a permanent magnet with different Jj properties in order to reduce the strong magnetism +/nu by 1°, which has the disadvantage of increasing cost and increasing the positive amount.

Incidentally, in Machikai No. 58-168069, a magnetic toner developing device is proposed in which N poles and S poles are alternately arranged around the outer periphery of a non-magnetic metal cylinder, but in this case, the non-magnetic metal cylinder Both the magnet roll and the magnet roll inside must be rotated, and the magnet roll also requires a large number of magnetic poles, which tends to result in a double-flow structure.

(Means for Solving the Problem of Points Between Points) In view of the above points, the present invention provides a non-magnetic cylindrical sleeve rotatably around a permanent magnet shaft, and has multiple poles on the outer circumferential surface or inner circumferential surface of the cylindrical sleeve. By adopting a structure in which a magnetized permanent magnet layer is provided, the magnetic toner can be uniformly conveyed directly to the multi-polar magnetized permanent magnet layer 'C, and the structure of the permanent magnet shaft inside the sleeve is simplified. The present invention proposes a PPC type developing device that is possible to reduce the weight, simplify or omit the magnetic toner agitator groove that should be provided separately in the toner box, and reduce the cost. The purpose of this meeting is to fixedly support a permanent magnet shaft that always faces a photoreceptor drum, and A magnetized cylindrical sleeve is provided around the cylindrical sleeve so as to be freely rotatable. In the structure for attracting and transporting the magnetic toner as the third agent, the magnetic pole width W of the multipolar permanent magnet layer is set to 1till□75 to 6.5.
+nτ0, and determine the peripheral speed of the multipolar permanent magnet layer at the moving speed of the )5 images on the photoreceptor drum (ii). When setting it to
l) Preventing the increase in size and υ'' l-car 11ξ, so that a good image is obtained.

(Example): Below, a <PPC type embodiment according to the invention ('') An example of the wave device will be described according to the following.

Figure S1 shows a first embodiment of the present invention. 7 in this figure
・So, ;l:j+, 11112 yen 115 sleeves 10 are freely provided ' times i, and the non-magnetic cylindrical sleeve 10
The outer circumferential surface (not shown, but the inner circumferential surface may also be used) is wrapped with a composite permanent magnet sheet made of a mixture of rubber, polymeric abrasive (e.g. conductive resin) and magnetic particles, and magnetized with multiple poles. A permanent magnet layer 11 is provided over the entire circumference of the sleeve by inserting a cylindrical body of a permanent magnet, or by electrocoating a mixture of permanent magnet powder and conductive paint in a magnetic field. In the case of a non-conductive composite permanent magnet, conductive furrows are provided after winding or insertion. The permanent magnet layer 1
In No. 1, top poles and south poles are formed alternately and continuously in the axial direction of the sleeve. Also, inside the non-magnetic cylindrical sleeve 10, there is a permanent magnet fil11 concentrically therewith.
12 are fixedly arranged. Here, the permanent magnet shaft 12 has a permanent magnet 51.1 having a developing main pole (N44 in the figure) and a permanent magnet 15 having a stirring pole (alternating arrangement of N pole and Si surface) on the irregularly shaped shaft 13. It is fixed. The main developing pole is fixed in a direction facing the photosensitive drum 6. Note that +1 for the toner box 5, photosensitive drum 6, regulating charging blade 8, etc. is the same as in FIG.

Figure 2 shows the amount of iTj of the PPC type developing device shown in Figure 1.
This figure shows the magnetic distribution in the circumferential direction of the outer peripheral surface of the magnet Gr"I41i. From this figure, the magnetic flux density on the surface of the multipolar permanent magnet layer 11 can be determined by The value is the composite of the magnetic flux density due to the magnetic flux density due to the development main pole of the permanent magnet $*12 and the magnetic flux density due to the magnetic flux density due to the development main pole of the permanent magnet $*12, which is 100 to 1.
It is variable within the range of 400 Hauss and is J+7. This high value of the surface magnetic flux density makes it possible to reduce the content of magnetic components in the magnetic toner used, and increases the possibility of improving the fixing properties of the magnetic toner to the surface of the magnetic toner.

In the configuration of the first embodiment described above, the non-magnetic cylindrical sleeve 1
Multi-pole magnetized permanent magnet provided on the outer peripheral surface of 0; iJa
On the surface of 11, friction occurs due to the counterclockwise rotation of the non-magnetic cylindrical sleeve 11 (however, clockwise rotation may also be adopted due to the design), and the N pole of the foot plate. , S
The poles are arranged alternately (the magnetic toner is sufficiently agitated due to the reversal effect in the magnetic toner, etc., and separated into small magnetic toner particles, and the magnetic force of the multi-pole N pole and S pole is almost uniformly distributed. The permanent magnet layer 11 is directly attached to the surface of the permanent magnet layer 11 and is transported as the non-magnetic cylindrical sleeve 10 rotates, and as shown in the enlarged view of FIG. Due to the action of the main developing pole, the elongated brush shape extends up along the lines of magnetic force and rubs against the surface of the photosensitive drum 6. As a result, a predetermined developing action can be performed.

The above is an outline of the operation, but next is striped development unevenness, etc.
! , ``The development range for those who do not have one development is 4 yuan.

In the configuration of the embodiment of the present invention shown in FIG.
1 N pole, S pole and development of permanent magnet shaft 12! FL (N
As shown in FIG. 3, when the main developing pole and the magnetic poles of the permanent magnet layer 11 are of the same polarity, brush-like spikes of toner are observed due to the interaction with Fi). Between different poles, the toner will be directed toward the circumferential direction of the sleeve,
Emerging does not occur. Therefore, the only spikes that contribute to the electrostatic latent image on the photoreceptor drum 6 are the same polarity as the main developing pole.

Next, let us consider the relationship between the magnetic field on the multipolar permanent magnet layer 11 and the latent image surface of the photoreceptor drum 6: I series.

Moving speed of the latent image on the photosensitive drum 6: S (iun/5ec), Outer diameter of the multipolar permanent magnet layer 11: φ (llllfl), Number of rotations of the multipolar permanent magnet W111: N (rps), % FjL
The width of one magnetic pole of the permanent magnet layer 11: W (rQ+o), the number of magnetic poles of the multipolar permanent magnet layer 11 is 2P, the effective width of the spike at one magnetic pole width of the multipolar permanent magnet layer 11: W
Let it be e (+n m ).

Therefore, the effective P! on the multipolar permanent magnet layer 11! Standing 1 interval We
is continuously printed on the latent image surface and printed 4! :4 There is no L, so the current residents are two cows, so the conditions for rubbing are ;2W
2...(1) is f, (+ foot ゛V).

Further, the ratio Cr between the moving speed S of the latent image on the photosensitive drum 6 and the outer circumferential speed of the magnetic layer 11 is S W
e φπN 2W , and the development conditions are set by assisting with the effective earing width We shown in FIG.

However, here, the gap between the photoreceptor drum 6 and the sleeve-side permanent magnet layer 11 is about 0.3 to 3111 bl, which is small in line with the outer diameter of each, and is 1, so the effect is shall be ignored.

The effective spike width We is the magnetic toner or sleeve 1ll.
Although there are slight differences in the magnetic properties of the permanent magnet layer 11, 'N- to 'e+nip in Figure 4 for one magnetic pole width W
It has been found that the relationship between the songs d-Izumi to W-W e+nax is the same. The measurement conditions in this case are
The surface magnetic flux density of each magnetic pole of 1 is 300 to 800'i;
a 11 S S, the developing magnet of the permanent magnet shaft 12 (the surface magnetic flux density on the surface of the permanent magnet layer is 500 to 1000)
'i; a LISS, containing magnetic powder "fine 30
The values are for two general magnetic toners containing 60% by weight. In addition, the effective width NV e of FIG. 1 is determined by the gap a shown in FIG. It was measured in practical use.If the width of the main developing pole (N) of the permanent magnet shaft 12 is QWjυ, 2, then the electrostatic latent image on the photosensitive drum 6 is It was confirmed that the spikes of effectiveness, which are one in one, are satisfied.

ii'lj No. 2' [W-Wemax curve and W-
'vV em i n curve is 1γI permanent magnet layer 11
The graph shows the maximum and minimum values of the effective spike width We, including the variations in the above-mentioned range of the developing main poles of the magnetic trowel and the permanent magnets H and H12, and the variations in the IC toner.

・IM (from the result, the maximum effective effect on the magnetic pole width W)
+5 ffichi・V~' e Ill l :</W
And photoreceptor 1 shown by formula (2)! Figure 5) shows the relationship between the peripheral speed ratio Cr of the multipolar permanent magnet layer 1' and the peripheral speed ratio Cr of the multipolar permanent magnet layer 1'. In this diagram, 1 ho 1 chant 1. A
If / is less than 1 n, the magnetic properties of the multipolar permanent magnet layer 11 will deteriorate, resulting in failure to stand up.
It was not developed. Also, 'A'e+nax/\N! !
On the north side of line Il, there is ring-shaped development unevenness due to inappropriate circumferential speed ratio Cr.
Since it is within the range that can be developed, it is an unsuitable area for development.

On the other hand, the part where the circumferential speed ratio C[・=0.2 is smaller and the magnetic (・
A portion larger than 3-min width V=6,5+n+n is a range where a fogging phenomenon due to scattering of toner from the tip is likely to occur, and is also unsuitable for development. This phenomenon is particularly likely to occur when the latent image moving speed S of the photosensitive drum 6 is high, 600 to 1000 vn/sea. Therefore, We
The shaded area recessed by the max/2 W curve, the straight line of Cr''0,2, and the straight line of W=1 is the optimum range for practical development.

Note that it is obvious that if the value of We+oin is assumed instead of 'vVemax, the maximum jl range will be reduced.

According to the configuration of the first embodiment described above, the following effects can be achieved.

(1) The magnetic pole toner can be directly attracted by the multi-pole magnetized permanent magnet layer 11 which is wrapped around the circumferential surface of the non-magnetic cylindrical sleeve 10 and provided in a layered manner by means of power-saving coating or the like. , toner can be conveyed uniformly. Furthermore, by appropriately setting the developing conditions, it is possible to obtain good image quality without striped unevenness and without fogging caused by toner scattering.

(2: Non-magnetic cylindrical sleeve) The structure of the permanent magnet shaft 12 provided inside O is much simpler, and the irregularly shaped shaft 71
・Easy to make 13 structures, compared to conventional lano;)0
It is possible to increase the volume by 50%.

In addition, due to the interaction between the multipolar magnetic poles of the permanent magnet layer 11 and the permanent magnet shaft 12, the magnetic toner is It can also be used to stir and separate toner.

Note that the configuration of the permanent magnet shaft 12 can be changed as appropriate, and if a number of stirring mechanisms are separately provided in the toner box, the stirring mechanism (temporary) on the permanent magnet shaft 12 side can also be omitted.

(Effect of the invention) L, l: JL-, As explained, the PPC of the present invention
Mold development equipment::, 7! child,! : If it is a permanent magnet, 7 is II
Magnetization around 1-! -■ Cylindrical sleeve rotation: is freely provided, and the cylindrical sleeve has multiple 1'0t' on the outer circumferential surface or inner circumferential surface.
Since the permanent magnet R't magnetized by □' is provided, the permanent magnet inside the sleeve is:
: and the magnetic toner throwing mechanism can be simplified or omitted.

In addition, by appropriately setting the development conditions, it is possible to obtain a good image free from striped unevenness and curvature (t).

Furthermore, since the magnetic toner can be directly and uniformly attracted by the multi-pole magnetized permanent magnet layer, it is possible to demonstrate sufficiently good performance as a PPC molding device (5J), and it is also easy to manufacture and easy to reduce costs. Great effect.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a first embodiment of the PPC type developing device according to the present invention, FIG. 2 is a graph showing the surface magnetic flux density of the permanent magnet layer of the PPC type developing device of the first embodiment, and FIG. The figure is a photoreceptor drum: an enlarged side cross-sectional view of the facing part, FIG. 4 is a graph showing the relationship between the magnetic pole width W and the effective spike width We, and FIG. 5 is a graph showing the practical development/τ range. FIG. 6 is a side sectional view showing an example of the structure of a conventional PPCPP type developing device. 1゜10...Nonmagnetic cylindrical sleeve, 2.12.
・・Permanent magnet shaft, 3, 13 ・・Irregular shaft, 3, 1
・1,15...Permanent magnet, 5...Toner box,
6...Photoconductor drum,',)...2::::j Charging blade, 11...Permanent magnet JC't. Patent creator TDC Co., Ltd.

Claims (1)

[Claims] (1) A permanent magnet layer having a developing magnetic pole always facing the photoreceptor drum is fixedly supported, a non-magnetic cylindrical sleeve is rotatably provided around the permanent magnet shaft, and the outer circumferential surface or inner circumference of the cylindrical sleeve is A PPC type developing device in which a multi-pole magnetized permanent magnet layer is provided on a surface, and magnetic toner is attracted and conveyed by the permanent magnet layer, and the magnetic pole width W of the permanent magnet layer is 1 mm.
6.5 mm, and the ratio Cr of the moving speed of the latent image on the photosensitive drum to the peripheral speed of the permanent magnet layer.
A PP characterized by setting 0.2 to 0.36.
C type developing device.