JPS5862662A - Electrostatic recording device of transfer system - Google Patents

Abstract

PURPOSE:To improve the transfer efficiency, by controlling outputs of a pre- transfer destaticizing lamp and a transfer paper separating charger on the basis of the density of toner image. CONSTITUTION:A toner image density is detected by a detector 10 to control the output of a transfer paper separating charger 2, and the potential of the surface of a photoresnsitive drum and that of the rear face of a transfer paper are matched to each other to separate the transfer paper well. Similarly, the quantity of light of a pre-transfer destaticizing lamp 16 is controlled on the basis of the output value of the detector 10 to prevent the fatigue of the photoreceptor due to excessive exposure, thus impoving the transfer efficiency and the certainty of transfer paper separation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electrostatic recording device equipped with a corona discharger for separating transfer paper or a lamp for lightening a photoreceptor after development and before transfer.

In the conventional electrostatic recording device as described above, even if the original or the transfer paper □ changes, the pre-transfer exposure lamp irradiates the surface of the photoreceptor on which toner has been developed under constant conditions, and the transfer paper A corona discharger for separation, that is, a separation electrode that discharges discharge against the back side of the transfer paper. In general, an electrostatic recording device that uses a separation electrode to separate the transfer paper, Compared to transfer electrostatic recording devices that use separation claws or separation belts, there is no separation means that comes into direct contact with the photoreceptor, so there is no chance of damaging the photoreceptor or losing part of the toner image. It has a special flaw. However, in the conventional electrostatic recording device using four separate electrodes, i′
If the original is changed, the separation may not be stable or the transfer rate of the toner image may be poor! I get a boil that looks like it's turning into something.

The present invention has been made as a result of research into the causes of the above-mentioned problems.

For example, when the original is a photo manuscript, the area ratio of the part with high surface potential of the photoreceptor is large, and when the original is a single character, the area ratio of the part with high surface potential of the photoreceptor is large. When the ratio is small, if the irradiation conditions of the pre-transfer exposure lamp and the discharger i of the separation electrode are constant, separation will no longer be performed reliably in the same way.
Differences also occur in the transfer efficiency of toner.

Table 1 shows the relationship between the difference in the surface potential of the photoreceptor before toner and the difficulty of separating the transfer paper, which occurs when the original is changed as described above. This is the result of research using R. Note that the photoreceptor is Se.
-Te-based material is used.

In addition, the discharge current of the transfer electrode in this experiment was 30 μA.
(D, C) Table/Photoreceptor surface potential and separation characteristics (Note) 0. Each true weight and thickness! σf/111'
The results in Table 1 show that the photoreceptor surface potential was large due to changes in the original. However, it is shown that if the discharge current of the molecular Ilk electrode is varied accordingly, it is always possible to completely separate the transfer paper.

Regarding the separation of the transfer paper, the discharge chamber 15 of the separation electrode! teeth.

This should be more directly related to the surface potential after development than to the surface potential of the photoreceptor before toner development. Then another 1゛-
The effects of the discharge current of the separation electrodes were investigated and the results shown in FIGS. 7 and 1 are shown.

In FIGS. 1 and 1, vl and v2 are, respectively,
fL As shown in FIG. 3, these are the surface potential of the transfer paper 1 and the surface potential of the photoreceptor 3 below it immediately after the same transfer paper 1 as in the front passes through the separation electrode. It can be seen that the surface potential v2 is close to the surface potential of the photoreceptor after development. Figure 1 shows that the surface potential of the photoreceptor is 6θθ
Figure 2 shows the results when the surface potential of the photoreceptor is /-20V. In contrast to the result of 7, when the surface potential v1 of the transfer paper l after passing through the separation electrode becomes approximately the same potential as the surface potential v2 of the photoreceptor below it, the transfer paper l is completely separated. The potential on both surfaces is v1.
．． It can be seen that complete separation is not achieved in a state where there is a relative potential difference between V2 and V2.

What can be considered from the above is that in Figure 3, transfer paper/
Is the photosensitive JK attracted to I? , n is.

This is because the electric field caused by the electric charge on the photoreceptor 3 and the electric charge induced on the photoreceptor substrate acts on the electric charge on the transfer paper.

The charge on the transfer paper is the cause of preventing separation of the transfer paper, and the relative potential difference between the surface of the transfer paper, potential v1, and the surface of the photoreceptor 30 below, v2. When this electric charge is eliminated by the separation electrode 2, the transfer paper L exhibits a state M as if it had become a conductive material, and the electrostatic adsorption of the transfer paper L is released and separation is performed. In any case, IF! /Figure, No. 9 welfare,
Regarding the separation of the transfer paper, it is shown that the discharge current of the separation electrode is related to the surface potential of the photoreceptor after development, KR<O. There is a correlation with ° as will be explained later.

Therefore, we thought of using toner images and density.

The toner image ea111' can be stably sub-defined even without contact by the combination of the light emitting element and the receiving element. , is a graph examining FIA variation with toner image density.
, toner image! ! In #, two infrared LED light emitting elements having a peak at 9100λ are used, and a phototransistor is used as a light receiving element, and the amount of light reflected from the light emitting element on the surface of the photoreceptor both before and after the photoreceptor is developed with toner. is detected by the light-receiving element, and the concentration detection circuit outputs the difference between the two detection outputs of the light-receiving element, which is represented by its output voltage n.

As is clear from Fig. DA, toner m+,,11! It can be seen from Table 7 that the concentration t-1tll increases as the surface potential of the photoreceptor increases, and the relationship becomes looser as the surface potential of the photoreceptor exceeds 60[theta]Vt-y. As in, the discharge chamber fI1 of the separation electrode. Since the surface potential of the photoreceptor is within the range of too much, and the toner image contains information on the surface of the photoreceptor after development, it is necessary to change the separation electrode sufficiently. It can be used for discharge current control.

The above is a case where the pre-transfer exposure is not carried out, but if the pre-transfer exposure is carried out after the transfer, the surface potential of the photoreceptor decreases.

Therefore, from the results shown in FIGS. 1 and 2, it is obvious that the difficulty of separating the transfer paper changes depending on the pre-transfer exposure.

゛Table 7 shows how the surface Q results change depending on the pre-transfer exposure, and for the photoreceptor surface potential in Table 1, a cold cathode with a peak of about 4100 nw+ after toner development and before transfer. The surface of the photoreceptor is illuminated with 3θluX by a fluorescent tube!
This shows the difficulty in separating the transfer paper when irradiated with a light intensity of 1elc. The conditions for the photoconductor and transfer paper are of course the same as those in Table 2.
By performing pre-transfer exposure at θC, it is possible to completely separate the transfer paper even in the case of a photographic original under the same conditions as for a character original. However, pre-transfer exposure is necessary for the photoreceptor.

Light - It causes fatigue, so if you do it, use 1 ton of light as much as possible.
- Need to be reduced.

Figure 5 shows the changes in photoreceptor surface potential before exposure of an original image charged under the same conditions due to repeated transfers, when no pre-transfer exposure is performed and when transfer # side light is performed under the same conditions as in the table. 3θlux sea
It can be seen that the photoreceptor is considerably fatigued even by the pre-transfer shock light.0 In this figure, the photoreceptor is an Ss-Te type photoreceptor.0Tables 3 and 4tB Light amount and effect of pre-transfer exposure Table 3 shows the relationship between the pre-transfer exposure amount and transfer paper separation success rate for A4t size transfer paper of various thicknesses...1 Table 4t shows the pre-transfer exposure amount and transfer efficiency, that is, The relationship between the ratio of the amount of transferred toner to the amount of developed toner is shown in Tables 3 and 2. In both Tables 3 and 3, the photoreceptor and the pre-transfer light lamp were used under the same conditions as in Table 2.
In addition to setting the discharge current of the separation electrode to /30 JAI, the transfer electrode shown in Figure 3! The discharge current is set to 30 μA, and the thickness of the transfer paper on the front side is F1/If2.

Table 3 Pre-transfer exposure amount and separation success rate Table DA Pre-transfer exposure amount and transfer efficiency As can be seen from Table 3, even a small pre-transfer exposure amount can be sufficient to improve separation depending on the thickness of the VC1 transfer paper. Moreover, as can be seen from the table, even a small amount of pre-transfer exposure t''C improves the transfer efficiency.

The present invention has been made based on the above-mentioned results, and the transfer type electrostatic recording device of the present invention further includes a corona discharger or fc for separating transfer paper, and an Ie light body sliding light after and before transfer. In an electrostatic recording device rC equipped with a lamp, the discharge current of the corona discharger and/or the light irradiated onto the photoreceptor by the exposure lamp is determined based on the signal corresponding to the 1lii image density on the photoreceptor. 'fr It is a special mission that S has been made so that it can be changed.

The present invention will be described below with reference to FIGS. This will be explained with reference to the figures.

Fig. 6 is a schematic configuration diagram of the recording apparatus of the present invention which detects the toner image gIl density #i on the photoreceptor and controls the discharge current of the molecule I#1'IIK electrode, and Fig. 2 also shows the transfer FIG. 1 is a schematic configuration diagram of a recording apparatus of the present invention in which eC is used to control the photoreceptor irradiation light f of the exposure lamp, and FIG. 1 is a partial diagram of the light amount control circuit of the pre-transfer exposure lamp. In FIG. 2, O is a charging electrode that charges the surface of the photoreceptor 30;
7Fi original image projection light, tFi toner imager, 9ij
cleaner, IO is a concentration detection sensor consisting of a combination of a light-emitting element and a light-receiving element similar to that in Fig. D, l/ is the same concentration detection circuit, and /- is a control signal for amplifying the output of the concentration detection circuit /l. A generation circuit, a delay circuit that delays the output control signal of the control signal generation circuit 12 by the time until the surface of the 13Fi photoreceptor 3 reaches the position of the separation electrode from the position of the production detection sensor /θ, /4tIli delay circuit/ The AC voltage applying circuit 1zt is controlled based on the control signal from the control signal generating circuit 1zt or the control signal generating circuit 1zt, and the discharge current of the separation electrode λ is 7t.
This is a control circuit that changes the amount of light emitted from the pre-transfer exposure lamp/L6 using a cold-dry discharge tube similar to that in table #'i. Discharge is started when the leading edge of the transfer paper reaches the transfer electrode 5, taking into account variations in the feeding timing of the transfer paper and the delay in the rise of the discharge, etc., in order to ensure that static electricity is removed from the leading edge of the transfer paper. I am planning to do this beforehand.

In the recording device # of FIG. 4, the discharge current of the separation electrode is controlled by the control circuit/(tVc) at least based on the detection of the density detection sensor io, and the toner image density of FIG. If the control is performed to obtain a droplet with a 0 mark on the table/, the separation of the transfer paper will be performed stably even if the original changes, for example, between a photo original and a text original. In the recording apparatus shown in Fig. 2, under conditions such that the discharge current is greater than or equal to iaoum, when the toner image density exceeds a certain level, each pre-transfer exposure lamp is turned on, or By increasing the light intensity of the pre-transfer exposure lamp/B as the toner image density increases, as shown in Table 1, the separability of the transfer paper can be improved. As shown, transfer efficiency can also be improved.

FIG. 2 shows an example of an AC voltage applying circuit in which the light intensity of the pre-transfer light lamp/6 is switched and controlled in one step.The control circuit/4t in FIG. The output is 2. ! When the value is less than v, connect the selector switch to resistor RAVc and irradiate light amount of pre-transfer exposure lamp/B 'f/! 1u
x-sea, and when it becomes larger than 7, z't V, the selector switch Sft resistor R11 is switched to set the amount of light irradiated from the transfer pre-calculation light lamp to 3θlux sec.

As described above, according to the present invention, it is possible to stably separate the transfer paper using the h-negative electrode regardless of changes in the document size, and even when using a pre-transfer exposure lamp, the photoconductor fatigue can be minimized.

In the present invention, a divisor number of concentration detection sensors may be used, and they may be arranged in the longitudinal direction as well as in the width direction of the i photoreceptor. In addition, a fluorescent lamp other than a cold cathode fluorescent tube or an incandescent lamp may be used as the source light lamp before transfer.Furthermore, the amount of light irradiated onto the photoconductor may be changed using a filter, without changing the amount of light from the lamp. You may also do so.

[Brief explanation of drawings]

Figures 7 and 1 are graphs showing the influence of separation electrode discharge current on transfer paper separation, respectively. Partial quotation 1
The first view and the second figure show the surface potential of the photoreceptor before development and the toner 1iI.
A graph showing the relationship between I image # degree, FIG. 5 a graph showing photoreceptor fatigue due to pre-transfer exposure, FIG. FIG. 3 is a partial diagram of a light amount control circuit of an exposure lamp. /... Transfer paper, λ... Separation pole, 3.
...Photoreceptor! ...Transfer electric welding! ...
toner developing device, 10...density detection sensor, //
...me detection circuit, /-...control signal generation circuit, /3...f! Delay path, /ri...control circuit, /j...AC voltage application circuit, /≦・C pre-transfer fog light lamp 〇2 5 ge. ! f34Figure A Oh I book 5iliJtI fL(V)- -----

Claims (1)

[Claims] In an electrostatic recording device equipped with a corona discharge device for separating the transfer paper and a lamp for exposing the photoconductor after development and before transfer, the corona discharge is performed based on a signal corresponding to the oiii* density on the photoconductor. 1. A transfer electrostatic recording device characterized in that the current and/or the light irradiated onto the photoreceptor by the exposure lamp can be changed.
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