JPS62119563A - Electrostatic copying device - Google Patents

Abstract

PURPOSE:To obtain a good transfer image even if a transfer material whose moisture content is high is used, by attaining and setting conditions where transfer is performed surely between an alternating voltage applied to a developer carrier and transfer conditions. CONSTITUTION:Required relations are obtained between the development condition, namely, the intensity of the electric field in the gap between a latent image carrier and a developer carrier an the transfer condition, namely, the value of current flowing to the latent image carrier by discharge of a transfer corotron. That is, transfer is performed on the condition of a formula (1) where EP<->P(V/m), Io(A/m), and VP(m/sec) are the width from the maximum voltage to the minimum voltage of the electric field per unit length which is formed in the gap between the electrostatic latent image carrier and the developer carrier by the alternating voltage applied to the developer carrier, the value of current part unit length which flows from a transfer device with the electrostatic latent image carrier as a good conductor, and the moving speed of the electrostatic latent image carrier respectively, and EP<->P(V/m) is set within the range given by a formula (2). Thus, an image is transferred surely in accordance with the change of the development condition and for paper whose moisture content is high.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrostatographic apparatus that visualizes electrostatic latent images.

More specifically, in the present invention, a one-component developer supplied onto a developer carrier is formed into a developer layer having a predetermined thickness and charge amount by a regulating member, and an alternating voltage is applied to form this developer layer. This relates to an electrostatic copying device that conveys and visualizes an electrostatic latent image.

[Prior Art] Conventionally, as a method for developing an electrostatic latent image formed on an electrostatic latent image holder, a two-component developer consisting of toner and a carrier is used, and a one-component developer is used due to frictional charging with the carrier. ~
A two-component development method has been put into practical use in which a charge is applied to a toner and the charged toner is electrostatically attracted to an electrostatic latent image. In this way, the method of using a two-component developer consisting of a toner and a carrier is fully practical.
7111 to prevent developer deterioration as it approaches I4! From point I
Component development using a single-component developer consisting only of No.
η, or as proposed, such a -component development method (one using a three-dimensional developer, one using a non-magnetic 1'l developer), There are two methods: one in which the developer is brought into contact with the electrostatic latent image carrier, and the other is in which the development is carried out without contact.

Is it possible to mix without directly touching the developer? 11 Apply voltage/Ill
As a one-component developing device which performs development by moving a developer to a latent image in step b, for example, there is known a small J'J and a fb shown in FIG. In the figure, reference numeral 8 denotes an electrostatic latent image carrier 8, which holds an electrostatic latent image 9 with a potential of about 200 to 900 V on its surface. A developer carrier 7 made of 1.Norl added with carbon and glass fiber 2Q having a thickness of JNlmm, a specific resistance of 10100cm, and a relative permittivity of ε-20-C is placed in the gap/
10−/l (1) 0μ is il”io and λ・1 side.
The supply section 4 A3 that supplies the developer 6 stored therein to the developer JQ holding body is pressed at a depth of about 1 g, and is moved at the same circumferential speed as the developer carrier 7 in the direction of the arrow in the figure. C is spinning. As the supply member 3, in order to reduce the amount of the cart applied to the developer carrier 7 during pressure contact, a foam material 3b such as urethane is wrapped around the sheet A771-3a, and an E film with a thickness of 0.5 to 1 mm is applied to the surface.
A material coated with PDM rubber or the like is used. The height of the rubber surface is approximately 200μ717. ．． Concave and convex portions are provided at equal intervals of 15 degrees, and the developer 6 trapped in the convex portions is necessarily sent onto the developer carrier 7. The developer 6 that has been sent is sent to the regulating portion 4711 by the rotation of the developer carrier 7 (in the direction of the arrow in the figure), where the developer 6 is given a desired charge by frictional electrification, and the developer carrier 7 On top is a uniform layer of developer 5 (0,3-1
, 0mg/cni> and is sent 110 to the electrostatic latent image area] surface position.

A DC voltage of 200 to 400 V is applied to the developer carrier.
frequency 1~10KI-1z,v,-p is 400~
A high frequency alternating voltage of /150 QV is applied, and a peripheral electric field is formed in the electrostatic latent image portion 9 on the electrostatic latent image holder 8, and the developer 5 is moved to perform development.

However, when transferring this type of developer, especially the transfer paper or r! When the water content is 1 (moisture content 10% or more), there is a problem in that poor transfer occurs.

Such transfer defects occur in electrostatic copying machines that use the two-component development method, but as is well known, it is necessary to install a pre-transfer static eliminator (or worse, to remove electricity from the transfer paper conveyance system). It is possible to respond sufficiently by applying bias-applying measures.

However, under the same conditions as the two-component developing method, a developing method using an insulating component developer ay; and applying an alternating voltage;
More than one high moisture content transfer paper tj,'IIIL 15
゛・１〕1 was defective, and the same developer was used again.
However, the transfer characteristics vary depending on the applied alternating voltage, and it is difficult to set the transfer conditions independently.The reason for this is as follows. When the alternating voltage is applied and the developer reciprocates in the gap between the latent image carrier and the developer carrier, the developer forms a latent image 1'j l,''
4 - Electric charge is generated on the surface of the developer due to dielectric breakdown of the air inside the developer.
This is thought to be due to the fact that the adhesion force of the developer to the latent image carrier increases due to changes in i.

[Problems to be Solved by the Invention] An object of the present invention is to prevent transfer defects when transferring the developed image onto high moisture content paper by applying an alternating voltage to cause the developer to fly to the latent image. To resolve the above-mentioned problem of the above-mentioned problems occurring, we sought conditions that would ensure reliable transfer between the developing conditions, especially the alternating voltage applied outside the developer carrier, and the transfer conditions. An object of the present invention is to provide an electrostatic copying apparatus that can obtain good transferred images by scanning.

[Means for Solving the Problems] The present inventors formed a developer layer on a developer carrier, and formed an electrostatic latent layer facing the developer carrier with a constant gap. In an apparatus that develops a latent image on an image carrier by applying an alternating voltage to cause the developer to fly, and then electrostatically transfers the developed image to make a copy, The electric charge per unit length formed in the gap between the electrostatic latent image carrier and the developer by the applied suspension voltage!I'l!r/)! +u li“：
+ liu low electric moon-11'' is Ep-0 (V/m>, electrostatic latent 1! & Ill 1.' When the + body is 029 body, the medium length flowing from the transfer device Current value
. (△/m), electrostatic potential (τ month l) Transfer is performed under the conditions shown by the movement of the support body, and (n) the Ep-' (V/m) is expressed by the following formula (2)%.
The present invention was completed based on the discovery that a good transferred image can be obtained even when using a transfer film with a high water content by setting the amount within the range shown by the formula % (2).

The present invention will be explained below based on the drawings.

Development as shown in Figure 1 above! f? At the position, the thickness of the photosensitive layer of the latent image carrier 8 is dl, the dielectric constant is 9, the gap between the latent image carrier 8 and the developer 11'' carrier 7 is dg, and the sleeve 2 of the developer carrier 7 is The thickness is dd, and the dielectric constant is εd.
When the maximum and minimum voltage width of the alternating voltage applied to the developer carrier 7 is Vp-p, the maximum and minimum voltage of the electric field generated in the gap between the developer carrier 7 and the latent image carrier 8 due to vp-p is [ 1]E l]-1) can be determined by the following equation since the contribution by the developer can be ignored.

E" = V / (d, /εp 10d g10-p d, /ε,) Also, as shown in FIG. 2, which is a schematic diagram of the entire copying apparatus, Image static neutralization corotron 11
When the transfer corotron 12 transfers onto the high water content transfer paper 13, which has been statically removed by
m> was measured using a current measuring jig 14 as shown in Fig. 3, and it was found that good transfer was achieved by dividing IO by the moving speed of the latent image carrier, (m7 seconds). 9. It was determined that the value was above the straight line shown in Figure 4, that is, within the range of the following formula 1.9. △ in Figure 4
.

This value is for a two-component developer to which no alternating voltage is applied.

In addition, in the region below the value of E p /x l O6 (V, /r 1), the developer cannot fly toward the latent image, so that sufficient development efficiency (j) is not achieved.

Is the upper limit of (i (j 4J) El)-1) within the range where air breakdown does not occur in the gap between the developer carrier and the latent (image carrier)?The minimum value of the gap is 40 μm considering the accuracy of the developing sleeve. The air breakdown audible electric field strength at that time is 1.5X107V/m, so the second range of [0-D practical use] is 4X106 to 1.5x.
``This means 107 (V/m).

It has been found that the above-mentioned conditions apply not only to non-magnetic components but also to magnetic components.

[Example] Example 1 A polarity control agent such as carbon 1 and metal-containing dye O': 1 was dispersed in styrene/acrylic resin as a developer, and crushed and classified to a size of 5 to 20 μm. Tests 1 to 1 were carried out using a non-magnetic component developer to which 1% hydrophobic silica was added and a developing device having the configuration shown in FIG. 1.

Development strip A (1 is as follows.

d = 6011m, ε, -6, dg = 200
μ tile, dd = 1000μ set εd = 10, V, -p = 2400V, frequency f = 2.5KHz, V
p = 100 mm / sec, and as a developer carrier, a phenol resin treated with electrical conductivity so that ρ = i o 11 Ω·cm was used,
A sine wave was used as the alternating voltage.

Transfer efficiency when paper with a moisture content of 10% is used and the current value of transfer rollers 1 to 1 is varied [Efficiency when developing and transferring a solid with an original reflection temperature of 1.3, i.e. (small amount of transfer/development) weight@)X100] and 1. /V, is shown in FIG.

From FIG. 5, under the above development conditions, I/V≧4.5×10-30/bottom area, preferably P or ■. /v, ≧4.9×10 c/It was found that good transfer could be obtained in the region of the butt.

In addition, with respect to the above developer, development was carried out using a two-component powder (Feray 1~=1-Yaya as the developer, that is, without applying an alternating voltage), and Even though the amount of charge in the toner was the same as in the one-component mode, sufficient p transferability was achieved in the region of I/v≧2.oxio-3c and T/1. From this fact, the non-electrostatic adhesion force or electrostatic adhesion force between the toner and the photoreceptor increases due to the reciprocating motion of 1 to J' caused by the alternating electric field in the development gap, and the one-component developer It is obvious that there will be a malfunction in the rotation.

Example 2 As shown in FIG. 6 (111 composition I) I-component development
? Execute C-series 1~ in the same manner as in Example 1 using the
in L/ta. Note that the photoconductor 8 is Ij, lj, I
, a system photoreceptor is used, and the developer 6 is stylene resin,
Low molecular weight 1ζ lyethylene wax and magnetic powder 71
+', which was milled and mixed with 0.5% by weight of carbon black.

The developing roll used was one consisting of a phenolic resin cylindrical sleeve 17 (thickness t=1.2 mm) of ρ-5×10”Ω·Cm and an internal magnet roll 16, and the developing conditions were as follows.

d = 60μm, ε, -18, d = 330
μ7rL, dd = 1200μm, εd = 20°V, -100mm/sec, using paper with a moisture content of 10% as a transfer shrine, we conducted a test by varying the current values of Vp-p and transfer 1 to ron. We found the range in which this can be performed well, and the results shown in Figure 7 are 17. In addition, in Figure 7, ■ o/V1) is on the vertical axis, and ■
, -1 is shown on the horizontal axis, and Vp-p is F p-13
If the range is changed to , the range will be the same as in the case of non-magnetic component development in Example 1.

[Effects of the Invention] The present invention uses a one-component developer, and by applying an alternating voltage, the developer layer on the developer carrier is caused to fly toward the latent image for development, and the soul image is transferred to the transfer paper. In an electrostatic copying device that performs transfer and fixing, the development conditions are dependent on the electric field strength in the gap between the latent image carrier and the developer carrier, and the transfer corotolumn (1). We clarified the necessary 4T relationship between the value of the current flowing into the body, and provided one article ('I 1.: Setting/Ji' + ? l electric copy 1 ? setting) that satisfies the above relationship. It is a thing,
Transfer can be performed reliably in response to changes in development conditions, and can be transferred favorably even to high moisture content paper.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of a one-component developing device having a developing gap, FIG. 2 is a schematic diagram of an electrostatic copying device in which the developing device of FIG. Figure 4 is a graph showing the relationship between the maximum and minimum voltage rlJ of the alternating electric field in the development gap, the inflow current value by the transfer corotron, and transferability, and Figure 5 is a graph showing the relationship between the transferability and the inflow current value of the transfer corotron. - A graph showing the relationship between the transfer efficiency and the current value flowing through transfer rollers 1 to 1 when using component developers; - It is a graph showing the relationship between the maximum and minimum voltage 1j of the alternating applied voltage, the inflow current value by the transfer corotron, and the transfer property for the -component developing device. In the figure, reference numeral 1: Developer regulation part shrine; 2: Ei Image carrier sleeve; 3... Supply member; 4... Seal member; 5
... Small brim; 6... Developer; 7... Developer carrier; 8... Electrostatic latent image carrier; 9... Electrostatic latent image; 10.18... Alternating current Power supply; 11... Static elimination] - Ron; 12... Transfer roller] Heron; 13...
Transfer paper; 14... Current measurement jig; 15... High voltage power supply; 16... Magnet roll; 17... Non-magnetic sleeve. □ Ep-p Figure 4

Claims (1)

[Claims] A developer layer is formed on a developer carrier, and a latent image on an electrostatic latent image carrier, which is disposed facing the developer carrier with a constant gap, is coated with an alternating pattern. In an electrostatic copying device that performs development by applying a voltage to cause the developer to fly and electrostatically transfers the developed image, (I) an electrostatic latent image carrier is transferred by an alternating voltage applied to the developer carrier; The maximum and minimum voltage width of the electric field per unit length formed in the gap between and the developer carrier is E.
^p^-^p (V/m), the current value per unit length flowing from the transfer device when the electrostatic latent image carrier is a good conductor is I_0 (A/m), the value of the current per unit length of the electrostatic latent image carrier is Set the movement speed to V_
When p (m/sec), the following formula (1) I_0/V_
p≧0.38×10^-^9E^p^-^p+1.5×
Transfer is performed under the conditions shown in 10^-^3...(1), and (II) the above E^p^-^p (V/m) is expressed by the following formula (2).
4 x 10^6≦E^p^-^p≦1.5 x 10^7...
- An electrostatic copying apparatus characterized by being set within the range shown in (2).