JPS60131555A - Developing method - Google Patents

Abstract

PURPOSE:To adjust development density through simple constitution over a wide range by generating an oscillating electric field in a development area with a periodic wave mode voltage which varies in voltage waveform. CONSTITUTION:The periodic wave mode voltage applied from a sine wave oscillation circuit 10 through an amplifying circuit 13 is boosted by a boosting transformer 14, and then supplied to a phase controlling circuit 15 applied with a DC voltage from a DC power source circuit 12 and waveform-shaped, to obtain a voltage by superposing the direct current upon the periodic wave mode voltage having the waveform different in phase. When the oscillating electric field is established in the development area with said voltage, the electric field in a periodic wave mode which varies not in intensity, but phase over a wide range is obtained; development density by developer oscillation is generated without fogging, and a large adjustment is executed without making a power unit complex. Consequently, the constitution is simplified, and a sharp image having reproduced gradations is formed.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for developing an electrostatic image in an electrophotographic copying device or an electrostatic recording device, and particularly relates to a method for developing an electrostatic image in an electrophotographic copying device or an electrostatic recording device. The present invention relates to a developing method that generates an electric field and develops an electrostatic image on an image carrier with toner in a cough development area.

[Prior Art] □ Conventionally, developing methods are known in which alternating voltage is used to generate an oscillating electric field in the developing area; A developing method that adjusts the developed density by changing the voltage value is disclosed in Japanese Patent Application Publication No.
It is known from Publication No. 55.1'l'8048,
Furthermore, a developing method in which the developing density is adjusted by changing the frequency of the alternating voltage is also disclosed in Japanese Patent Application Laid-Open No. 55-1≦3-0. fi
No. 8, is better known. The method of adjusting the development density by changing the strength and frequency of vibrations and electric fields is as follows:
It has the advantage of being cheaper than the photometric method of changing the aperture and more adaptable than the method of changing the light source intensity, but it still has the advantage of changing the intensity of the oscillating electric field. This method has the risk of causing fog and fog, and the method of changing the frequency has a narrow range of change in developing density, so even if KFI is used, it will not be possible to reproduce the KFI tonality clearly enough. - It is difficult to adjust the development density to obtain a recorded image. Also・1
．． , -C vibrational electric potential, depending on changes in electrostatic image potential and background potential.
In order to change the intensity of the field, two different voltages are required, so the power supply is complicated, and converting the frequency requires an even more complicated power supply. There is also.

[Purpose of the invention]

In the present invention, the oscillating electric field applied to the development area allows sufficient Wt
To provide a developing method in which the developing density can be adjusted so as to obtain a clear recorded image with reproduced tonality, and in which a power supply device is relatively simple.

[Structure of the invention]

The present invention provides a developing method in which an oscillating electric field is generated in a developing area using a periodic waveform voltage, and an electrostatic charge on an image carrier is developed with toner in the development area, in which the waveform of the periodic waveform voltage is changed. The present invention is a developing method characterized by the following, and with this configuration, the above object is achieved.

〔Example〕

Hereinafter, the present invention will be explained with reference to the drawings.

Figure Wc1 is a schematic configuration diagram showing an example of a developing device that implements the method of the present invention.

In FIG. 1, l rotates in the direction of the arrow and forms an electrostatic latent image on one surface using a known charging and exposure device (not shown) or an electrostatic image forming device using multiple stylus electrodes or ion control electrodes. A drum-shaped image carrier having an electrophotographic photoreceptor layer or a dielectric layer, 2 is a developing sleeve made of a non-magnetic material such as aluminum, and the 3D developing sleeve 2 is provided inside with a plurality of N, S The developing sleeve 2 and the magnet 3 constitute a developer transport carrier, which is a magnet having magnetic poles in the circumferential direction. The developing sleeve 2 and the magnet body 3 can rotate relative to each other, and the figure shows that the developing sleeve 2 rotates to the left and the magnet body 3 rotates to the right. Further, the ON and S magnetic poles of the magnet body 3 are normally magnetized to a magnetic flux density of 500 to 1500 Gauss, and the magnetic force causes a layer of developer consisting of toner particles and carrier particles to adhere to the surface of the developing sleeve 20, thereby creating a so-called magnetic field. , form a brush. This magnetic brush is moved to the developing sleeve 2 by the rotation of the developing sleeve 2 and the magnet 3.
It moves in the same direction as the 0 rotation and is transported to the developing area AK. 4 is a layer thickness regulation blade made of magnetic or non-magnetic material that regulates the height and amount of the magnetic brush on the surface of the developing sleeve 2; 5 is a cleaning blade that removes the magnetic brush that has passed through the developing area A from above the developing sleeve 2; , 6 is a developer reservoir, 7 is a stirring screw that stirs the developer reservoir in the developer reservoir 6 to uniformly mix toner particles and carrier particles, 8 is a toner hopper for replenishing toner particles T, 9 is a toner hopper. Developer reservoir 6
tC) A toner supply row having a concave portion on its surface for dropping off toner particles 'T; 10 is a periodic voltage generating circuit that generates a sinusoidal voltage (wavelength T) as shown in FIG. 2; 11 is from 10; The phase of the output periodic voltage wave is controlled and each half wave (
T/2), extract only the specific part (τ) and calculate the third
Figure (A) A waveform shaping circuit configured to convert or further amplify it as shown by the solid line K; 12 is a DC power supply that superimposes a DC bias voltage on the AC voltage obtained by 5K as described above; It is a circuit. The value of T is determined by the waveform shaping circuit 1.
It can be changed by adjusting the constant 1, and the output waveform changes as shown in FIG. 3(B) or (C) by changing τ.

Figure 1g4 shows the output of the periodic voltage generation circuit 10 (a waveform obtained by performing phase control on Figure 2 after external pressure and further superimposing a DC bias voltage,
FIG. 5 is a waveform obtained by superimposing a DC bias voltage on the waveform in FIG. rear.

Although the waveform is slightly more distorted, the same effect can be obtained in practical terms.

The output thus obtained is applied to the °C developing sleeve 2 via the protective resistor 13, and an AK oscillating electric field is generated in the developing area between the image carrier 1 whose conductive base is grounded and the developing sleeve 2.

6-7 are block diagrams of circuits used to obtain the outputs of FIGS. 4 and 5, respectively. Figure Wc8 is an example of a phase control circuit used for the waveform shaping shown in Figure 7, and is a relatively simple circuit using a trigger diode and a trigger.

The output of the periodic voltage amplification circuit is indicated by 1 in the figure. connected to P.

When the breakover voltage of -T is reached, the trigger diode switches and C discharges, the GK signal current is applied to start the trier, and the voltage applied to the primary side of the step-up transformer is A voltage with a shaped waveform is output from the secondary side 0, P of the transformer. When the island is changed, the charging speed of C0 changes, and at the same time, the conduction angle of the tria changes, so that the value of T can be adjusted.

The copying machine used for the desk test, which uses a copying machine equipped with this present machine, is the same as the one shown in Fig. 1, and the frequency wave voltage generating circuit is the one shown in Fig. The image carrier 1 and 1° C. used a photoreceptor consisting of a charge generation layer and a charge transport layer made of an organic photoconductor. In the experiment, the surface velocity of the image carrier in the arrow X direction was 12
0 ml sec, the gap between the image carrier L and the developing sleeve 20, that is, the gap between the developing area A, is 750 μm, and the outside is 4130 μm.
The number of rotations in the direction of the arrow of the developing sleeve 2 of m is 65 r,
pm, the gap between the layer thickness regulating blade 4 made of a non-magnetic material and the developing sleeve 20 is 350 μm, the rotation speed in the direction of the arrow of the magnet body 3 having N, 8 magnetic poles equally spaced 11 with a magnetic flux density of 900 Gauss is 7 GOr, p, m, the weight average particle size of the developer is about (capital) μm, the resistivity of the magnetic powder dispersed in the resin is about 1 x 10'', and the weight average particle size of the insulating magnetic carrier of gfi. The test was carried out under the conditions of using a two-component developer (developer for EP 310 manufactured by Minolta) consisting of an insulating non-magnetic toner with a diameter of 13 μm.

Electrostatic images with various potentials are formed on the image carrier using a gray scale, and an oscillating voltage with a period T or 500 μ$eC having a waveform as shown in FIG. 5 is applied to the developing sleeve 2 for development. The relationship between electrostatic image potential and recorded image immersion was determined. The Celsius experiment was repeated by changing the τA ratio of the applied periodic wave voltage, and the results shown in FIG. 9 were obtained.

Note that the development in this case is carried out without the magnetic brush formed on the developing sleeve 2 rubbing against the surface of the image carrier l.
A so-called non-contact jumping development method is used in which toner particles fly from a magnetic brush onto the surface of the image carrier l. The recorded image density is the image density of the recording paper obtained by transferring the developed toner image onto the recording paper by a transfer device (not shown) and fixing the transferred toner image by a fixing device. Even if development is performed by applying a periodic waveform voltage (FIG. 5) oscillated by a circuit as shown in FIG. 1M6, a recorded image density crystal and line similar to that shown in FIG. 9 can be obtained.

As is clear from Fig. 9, by simply changing the τ ratio without changing the amplitude, bias, or frequency of the periodic wave voltage, the recorded image density, that is, the development immersion level, can be improved even if the electrostatic image potential changes by aoovs. can be adjusted to 5 so that it remains constant, and this adjustment method allows the amplitude and bias to be
Since no change is made, there is little need to get used to the occurrence of fogging (therefore, it is possible to easily obtain clear recorded images with excellent gradation reproducibility).

Note that the method of the present invention is not limited to the above-mentioned example, and the waveform of the periodic wave voltage may be a rectangular wave, a sine wave, or another waveform to which phase control is applied.

In addition, in the above example, a trigger diode was used to configure the phase control circuit and waveform shaping was performed, but the circuit configuration is not limited to this.
), a silicon unilateral switch (8U8), a combination of a trigger element such as a neon tube and a thyristor, etc. may also be used. Furthermore, between the carrier l and the developing sleeve 2, a wire, hole, or dot-shaped control electrode is provided so as not to prevent the toner from flying from the magnetic brush to the electrostatic image, and the control electrode is connected to the control electrode. An oscillating electric field may be generated in the developing area by applying an oscillating voltage, and the present invention can also be applied to problems in which a magnetic brush rubs the surface of the image carrier 10. Furthermore, as in the examples, the challenge agent is a carrier (preferably one having a high resistivity of 1 QliΩ or more and a weight average particle size of (to) μm or less, and the above-mentioned resistivity is such that the particles are .150 (after placing in a container with a cross-sectional area of This is the value obtained by reading the current value when a This method is preferable because a clear recorded image can be obtained.
The present invention is not limited to this, but can also be applied to those using a -component developer. When the present inventors actually conducted an experiment using a one-component developer, it was possible to adjust the density of the recorded image, and favorable results were obtained.

In the present invention, it goes without saying that changes to change the τ/T ratio (change the conduction angle) can be made manually.
This can easily be done automatically using a computer or the like based on detection of electrostatic image potential, toner image density, etc. Of course, it can also be used in combination with the previously known conventional lobby level adjustment method. .

〔Effect of the invention〕

According to the present invention, as mentioned above, by changing the selection time of the time selection conversion, it is possible to greatly adjust the developing density without causing fog, and it is possible to achieve sharpness with excellent gradation reproducibility. The excellent effects of being able to obtain a recorded image and also being able to purchase a power supply device relatively easily can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a developing device that implements the method of the present invention, FIGS. 2 to 5 are waveform graphs showing examples of periodic waveform voltage, and FIG. Figure 7 is a professional diagram of a periodic wave voltage generator with variable waveform. Figure 8 is an example of a phase control circuit. Figure J9 is a graph showing the relationship between electrostatic image potential and recorded image immersion degree when the characteristics are changed. l... Co-carrier 2... Developing sleeve 3... Magnet 4... Layer thickness regulating blade 5... Cleaning blade 6... Developer reservoir 7... Stirring screw 8...
Toner hopper 9...Toner supply roller 1O...
Periodic voltage generation circuit 11...Waveform shaping circuit...DC power supply 53...
Protection Resistance Agent Yoshimi Kuwabara Figure 1 211 Figure 2 Figure 3 Figure 4 Figure 5/Figure 6/l Figure 7 1/ Figure 8 Figure 9 Blue War q1 Multi-Electric I,, ff) Procedure Written amendment dated July 18, 1980 Manabu Shiga, Commissioner of the Patent Office, Patent Application No. 240072 of 1988 2, Name of the invention Developing method 3, Name of the person making the amendment (127) Roku Konishi Photo Industry Co., Ltd. 4, Agent Person 〒191 Voluntary 6, "Detailed description of the invention" column of the specification subject to amendment, and drawings. 7. Contents of amendment (1) Specification page 6, line 1 d [Figure 4] is corrected to [Figure 5 1, (2) Specification #16 page 1 line d [Figure 2 [(Second
(3) In the third line of page 6 of the specification, [Fig. 5 is for Fig. 3 (B)] is corrected to [Fig. ) Specification w, page 46, line 3 [. "after" [. (5) Photoconductor consisting of #13th line F of specification book 7 purchase” was corrected to “before”.
[Negatively charged photoreceptor]. (6) Figure 9 of the drawings shall be corrected as shown in the attached sheet.

Claims (2)

[Claims] (1) A periodic waveform voltage is used to generate an oscillating electric field in the development area, and the electrostatic image on the image carrier is mapped by toner in the development area.
A developing method characterized in that the waveform of the periodic wave voltage is changed. (2) The developing method according to claim 1, wherein the oscillating electric field is formed using a 5K superimposed voltage of a periodic wave voltage and a DC voltage adjusted by phase control.