JPH0531147B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention is applicable to, for example, an electronic copying machine, etc.
The present invention relates to a novel developing device that develops an electrostatic latent image formed on a photosensitive drum in a non-contact manner. [Technical background of the invention and its problems] Conventionally, the magnetic brush development method, cascade development method, fur brush development method, etc. have been well known as developing methods for electrostatic latent images, but recently a method completely different from these has been developed. New development methods are being considered. For example, as shown in FIG. 1, a toner carrier 3 is provided opposite to a photoreceptor drum 1 and has linear electrode groups 2 arranged at regular intervals on its surface.
By sequentially applying a potential that changes over time to generate an alternating electric field between each electrode, the non-magnetic toner 4 is moved between each electrode along the direction in which the electrodes are arranged, and the lines of electric force are Therefore, by moving the toner 4 upward toward the photoreceptor drum 1 while vibrating, floating, and turning into smoke, the toner 4 is transferred to the electrostatic latent image on the photoreceptor drum 1.
It is intended to supply However, this developing method had the following problems. That is, in the portion of the electrode group 2 that does not face the electrostatic latent image surface of the photoreceptor drum 1, toner conveyance is important, and there is no need for the toner to fly up excessively. On the other hand, in the electrode group facing the electrostatic latent image surface, toner transportability is also important, but the most important thing is that the toner flies high and is sufficiently smoked. However, if the voltage application method to the electrode group is the same, it is impossible to fully satisfy both functions at the same time. For this reason,
Reliable development cannot be performed, uneven development occurs, and high-quality images cannot always be obtained. [Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to provide a developing device that enables more reliable development and always provides high-quality images without uneven development. Our goal is to provide the following. [Summary of the Invention] The present invention applies a time-varying potential to a group of electrodes provided near the surface to be developed, some of which are provided opposite to the surface to be developed. In a developing device that moves developer and conveys the developer to a surface to be developed, a method for applying voltage to an electrode group not facing the surface to be developed and a method for applying voltage to a group of electrodes facing the surface to be developed are separated. , the conventional problems are eliminated by providing potential distribution changes suitable for each function. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 11 denotes, for example, a photosensitive drum of electronic copying material, which rotates in the direction of arrow a in the figure. The photosensitive drum 11 is an aluminum drum 1.
A selenium/tellurium based photosensitive layer 13 as an electrostatic image carrier is formed on the surface of the photosensitive layer 13.
For example, a negatively charged electrostatic latent image 14 is formed thereon. Note that the drum 12 is grounded. A developing device 15 according to the present invention is provided opposite to the photosensitive drum 11, and is configured as follows. That is, a toner container 16 stores non-magnetic toner 17 as a developer. This toner container 16 has an opening 18 formed on its upper surface at a portion facing the photoreceptor drum 11, and its bottom surface is formed into an inclined surface that descends from the right end toward the left end in the drawing. ing. A plate-shaped toner carrier 19 is provided within the toner container 16 . The toner carrier 19 has a horizontal portion 19a and an inclined portion 19b that bends downward from approximately the center and descends toward the left end. The horizontal portion 19a faces the surface of the photoreceptor drum 11 through the opening 18 of the toner container 16, and the distance from the surface of the photoreceptor drum 11 is maintained at about 2.0 mm. Further, the end portion of the inclined portion 19b is immersed in the toner 17. On the surface of the toner carrier 19, there are provided electrode groups 20 made of copper and arranged in parallel with the axial direction of the photoreceptor drum 11 at equal intervals, each of which has a linear shape. This electrode group 20 is formed on the toner carrier 19 by, for example, printing, etching, or vapor deposition.
Its electrode width is about 0.1~0.5mm, and the electrode spacing is about 0.1~0.5mm.
It is kept at 0.5mm. In addition, 21 is toner 17
It is a stirrer that stirs. Now, each electrode of the electrode group 20 configured as described above is connected and grouped as shown in FIG. 3, for example. That is, electrode group 2
The electrode group 20a is provided at a portion that does not face the photosensitive drum 11 of No. 0, that is, at the left end of the inclined portion 19b of the toner carrier 19 and the horizontal portion 19a following the inclined portion 19b.
is divided into, for example, eight groups n0 to n7, and the electrodes belonging to one electrode group are connected every eight. Further, the electrode group 20b excluding the electrode group 20a (that is, the horizontal portion 19
The electrode group (a) provided opposite to the photosensitive drum 11 and the surrounding electrode group) are divided into, for example, two groups m0 and m1, and are alternately connected to each other. And each electrode group n0~
Voltages are applied to n7, m0, and m1 by the control circuit shown in FIGS. 4 to 8, and the details thereof will be explained below. FIGS. 4 to 8 show a control circuit that controls the application of voltage to the electrode groups 20a and 20b grouped as shown in FIG. First, FIG. 4 schematically shows the overall configuration. A reference oscillator 31 determines the scanning speed of the voltage applied to the electrode group, and a counting operation is performed by the pulses output from this oscillator 31. an octal counter 32 that controls the voltage scanning period;
Depending on the value of voltage control code VC ₀₀ ~ VC ₀₃ , VC ₁₀
~VC ₁₃ , VC ₂₀ ~VC ₂₃ , VC ₃₀ ~ _{VC 33} , VC ₄₀ ~
VC ₄₃ , VC ₅₀ ~ _{VC 53} , VC ₆₀ ~ _{VC 63} , VC ₇₀ ~ _{VC 73}
A voltage control code generation circuit 33 generates voltages E _o0 to _{E o7} corresponding to each voltage control code from the voltage control code generation circuit 33.
The first control voltage generating circuit 34 generates a voltage and applies it to the electrode group 20a, and operates based on the outputs of the oscillator 31 and the counter 32, and alternately outputs "1" level signals VC ₈ and VC ₉ . a second control voltage generator that generates voltages E _n0 and E _n1 according to the respective signals VC ₈ and VC ₉ from the alternate on signal generation circuit 35 and applies them to the electrode group 20b; It is constituted by a circuit 36. FIG. 5 shows the voltage control code generation circuit 33 in detail, and shows the output of the counter 32 (A ₀ ,
A decoder 37 for decoding (A ₁ , A ₂ ), and code generation circuits 38 ₀ to 38 ₇ connected in cascade to each output terminal of this decoder 37 and generating voltage control codes to each electrode group n0 to n7. be done.
Each of the code generation circuits 38 ₀ to 38 ₇ is constructed of, for example, a diode matrix circuit (ROM), and stores an output code corresponding to an address in advance, and outputs it as the address changes specified by the counter 32. The code is starting to change. FIG. 6 shows the first control voltage generation circuit 34 in detail, and shows the voltage control code generation circuit 33 in detail.
Voltage E _o0 ~ _{E o7} corresponding to each voltage control code from
It is constituted by voltage generating circuits 39 ₀ to 39 ₇ that generate and apply voltage to each electrode group n0 to n7, respectively. The voltage generation circuits 39 ₀ to 39 ₇ include output voltage control transistors Q ₀ that are turned on and off in response to voltage control codes (for example, VC ₀₀ to _{VC 03} ).
~ _Q3 , resistors _R1 ~ _R8 for operating these transistors _Q0 ~ _Q3 , resistors _R9 ~ for dividing the power supply voltage E according to the ON/OFF operation of the transistors _Q0 ~ _Q3 . Composed of R ₁₂ . Note that the resistors R ₉ to R ₁₂ are set to, for example, the value of the resistor R ₁₀ as R, the resistors R ₉ and R ₁₁ are set to 3R, and the resistor R ₁₂ is set to 9R. Here, the voltage control code (for example,
The relationship between VC ₀₀ to VC ₀₃ ) and output voltage (E _o0 ) is shown in the table below.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a developing device that enables more reliable development and that consistently produces high-quality images without uneven development.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining a conventionally considered developing method, FIGS. 2 to 9 are for explaining an embodiment of the present invention, and FIG. 2 is an overall configuration diagram, Figure 3 is a diagram showing the connection state of the electrode group, Figure 4
The figure is a schematic diagram of a control circuit that controls the application of voltage to the electrode group, Figure 5 is a diagram of a voltage control code generation circuit, Figure 6 is a diagram of a first control voltage generation circuit, and Figure 7 is a diagram of a control circuit that controls voltage application to an electrode group. is the configuration diagram of the alternating ON signal generation circuit,
FIG. 8 is a block diagram of the second control voltage generation circuit, and FIG. 9 is a diagram schematically showing an example of potential distribution applied to each electrode of the electrode group. 11... Photosensitive drum, 14... Electrostatic latent image, 1
5...Developing device, 16...Toner container, 17...
Non-magnetic toner, 19... Toner carrier, 20...
Electrode group, 20a... Electrode group not facing the photosensitive drum, 20b... Electrode group facing the photosensitive drum, 31... Oscillator, 32... Counter, 33...
...Voltage control code generation circuit, 34...First control voltage generation circuit, 35...Alternate ON signal generation circuit, 3
6...Second control voltage generation circuit.

Claims (1)

[Scope of Claims] 1. Applying a potential that changes over time to a group of electrodes provided near the surface to be developed of the image carrier, some of which are provided opposite to the surface to be developed of the image carrier. In a developing device that moves developer between electrodes and conveys the developer to a surface to be developed, the developer is provided at a position facing the surface to be developed and a position not facing the surface to be developed; It has a developer carrier that carries a developer, and a plurality of electrode groups are arranged on the developer carrier in parallel with the axial direction of the image carrier, and further includes a plurality of electrode groups arranged on the developer carrier in parallel with the axial direction of the image carrier. The first electrode group includes a first electrode group provided at a position not facing the surface, and a second electrode group provided at a position facing the developed surface of the image carrier, and the first electrode group
A voltage is applied to the second electrode group so that the potential distribution changes over time in the form of a traveling wave with a constant traveling direction, and to the second electrode group, A developing device characterized in that a group is divided into a plurality of groups, and different voltages are applied to each of the plurality of groups so that the potential distribution changes over time without having a fixed direction of progress.