KR100354761B1 - Developer conductivity measurement apparatus and developer supply apparatus of the printer employing the same - Google Patents

Abstract

Disclosed are a conductivity measuring device of a developer and a developer supplying device of a printing press to which the same is applied. The conductivity measuring device generates an alternating current signal through a plurality of first and second electrodes provided in a container in which the developer to be inspected is stored, and both ends thereof, and one end thereof is connected to the first electrode through the first resistance element. An alternator connected to the second electrode, a rectifier for rectifying and converting a signal generated between the first resistor element and the first electrode into a direct current signal, and generating a frequency signal corresponding to a change in the voltage signal output from the rectifier A voltage controlled oscillator and a conductivity measuring unit for measuring the conductivity of the developer from the frequency output from the voltage controlled oscillator. According to the conductivity measuring device of the developer and the developer supplying device of the printing press to which the developer is applied, the conductivity measurement resolution of the developer under test becomes high, and as a result, the developer under test can be easily adjusted within the target conductivity range. In addition, the use of a constant voltage AC power supply reduces the possibility of signal distortion by external factors, thereby increasing measurement accuracy.

Description

Developer conductivity measuring apparatus and developer supply apparatus of the printer employing the same {developer conductivity measurement apparatus and developer supply apparatus of the printer employing the same}

The present invention relates to a device for measuring conductivity of a developer and a developer supplying device of a printing machine to which the same is applied.

1 is a cross-sectional view showing a general wet printing machine.

Referring to the drawings, a printing machine using a developing solution includes a plurality of rollers (11, 12, 13), a photosensitive belt (14), a reset device (15), optical scanning devices (16), developer (30), The drying apparatus 18 and the transfer apparatus 20 are provided.

The reset device 15 includes an exposure machine 15a for irradiating light to the photosensitive belt 14 to remove the electrostatic latent image, and a charger 15b for charging the photosensitive belt 14 with a potential of a predetermined level. .

The four optical scanning devices 16 scan yellow (Y), magenta (M), cyan (C), and black (K) color information, and the four developing devices 30 are yellow (Y) and magenta ( The developer of M), cyan (C), and black (K) colors is supplied to the photosensitive belt 14.

The developing device 30 includes a developing solution supply container 32 for supplying a developing solution to the photosensitive belt 14, and a developing tank 31 for recovering the developing solution falling from the photosensitive belt 14. In the developing tank 31, the developing roller 36, the brush roller 37 for removing the developer from the developing roller 36, and the developing solution supplied to the photosensitive belt 14 are not involved in image formation. In this case, a squeeze roller 34 for separating the liquid carrier element as a solvent and a plate 35 for recovering the carrier element of the liquid sand flowing along the outer circumferential surface of the squeeze roller 34 into the developing tank 31 are provided. .

The developer supply container 32 supplies the developer stored in the developing tank 31 and the developer carrier N (nopar), which is a solvent, and a toner or a highly concentrated developer, which is a charged developer, from the developer supply unit 38, respectively. I can receive it. The developer stored in the developer supply container 32 is supplied between the developing roller 36 and the photosensitive belt 14 by the driving of the pump P. FIG.

Looking at the printing process of such a wet printer, first, the optical scanning device 16 scans the light to a predetermined region of the photosensitive belt 14 circulating through the reset device (15). An electrostatic latent image is formed in the photosensitive belt 14 by the scanned light, and the electrostatic latent image is developed by the toner charged in the developer supplied from the developer supply container 32 of the developer 30. A color image is formed on the photosensitive belt 14 by the optical scanning devices 16 and the developing devices 30 which scan light of mutually different color information and develop the developer with a color corresponding thereto. Most of the liquid carrier elements which are not involved in image formation among the developer supplied from the developing device 30 to the photosensitive belt 14 during the developing process are mostly recovered into the developing tank 31. Drying apparatus for adsorbing and evaporating and recovering the liquid carrier element remaining on the photosensitive belt 14 by the continuous movement of the photosensitive belt 14, the color image formed by the toner as the developing material on the photosensitive belt 14 Through 18, the photosensitive belt 14 and a portion thereof are primarily transferred to the transfer roller 21 which is rotated in engagement with the photosensitive belt 14. Subsequently, the image on the transfer roller 21 is rotated by the rotation of the transfer roller 21 and the fixing roller 22, which advance the paper 23 by the interlocking rotation with the inserted paper 23 therebetween. 23) secondarily.

On the other hand, in order for the desired amount of toner to adhere to the electrostatic latent image formed on the photosensitive belt, the conductivity of the toner must be maintained within a predetermined range. The change in the conductivity of the toner is directly related to the change in the amount of toner attached to the unit area of the electrostatic latent image area of the photosensitive belt 14 charged to a predetermined potential and affects the image quality. By the way, a toner made of a mixture of various components has a change in conductivity depending on temperature.

U.S. Patent Nos. 4,310,238 and 4,860,924 disclose techniques for controlling the conductivity of a developer to a certain range. However, the above-described conventional conductivity measuring device is capable of determining whether to supply a component capable of adjusting conductivity only by comparing a signal generated corresponding to the conductivity with a reference signal, so that the conductivity of the developer cannot be accurately measured. By using a commercial AC power supply across both electrodes, the AC power fluctuations are caused by measurement errors.

The present invention was devised to improve the above problems, and provides an apparatus for measuring the conductivity of a developer capable of precisely measuring the conductivity of the developer and increasing the measurement accuracy, and a developer supplying device of the printing press using the same. There is this.

1 is a view showing a general printing press,

2 is a view showing a printing machine according to the present invention,

3 is a flow chart illustrating a process of measuring the conductivity of the developer and controlling the developer supply therefrom.

<Explanation of symbols for the main parts of the drawings>

14: photosensitive belt 15a: exposure machine

15b: Daejeon 16: Gwangjusa Unit

18: drying apparatus 20: transfer apparatus

21: transfer roller 22: fixing roller

23: paper 30: developer

31: developer tank 32: developer supply container

34: squeeze roller 35: plate

36: developer roller 37: brush roller

38, 83: developer supply portion 41: first electrode

42: second electrode 43: DC-AC converter

50: rectifier 60: voltage controlled oscillator

70: counter 80: controller

81: conductivity measuring unit 82: look-up table (LUT)

84: input device 85: display device

In order to achieve the above object, the conductivity measuring device of a developer according to the present invention comprises: a plurality of first and second electrodes installed in a container in which a developer under test is stored; An alternating current signal generated through both ends thereof, one end of which is connected to the first electrode via a first resistance element, and the other end of which is connected to the second electrode; A rectifier for rectifying the signal generated between the first resistance element and the first electrode and converting the signal into a DC signal; And a voltage controlled oscillator for generating a frequency signal corresponding to a change in the voltage signal output from the rectifier; a conductivity measuring unit measuring a conductivity of the developer from a frequency output from the voltage controlled oscillator.

Preferably the rectifier is a voltage follower; And a diode for rectifying the signal output between the first resistance element and the first electrode via the voltage follower and outputting the signal to the voltage controlled oscillator.

The apparatus may further include a discharge circuit capable of charging / discharging the signal passing through the diode such that the signal passing through the diode is changed to correspond to the conductivity of the developer.

The alternator includes a direct current power source; And a DC-AC converter converting the DC power into AC power and outputting the DC power to the first and second electrodes.

In addition, the developer supplying apparatus of the printer according to the present invention comprises: a plurality of first and second electrodes installed in a container in which a developer to be supplied to the photosensitive medium is stored; A developer supplying unit configured to supply a liquid carrier element and a highly concentrated developer or toner into the container; An alternating current signal generated through both ends thereof, one end of which is connected to the first electrode via a first resistance element, and the other end of which is connected to the second electrode; A rectifier for rectifying the signal generated between the first resistance element and the first electrode and converting the signal into a DC signal; A voltage controlled oscillator for generating a frequency signal corresponding to a change in the voltage signal output from the rectifier; measuring the conductivity of the developer from the frequency output from the voltage controlled oscillator and maintaining the conductivity of the developer in the container within a set range And a controller for controlling the developer supply unit so as to be possible.

Hereinafter, an apparatus for measuring conductivity of a developer according to a preferred embodiment of the present invention with reference to the accompanying drawings and a developer supplying device of a printer to which the same is applied will be described in detail.

2 is a view showing a printing machine according to the present invention.

Referring to the drawings, the conductivity measuring device includes a first and second electrodes 41 and 42, a DC power supply (Vo), a DC-AC converter (43), a rectifier (50) and a voltage controlled oscillator. a voltage controlled oscillator 60, a counter 70, and a conductivity measuring unit 81 are provided. Reference numeral 44 is an equivalent circuit for when the first and second electrodes 41 and 42 are contained in the developer, and the effective resistance component between the first and second electrodes 41 and 42 is denoted by Re, and is effective. The capacitance is indicated by Ce. Reference numerals a and b denote corresponding positions to which the first and second electrodes are connected in the circuit diagram labeled equivalent circuit.

The first and second electrodes 41 and 42 are provided at predetermined intervals in the container 45 in which the developer under test is stored. The container 45 corresponds to the developer supply container 32 in FIG. 1.

The DC-AC converter 43 generates an AC signal to be applied to the first and second electrodes 41 and 42. The DC-AC converter 43 converts the DC signal input from the DC power source Vo into an AC signal. The AC signal generated from the DC-AC converter 43 can reduce the voltage fluctuation rate rather than directly applying the commercial AC power to the first and second electrodes 41 and 42 so that the conductivity measurement error can be suppressed. Do it.

The signal generated at one end of the AC signal generated at both ends of the DC-AC converter 43 is applied to the first electrode 41 through the first resistance element R1.

The rectifier 50 receives the voltage signal V1 generated between the first resistor element R1 and the first electrode 41. A voltage signal corresponding to a change in the effective resistance Re, which is substantially changed corresponding to the conductivity of the first resistance element R1 and the developer, is applied to the rectifier 50.

The rectifier 50 includes a voltage follower 51, a diode 52, and a discharge circuit 53.

The voltage follower 51 has the effect of increasing the input impedance and lowering the output impedance. The AC signal passing through the voltage follower 51 is rectified by the diode 52 and then converted into the DC signal V2 through the capacitor C1.

The discharge circuit 53 is provided with a discharge resistor R2 for discharging the DC voltage signal V2 generated by being charged in the capacitor C1 to be linked to the variation of the input voltage. The discharge time constant of the discharge circuit 53 is preferably set at least five times larger than the frequency of the AC signal generated by the DC-AC converter 43.

The voltage signal V2 generated through the rectifier 50 is converted into a frequency signal through the voltage controlled oscillator 60.

The voltage controlled oscillator 60 outputs a result of comparing the signal V2 passed through the rectifier 50 with the voltage signal of the capacitor C2 connected in series from the DC power supply Vo through the resistor R3. Comparator 61 is provided. The output signal of the comparator 61 is connected to the base terminal of the transistor 62 which is a switching element, and the collector terminal of the transistor 62 is connected between the resistor element R3 and the capacitor C2. At the output terminal of the comparator 61, a square wave of a frequency corresponding to the level variation of the voltage signal V2 output from the rectifier 50 is generated.

The counter 70 receives the square wave output from the output terminal of the comparator 61 and counts it.

The conductivity measuring unit 81 calculates the conductivity of the developer from the number of square waves counted by the counter 70 during the set time. In the look-up table (LUT) 82, a conductivity value corresponding to the number of square waves generated during a set time is obtained by experiment and recorded. Therefore, the conductivity measuring unit 81 resets the counter 70 in the conductivity measurement mode, receives the number of square waves counted from the counter 70 for a set time, and looks up the conductivity of the developer corresponding to the number of square waves received. The table 81 finds and calculates.

As described above, in the conductivity measuring device according to the present invention, the conductivity measurement resolution is improved by measuring the conductivity by changing the voltage signal input corresponding to the conductivity of the developer under test from the electrodes 41 and 42 into a frequency signal.

In the developing solution supply apparatus of the printing machine to which the conductivity measuring device is applied, the conductivity measuring unit 81 may be installed on the controller 80 that controls the overall printing press.

The controller 80 processes the signal input from the input device 81, displays necessary display information through the display device 82, and controls the developer supply unit 83 so that the conductivity is maintained within a predetermined range.

The developer supply unit 83 is a container 45 in which the electrodes 41 and 42 are installed, for example, a developer supply container for supplying a developer to a photosensitive medium (see FIG. 1; 32). It is possible to supply.

Therefore, the controller 80 controls the developer supply unit 83 such that the highly concentrated developer or liquid carrier element is supplied into the container 45 so that the conductivity of the developer calculated by the conductivity measuring unit 81 does not deviate from the set range. .

The conductivity measurement process and the supply control process of the developer will be described with reference to FIG. 3.

First, in the conductivity measurement mode, the counter is reset (step 100). Then, the count of the number of square waves output from the counter is started (step 110).

In step 120, it is determined whether the square wave counting time of the counter reaches the set target count time.

If it is determined that the target count time set in step 120 has been reached, the counted value is read from the counter (step 130).

Next, the conductivity corresponding to the read count value is found in the lookup table 82 to calculate the conductivity of the developer (step 140).

In step 150, it is determined whether the conductivity calculated in step 140 matches the set reference value.

When the conductivity calculated in step 150 coincides with the set reference value, the conductivity measurement mode is terminated. When the calculated conductivity is different from the set reference value, the set conductivity control routine, which is a subsequent step, is performed (step 160).

As the conductivity control routine (step 160), for example, when the measured conductivity is lower than the reference value, a highly concentrated developer is supplied to the container 45 to control the conductivity of the developer under test to reach the set reference value. Alternatively, when the developer supply unit 83 is able to directly supply the charge director (charge director), which is a component directly related to the conductivity of the components of the toner, to the container 45, the charge director is supplied into the container 45. do.

On the contrary, when the measured conductivity is larger than the reference value, the liquid carrier element is supplied to the container 45 to control the conductivity of the developer under test to reach the set reference value.

In addition, as the conductivity control routine (step 160), the display device 82 may be notified to the user that the conductivity control process is performed.

As described so far, according to the conductivity measuring device of the developer according to the present invention and the developer supplying device of the printer to which the same is applied, the conductivity measurement resolution of the developer under test is increased, and as a result, the developer under test can be easily adjusted within the target conductivity range. Become. In addition, the use of a constant voltage AC power supply reduces the possibility of signal distortion by external factors, thereby increasing measurement accuracy.

Claims (8)

A plurality of first and second electrodes provided in a container in which the developer to be inspected is stored; An alternating current signal generated through both ends thereof, one end of which is connected to the first electrode via a first resistance element, and the other end of which is connected to the second electrode; A rectifier for rectifying the signal generated between the first resistance element and the first electrode and converting the signal into a DC signal; A voltage controlled oscillator for generating a frequency signal corresponding to a change in the voltage signal output from the rectifier; And a conductivity measuring unit for measuring the conductivity of the developer from the frequency output from the voltage controlled oscillator. The method of claim 1, The rectifying unit Voltage follower; And a diode for rectifying the signal output between the first resistance element and the first electrode via the voltage follower and outputting the signal to the voltage controlled oscillator. The method of claim 2, And a discharge circuit capable of charging / discharging the signal passing through the diode so that the signal passing through the diode is changed to correspond to the conductivity of the developer. The method of claim 1, The alternator is DC power supply; And a DC-AC converter for converting the DC power into an AC power and outputting the DC power to the first and second electrodes. A plurality of first and second electrodes provided in a container in which a developer to be supplied to the photosensitive medium is stored; A developer supplying unit configured to supply a liquid carrier element and a highly concentrated developer or toner into the container; An alternating current signal generated through both ends thereof, one end of which is connected to the first electrode via a first resistance element, and the other end of which is connected to the second electrode; A rectifier for rectifying the signal generated between the first resistance element and the first electrode and converting the signal into a DC signal; A voltage controlled oscillator for generating a frequency signal corresponding to a change in the voltage signal output from the rectifier; A developer for measuring the conductivity of the developer from the frequency output from the voltage controlled oscillator and controlling the developer supply unit so that the conductivity of the developer in the container is maintained within a set range. . The method of claim 5, The rectifying unit Voltage follower; And a diode for rectifying the signal output between the first resistance element and the first electrode via the voltage follower and outputting the signal to the voltage controlled oscillator. The method of claim 6, And a discharge circuit capable of charging / discharging the signal passing through the diode so that the signal passing through the diode is changed to correspond to the conductivity of the developing solution. The method of claim 5, The alternator is DC power supply; And a DC-AC converter for converting the DC power into an AC power and outputting the DC power to the first and second electrodes.