JPS61189580A - Developing device unit - Google Patents

Abstract

PURPOSE:To increase the number of colors of toner without any hindrance and to perform development with a proper developing bias corresponding to the kind of toner without any user's switching operation by providing a power source device for the developing bias. CONSTITUTION:The power source device for the developing bias is supplied with electric power of 5V from the control part 6 of a recording device side at such timing that the developing sleeve 4a of a developing device 4 performs development. A transistor Tr is turned on and off with a pulse of tens of kHz supplied from an oscillator 5a to switch a pulse transformer T1, thereby applying the developing bias voltage to the developing sleeve 4a. The developing device unit equipped with the power source device for the developing bias like this is used to detect the kind of toner of the developing device at the recording device side, thereby eliminating the need to control the developing bias voltage. Consequently, even if the number of colors of toner increases, the recording device body need not be altered at all and development is carried out on developing bias condition corresponding to the kind of the toner at any time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device used in a recording device such as an electrophotographic copying machine, and particularly to a developing device unit that is replaceably mounted.

[Prior art]

In conventional developing devices, whether the developing device is fixedly inserted into the recording device or the type is replaceably attached, a power supply device for developing bias is provided in the recording device main body other than the developing device. That is, the developing bias power supply device has been provided within the control board of the recording device, the low voltage or high voltage power supply device, or the like. There is also an example in which a power supply exclusively for developing bias is installed in the main body of the recording apparatus.

FIG. 1 shows an example of a conventional developing device, where l is a developing device that is either built into the main body of the recording device or is replaceably attached, 2 is a power supply device for developing bias, and 3 is a control device for the recording device. When the developing device 1 is a replaceably mounted unit, the developing sleeve 1a of the developing device 1 and the developing bias power supply device 2 are connected by being mounted.

On the other hand, in recent years, there has been an increase in the use of monochrome copiers that change the color of toner using replaceable developing unit units to produce high-quality images. In this case, in order to obtain a high-quality image by changing the toner color, it is necessary to change the developing bias voltage depending on the toner color. This point will be explained with reference to FIGS. 2 and 3.

Figure 2 shows the difference in the copy reflection density curve due to the difference in toner when developing with a single-component developer using magnetic toner.Track #A is a black color mixture containing FesOa powder as a magnetic material. For component magnetic toner, curve B
This is the case of a sepia-colored one-component magnetic toner containing γ-Fe 20 s powder as a magnetic material. Incidentally, the development was performed under the condition that the development bias voltage applied to the development sleeve having a surface magnetic flux density of 1000 Gauss was set to OV. Also,
The toner in Figure 2 is generally a magnetic toner. For black toners, black magnemate is used as the magnetic material, but for toners other than black, the desired color is used in combination with pigments or dyes. In order to obtain color, a magnetic material other than black, such as γ-Fe20B or Fe powder, is used as the magnetic material, so this is cited as a representative example of the difference in color. In this way, since the magnetic material of magnetic toner differs depending on the color, the magnetic properties of the toner also change, and therefore the curve A in Figure 2,
As shown in B, the development characteristics change. That is, song f
j! In the case of sepia toner B, the photoreceptor surface potential is O.
In contrast, when using the black toner of song 11A, fogging is less likely to occur. The developer bias voltage that must be applied to the developer sleeve to obtain a proper copy without fog was approximately -1207 volts for sepia toner and approximately -80 volts for black toner.

In addition, in the case of black toner, the reproducibility of documents with thin text deteriorated at a developing bias voltage of -120V. As can be seen from the above, in order to stably reproduce high-quality images with magnetic toner, it is necessary to change the developing bias voltage depending on the color.

Figure 3 shows the difference in the copy reflection density curve due to the difference in toner when developing with a 92-component developer using non-magnetic toner. Song IwC is for black toner, song @D is for red toner. be. Note that the conditions for the magnetic carrier of the developer are the same for both toners, and the conditions for the developing sleeve and developing bias voltage are the same as in FIG. Even in the case of non-magnetic toner colored with pigments or dyes using thermoplastic resin as a base, the development characteristics of the pigments or dyes are different as shown in Figure 3.In order to obtain proper copies without fogging, an electric current is applied to the developing sleeve. The developing bias voltage to be applied was about -200 V for the black toner of curve C, and about -140 V for the red toner of curve C. In other words, even in the case of non-magnetic toner, in order to obtain character reproducibility and stable image reproducibility,
The developing bias voltage must be changed depending on the color.

When the color of toner is changed by the developing device unit, in order to obtain a high-quality image, it is necessary to change the developing bias voltage depending on the color as described above. If the developing device unit is installed, a means for detecting which color toner is contained in the installed developing device unit is provided, and the developing bias voltage is set based on the detected information. Otherwise, the user is forced to switch the developing bias voltage. When the developing bias voltage is automatically set by the detection means, the device for this is quite complicated, and it is difficult to cope with the increase in the number of toner colors, and even if it could be done, There is a problem in that the number of sensors such as microswitches as a detection means increases, which greatly affects space and cost. Further, when the user switches, there is a problem that troubles may occur due to incorrect switching or forgetting to switch.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and does not require a detecting means for identifying toner supplies in the main body of the recording apparatus, so that the number of toner colors can be increased without any problems. Moreover, it is an object of the present invention to provide a developing device unit in which development can be performed with an appropriate developing bias according to the type of toner without requiring a switching operation by the user.

[Structure of the invention]

The present invention resides in a developing device unit characterized by comprising a source device for developing bias, and achieves the above object with this configuration.

〔Example〕

The present invention will be explained below with reference to the embodiments shown in FIGS. 4 to 8.

4 and 5 are circuit diagrams showing an example of the developing device unit of the present invention installed in a recording device and a circuit diagram of a developing bias power supply device, and FIGS. 6, 7, and 8 are circuit diagrams of the developing device unit according to the present invention. 4 is a schematic side view showing a configuration of another example of a developing device unit, a circuit diagram of a power supply device for developing bias, and a partial side view showing a switch opening/closing mechanism of a power supply battery circuit ◇ The developing device unit 4 in FIG. A developing bias power supply device 5 consisting of a circuit as shown in the figure is integrally provided, and by being installed in the recording device, the developing bias power supply device 5 can be connected to a control section 6 provided in the recording device main body. 11 source s7.

The developing bias power supply device shown in FIG. 5 is supplied with a power of 5 cm from a control section 6 on the recording apparatus main body side at the timing when the developing sleeve 4a of the developing device unit 4 performs development, and a power of several tens of kHz provided by an oscillator 5a. The transistor Tr is turned on and off by the pulse to switch the pulse transformer T1, and a developing bias voltage is applied to the developing sleeve 4a. This developing bias voltage can be adjusted by a variable resistor VR, and a high voltage of several hundreds of volts can be obtained.

By using a developing device unit equipped with such a power supply device for developing bias, there is no need to detect the type of toner in the developing device and control the developing bias voltage on the recording device main body side. Even if the number of toners increases, it can be adjusted by the developing device unit, so there is no need to make any changes to the main body of the recording apparatus, and development is always performed under developing bias conditions that are suitable for the type of toner.

The developing device unit 4 in FIG. 6 is integrally equipped with a developing bias power supply device 5 consisting of a circuit as shown in FIG. 7, and the developing bias power supply device 5 includes a drive battery circuit 5b. Since it is installed in the main body of the recording device, it does not require any electrical connection.

The developing bias power supply device shown in FIG. 7 is the same as the developing bias power supply device shown in FIG. 5 except that it includes a drive battery circuit 5b. In the drive battery circuit 5b, Sl is a switch that is turned on when the developing device unit 4 is attached to the recording apparatus or manually operated prior to attaching the developing device unit 4, and S2 is the developing sleeve 4a or This is a switch that turns on by detecting the rotation of the magnet inside it. G in FIG. 8 is a centrifugal governor that rotates with the rotation of the developing sleeve 4ai or the magnet, and the rotation is started before the latent image surface of the photoreceptor reaches the position of the developing sleeve 4a. Since fK is stopped after passing the position, development can be carried out under sufficient developing bias even if the switch S2 is turned on and off by the centrifugal governor G.

The current consumed by the application of the developing bias voltage is very small, on the order of μA, but as shown in FIGS. 7 and 8, the battery supplies power only when developing is performed using the switch S2. This can extend the life of your battery.

If such a developing device unit also includes a power source battery, there is no need to provide a power supply device on the recording device main body side.

〔Effect of the invention〕

According to the present invention, even if the number of toner colors increases and the number of developing device units increases, the developing units can have the same structure, and there is no need to change the main body of the recording device. An excellent effect can be obtained in that development can be performed under appropriate development bias conditions.

[Brief explanation of the drawing]

Fig. 1 is a developing bias voltage supply circuit diagram showing an example of a conventional developing device, Figs. 2 and 3 are development characteristic graphs showing that the appropriate developing bias voltage differs depending on the color of toner, and Figs. FIG. 5 is a circuit diagram showing an example of the developing device unit of the present invention when it is installed in a recording device and a circuit diagram of a power supply device for developing bias, and FIGS. FIG. 2 is a schematic side view of the configuration, a circuit diagram of a developing bias SM device, and a partial side view of a switch opening/closing mechanism of a power supply battery circuit. 1...Developing device, 1a...Developing sleeve,
2... Source device for development bias 1, 3... Control device, 4... Development device unit, 4a... Development sleeve, 5... Power supply device for development bias, 5a... Oscillator, 5b... Drive battery circuit, 6... Control section, 7... Power supply section, Tr.
...Transistor, T1...Transistor, VR, IJ variable resistance Sl, 82.2 (', /CH, G...Centrifugal governor. Patent applicant Konishi Rokuyoshin Kogyo Co., Ltd. Figure 1 Figure 2 6pt A book & 6J (standing (v) Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (3)

[Claims] (1) A developing device unit characterized by comprising a developing bias power supply device. (2) The developing device unit according to claim 1, wherein the power supply device is capable of changing a developing bias voltage. (3) The developing device unit according to claim 1 or 2, wherein the power source device includes a battery for driving the power source device, together with means for detecting rotation of the developing device and connecting the battery to the power source device.