JPH01133079A - Image forming device using developer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an image forming apparatus that attaches developer to a recording medium.

(Prior art) As an image forming method in which a developer is attached to a recording medium,
There is a method known from Japanese Patent Publication No. 51-46707.

In this method, as shown in FIG. 3-(a), a conductive magnetic developer 1 (hereinafter referred to as developer) is conveyed over a non-magnetic cylinder 3 by a rotating magnet 2 and passed over a recording electrode 4. .

Then, a voltage is applied between the conductive layer 7 of the recording medium 5 having the insulating layer 6 on the surface thereof and the recording electrode 4 through the power supply 14 and the recording control circuit 13, and the developer 1 is applied to the recording medium '5 to form an image. .

FIG. 3-(b) shows a schematic diagram of the recording electrode 4 seen from the front. The recording electrode 4 is formed by an electrode 4-1 and an insulation f4°-2 by etching a flexible printed board 4-3. Furthermore, flexible printed board 4-3
At the top, there is a connector for connecting a cable connected from outside the IC 1 that latches image information input from outside the driving IC 1 to drive the electrode 4-1.
The explanation will be given later.

As an advanced form of the image forming apparatus described above, a display apparatus using the recording electrode 4 has been considered.

When such a display device is used only for display purposes, the developer can be collected and used repeatedly. However, during repeated use, foreign substances other than the developer may be mixed in, or the developer itself may be destroyed, resulting in a decrease in the conductivity of the developer and deterioration of the image formed on the recording medium.

〔the purpose〕

The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide an image forming apparatus that can detect a decrease in the conductivity of a developer and prevent deterioration of an image formed on a recording medium. It is something to do.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows a sectional view of an image display device to which the present invention can be applied. 1 is a developer (toner), 4 is a recording electrode arranged in a row in the width direction of the recording medium 5, 8 is a cleaning member, 10 is a toner container, 11 is a recording medium support member, 12 is a main body frame, and 13 is a recording member. A control circuit, 14 a back plate provided opposite the cleaning member 8 via a recording medium, and 25 a display window provided with a cover such as a transparent acrylic plate.

In the above configuration, the toner 1 is attached or not attached to the recording medium 5 depending on the signal voltage from the recording electrode 4 to form an image. For example, when a signal voltage of 40 V is applied from the recording control 13, the toner 1 adheres to the recording medium, and when the voltage is OV, the toner 1 does not adhere, thereby forming an image. After an image is formed by the developer 1, the recording medium 5 is conveyed in the direction of the arrow and displayed on the display window 25, the image is further conveyed, and the toner on the recording medium is removed by the cleaning member 8, preparing for the next recording again. Note that the developer 1 stripped off by the cleaning member 8 is collected by gravity falling into the toner container 10 and is reused.

Next, the recording electrode 4 mentioned above will be explained in more detail.

FIG. 5(a) shows a structural diagram of the recording electrode, and FIG. 5(b) shows an enlarged view of the electrode portion. 4-4 is a connector for connecting an external cable, and 4-5 is an IC for receiving and amplifying external signals, for example, 5N7406 is used.

4-61 to 4-6a+ are 40-bit anode drivers, for example, MSCI 163GS manufactured by Oki Electric Co., Ltd. is used.

Therefore, the number of recording electrodes in this example is 40×41=1641
It is made up of dots.

FIG. 5-(a) shows an enlarged view of the electrode portion. The width of the electrode 4-1 in this example is 0.11 mm, and the insulation f
The width of 4-2 is 0.25 mm.

FIG. 6 shows a circuit diagram of the recording electrode 4, and FIG. 7 shows a timing chart. In FIG. 6, the same numbers are used for the same components as in other figures. 6-1 to 6-16
40 indicates the number of the portion in contact with the developer 1.

FIG. 7 shows a timing chart of signals received by the connector 4-4 in FIG. FIG. 7(a) shows the power source 14 in FIG.
The voltage generated is 40V, and (b) is the clear manual power, and the 40-bit anode driver 4-
The contents of the latch in 6 are not output to the output stage, and the latch output is output at a low level. (C) is a latch strobe signal, which is kept at a low level. (d) Data 40-bit anode driver 4-
This is a clock for reading into the shift register in 6, and (e) is data to be read by clock (d). In the case of Fig. 7, electrodes 6-1 to 6-164
0 alternates between high level (40V) and low level (OV), and black, white, black, and white images are printed.

In the timing chart of FIG. 7, when the CL signal (b) is Hi, one line of data (1640 bits) is read, and when it becomes Low, printing is started.

In the structure and developing method described above, the cleaning section 8
The developer 1 is collected and reused by passing the developer 1 through the recording medium 5. However, there is a method in which the cleaner section 8 forcibly strips the developer 1 from the recording medium 5 by mechanical means, such as a cleaning section. 8 is formed with a rubber blade, etc., and when it is pressed and rubbed, it may damage the recording medium 5 or scrape off the surface layer (dielectric layer), as shown in FIG. This creates a problem of mixing them within 1.

Furthermore, if an attempt is made to make the recording medium 5 endless using a material such as a resin (for example, polyethylene terephthalate (PET)), the seams may be damaged or fine powder of the resin may be mixed into the developer 1.

Furthermore, if the developer 1 is reused many times, the developer itself may scatter and become insufficient in quantity.

As mentioned above, if slag or fine powder is mixed into the developer 1, the magnetic force or conductivity of the developer 1 will be reduced (the life of the developer will be shortened), and
If the developer 1 is insufficient, the recording density may decrease, or in some cases, development may not occur.

Next, detection of the conductivity of the developer will be explained.

FIG. 1 is a diagram showing the basic configuration for detecting the conductivity of developer.

A resistor 15 detects the current flowing through the recording electrode 6, and a value is determined that does not affect the recorded image. In this embodiment, 10Ω is used. 18 is a comparator that compares the detected current with a predetermined value; 16.17 is the comparator 18;
This is a resistor that determines the slice level. In this embodiment, the slice level is set to 4V.

19 is a display device, and the output of the comparator 18 is Low.
It lights up when , indicating to the operator that the life of the developer 1 has come to an end or that there is a shortage of developer.

FIG. 2 is a diagram showing the principle of detecting the conductivity of developer. Figure 2-(a) shows the case where the developer 1 is new and there is a sufficient amount of it, and Figure 2-(b) shows the case where the developer 1 is old and contains dust 1' etc. This shows that the amount of the drug is also decreasing. As is clear from the figure, in (a), the magnetic brush of the conductive magnetic developer 1 formed by the rotating magnet 2 (not shown) is long enough to reach the recording medium 5.

In (b), the length of the magnetic brush of the developer 1 formed by the rotating magnet 2 (not shown) is shortened due to the lack of developer and the amount of 1' mixed in the developer, and the recording medium 5 has not been reached. As a result, image loss occurs on the recording medium or the density decreases.

The voltage applied to the recording electrode in FIG. 2 when detecting the conductivity of the developer is 40V for the recording electrode 6-1.
, 6-2 is OV, 6-3 is 40V, 6-4 is OV, 6-
5 is applied with 40V, and 6-6 is applied with OV. When voltages of 40V and OV are applied alternately to the recording electrode 6 in this way, the current flowing from the recording type Vj16-1 to which 40V is applied flows to the recording medium 5, and the current flowing to the adjacent o The current flows to the electrode. That is, if the current flowing to the electrode applied to 40V is 1, the current flowing to the recording medium is i, and the current flowing to the electrode applied to OV is 12, then I, = i, +i.

becomes. When the developer is new as shown in (a), 11 has a value of 100 μA, and i has a value of about 500 μA.

In the case of this example, since the number of electrodes is 1640, the power supply 1
The current A1 flowing from 4 is AH= (il +i2)xi 640÷2=600
X820 = 492mA.

However, as shown in (b), if the developer 1 is insufficient or if dust 1' is mixed in, the conductivity of the developer decreases, and the resistance value between the recording medium 5 and the recording electrode 6 and the resistance value between the electrodes decreases. The current i5 between the upstream recording medium 5 and the electrode 6, and the current i4 between the recording electrodes are (
It is extremely small compared to case a).

As confirmed experimentally, the current value A1 flowing out from the power supply 14
It has been found that when the current reaches about 300 mA, recorded images become blurred or faded.

In this embodiment, deterioration of the developer is detected and notified by detecting the change in the recording current due to the deterioration of the developer.

Its operation will be explained with reference to FIG. While the image forming apparatus is on standby, an ON/OFF alternating signal, which is a test pattern built in an image reading device (not shown), an image generating device such as an electronic file, or the recording control circuit 13, is manually input, and the control electrode 6 is turned on. A voltage is applied as shown in Figure 1. Then, when the developer 1 is in the state shown in FIG. 2-(a), the current value flowing through the resistor 15 is 492 mA, and the voltage generated across the resistor 15 is: ■=10Ωxo, 492=4.92V It is. This voltage is input to the normal input terminal of the comparator 18, and as described above, the slice level of the comparator 18 is set to 4. Ov, the output of the comparator 18 becomes high level, and the display 19 does not display anything.

However, in the state shown in Figure 2-(b), the resistance 1
The current value flowing through 5 is 300 mA, and 3 is applied to the normal input of the comparator. OV is applied. Therefore, the output of the comparator 18 becomes Low, and the display 19 lights up to notify the operator of the lack of developer or the end of its life.

In the embodiment described above, an image forming apparatus using a stylus head was used, but the present invention can also be used as a device for detecting the contact state of a Lina device as shown in FIG. 20 is a drum on which recording is performed by a recording means (not shown); 21 is a cleaner configured with a conductive brush and erases the image recorded on the drum; and 22 is an aluminum member that supports the cleaner. In this embodiment, if the brush constituted by the conductive brush wears out and the contact condition deteriorates, the current flowing through the brush decreases, and the lifespan of the brush can be determined by detecting the current value used in the above embodiment.

〔effect〕

As described above, according to the present invention, when developer deteriorates or becomes insufficient, this abnormality can be detected with a simple structure.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams for explaining the detection of the conductivity of the developer, Figure 3 is a diagram for explaining the developing method, and Figure 4 is a cross-sectional diagram of an image display device to which the present invention can be applied. , FIG. 5 is a diagram showing a recording electrode, FIG. 6 is a circuit diagram inside the recording electrode, FIG. 7 is a timing chart, and FIG. 8 is a diagram showing another embodiment of the present invention. 1 is a conductive magnetic toner, 2 is a rotating magnet, 3 is a non-magnetic cylinder, 4 is a recording electrode, 5 is a recording medium, 6 is an insulating layer, 7 is a conductive layer, 8 is a cleaning member, 10 is a toner container, 11 is a recording medium support member, 13 a recording control circuit, 14 a power supply,
15, 16, and 17 are resistors, 18 is an operational amplifier, and 19 is a display.

Claims (2)

[Claims] (1) In an image forming apparatus that includes a recording medium for forming an image and a developing means for developing an image on the recording medium and repeatedly uses a developer, a means for detecting the conductivity of the developer; An image forming apparatus using a developer, characterized in that the image forming apparatus uses a developer, further comprising a notification device for notifying an abnormality of the developer when the electrical conductivity detected by the detection device is smaller than a predetermined value. (2) According to claim 1, the developer is characterized in that it has an electrode for forming a latent image on the recording medium, and the detection means detects the value of the current flowing through the electrode. Image forming device.