JPH01227167A - image forming device - Google Patents

Abstract

PURPOSE:To obtain stable recorded images constantly by controlling a voltage impressed on a recording electrode according to the fatigue of developer or that of an image carrying means. CONSTITUTION:A recording medium using signal 17' of one pulse is generated whenever a recording medium makes a round. An impressed voltage control circuit increases the voltage impressed on the recording electrode 4 through a recording control circuit 13 along with an increase in the using frequency of the recording medium. The title device is provided with a counter 18 counting up the pulses of the recording medium using signals 17' and a D/A converter 19 boosting an output voltage along with an increase in the number counted by the counter 18. Decrease in image density, which is caused by the fatigue of the image carrying means and deterioration in toner developer due to increase in the using frequency of the device, can be prevented by varying the voltage impressed on the recording electrode. Thus, a stable image can be formed constantly.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention applies a voltage between a recording electrode and a recording medium to attach image forming particles (developer) to the recording medium, such as in a printer or a display device. The present invention relates to a forming device.

[Prior art] Such an image forming method is disclosed in Japanese Patent Publication No. 51-4870.
There is Publication No. 7.

In this method, as shown in FIG. 6-(b), a conductive magnetic developer 1 (hereinafter referred to as developer) is transported over a non-magnetic cylinder 3 surrounded by a rotating magnet 2. It passes over the recording electrode 4 provided on the outer peripheral surface. Then, a voltage is applied between the conductive layer 7 of the recording medium 5 having the insulating layer 6 on the surface and the recording electrode 4 through the power supply 14 and the recording control circuit 13, and the developer 1 is attached to the recording medium 5 to form an image. .

As shown in FIG. 7, the recording electrode 4 is formed by etching a large number of electrodes 4-1 on a flexible printed board 4-3.
A drive IC for driving the electrode 4-1 and an IC for latching image information input from the outside are provided on the flexible printed board 4-3 with an insulating band 4-2 separating them.
, a connector for connecting a cable connected from the outside, etc. are provided.

A display device as shown in FIG. 8 has been proposed using such an image forming method. 1 is a toner developer, 4 is a recording electrode, 5 is an endless belt-shaped recording medium, 8 is a cleaning member, 10 is a toner container containing the toner developer, 11 is a recording medium support member, 12 is a main body frame, 13 is a The recording control circuit 14 indicates a back plate provided facing the cleaning member 8 with the recording medium 5 interposed therebetween.

In the above configuration, an image is formed by toner 1 adhering or not to the recording medium 5 depending on the signal pressure from the recording electrode 4, for example, the signal voltage from the recording control circuit 13. When 40V is applied, the developer 1 adheres to the recording medium 5, and when the voltage is 0V, it does not adhere, forming an image. After that, it is erased by the cleaning member 8 and prepared for the next recording again. The toner 1 scraped off by the cleaning member 8 is collected in the toner container 1° by nature and reused.

[Problems to be Solved by the Invention] Incidentally, in such a display device, the developer 1 is collected by the cleaning member 8 and reused, but the cleaner member 8 is forced to record by mechanical means. A method of stripping the developer 1 from the medium 5, for example, when the cleaning member 8 is formed of a rubber plate or the like and is pressed against the recording medium 5 and rubbed, as shown in FIG. or damage the surface layer (conductive layer)
A problem arises in that the particles are scraped off and mixed into the developer 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 will be damaged, and fine powder of the resin or the like will be mixed into the developer 1.

Furthermore, when the developer is reused many times, the developer itself scatters, resulting in a quantity shortage.

As mentioned above, if dust or fine powder gets 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),
Furthermore, if the developer 1 is insufficient, the recording density may decrease or printing may not be possible.

In other words, when the developer 1 is new and has a sufficient amount, as shown in FIG. As the developer 1 gets older and the amount decreases, the spikes caused by the rotating magnet 2 become smaller, and even if a voltage is applied between the conductive layer 7 and the recording electrode 4, the developer 1 cannot be attached to the recording medium. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can form high-quality images that keep the recording density constant even when the amount of use of the apparatus increases.

[Means for Solving the Problems] The gist of the present invention is to provide an image bearing means in a relatively movable opening p in close opposition to a recording electrode to which toner developer is supplied; In an image forming apparatus that forms an erasable image by applying a voltage to a recording electrode to cause toner developer to adhere to the image bearing means,
It is characterized by comprising a detection means for detecting the usage amount of the device, and a control means for controlling the voltage applied to the recording electrode to a voltage that obtains an appropriate image density based on the usage amount of the device detected by the detection means. The image forming apparatus has the following features:

[Function] According to the present invention configured as described above, the voltage applied to the recording electrode can reduce image density due to wear of the image bearing means, deterioration of toner developer, etc. as the usage of the device increases. This can be prevented by changing the , and a stable image can be formed at all times.

[Example] The present invention will be described in detail below based on an example shown in the drawings. For the same parts between the structure in this example and the structure shown in the conventional example, the reference numerals cited in the conventional example will be used. A description of the structure in the embodiment will be omitted.

FIG. 1 is a schematic perspective view showing an embodiment of a display device to which the present invention is applied.

In the figure, 15 is a first motor that rotates the upper recording medium support member 11 on which the recording medium 5 is stretched in the direction of the arrow, and 16 is a second motor that rotates the lower recording medium support member 11 in the direction of the arrow. , the recording medium 5 is rotated by driving both motors 15 and 16. Reference numeral 17 denotes a photointerrupter, which controls the applied voltage as shown in FIG. 4 by applying a one-pulse recording medium use signal 17° every time the convex portion 5a protruding from the side edge of the recording medium 5 passes, as shown in FIG. In this embodiment, one pulse of the recording medium use signal 17° is generated every time the recording medium 5 makes one revolution. Although not shown in this embodiment, as in FIG. 8, the displayed toner developer 1 adhering to the recording medium 5 is removed by the cleaning member 8, collected in the toner container IO, and recorded. The electrode 4 is then resupplied.

The applied voltage control circuit gradually increases the voltage (V) applied to the recording electrode 4 via the recording control circuit 13 as shown in FIG. 3 as the number of times (N) the recording medium 5 is used increases. A counter 18 counts up the 17° pulse of the recording medium use signal, a D/A converter 19 increases the output voltage as the count number of the counter 18 increases, and the output of the D/A converter 19 is connected to a resistor 26.
The operational amplifier 20 is connected to the non-inverting side via the operational amplifier 20, and a life indicator 21 that lights up when the counter 18 counts that the number of times the recording medium 5 has been used has reached a preset lifetime number. A voltage (1) is applied from the power source 14° to the non-inverting side of the inverter 27 through the resistor 27. Note that 14 is a power source that drives the operational amplifier 20. This voltage v1 is an appropriate voltage when the recording medium 5 and developer 1 are new, and is set to, for example, 30V, and the output side of the operational amplifier 20 outputs a voltage that is the voltage v1 plus the output voltage of the D/A converter 19. will be output.

That is, as the use of the recording medium 5 increases, the performance of the recording medium 5 decreases, and as described above, dust and the like get mixed into the developer 1, and the voltage applied to the recording electrode at the beginning of use of the display device decreases. However, as the use of the recording medium 5 increases, by gradually increasing the voltage applied to the recording electrode 4 to an appropriate voltage, sufficient recording density can be obtained with the voltage V1 that is unchanged from the initial state of use. The concentration will be obtained.

On the other hand, since the recording medium 5 has a limited lifespan, when the counter 18 counts the number of times it has been used, for example, 500,000 times, the lifespan indicator 2
1 is turned on to notify an operator etc. that the life of the recording medium 5 has come to an end, thereby preventing troubles such as image defects and missing images. Note that the output voltage of the operational amplifier 20 at that time is V2, and thereafter the voltage applied to the recording electrode 4 is not increased, and this voltage 2, for example 60 V, is continued to be applied.

FIG. 5 shows another embodiment of the applied voltage control circuit, in which the output voltage of the operational amplifier 20 is monitored and the life indicator 21 is controlled.

That is, the output 25 of the operational amplifier 20 is connected to the non-inverting input of the comparator 25. Furthermore, comparator 2
A voltage v2 generated by a resistor 22 and a Zener diode 23 whose Zener voltage is v2 is applied to the inverting input side of the transistor 4. As a result, the output voltage of the operational amplifier 20 becomes v2
When this happens, the lifespan indicator 21 lights up, allowing the operator to know that the lifespan of the image recording device has come to an end.

In the embodiment shown in FIG. 1 described above, the wear of the recording medium 5 and the degree of contamination of the developer 1 with dust, etc. are estimated from the number of times the recording medium 5 is used, and the voltage applied to the recording electrode 4 is adjusted accordingly. Although the voltage is gradually increased, the image formed on the recording medium 5 is recorded! 3. The concentration may be detected and the voltage applied to the recording electrode 4 may be controlled so as to have an appropriate concentration, and the amount of current applied to the recording electrode 4 and the first and second motors 15 and 16 for driving the recording medium may be controlled. The usage amount of the device is estimated from the amount of current applied to the motor that drives the rotating magnet 2, and the amount of current applied to the motor that drives the rotating magnet 2 is estimated.
It may also be possible to control the voltage applied to.

[Effects of the Invention] As described above, according to the present invention, since the voltage applied to the recording electrode is controlled according to the wear of the developer and the image bearing means,
A constant recorded image is always obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an embodiment of an image forming apparatus according to the present invention, FIG. 2 is a partially enlarged perspective view thereof, and FIG. 4 is a circuit diagram showing one embodiment of the applied voltage control circuit. FIG. 5 is a circuit diagram showing another embodiment of the applied voltage control circuit. Figure 7 is a diagram illustrating a method of forming a toner image using recording electrodes.
The figure is a plan view of the recording electrode, and FIG. 8 is a schematic sectional view of the display device. 1...Developer 2...Rotating magnet 3...
Non-magnetic cylinder 4... Recording electrode 5... Recording medium 8... Cleaning member lO... Toner container 13... Recording control circuit 14.14°...
・Power supply Is, 16... Motor 17... Photo interrupter 18... Counter 19-D/A converter 20... Operational amplifier 21... Life indicator Figure 1 Figure 3 Section 5 Figure 7

Claims (1)

[Scope of Claims] 1. An image bearing means is movably provided in close proximity to a recording electrode to which toner developer is supplied, and by applying a voltage to the recording electrode, toner developer is supplied to the image bearing means. An image forming apparatus that forms an erasable image by depositing an image includes a detection means for detecting the usage amount of the device, and a voltage applied to the recording electrode to determine the appropriate image density based on the usage amount of the device detected by the detection means. 1. An image forming apparatus comprising: a control means for controlling a voltage to obtain a voltage.