JPH01280780A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of image quality and the damage to devices caused by using inappropriate toner by detecting the electric characteristic of toner and displaying toner abnormality or stopping the action of a main body when it is judged that the toner is not in the range of normal value. CONSTITUTION:An output voltage Va in response to the resistance value of the toner outputted from the detection electrode 7 of a resistance detection circuit 21 provided in the toner case of a developing unit is amplified in an amplification circuit 22 and inputted into a comparator circuit 24. The output voltage Vb of the amplification circuit 22 is inputted into the -input terminal of the IC27 and the +input terminal of the IC28 of the comparator circuit 24. A reference voltage Vr1 outputted from a reference voltage generation circuit 23 is inputted into the +terminal of the IC27 and the reference voltage Vr2, into the -input terminal of the IC28. The output of the IC 27 and 28 for a comparator is inputted into an AND circuit 29 and a decision signal RT is outputted from the output terminal of the AND circuit 29. When the inputted decision signal RT is 'L', a CPU 30 stops the devices of a main body and displays 'toner abnormality' on a display device 31.

Description

DETAILED DESCRIPTION OF THE INVENTION Advice ■ This invention relates to an image forming apparatus using a one-component toner.

Jubeigi Arashi For example, laser printers, LED printers.

There are image forming apparatuses that form images by electrophotography, such as optical printers such as LC3A (liquid crystal) printers, hard copy machines, copiers, and facsimile machines.

Generally, the developer used in these image forming apparatuses includes a toner (for example, a highly resistant styrene resin containing a color pigment) or a one-component toner made by adding some additives to an I-toner. There is a two-component toner made by mixing a carrier (for example, iron powder) and a toner at a certain ratio.

With a two-component 1-toner, during use, only the 1-toner is consumed and the mixing ratio, that is, the toner concentration, decreases, resulting in a decrease in image density. Therefore, the 1-toner concentration is always detected and the toner concentration remains constant. It was necessary to manage it so that

Since the one-component l-ner has a simple structure and does not have the above-mentioned problems, it is only necessary to manage l-ner ends due to consumption.

However, commercially available toners other than the specified toners have characteristics that are not compatible with the image forming apparatus, and even if the specified toners are used, I-toners whose characteristics have changed due to being left unused for a long period of time or becoming damp are being used. In this case, not only the quality of the formed image deteriorates, but also abnormal fixation and coagulation occur, which may lead to problems such as damage to the sharp edge of the blade.

Therefore, there have been problems such as causing inconvenience to users and impairing the reliability of the image forming apparatus and the manufacturer.

Purpose This invention has been made in view of the above points, and an object thereof is to prevent deterioration in image quality and damage to equipment due to the use of unsuitable toner.

In order to achieve the above object, the present invention provides an image forming apparatus using one-component toner, which includes a characteristic detection means for detecting the electrical characteristics of the toner, and an electrical characteristic detection means for detecting the electrical characteristics of the toner. A determination means for determining whether or not the characteristic value is within the normal value range, and whether to display 1 to ner abnormality when the determination means determines that the electrical characteristic value is not within the normal value range. or control means for controlling the operation of the main body to be stopped.

Hereinafter, the present invention will be specifically explained based on embodiments.

FIG. 2 is a schematic sectional view showing an example of a mechanism related to development of an image forming apparatus according to an embodiment of the present invention.

○The surface of the PC (photoconductor) bell 1-1 is charged in advance, and then exposed to light such as modulated scanning light based on the copied image of the original or image data to form an electrostatic latent image, and the main motor (not shown) is sent in the direction of arrow A.

○The developing unit 2, which attaches toner to the electrostatic latent image on the PC belt 1 and converts it into a visible toner image, includes a case 4 that houses the I-ner 3, and a developing roller that comes into contact with the ○I) C-held 1. 5, a stirrer 6 for stirring the I-ner 6, and a detection electrode 7 consisting of a pair of mutually insulated electrodes 7a, 71).

A removable l-ner car ridge 10 for replenishing the l-ner is attached above the case 4, and the car 1-
It is held by a rigid cover 11.

When the image forming apparatus main body (hereinafter referred to as the "apparatus main body") is powered on, the agitator 6 always rotates in the direction of arrow B to gently agitate the toner 3 and prevent abnormal coagulation of the toner B. At the same time, the toner 6 is charged by the friction involved in stirring.

Furthermore, a coil 12 is provided at the tip of the stirrer 6 to increase stirring efficiency.

The developing roller 5 is driven by a developing motor (not shown), and always rotates in the direction of arrow C at the same speed as the PC belt 1.

The agitated and charged toner 3 is transferred to a rotating developing roller 5.
After being formed into a layer with a uniform thickness by the doctor plate 13, it comes into contact with the OPC belt 1 together with the developing roller 5, and is transferred to the OPC belt 1 depending on the presence or absence of charge of the electrostatic latent image. to form a toner image.

The toner remaining on the developing roller 5 is stored in the case 4 again.

The detection electrode 7 provided in the case 4 may be placed anywhere within the range where toner 1 to toner 3 are present, but it should be placed as close to the agitator 6 as possible when the toner 3 has decreased to the extent that it requires replenishment. It is desirable to be in a position where it will be exposed when exposed.

In addition, 1 to 3 have considerably high resistance values (for example, 1010 to 1013 Ω
- about σl), therefore, the insulation between the pair of electrodes of the detection electrode 7 for detecting the resistance value, which is a type of electrical property of the toner, requires a high degree of insulation.

Since the toner 3 has a high resistance value as described above and retains its charge well, aggregation of toner powders having the same polarity is prevented.

If 1 henna solidified due to being left unused (stirred) for a long time in case 4 or becoming excessively humid,
Alternatively, if a toner or the like that originally has a low resistance value is used, problems such as deterioration of image quality and damage to equipment may occur due to coagulation or insufficient charging.

FIG. 1 is a circuit diagram showing an example of a control system of the main body of the apparatus.

In the figure, a resistance detection circuit 21 and an amplifier circuit 22 which are toner characteristic detection means according to the present invention, a comparison circuit 24 and its reference voltage generation circuit 23 which are determination means,
A CPU (microcomputer) 30, which is a control means for the main body of the apparatus, is shown, and other control systems are omitted.

The resistance detection circuit 21 is formed by connecting a DC power supply 25, a resistance R, and a detection electrode 7 in series, and the DC current flows through the toner between the resistance R1 and the pair of electrodes 7a and 7b of the detection electrode 7. , the output voltage generated across the resistor R1 changes depending on the resistance value of the toner.

That is, if the resistance value of the toner is low, the resistance detection circuit 21
The output voltage increases, and if the resistance value of the toner is high, the output voltage decreases, and when the toner runs out, the output voltage becomes 0.
become.

Note that in order to increase the output voltage of this resistance detection circuit 21, it is desirable that the voltage of the DC power supply 25 is high and the resistance value of the resistor R1 is also high, but in order to prevent abnormal charging of the toner, it is desirable that the power supply voltage is 20 V or less. Although it varies depending on the effective area and spacing of the sensing electrodes 7, the resistance value of the resistor R1 is 10! ′～
It is on the order of 10''Ω.

The amplifier circuit 22 includes an operational amplifier circuit C2Ei and a resistor R2.
~R5, and the + and - input terminals of IC2B are connected to the + and - output terminals of the resistance detection circuit 21 via resistors R3r and R2, respectively.

Further, the ten input terminal of the IC 26 is connected to ground through a resistor R5, and the negative input terminal thereof is connected to its output terminal through a feedback resistor R4.

Therefore, the output voltage vb of the amplifier circuit 22 is O or positive with respect to the ground potential, and when the resistance value of the toner is low and the output voltage Va of the resistance detection circuit 21 is large, the output voltage v
When b is high and the resistance value of the toner is high, the output voltage vb is low, and when the toner runs out and the current 1 in the resistance detection circuit 21 stops flowing, the output voltage vb becomes O.

The base voltage generation circuit 23 includes a resistor R6 and a variable resistor VRI,
VH2 are connected in series, one end of the resistor R6 is connected to the positive power supply VCC, and one end of the variable resistor VR2 is connected to the ground.

Reference voltages Vr1 and Vrz are output from the sliding terminals of variable resistors VR1 and VR2, respectively (Vrl>Vrz).
, variable resistors VR1 and VH2 each have a reference voltage Vr1
, Vrz adjustment.

The comparison circuit 24 is composed of a comparator IC 27゜28 and an AND circuit 29, the reference voltage Vr1 is connected to the ten input terminal of the IC27, and the one input terminal of the IC27 and the ten input terminal of the IC28 are connected to each other. The output voltage vb of the amplifier circuit 22 is connected to the reference voltage Vrz at one input terminal of the IC 28.
input each.

The outputs of the ICs 27 and 28 are respectively input to the AND circuit 2, and the output terminal of the AND circuit 29 outputs the determination signal RT.

FIG. 3 is a waveform diagram showing an example of changes in the signal level of each of these circuits, and (a) shows the current i of the resistance detection circuit 21.
, (b) and (C) show the input voltages (Vb, Vrl, Vrz) and output voltage (judgment signal RT) of the comparator circuit 24, respectively.

Therefore, the resistance value of the 1-ner is too high and the current j decreases,
As shown by arrow P, the input voltage vb becomes low and Vrl
>Vr2≧V b In the case of i, -c, the output of IC27 is H'' and the output of IC28 is r,°, so the determination signal RT becomes L°.

The resistance value of the toner is too low, the current i increases, and the input voltage vb increases as shown by the arrow Q, so that V b≧Vr+,
>Vrz, the output of IC27 is L”, IC
Since the output of 28 is H, the judgment signal RT is also L°.
become.

The resistance value of the toner is within the normal value range, and the input voltage vb
is between the reference voltages Vr1 and Vrz, and if V rt > V b > V r 2, IC2
Since the outputs of 7 and 28 are both H'', the judgment signal RT is H.
It becomes °.

The CPU'50, alone or in cooperation with other CPUs, executes sequence control of each device constituting the main body of the apparatus, optimal control by determining input signals from sensors, display control, etc. Furthermore, when connected to a host machine, such as a printer, it also performs input/output of various data, editing of image data, etc.

In this embodiment, in addition to the above-mentioned control, the CPU 30 displays a toner abnormality on the display device 31 when the judgment signal RT or “L” from the comparator circuit 24, and controls the entire device to stop operating. .

FIG. 4 is a flow diagram showing an example of the control routine.

When the CPU 00 receives an interrupt from its built-in timer or the like, it jumps from the main routine to this control routine and starts this control routine.

First, it is determined whether or not the above-mentioned determination signal RT is H''.
That is, if the resistance value of the toner is within the normal value range, the process returns to the main routine without doing anything.

If the judgment signal RT is L, that is, the resistance value of the toner is abnormal, each device in the main body of the apparatus is stopped, ``toner abnormality'' is displayed on the display device 31 (Fig. 1), and the process returns to the main routine. do.

As explained above, in this embodiment, when a 1 to 1 to 10 tonner whose resistance value is outside the normal value range is used, a message ``-1 tonner error'' is displayed and each device in the main body of the device is stopped. However, in general, In one-component systems, failures occur mainly due to the low resistance of 1 to 1.
Problems are unlikely to occur due to resistance or toner that is too high.

Therefore, in the comparison circuit 24 shown in FIG. 1, the ant circuit 29 is omitted, and the outputs of the IC 27 for determining the lower limit of the 1-ner resistance value and the output of the IC 28 for determining the upper limit are input to the CPU 30. You may also do so.

The control routine in that case is as shown in FIG. 5, for example, and when an interrupt occurs, this control routine starts from I to
Then, the output of the IC 27 is judged, and if °L-, that is, the resistance value of the toner is too low, "toner abnormality" is displayed, and each device in the main body of the apparatus is skipped, and the process returns to the main routine.

If the output of IC27 is H, then the output of IC28 is judged, and if the resistance value of the toner is too high, the output is L°.
``Toner End'' is displayed, each device in the main body of the apparatus is skipped, and the process returns to the main routine.

If the output of the IC 28 is H°, the process directly returns to the main routine.

In this way, the detection electrode 7 can also be used as a toner end sensor.

Another embodiment of the present invention is shown in FIG. 6, in which a sensing electrode is provided on a stirrer.

The stirrer 6 rotates in the direction of the arrow around its rotating shaft 14,
A pair of circular electrodes 7a and 7b forming the detection electrode 7
are each fixed to a stirring bar 15 made of an insulator eccentrically provided on a rotating shaft 14, and are connected to a DC power source 25. shown in FIG. 1 via a coil 12 wound around the stirring bar 15.
It is connected to the resistor R1 to constitute a resistance detection circuit.

As can be clearly deduced from FIG. 2, the sensing pole 7 is moved by the coil 12. Since the stirrer 6 revolves around the rotating shaft 14 while stirring the toner 3 together with the stirring bar 15, the 1-toner flows smoothly between the electrodes 7a and 7b.

Therefore, compared to the case where the detection electrode is fixed as in the above embodiment, the resistance value of the 1-ner is always detected in a well-stirred state, and a stable and reliable detection signal can be obtained. be.

On the other hand, depending on the amount of toner 3 in the case 4 of the developing units 1 and 2, there is a problem in that the detected resistance value of the toner appears to be liquefied.

FIG. 7 is a curve diagram showing an example of a change in the detected resistance value of toner, in which the horizontal axis represents time and the vertical axis represents resistance value.

When there is enough toner, the detection electrode 7 is always inside the toner, so it is stable as shown in TO.

When the toner decreases and a part of it comes out of the toner when the detection electrode 7 comes upward, T
As shown in 1 to T3, the portion where the apparent resistance value has increased spreads.

Even when the toner decreases further and the detection electrode moves downward, some of it comes out of the toner, as shown at T4.
The apparent minimum resistance value is also greater than the correct 1 henna resistance level.

Therefore, for example, a rotational position sensor is provided on the rotating shaft 14 of the stirrer 6, and a resistance value of 1 henna is detected when the detection electrode 7 is at the lower position. Toner end may be detected by determining the apparent maximum resistance value or the width (time) in which the resistance value exceeds a certain threshold value in the state shown in ~T3.

FIG. 8 is an explanatory diagram showing an example of a resistance detection circuit that detects a more stable resistance value of toner.

Of the pair of electrodes of the sensing electrode 7', one electrode 7a is integrated as in the past, and the other electrode is a ring-shaped insulator 7h that surrounds the measuring electrode 7b'. It consists of a guard electrode 7g.

The electrode 7a is connected to one pole of the DC power source 25, the measuring electrode 7b' is connected to the resistor R1, and the guard electrode 7g is connected to the electrode of the DC power source 25 via the cart resistor Rg, thereby forming a resistance detection circuit. do.

It is desirable that the cart resistance Rg has a resistance value that is equal to the resistance R1 or inversely proportional to the area ratio of the measurement electrode 7b' and the go 1 to electrode 7g, but in some cases the resistance value O
That is, the guard electrode 7g may be directly connected to the electrode of the DC power source 25.

Therefore, the 2
A closed circuit is formed, and the voltage V generated across the resistor R1 is
a is output to the next stage.

Generally, when there is a potential difference between a pair of plate-shaped electrodes placed in parallel in a high-resistance medium (toner in this case), the lines of electric force in the medium are uniform in density and parallel at the center inside the plate-shaped electrode. However, at the edge or outside of the electrode, the lines of electric force curve and the density changes significantly.

The measurement electrode 7b' is surrounded by a guard electrode 7g, and a counter electrode 7a has an area shape comparable to that of the picture electrode combined.
By providing this, the resistance value of the toner is detected in a portion where the lines of electric force are parallel to each other and the density is uniform, so that a stable and reliable detection signal can be obtained.

As explained above, according to each of these embodiments, when a toner other than the specified toner that is not compatible with the image forming apparatus or a toner from 1 to 1 whose resistance value has changed due to long-term storage or humidity is used, " Since the main body of the device stops displaying the message "toner abnormality," it is possible to prevent problems such as deterioration of image quality and damage to equipment.

However, either one of displaying "toner abnormality" and stopping the main body of the apparatus may be performed.

Furthermore, although each of the above-mentioned embodiments describes an example in which the resistance value of the toner is detected, the electrical characteristics of the toner are not limited to the resistance value.・It is also possible to judge unsuitability. Furthermore, it is also possible to measure a plurality of electrical characteristics of the toner and comprehensively determine whether the toner is suitable or not.

As described above, according to the present invention, it is possible to prevent deterioration in image quality and damage to equipment due to the use of inappropriate I/N.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a control system in an embodiment of the present invention, FIG. 2 is a schematic sectional view showing an example of the developing mechanism, and FIG. 3 is an example of signal levels of each part of the control system. FIG. 4 and FIG. 5 are flow diagrams showing different examples of the control routine, FIG. 6 is a perspective view showing an example of a sensing electrode mounting structure according to another embodiment of the present invention, and FIG. FIG. 7 is a curve diagram showing an example of a change in a detection signal of the resistance value of the toner, and FIG. 8 is a circuit diagram showing another example of a detection electrode and a resistance detection circuit using the same. 10PC (photoreceptor) Bell 1 to 2 Developing unit 3.
Toner 4, case 5, developing roller
6- Stirrer 7... Sensing electrode 12 - Coil 13...
Doctor blade 14, stirring shaft 15, stirring bar 21, resistance detection circuit (characteristic detection means) 22, amplifier circuit 26, reference voltage generation circuit 24,
Comparison circuit (discrimination means) 25-DC power supply 26-28・
・IC29・Ant circuit 30・CPU (microcomputer control means) 3
1 Display device O, Ω O work ” - Information 〉 Torbi Fig. 6 Fig. 7 Fig. 8 Fig. 8 7' F a 7b' p, p, v. 11-t

Claims (1)

[Claims] 1 In an image forming apparatus using one-component toner,
A characteristic detecting means for detecting the electrical characteristic of the one-component toner, a determining means for determining whether the electrical characteristic value detected by the characteristic detecting means is within a normal value range, and the determining means and control means for displaying a toner abnormality or for controlling the operation of the main body to be stopped when it is determined that the electrical characteristic value is not within a normal value range. Image forming device.