JPS5965873A - Magnetic brush cleaning device - Google Patents

Abstract

PURPOSE:To stabilize magnetic brush cleaning effect by detecting the toner density of a magnetic toner brush for removing residual toner from a photoreceptor, and controlling a bias voltage to a toner collecting member which performs electrostatic recovering operation. CONSTITUTION:When a switch SW is turned on for a specific time in response to a print button, a specific DC voltage is impressed to the toner collection member 6 which recovers the toner of the magnetic brush 5 electrostatically. Then, a current flows through a detection resistance 11 by resistance value variation corresponding to the toner density of the magnetic brush 5 which removes the magnetic toner from the photoreceptor 1 by frictional rubbing and the voltage across the resistance 11 is compared with a reference voltage by a comparator 14. A contact 12-1 is controlled through a transistor 16, relay 12-2, etc., which turn on and off according to the comparison result of the comparator 14 to vary the bias voltage impressed to the member 6, holding the toner density of the brush 5 constant. Therefore, the deterioration of the carrier is reduced and its life is prolonged to improve the stability of the cleaning effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic brush cleaning device, and more particularly, to a magnetic brush cleaning device that controls the optimal value of 1.ner concentration in a magnetic brush by a resistance value that changes depending on an excessive amount of 1.ner. Regarding equipment.

In recent years, for example, dry electronic copying machines have become widely available. Is this photoconductive? ′! Electrostatic charge is applied to the V film by corona discharge, and the desired image 13! A corresponding electrostatic latent image is formed on the photoconductive thin film, and iron 1 is applied to the electrostatic l1·1 scratch.
5), etc., and transfers the 1-toner to a copying file.・Second 1・+t
In dry-type electronic copying machines, when the 1-toner electrostatically attracted to the photoconductor is transferred to copy paper, some 1-toner remains on the photoconductor, making it difficult to obtain good copies. In order to prevent this, various photoreceptor cleaning devices have been proposed.

Conventionally, as a cleaning device for the photoreceptor surface layer, for example, a device using a fur brush, a device using a fibrous web paulownia material, a device using a cleaning plate 1, and a device using a Magneno 1 brush. There are devices etc.

Cleaning devices using fur brushes are widely used in general electrophotographic copying machines, etc., but in such cleaning devices, the cleaning pre-effect is good at the initial stage, but the brush has a short lifespan. Therefore, as the number of copies used increases, the brush and the 1-ner fuse together, and the cleaning performance gradually decreases to 11(]ζ'3°.

In addition, the structure is such that the leading overlayer surface of the photoreceptor is moved strongly < IF5 to mechanically remove residual 1-Lee on the photoreceptor surface, so the photoreceptor may be damaged by 1i-1 or deteriorated due to friction. It also has drawbacks such as a significant decrease in service life.

Furthermore, the cleaning device has to be forcibly sucked with a 1:1 atomizer that has been wiped off with a brush, etc., and then collected in the filter box, which increases the size of the cleaning device and, by extension, the copying machine itself. There is no choice but to increase the size.

Additionally, in cleaning devices that use a fibrous web paulownia material, the web is used to remove residual toner from the photoreceptor, thereby requiring cleaning of new photoreceptors. Therefore, when high-speed copying is performed, the cleaning effect tends to be significantly reduced, and to solve this problem, it is necessary to constantly supply a new web with a new amount of sand.

In addition, there is a problem that IIj scratches caused by sliding between the web and the photoreceptor are spread all over the surface, so there is still a lot of room for moss.

Cleaning Equipment that uses Cleaning Sole 1 may suffer from, for example, wear of the blade, damage to the surface of the photoconductor, or damage to the photoconductor caused by keys 1 and rear being mixed in. Problems such as severe damage to the aircraft are significant drawbacks, and these problems are even more severe in high-speed aircraft.

In an apparatus using a magnesol brush, in order to electrostatically remove residual 1. toner on the surface of the photoreceptor, the tji (merino 1. The drawback is that the cleaning effect decreases rapidly when Or arrange an I-S collection member close to each other,
By transferring the 1-toner in the Magneto brush to the 1-toner collection part, 81 minutes of toner is removed from the Magneto brush. As such a toner collecting method, for example, the following method is proposed in Japanese Patent Publication No. 37382/1982.

(1) A voltage of opposite polarity to 1.nar is applied to the l.nar trapping part.

(2) 1. The collecting member is formed of a conductive metal with an insulating surface, and a charge is generated on the toner collecting portion by friction with the magneto brush. .

(3) 1.S-1+Ii The 1ts portion 4A is formed with conductive full bending. When it comes into contact with 1., 1-.No., it generates Iv' triboelectric charging or mirror image force.

As described above, I'+li of 1.s.
When performing Hayabusa, the residual toner on the surface of the photoreceptor is
In some cases, a larger amount of toss than the amount of toning can be recovered from the magnet.

In this case, it got mixed into the magnetic brush! -Nl is extremely reduced, and carriers mixed in the magnetic brush may conversely adhere to the photoreceptor, resulting in failure to obtain a good leaning effect.

In other words, in order to obtain the best leaning effect,
It is necessary to maintain and control the toner concentration in the magnetic brush within a predetermined range, and this has been neglected in the past.

In view of the above-mentioned conventional drawbacks, the object of the present invention is to solve the problem of mixing in a magnetic brush! - To provide a magnetic brush cleaning device that stabilizes the magnetic brush cleaning effect by controlling the depth of the magnetic brush by the resistance value of the magnetic brush that correlates with the depth of 1-7i. .

In addition, the present invention is characterized in that a magnetic brush containing a magnetic carrier as a main component is brought into sliding contact with the surface of the photoreceptor, and a toner is removed from the surface of the photoreceptor. a removal device; a toner collecting member to which a bias voltage is applied and which electrostatically collects the residual I/toner from the magnetic brush; and a detection unit 1 for detecting the degree of toner on the magnetic brush; This is achieved by providing a magnetic flange cleaning device comprising a bias voltage control means for controlling the voltage value of the bias voltage applied to the I·Nar+Ii jW phase in accordance with the detection output of the detection means. be done.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a cleaning device using the present invention.

fls 1 In the figure, 1 is a photoreceptor that forms an electrostatic latent image, 2 is a l-toner removing device, and the toner removing device 2 is installed on the magnetol I.1''-le 3 and its outer periphery. It has a rotatable conductive sleeve 4. A magnetic brush 5 is formed on the i'+ij surface of the conductive sleeve 4 by the magnetic force of the magnet roll 3, and is in sliding contact with the surface of the photoreceptor 10. 5. A high voltage 1, for example 400, is applied to the conductive sleeve 4 (electricity j of the δ light body 1: j, l', sl) via a +4L electric brush that does not indicate IMI. , Also, in part 1, it falls from inside the magnetic brush 5;
A carrier 1-ner receiver 8 is provided to receive the carrier.

Magnetic brush 5 formed by magnet l-t+-ru 3
On the other hand, the toner collecting part 6 for collecting excess toner and maintaining the l-toner concentration in the magnetic brush 5 at an appropriate value is, for example, a conductive 44 formed from quality. Then, switch SW or relay contact 1
2-1 closes, the I-ner collection part shrine 6,
Voltage ■1 of the DC power supply 10 applied to the magnetic brush 5
A DC power supply 13 having a voltage of 1-IV2, for example 600 µ, is similarly applied by the collector so that a voltage higher than ゛・;° is applied by the current collector. Furthermore, a scraper 7 is provided separately to scrape off the toner that has come into contact with the toner trapping member 6 and has adhered to the surface of the toner trapping member 6. The toner is collected in the 1-toner receiver 9.

The negative side of the i'ili power supply IO is grounded,
The positive example is connected to the conductive sleeve 4, while the negative (inverting) input terminal of the comparator 14 and the sensing resistor 1
1 is connected. In addition, the positive (non-inverting) input 6 (i+) of the comparator ■4 is connected to the positive side of the DC power supply 15. The negative side of the DC power supply 15 is connected between the detection resistor 11 and the negative side of the DC power supply 13. and 1~
It is connected to a bias resistor 1-1 provided between the base and emitter of the random disk 16. On the other hand, the output of the amplifier lake 14 is input between the voltage dividing resistors R2 and R3, and the relay RLI which opens and closes the relay contact 12-1
I-2 is provided between the voltage dividing resistor R3 and the collector of the transistor 16, and is further connected to the emitter and the relay RL1.
2-2, a bias power supply 17 is provided.

In addition, for Suisou f-S W, the copy operation is for the first sheet and the second sheet I.
'', 1 in 3 sheets, etc. 61 is configured to operate for a predetermined time at the start of each. Also, Rishi, -1'1! +
, ', j I 2-1 is opened and closed under the control of L2 in response to the output of the 11 comparator 14], -RL 2-2, and 7. .

The residual toner on the photoconductor 1 is charged and adsorbed to a predetermined pole 1, so that the toner is negatively charged on the photoconductor 1 to which a potential of, for example, 1F is applied. The superimposed i is electrically conductive: i"i L-ζ, while the conductive sleeve 4 on the lead 1-11-3 has positive polarity and...
However, a higher potential than the photoconductor is applied.

In general, if there is a charge c′hXli· at an arbitrary point and the electric field strength at that point is E, then jj, ! , i
The force F exerted by load Lj is F = elE (11
In addition, in an electrostatic field, the electric field strength F·' is established from the electrostatic potential (scalar potential) ψ.

Above (11, (In a field where Equation 21 holds true and which follows Coulomb's law, the bias voltage E is generally
= -Hradψ... It can be seen that the higher the value of (2), the greater the force acting on the charge. Of course, the amount of residual toner on the culm magnetic powder 5 (((J7iT) increases and the cleaning 9JJ effect becomes higher. Therefore, the I.S-
Regarding the collection efficiency of toner collecting part 6, the bias voltage ■11V2 to toner collecting part 6 is...
+i from the bias voltage V1 applied to the conductive sleeve 4
'b The more it's related, the more it's collected! It can be seen that the recovery efficiency of 1st item ``I'' (j...) is improved.

In addition, magnetic brush 4 formed on the outer periphery of magnetic 1: I-ru.
kl: It is composed of a mixture of =l-yaria and ]・nar, of which the carrier has some degree of conductivity, but since l・nar is an insulator, the mixing ratio of 1 to nar is high. In this case, the resistance value across the entire magnetic brush increases.

After the electrostatic latent image is transferred onto the transfer paper on the photoreceptors 1 and 2, the untransferred residual toner enters the magnetic brush cleaning section while remaining on the photoreceptors I and I.

In the magnetic brush cleaning section &, I, the voltage ■1 higher than the voltage applied to the photoreceptor 1 is j11 current power source 10
The residual toner is applied to the magnetic brush on the conductive sleeve 4, and since the residual toner on the photoreceptor 1 has an opposite charge to that of the conductive sleeve 4, the residual toner is applied to the magnetic brush on the conductive sleeve 4. (if) to clean the photoreceptor 1.Then, the toner on the magnetic brush 5 is -
f (To 1~Yaria I falls into the holder 8, and the remaining 1-
The conductive sleeve 4, l:, ':l 13 has a high voltage, e.g.
+ + V2 is applied, ' and ° (-U, how many toners are deposited on the toner collecting section opening 6, and the toner is scraped off by the abutting scraper, and the toner is collected at 9).

Here, regarding the cleaning action described in section 2, for example, when a copying machine is used continuously for a long period of time, the specified cleaning efficiency may decrease due to an increase in the concentration of 1-s in the magnetic brush. It happens. However, each time the switch SW is turned on for a predetermined period of time at the start of each copy operation,
Closed circuit: A current flows through the DC power supply 13 - switch sw - toner collection part 6 - magnetic brush 5 - conductive sleeve 4 - detection resistor 11, and the current value changes when a constant voltage is applied. The resistance value increases or decreases as the resistance value changes depending on the mixing ratio of toner in the brush 5. Therefore, when the toner concentration in the magnetic brush is at a previously set standard concentration, the voltage at the detection resistor 11 installed in the closed circuit is set as the standard voltage, and the increase or decrease in the toner concentration is controlled via the standard voltage. This makes it possible to control the Next, toner concentration and standard voltage will be explained using FIG. 2.

FIG. 2 is a graph showing the relationship between l.ner concentration and detection voltage in the present invention. From the same figure, toner 61 in the developer
It can be seen that 14 degrees is inversely proportional to the voltage at the detection resistor for the constant detection type IL. This is because as the toner concentration in the magnetic brush increases, the resistance value of the β2 air brush increases, so the current flowing through the circuit decreases, and the voltage generated across the sensing resistor 11 decreases accordingly. Note that when the concentration of the toner mark 11 is set to G318%, and the current flowing through the closed circuit is, for example, 100 μ8, a voltage of IOV is generated across the detection resistor 11 of 100Ω. !The voltage is set to IOV.The resistance value of Yayaria is usually 105"~106Ωc
m, or 10 to 100 cm if toner is mixed
becomes.

Here, if you do not press the print button (not shown), the photoreceptor 1, conductive strip 11-7'4, tri-
The collection part +A6 starts rotating and becomes even more magnetic! 1. brush 5
also starts rotating. At the same time, during a predetermined period of 111i, the switch SW is turned ON and the circuit is closed. %i
, electric current 1 lower ■ 2 is applied to 1-ner ura collection +716 F
Ji ′) i' Il, blasphemous (switch s after
w is OFFL, Il old: '31L l! It h't,
be done. This DC voltage V? Ka1-ner falcon 1' (1 heron 1
+; When t, - is applied, L+·1. to 1 concentration in the magnetic brush. At 7, a current flows through the detection resistor 11, and the voltage across both 1'AI of the resistor 11 is transferred to the comparator 14.
ζ Separately installed) ノ, - curved power supply 15 mark? Compare with lN voltage ■3.

When the switch SW is turned on for a predetermined period of time, for example, if the concentration of l~luna in the magnetic brush is higher than the standard concentration, the current flowing through the detection resistor 11 will be small, and the voltage generated at the detection resistor 11 will be The input voltage to the negative input terminal of the comparator 14 becomes lower than the standard voltage (3) input to the positive input terminal of the comparator 14, and the output of the comparator 14 becomes high level II. Therefore, 1-run disk 16 switches and relay RL12
A large current flows through -2, and relay contact 12-1 is also turned on. Even if the switch SW is opened, the relay contact 12-1-toner collection section 4.46-condolence;
- The closed circuit of the conductive sleeve 4 and the resistor 11 remains closed, so V 2 tel continues to be applied. And 1-
Iv2 or toner collection riB Ll' 6 ” Fl'
JJII Sal'1. to C. 1, for example] world i 1b -ka I.na 141i i? In order to be collected into the Σ part shrine 6, the concentration of I-ner in the magnetic brush 5 gradually decreases -c4
Hilt1',? When the voltage reaches a degree, the current flowing through the detection resistor II becomes constant, and the detection voltage also becomes constant, returning to the corresponding standard voltage, so that the output of the comparator 14 becomes 1'J-level L.

Therefore, the l transistor 16 is OF FL, and the relay R is
Relay contacts 12-1 and b are opened under the control of L12-2.

First, when the switch SW is ONL for a predetermined period of time, when the concentration of the magnetic brush 501-ner is smaller than the standard concentration, a large current flows through the closed circuit, and the detection voltage of the detection 11 (the detection voltage of the resistor 11 is set to 3, the output of the comparator 14 is a low-level monthly signal.The transistor 16 is switched to 1', and the relay RL 1 is switched to 1'.
2-2, the relay contact 12-1 also remains open, so the closed circuit is opened. The closed circuit remains open even after the switch SW is turned off.

Therefore, since the voltage Vl+V2 is not supplied to the 1-toner collecting section JIA6, the collection of toner from the magnetic brush 5 to the toner collecting section +A6. is supplied from the photoconductor 1 with the magnetic plan 5\(Jli) every time the switch SW is turned on.
-ner depth increases by 1 (+'Lt, 1'4).As mentioned above, the 24th invention checks whether the toner depth of the magnetic plan is equal to the target 11A concentration each time the switch SW is turned on. There are things to detect.

In the case of repeated copying, the voltage V2 is applied for a predetermined period of time before each image is formed at the beginning of each number of copies) (I+Ii 3JS)
It is determined whether the detection voltage d= applied to the member 6 and generated at both ends of the detection resistor is standard (that is, whether the toner concentration in the magnetic brush is appropriate) as shown in FIG. , if it is below the standard, the 1-ner concentration is too high]'
Voltage 2 from the DC power source is continuously applied to the toner collecting section 6, and the toner in the magnetic brush is further attracted and collected by the toner collecting section 6, which is detected by the detection resistor 11. If the detected voltage is higher than the standard, it is determined that the toner density is too low, and the output of the comparator 14 becomes l''-level monthly rate 7, and the I transistor 15 and the relay RL l 2-2 is in the OFF state, so relay 1'
The concubine point 12-1 is also open, and the voltage 2 from the DC power source is applied to the 1.sup.-1+li concentrator 6. Therefore, since toner is not collected from the toner collecting section 6, as the number of copies increases, the tree density gradually increases and approaches the appropriate value, and the detection voltage gradually increases. The voltage decreases to near the standard voltage.

Using the method described above, each time the 1-relay concentration is reduced, it is contained in the magnetic brush!・The concentration of the toner can be controlled almost constant.

Further, in the present invention, proximity to the conductive sleeve 1. The toner concentration is determined by detecting changes in the current flowing between the conductive sleeve and the collection part, which are connected via a magnetic brush, using the collection DC voltage applied to the conductive toner collection member. The object to be controlled and therefore opposed to the magnetic brush is not limited to an electrically conductive toner collecting member, and may of course be constructed simply from a metal plate or a metal roll, for example.

As described above, when the present invention is used, the cleaning effect is i+'(i+'), so it has the effect of making it possible to obtain a very clear copy image. , High cleaning effect < t,,,q Since the photoconductor can always be used in a clean state, toner does not fuse to the photoconductor and has the effect of improving the durability of the photoconductor. . Furthermore, the present invention is used. 1. The amount of toner in the magnetic brush can be controlled, the deterioration of K, +, +JA is reduced, and the life of the carrier is long.<1.1: The refreening effect is also stabilized.

[Brief explanation of the drawing]

FIG. 1 is a cleaning principle diagram showing one embodiment of the present invention (several shields 118), and FIG. 2 is a graph showing the relationship between the toner concentration in the magnetic brush and the detection voltage generated by the detection resistor. Yes.■...Photoreceptor, 2...I-ner removal device, 3.
... Magnet roll, 4... Conductive sleeve, 5... Magnetic brush, 6... Toner collection part shrine, 10... DC power supply (Vl), 11... Detection resistor, 12-1. ...Relay contact, 12
-2...Relay en, 13...DC 7Id
, Gt (V 2 ), l 4... comparator,
15...DC power supply (■3), 16...Transistor. Patent applicant: Casio Computer Co., Ltd. I.D. Co., Ltd. (Company attorney: Yoshiyuki Osuga)

Claims (9)

[Claims] (1) A toner removal device that removes residual 1-toner adhering to the surface of the photoreceptor by sliding a magnetic brush containing magnetic S toyaria as a main component onto the surface of the photoreceptor; a 1-toner collector for electrostatically collecting the residual toner from the magnetic brush using a voltage; a detection means for detecting the 1-KJ degree of the magnetic brush; 1. A bias voltage that is not applied to the toner collecting section and controls the voltage value of the repeated bias voltage. A magnetic grating/cleaning device comprising: one stage of control P; i, A, lr L; (2) The 1-ner removing device includes a cylindrical conductive sleeve that rotates in the Ii'/J direction, and a magnetic brush that is disposed inside the conductive sleeve and forms a magnetic brush on the surface of the conductive sleeve. The magnetic brush cleaning device according to claim 1, characterized in that it has a fixed angle tip. (3) The t-gas cleaning device according to claim 1 or 2, wherein the 1-ner concentration detecting means detects from the resistance value of the magnetic brush. (4) The resistance detecting means is connected to the conductive sleeve at 1-
4. The magnetic fly cleaning device according to claim 3, wherein a resistance value between the magnetic brush cleaning device and the magnetic brush cleaning device is detected. (5) The 2002 brush cleaning device according to claim 1, wherein the toner collecting member is made of metal. (6) The magnetic brush cleaning device according to claim 1, wherein the toner density detection means detects the toner density in conjunction with the copying operation. (7) The scope of the invention claimed in item 2, characterized in that the voltage applied to the conductive sleeve is lower than the potential applied to the 1-chi 1'ili convergence shrine. Magnetic brush cleaning device. (8) The magnetic bra 7 cleaning device according to claim 2 and ΣfS 7, wherein the electrons impinging on the conductive sleeve are higher than the surface potential of the phosphor. (9) The high-ass voltage control means is controlled by an output from a comparator via a voltage change in a detection resistor provided in the IE (anti-detection means). A magnetic brush cleaning device according to scope 1.