JPH01255877A - Developing device for copying machine - Google Patents

Abstract

PURPOSE:To prevent the stain in the vicinity of a nozzle by using a toner supply pressurizing can as a toner container and providing an opening means of its nozzle, a developer supplying means and a valve means placed between them. CONSTITUTION:When the nozzle 16 of a toner supply pressurizing can 1 is opened by an opening means, a toner in the pressurizing can 1 is replenished to a liquid supplying means by opening/closing a valve means 36, or it is stopped. The toner replenished in such a way is supplied to a developing unit together with a developer by the liquid supplying means. In this case, in the vicinity of the nozzle 16 of the pressurizing can 1, the developer is always supplied by a liquid supplying member 33 for drawing the developer of a developing tank 4 by a capillary phenomenon. In such a way, it does not occur that the can body is stained by an ascent and a descent of the liquid level of the developer in the tank 4, and the nozzle 16 is exposed in the air.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a developing device for a copying machine that uses a toner container to replenish toner into a developing tank.

BACKGROUND OF THE INVENTION In the above-mentioned type of developing device, a toner bottle is used as a toner container, and a valve provided on the toner bottle is operated to allow the toner to fall naturally into a developing tank by its own weight. , or caused to fall by forced suction.

Problems to be Solved by the Invention However, in the case of the above-mentioned toner bottle, the vicinity of the mouth of the toner bottle becomes severely soiled due to use, making it difficult to handle. Therefore, it is difficult to store a large amount of toner, and there is a problem that the toner is consumed in a short period of time.

Therefore, the applicant of this application previously proposed a toner container useful in such cases by applying
We proposed a pressurized can for developer injection supply (hereinafter referred to as PTC), which consists of a first chamber that expands with gas, and a container that contracts as the first chamber expands and stores toner inside. It has a second chamber in which it is located.

An object of the present invention is to solve the problems of the conventional developing device using a toner bottle as described above, by using PTC, a container of the same capacity can be used without contaminating the opening and its vicinity. An object of the present invention is to provide a developing device capable of supplying a large amount of toner.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention provides a PTC
The apparatus has an opening means for opening the nozzle of the apparatus, a liquid supply means for supplying liquid to the related unit, and a valve means disposed between the opening means and the liquid supply means.

At least the vicinity of the nozzle receiving portion of the nozzle opening means is supplied with developer from the tank by a liquid supply member.

Further, the liquid supply member is formed of a member exhibiting capillary action, such as cotton cloth, extending from the developer solution to the nozzle receiving portion.

Further, the valve means includes a valve member that is sealed by pressure from a direction opposite to the direction in which the toner is discharged from the p'rc.

The minimum diameter d2 of the inlet passage of the valve means is the same as or smaller than the minimum diameter d1 of the toner discharge passage of the PTC nozzle opening means.

Further, when the internal pressure in the connecting means that connects the opening means and the valve means is Pl, the valve closing force for sealing the valve means is P2, and the valve opening force for opening the valve means is P3,
P3>P2>PL.

In addition, the relationship between P2 and P3 in this case is sometimes
It may be set as ≧P3.

Function: In the developing device as described above, when the nozzle of the pressurized can for toner supply is opened by the opening means, the toner in the pressurized can is replenished to the liquid supply means by opening and closing of the valve means, or it is stopped. The toner thus replenished is supplied to the developing unit together with the developer by the liquid supply means.

In this case, developer is constantly supplied to the vicinity of the nozzle of the pressurized can by a liquid supply member that pumps up the developer in the developer tank by capillary action. the nozzle is not exposed to air.

Further, since the valve means is sealed by pressure in the opposite direction to the toner discharge direction, when opening the valve means, the valve opening force for that purpose cooperates with the toner discharge pressure, so the member for opening is For this purpose, if the discharge pressure is Pl, the valve closing force is P2, and the valve opening force is P3, in the normal case, P3>P2>Pi. In particular, when toner and discharged gas coexist, P2≧P3>P L is valid.

Embodiment In FIG. 1, 1 indicates a PTC, which is supported by a holder 2, which can be rotated by a pivot 3 between a use position shown by a solid line and an attachment/detachment position shown by a chain line. It is provided on one side wall of the developer tank 4.

As shown in FIG. 2, the mouth of the PTCI is provided with a housing 23 in the cylindrical part of the mouth, into which the stem 7, which is always given a tendency to protrude by a spring 27, is slidably fitted. The inside of the (right half) is sealed, but when pushed up (left half) by a stem receiver 26 (described later), the nozzle 16 becomes open and communicates between the inside and outside.

A stem guard 6 is attached around the stem 7, and this stem guard 6 protrudes from the tip of the nozzle 16 of the stem 7 by an amount Q, preventing PTCl from being accidentally spilled onto the stem 7.
Even if you fall with the guard facing downward, this guard 6
The nozzle 16 hits the surface of the falling place and opens,
This prevents the toner inside the PTCl from being ejected, the stem 7 from deforming, and the user from tampering with the stem 7 unnecessarily.

The holder 2 has an upper support plate 9 extending horizontally on the top of the holder main body 8 extending vertically to support the bottom of the PTCI.
A lower support plate 10 that supports the shoulder portion of the PTC 1 is attached at the lower part of the lower support plate IO and PTC1.
A spring 11 is interposed between the shoulder of the TCI (
(Fig. 4), this spring 11 and the upper support plate 9
The lower support plate 10 is attached to a bracket 12 rotatably attached to the pivot 3. There is. A hanging screen 1 of the bracket 12
3 forms a cam surface, and a recess 14 is formed in the upper part of the cam surface.

On the other hand, one end of the L-shaped rod 18 is attached to the upper plate 17 of the tank 4 with a pivot 22.
A roller 19 is provided at the bent portion of the roller 19, and a tension spring 21 is tensioned between the other end and a bracket 20 provided on the back surface of the upper plate 17.
9 is always urged in the direction of contacting the side surface 13, and FIG. 3 shows a state in which the roller 19 engages with the recess 14 and holds the holder 2 in the use position. In this case, a force for pushing up and opening the stem 7 is applied to the PTC 1 by a stem receiver 26, which will be described later, so the roller 19 must resist that force and hold the holder 2 at the position shown.

For this reason, the position of the pivot 22 is preferably in the fourth or third quadrant of the coordinates formed by the horizontal axis passing through the pivot 3 and the central axis of PTCl as shown in FIG.
Further, the angle θ formed by the pivot shaft 22 and the roller 19 is small, and the resultant force F of the force F1 pushing up the stem 7 and the force F2 applied to the roller 19 is in the second quadrant direction, and the angle θ is closer to the F1 side. is preferable, and with such a positional relationship, the holder 2 can be reliably held in the working position and can be easily rotated.

One end of a stem holder bracket 24 is also pivotally supported on the pivot 3, and a stem guide 25 that self-centers the stem 7 on the upper part of the bracket 24 and a stem guide 25 that abuts against and pushes up the nozzle 16 of the stem 7 in the use position. A stem receiver 26 that is open and discharges toner is attached. The other end of the bracket 24 is always given an upward tendency by a spring 28 provided on the upper plate 17 of the tank 4.
Its rise is limited to a predetermined position by a stopper 29 (fifth
figure). The stem receiver 26 is provided with a supply port 30 having approximately the same diameter d1 as the discharge passage 15 of the nozzle 26 (FIG. 8).
A replenishment tube 31 is connected to the replenishment port 30, and a coil 32 is wound around the tube 31 to prevent expansion thereof. A member 33 exhibiting capillary action, such as cotton cloth, whose upper end is wrapped around the stem 7 is provided between the stem guide 25 and the stem receiver 26, and its lower end is suspended into the developer 5 in the tank 4. The developing solution is supplied around the nozzle 16 by the capillary phenomenon.

As shown in FIG. 6, the other end of the tube 31 is connected to a valve means 36.
The cylinder 37 is connected to the cylinder 37, and the cylinder 37 has a supply port 3.
An inlet 35 having a diameter d2 that is equal to or smaller than the diameter d1 of the 0 is provided, and an 0 ring 38 is provided around the outlet of this population 35.

A piston 39 whose tip comes into contact with and separates from the piston 39 is disposed within the cylinder 37, and this piston 39 is urged toward the O-ring 38 with a sealing pressure P2 by a spring 47 wound around the piston 39. The tip of the connecting rod 40 is pivotally supported. At the rear end of this connecting rod 40 is a tank 4.
A bell crank 42 whose base is pivotally supported on a pivot 41 provided in
The lower end of one arm 43 is pivotally supported, and the other arm 4
The rear end of the solenoid 4 is pivotally supported by the lower end of the operating rod of the solenoid 45. When the solenoid 45 is turned on, the piston 3
Apply valve opening force P3 to spring 47 to separate it from O ring 38 and open inlet 35, and when it turns OFF, valve opening force P2 of spring 47
The cylinder 37 contacts the O-ring 38 to close the inlet 35, and a communication hole 46 is provided in the peripheral wall of the cylinder 37 near the inlet.

In this way, the pressure P1 inside the supply tube 3I is applied to the tip of the piston 39, so the piston 39
If the diameter of the valve 9 is large, the force in the opposite direction to the valve closing force P2 applied to the piston 39 when closing the inlet 35 after opening becomes large, making it difficult to close. Preferably, for this purpose the inlet 3 of the cylinder 37
5 is also preferably the same as or smaller than the diameter d1 of the supply port 30.

In FIGS. 9 to 11, a liquid supply means 4 is provided in the tank 4.
8, this liquid supply means 48 has a cleaning unit pump 56 and a developing unit pump 57, and the pump 56 has a casing 49 disposed in the tank 4 as shown in FIG. A communication path 62 is formed by the guide member 50 extending from 49 to surround the cylinder 37, and this communication path 62 opens at the bottom of the casing 49. A liquid supply rotor 51 is arranged inside the casing 49, and its drive shaft 5
2 penetrates the upper plate 17 of the tank 4 and protrudes outside the tank,
A gear 53 is attached here. Also casing 4
Liquid supply pipes 54 and 55 for supplying liquid to the cleaning unit 81 and the concentration sensor 82, respectively, are connected to the upper part of the cleaning unit 9.

A drive pulley 59 is provided which is rotated by a drive source of the copying machine main body (not shown), and the rotation of the drive pulley 59 is caused to slide onto the drive shaft 52 via a pair of guide pulleys 60 supported by a belt 63 and a bracket 61. drive vehicle 64
The large gear portion of this drive wheel 64 rotates the rotor 51 of the cleaning unit pump 56 via the gear 66 that meshes with this and the gear 53 that meshes with this.

On the other hand, the gear 66 rotates a gear 78 via an intermediate gear 77, and a liquid supply rotor 96 of the developing unit pump 57 is attached to the lower end of a rotating shaft 79 of this gear 78. A liquid supply pipe 98 that supplies liquid to the developing unit 84 is provided in the casing 97 that houses the liquid rotor 96.
is connected. In this case, the diameter of the liquid supply rotor 96 is preferably larger than the diameter of the liquid supply rotor 51.

9 and 10 also show an agitator drive mechanism, 58 designating an agitator which moves over the bottom of the tank 4 in order to disperse the toner components settled at the bottom of the tank 4. belongs to.

In the figure, the small gear portion of the drive wheel 64 is the adjacent gear 67.
This gear 67 is attached to and rotates a driven shaft 69 rotatably established on the upper plate 17.

An eccentric cam 68 is attached to the driven shaft 69, and an eccentric pin 70 of the eccentric cam 68 is slidably fitted into a long hole 72 provided in a direction perpendicular to the axial direction of a sliding plate 71. A long hole 73 is provided in the direction perpendicular to this on the opposite side, and a stop pin 74 provided on the back surface of the upper plate 17 is slid into this long hole 73, and the sliding plate 71 is supported by the head of the pin 74. has been done. The upper end of a column 75 erected from the agitator 58 is slidably fitted into the sliding plate 71 in the middle of these elongated holes 72 and 73. Note that the agitator 58 has a support 75 in addition to the support 75.
', and this support 75' is slidably fitted into an elongated hole 99 provided in the upper plate 17 in the same direction as the elongated hole 73. In this case, the strut 75 may be integrally attached to the sliding plate 71, but since it is preferable that the agitator 58 be in constant contact with the bottom of the tank 4, an umbrella-like structure provided on the sliding plate 71 as shown in the figure It is preferable to fit into the member 76 so as to be able to move up and down.

FIG. 12 shows details of other parts related to the above-mentioned parts, in which 82 is a photosensitive drum, 85 is a developing roller, and 85 is a developing roller.
6 is a squeeze roller, 87 is a cleaning roller, 89
is a cleaning blade, 90 is an electrostatic charger, 91
92 represents a registration roller, 92 represents a transfer charger, and 93 represents a separator roller.

FIG. 13 shows a concentration sensor 82, in which 105 indicates a liquid discharge port, 106 indicates a lamp, and 107 indicates CdS.

In this copying machine, in addition to replenishing toner into the tank 4, it is necessary to replenish dispersant as a diluent, and an example of a replenishing member for this purpose is shown in FIG. This dispersant bottle is installed upside down on the upper plate 17 of the tank, and the appropriate amount of dispersant is replenished into the tank by means of a chicken feed valve 102, similar to the conventional bottle.

The state of use of the above-mentioned copying machine will be explained.

(1) Dispersant bottle 1 in developer tank 4
01 and fill the developer to the level of the chicken feed valve 102.

(2) Next, the PTCI is set. To do this, the holder 2 is tilted around the pivot 3 to the position indicated by the chain line in FIG. 1, and the PTCI is set in the holder 2. When the holder 2 is rotated clockwise, the PTCl moves to the position shown in FIG. 5, where the nozzle 16 of the stem 7 engages with the stem receiver 26. The force required to open the stem 7 of the PTCI is 2 kgf/+++” to 4 kgf/
At this point, the nozzle 16 is attached to the stem receiver 26.
By moving the PTCI to the use position shown in the third and fourth figures while engaged with the PTCI, an equivalent force is applied to the stem 7, pushing the stem 7 into the open position and opening the nozzle 16. After that, the toner inside is continuously supplied to the supply tube 31.
The valve means 36 is replenished through the process.

(3) In the valve means 36, the piston 39 is connected to the bell crank 42 and the connecting rod 4 by the operation of the solenoid 45.
A valve opening force P3 in the same direction as the toner pressure P1 in the tube 31 acts through the spring 47.
A force greater than the valve closing force P2 is applied, and the piston 39 is moved to the right in the drawing to open the inlet 35, and the toner is discharged out of the cylinder 37 through the communication hole 46.

(4) At this time, the liquid supply means 48 is connected to both pump units 5
6 and 57 are in operation, the toner is mixed with the developer by the action of the rotor 51 and passes through the communication path 62.
The liquid is sucked into the casing 49 of the pump 56 and supplied to the cleaning unit 81 and the concentration sensor 82 via the supply pipes 54 and 55.
After the cleaning is completed, the mixed liquid supplied to the tank 4 is returned to the tank 4 through the return flow tube 88.

(6) On the other hand, due to the operation of the developing unit pump 57,
The mixed liquid is supplied to the developing unit 84 through the liquid supply pipe 98, and after the development is completed here, it is returned to the tank 4 through the return flow tube 94.

(7) During the above-described operation, the concentration sensor 82 measures the concentration, and when a predetermined concentration is reached, the solenoid 45 is turned OFF and the piston 39 is moved by the valve closing force P2 of the spring 47 to close the inlet 35. Then, toner replenishment is stopped, and when the concentration falls below a predetermined concentration, the solenoid 45 is turned on to restart toner replenishment.

(8) After repeating this process, if the toner density does not reach the predetermined density even after the predetermined number of replenishments and a replenishment signal is issued, the density does not change or the toner density does not reach the predetermined density. Display the end.

(9) When the toner end is displayed in this way, when the PTCI is rotated counterclockwise in FIG. 1, the bracket I2 passes through the position shown in FIG. 5 and returns to the position shown by the chain line in FIG. Moving. At that time, bracket 1
The roller 19 that was engaged in the recess 14 of No. 2 also acts on the stem holder bracket 24 due to the force exerted by the spring 28.
It detaches from the four parts 14 against the tensile force of the spring 21 and the side surface 3
However, since the bracket 24 stops at the position shown in FIG. 5, the stem 7 separates from the stem receiver 26.

When the PTCI is in the position indicated by the chain line in FIG. 1 in this way, the PTCI is removed from the holder 2, replaced with a new PTCI, and then set in the use position again as described above.

When setting in this way, the stem holder bracket 24 is always pushed upward by the spring 28, so even if the dimensions of the PTCl body, mouth, stem, etc. are not necessarily exactly uniform, This dimensional variation is compensated for by displacement of the bracket by the push-up blade of the spring 28.

(10) When the dispersant is insufficient as a result of performing the work as described above, a predetermined amount of dispersant is automatically replenished by the operation of the chicken feed valve 102 of the dispersant bottle 101. As a result, when the bottle 101 becomes empty and the amount of liquid in the tank 4 becomes less than a predetermined amount, a liquid level gauge with a float (not shown) will indicate dispersant end, and conversely, if the amount exceeds the predetermined amount, the liquid level gauge will display dispersant end. Show overflow.

(11) Since the valve means 36 is frequently opened and closed during the above-described operation, the valve means 36 is placed inside the tank 4 and in the developer 5, and the liquid supplied from the tank 4 is connected to the developer unit 84.
Since it is necessary to circulate the liquid to the cleaning unit 81, the amount of liquid in the tank 4 is small while the liquid is being supplied to each unit, and increases after the machine stops because the circulating liquid is recovered.
This causes the height of the liquid level in the tank 4 to change.

Therefore, if the position of the stem 7 of the PTCl is too low, the mouth of the PTCl including the stem 7 will be contaminated when the liquid level rises.To avoid this, if the position is set high, the liquid will become dirty when the liquid level falls. This results in more exposure to the outside atmosphere.

Therefore, in the present invention, in order to avoid these inconveniences, the stem 7 and the developer 5 are connected using the member 33 exhibiting capillary action as described above.

(12) In the above, the operation of the valve means 36 will be described with reference to FIG.

Piston 39 due to internal pressure P1 of tube 31 and spring 47
The valve closing force P2 is opposite in direction and cancels out, so the solenoid 45 required to open the valve
The valve opening force P3 of the piston 39 due to the valve closing force P2 is smaller than that applied in the opposite direction.
In the PTCI of this invention, this means that the internal pressure P
This is a particularly effective condition because the fluctuation of 1 is small.

Furthermore, when the developer is created by sucking toner at the start, the number of times the toner is sucked increases in a short period of time, so it is advantageous when the internal pressure P1 is high.

On the other hand, when the internal pressure P1 is low, even if the number of suctions is increased, the discharge amount may be small and the toner end may be displayed. Also, due to the decrease in the internal pressure P1, P1+P3 becomes smaller and it becomes difficult to open the toner. Even if this happens, it does not cause any particular problem because it can be called a toner end state.

Figure 15 shows the PT per suction when the suction time is constant.
It is a graph showing the amount of toner ejected from Cl based on the cumulative number of suctions. As you will see, the discharge amount is large at the beginning, but the discharge amount becomes extremely small towards the end.

Here, regarding the discharge amount and the conditions for toner end detection, the valve closing force P2 of the valve means 36, the valve opening force P3 of the valve means 36, and the conditions for toner end detection are as follows. (ii) If there is a certain amount of density change but the specified density is not reached, it is considered toner end. (iii) If there is a certain amount of density change but the specified density is not reached, it is considered toner end. Assuming that the end is near, and considering the three methods, naturally P 2 > P 1 for forces P1 and P2, but
It has been found that the forces P2 and P3 should normally be set as P3>P2, and therefore, the relationship between the three forces may be set as P3>P2>P1 regardless of which of the three methods is adopted.

However, if the gas which is the internal pressure generating means in PTCl and the toner are mixed together, in many cases only the gas will come out in the end. In this case, setting P 2 > P 3 will make the apparent discharge rate worse, but since the force relationship is only with the internal gas pressure, it is better than discharging only the gas into the developer. It will be a good thing.

Effects of the Invention The present invention is as described above, and uses a pressurized can for toner supply as a toner container, and has a nozzle opening means, a developer supplying means, and a valve means disposed between them. When the nozzle of the pressurized can is opened by the opening means, the toner is supplied under pressure toward the valve means without contaminating the vicinity of the nozzle. It has the effect of being able to hold a large amount of material compared to its volume, and allowing it to be used for a long period of time.

Furthermore, in addition to preventing the vicinity of the nozzle of the pressurized can from being contaminated as described above, the effect is further amplified because the developer is constantly supplied by the liquid supply member exhibiting capillary development. This also has the effect of preventing the pressurized can from being placed in a position where it would be immersed in the developer, and further preventing the nozzle from being exposed to air at that time.

Furthermore, since the valve means has a valve member to which a valve closing force is applied from the direction opposite to the toner discharge direction, the load required by the member that operates the valve member to open the valve means can be reduced. By making the minimum diameter of the inlet passage of the valve means equal to or smaller than the minimum diameter of the toner discharge passage of the opening means of the pressurized can nozzle, the diameter of the valve member can also be made small; It also has the advantage that the required load on the opening member of the valve means can be further reduced. Including these, the opening and closing action of the valve member is determined by the pressure P1 in the connecting means, the valve closing force P2 and the valve opening force P3 of the valve member.
By setting Pl, it can be realized more effectively depending on the situation at that time.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal sectional front view of an embodiment of the present invention, FIG. 2 is an enlarged vertical sectional view of the mouth of the pressurized can for toner supply in the same embodiment, and FIG. 3 is a pressurized toner supply can of the above embodiment. A front view of the can when it is in use, Figure 4 is a partially longitudinal front view of the same as above,
FIG. 5 is a partially longitudinal front view of the same as above when it is in the tilted position, FIG. 6 is an enlarged view of the part surrounded by line 6 in FIG. 1, and FIG. A drawing showing the orientation state of
Figure 8 is an explanatory diagram showing a part of Figure 6 enlarged;
10 is a schematic plan view of the drive system of the above embodiment; FIG. 11 is a partial perspective view of a copying machine in which the present invention is used; 12th
The figure is a vertical cross-sectional view of the main parts of the same as above, FIG. 13 is a partial slope view (A) and a front view (B) of a part of the concentration sensor of the above embodiment, and FIG. 14 is a partial front view of the concentration sensor of the above embodiment. FIG. 15, which is a longitudinal sectional front view of the dispersant member, is a graph showing the relationship between the number of discharges and the discharge amount according to the embodiment. 1...PTC2...Holder 3...Pivot 4...Developer tank 5...Developer solution 7...Stem 15...Discharge passage
16... Nozzle 26... Stem receiver 30...
Supply port 31... Supply tube 33... Liquid supply member 3
5... Inlet 36... Valve means 37... Cylinder 39... Piston 45... Solenoid 46... Communication hole 48... Liquid supply means 49.
...Casing 51...Liquid supply rotor 54, 55.
98...Liquid supply pipe 56...Cleaning unit pump 57...Developing unit pump 81...Cleaning unit

Claims (1)

[Scope of Claims] 1. In a developing device of a copying machine that uses a toner container to replenish toner into a developing tank, a first chamber that is expanded by gas as the toner container;
A pressurized can for supplying toner is used, which has a second chamber that contracts when the chamber expands and stores toner therein. 1. A developing device for a copying machine, comprising: a liquid supply means for supplying liquid; and a valve means disposed between the opening means and the liquid supply means. 2. At least in the vicinity of the nozzle receiving part of the nozzle opening means,
2. The developing device for a copying machine according to claim 1, wherein the developer is supplied from a developer tank by a fluid supply member. 3. The developing device for a copying machine according to claim 3, wherein the liquid supply member is formed of a member exhibiting a capillary phenomenon, such as cotton cloth, extending from the developer solution to the nozzle receiver. 4. The developing device for a copying machine according to claim 1, wherein the valve means includes a valve member sealed by pressure from a direction opposite to the direction in which the toner is discharged from the toner supply pressurized can. 5. The copying machine according to claim 4, wherein the minimum diameter d2 of the inlet passage of the valve means is the same as or smaller than the minimum diameter d1 of the toner discharge passage of the opening means of the nozzle of the pressurized can. Developing device. 6. When the internal pressure in the connecting means that connects the opening means and the valve means is P1, the valve closing force for sealing the valve means is P2, and the valve opening force for opening the valve means is P3, P
5. The developing device for a copying machine according to claim 4, wherein the developing device satisfies the relationship 3>P2>P1. 7. When the internal pressure in the connecting means that connects the opening means and the valve means is P1, the valve closing force for sealing the valve means is P2, and the valve opening force for opening the valve means is P3, P
5. The developing device for a copying machine according to claim 4, wherein 2≧P3>P1.