DE2043158A1 - - Google Patents

Description

PATENT LAWYERS DR.-ING. WOLFF, H. BARTELS DR. BRANDES, DR.-iNG. HERO

48M75 kdk

STUTTGART 1

28 8,197

IANGE STREET 51 TELEPHONE (0711) 296310 and 297295

TELEX. 0722312

Registration number. 122 632

EASTMF KODAK 0OMPAKT, Rochester, New York State United States of America

Electrophotographic device

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The invention "relates to an electrophotographic apparatus having a development station for feeding toner particles disperse in a carrier liquid to a charge image to be developed that is based on electrographic recording material "is located.

According to a conventional ele & trophotographischen method is a provided with a photoconductive layer recording material such as a recording sheet, provided by a Koronaeinriehifrung having a substantially uniform charge, which is selectively removed locally by exposure to a S.trahlungsmusters to achieve an electrostatic image ₀ This image is then developed by guiding the recording sheet through a medium with toner particles that have a charge whose polarity is opposite to that of the electrostatic image ο This attracts the particles to the recording sheet to create a visible toner image, this image subsequently being melted can be fixed. Either a powder or a liquid can be used as the development medium. If a liquid is selected, the carrier liquid (eg Isopar) contains the toner particles in suspended form »

These particles are imagewise from d;: - m electrostatic Image drawn onto the receiving sheet to create a toner image. Make multiple copies one after the other made, then the number of the in the Liquid present toner particles, which leads to a reduction in the contrast of the subsequently- · .nd manufactured Copies leads. In addition, fluctuations in contrasts may occur, if the devolatilizing liquid: it is not the same

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BATH ORIGINAL

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moderately distributed over the surface of the receiving sheet is to ensure that all parts of the electrostatic image are essentially the same Amount of toner particles are exposed to achieve complete and even development.

Many attempts have been made to achieve uniform development. These include spraying the liquid onto the receiving sheet, applying the liquid by rolling, and the like

Immersing the receiver sheet in the liquid. However, each of these "known methods" has certain Disadvantages on. If the developer is sprayed on, the spray must be carefully directed, so that no spray liquid reaches the corresponding parts of the copier in an undesired manner. Furthermore is it is difficult to get the same spray performance from each nozzle. Application rollers can form defects in the circumference whereby the pressure applied against the receiving sheet becomes uneven and the developer is applied unevenly. Becomes the recording sheet immersed in the liquid, it can be complete

Impregnation of the same occur, so that a noticeable

Lent drying time is required before the copy is ready for use. In other devices, a flat trough is provided through which the receiving sheet is guided, but here it is difficult to achieve a uniform distribution of the developer fluid over the trough space. In addition, often remains between the copying work EntwicklerfTüssigkeit in the developing station and may then Freq ± he f spilling, when the copying machine is initiated or shaken.

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BATH ORIGINAL

In addition, the known devices either have no means for replenishing developing liquid and toner particles, or these are of such a nature that the quality of the copies is undesirable Dimensions fluctuates * In most cases, refilling the developer fluid is cumbersome and difficult, usually taking the entire machine out of service, and sometimes an extensive one Dismantling is required before additional liquid

P can be refilled. For example from the U.S. Patent 3,416,860 shows attempts have been made to remove spent toner particles to complete. In this device, however, refilling the carrier liquid is cumbersome and that Toner concentrate is filled into a storage container on the side opposite a pump, so that the dispersion of the toner particles in the liquid should take some time. This can lead to the fact that further copies are made with low contrast, although the operator an addition of further toner saving

& tikel has caused ο

The invention is based on the object _{/ to provide} a device of the type in question which makes it possible to achieve more uniform development results than was previously possible.

According to the invention, this object is achieved in a device of the type mentioned in that the Development station a liquid refill station with at least one container for carrier liquid and / or has toner particles. This is in the simplest way a proper supply of through the Carrier liquid with toner dispersed in this

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Particles formed developer liquid guaranteed to the material to be developed.

The refill station can be a liquid reservoir have, of which the developer liquid by means of a pump through a distribution pipe system to Development station can be pumped so that the Developer liquid evenly over the to be developed Receiving sheet is distributed when the latter passes through the development station. After completing the ™

You can copy the liquid from the development station Let it flow back into the storage container. This also makes it possible to a large extent Prevents liquid from spilling if the copier is knocked or jerked should ο

In addition, the storage container can be slidably mounted on rails so that it can be pulled out for refilling with carrier liquid and / or toner particles.

In one embodiment, two chambers or receptacles are assigned to the storage container, one of which holds a tear-open container for the carrier liquid and the other serves to hold an aerosol can with toner particles that the liquid can flow off immediately into the storage container. A float valve can also be provided which ^{interrupts the flow of liquid 1} into the storage container as soon as the liquid level in the same reaches a predetermined level.

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has enough.

The closure of the aerosol can "can be opened periodically in the relevant embodiment by means of an actuating magnet, which is excited during the first operation of the device after the operator has caused the addition of further toner particles by actuating a switch. Preferably, in a corresponding embodiment, the arrangement is like this made that the aerosol can enters the toner particle concentrate directly into a suction opening of the pump , which conveys the liquid from the storage container to the development station, so that the toner is immediately available for developing a subsequent copy explained in detail.

Show it:

Pig. 1 shows a stepped longitudinal section through the development station and refill part an embodiment of the device according to the invention j

Figure 2 is a section along line 2-2 in Figure 1;

Fig «, 3 is a partially exploded perspective Partial view of the development station and the arrangement of the trays located therein;

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Fig. 4 is a circuit diagram of part of the electrical circuit used;

FIG. 5 is an exploded perspective partial view of a drain trough and FIG Parts that connect to the refill part;

6 is an exploded perspective view of a distributor head and a Development trays as used in the development station shown in Figures 1 to 3;

Fig. 7 is a partial perspective view of the filler part and

Figure 8 is a vertical section through another embodiment of a development station.

A recording material provided with a photoconductive outer layer, for example a recording sheet as shown in FIG 10, is provided with an electrostatic charge to create an electrostatic image exposed to a radiation pattern and then through a Development station D guided with the image side of the sheet 10 facing down

The development station D has an upper arched trough 11 and a lower arched trough 12, the are arranged so that they form a channel through which the receiving sheet 10 by feed

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rolls 13 and 14 through "is moved. In.einer below "In the manner described, developer liquid is fed into the lower trough 12 and evenly over the receiving sheet distributed so that the electrostatic image on the receiving sheet to generate toner particles of a toner image. When leaving the development station, the receiving sheet runs through Pair of nip rollers 15 and 16, which remove the superfluous developer liquid from it. Appropriately the upper trough 11 has a curved surface 17 and has a curved protective hood 18 on, which covers the squeegee roller 15 and a splash of the developer liquid from the squeegee roller 15 prevented. Furthermore, the trough 11 is provided with side walls 19 and diagonally extending ribs 21, whose task it is to keep the receiving sheet 10 at a distance from the underside of the surface 17 and thereby prevent sticking to it. The lower trough 12 expediently has a arched bottom 22 with diagonally extending ribs 23, which - as best seen in FIG - Are arranged between the ribs 21. The ribs 23 serve as a support for the picture side of the Receiving sheet 10 if the liquid in the development station for carrying the sheet shouldn't be enough. The developer liquid is made up of a variety of between each Ribs arranged slots, .24 fed. The liquid pumped through the slots 24 runs via the front and rear edge of the lower trough 12 into a collecting trough 25, the bottom surface 26 of which in Is inclined towards a drain opening 27, the latter being substantially rectangular and for the inclusion of a later detailed

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written insert 28 is set up »Like Pig.3 shows, the lower trough 12 has a pair of outwardly projecting rims 22 'which are shown in Pig. 5 shown Lugs 26 '■ attack to the trough 12 in its position above the drip tray 25,

The developer liquid is supplied from a liquid supply station R, in which a supply of liquid developer is located in a substantially box-shaped storage container 30. Located in the storage container 30 is a pump 31 driven by a motor 32, which sucks the liquid from the storage container through an inlet opening 33 and conveys it into a flexible hose 34. This hose engages around a pin 35 and opens into a displaceable block 36 to which a tube 37 is connected, which in turn opens into a central bore 38 in the insert 28. The liquid then flows through a bent tube 39 connected to a distributor head 40 (FIG. 6). The distributor head 40 has a lower half 41 and an upper half 42, the upper half being molded onto the lower trough 12 Part 44 is a baffle 45 which deflects the developing liquid to the two ends of the distributor head. The lower half 41 corresponds to the upper half 42 so that a passage portion 46 mates in the upper half 42 with the baffle 45 to form eine3 single passage ₀ Further, the top 'half 42 to a larger part 47 which, together with the baffle 45 a bigger one. Space educates and trains

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which a baffle 48 at a greater distance from the passage than the baffle 45 is arranged in addition to support the distribution of the developer liquid over the distributor head, so that a substantially even amount of liquid flows through the slots 24. The pump 31 works continuously during the entire copying process, so that the developer fluid continuously darc la the slots 24 is pumped, the lower trough 12 fills, overflows at the front and rear ends and then into the Collecting trough 25 falls, whereupon it finally falls through outer openings 49 of the insert 28 into the storage container 30 flows back. The space between the upper trough 11 and the lower trough 12 is therefore completely with Liquid filled, with the continuous flow of this liquid through the slots 24, the receiving sheet 10 is held in a position above the ribs 24, so that the image side of the ο sheet at normal Operation not touching the lower trough or the ribs at all. This has the advantage of being one banding caused by touching the ribs 24 remains limited to a minimum on the copy

According to FIG. 4, a copying process is initiated by a - normally open - starter switch 51 closes, which is held by a delay circuit 52 in its closed position, so that the E'impenmotor 32 continuously for a predetermined period of time works sufficient to charge, expose and develop the receiving sheet After completion of the copying process, the liquid in the development station D runs through the slots 24 back into the storage container 30.

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When the supply!) Ehälter 30 developer liquid contained 29 is running low, a float switch 52 closes · accordance with Figo 4 the circuit to a lamp 53 which indicates to the operator that the processing liquid must be added. For this purpose, the storage container 30 can be pulled out of the device on a slide rail 54 shown in FIGS. 1 and 7, so that it is accessible outside of the device housing 55. The movement of the storage container 30 is made possible by the hose 34-, | which moves from the position shown with a dashed line in FIG. 7 into the position near the pin 35 shown with a solid line. To facilitate this process, the block 36 is arranged between a pair of parallel slide bearings 56 and 57. The storage container 30 has a top side 58 with a longitudinal slot 59 which is covered by a sliding bar 60 movable between guides 61, as best shown in FIGS Fig. 1 and 3 can be seen. According to FIG. 5, the sliding strip 60 has an opening 62 through which the insert 28 protrudes. So when the storage container 30, as shown in Fig. 1 and 7, is removed from the housing by "sliding it to the left on its slide rail 54, the slide bar 60 moves along the top 58 so that the hose connections in remain in their position «.

On the top 58 is a first erxiomer 63 for receiving a tearable container 64 with developing liquid and a second chamber 65 for receiving an aerosol can 66 arranged. When the reservoir 30 is pulled out of the housing 55, are

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the chambers accessible so that the container 64 and the aerosol can 66 can be exchanged. If the operator notices from the lighting up of the lamp 53 that the developer liquid is running low, the storage container 30 can be pulled out and the empty container 64 can be exchanged for a new container. These containers or bottles are preferably made of a tearable material, eg ₀ polyethylene, and can be pressed into the chamber 63 so as to be pierced by a needle 67 at one end and the developer liquid in the container 64 can flow into the reservoir 30th After the container 64 has been inserted, the storage container 30 can be pushed back into its original position in the device, as shown in FIG. 1. The cannula preferably has an enlarged tube end 68. The drilling end 68 is provided with a plurality of holes 69 through which the liquid pours from the container 64 into the reservoir 30. If necessary, a filter (not shown) can be provided in the pipe end 68, the task of which is to keep lint away from the storage container. A float valve 71 is provided in the pipe end 68, which closes the cannula 67 if the liquid level should reach a predetermined level. This prevents the developer liquid from overflowing.

7 The aerosol can 66 has a ZuineMüse 72 and is held by a flange 73 which is supported on the bottom of the chamber 65.

If it is found that the copies are deteriorating in contrast, a switch shown in FIG. 4 is turned on

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73 'closed by the operator, with the result that a storage circuit 74 briefly energizes an electromagnet 75 as soon as the starter switch 51 is operated the next time. As can be seen from FIG. 1, the magnet 75 is connected to an arm 76, the end of which engages the bottom of the aerosol can 66 and which is rotatably mounted on a pin 77 fastened to the housing 55. Accordingly, energizing the magnet 75 causes the arm 76 to pivot counterclockwise (see FIG. 1), thereby pushing the aerosol can 66 downward so that the nozzle 72 injects a measured amount of ionic particles into those of a jacket 78 in the reservoir 30 gives up limited space. As a result, the toner particles are immediately fed into the inlet opening 33 of the pump 31, which pumps them on together with the liquid sucked in through an opening 79 in the casing, so that the developer troughs are charged with a concentrated developer liquid for the immediately following copy. After the magnet 75 is briefly excited, it is moved back into its starting position by a helical spring 81, so that the right end of the arm 76 is again supported on a stop pin 82 projecting away from the housing 55.

8 shows a modified development station D ¹ , Ip which the upper and lower troughs 85 and 86 together form a channel through which the receiving sheet 10 is guided, for example driven by feed rollers 87 and 88. After development has taken place, the excess developer liquid is removed from the receiver sheet by nip rollers 89 and 91. The development

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winding troughs are arranged in a discharge trough 92, which serves to return the liquid to a storage station. Appropriately, the development is liquid through an inlet port 93 at the bottom of the trough 86 and through one near the front end of the Trough 86 arranged second inlet port 94 is pumped. The developer liquid is these inlet openings from one connected to a pump 98 via tubes 95 and 96, respectively T-piece 97 fed. Such an arrangement results in a one at the inlet opening 94 Waterfall effect, as the developer liquid over the curved surface of the trough 86 flows down. On the other hand, the quick filling of the trough is ensured because the liquid is also supplied through the inlet opening 93. When the trough fills, the liquid will run out flows from the trough 86 through a series of openings 99 provided at the front end of the trough then through the drainage opening 100 of the drainage trough and then back into the storage container. At the end of one Copying process, the liquid runs through the inlet opening 93 into the reservoir.

The foregoing sets out advantages of the present invention. So becomes a development station created for developing an electrostatic image in which a uniform distribution the developer liquid over the development trough and thereby over the electrostatic image supporting recording sheet is guaranteed. According to one embodiment, this is done by the use tion of a series of baffles having distributor head achieved, the baffles the Advantage liquid in such a way that it flows through evenly

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a series of slots is fed along the trough.

According to another embodiment, the Liquid is supplied near the front edge of the trough as well as at the bottom of the same. Furthermore, developing liquid and toner concentrate can be used without difficulty the reservoir can be refilled as the reservoir is conveniently pulled out of the housing can be either to insert a container of developer liquid when the liquid level is too low or to use an aerosol can of toner particle concentrate when the supply of toner particles is waning. When the operator notices while working that the contrast of the copies is no longer satisfactory, so may they close a memory circuit by pressing a button, so that the next Operation of the device briefly an electromagnet is excited to a measured amount of toner particles from the aerosol can into a position adjacent to the inlet opening of the pump. Through this a developer liquid enriched with toner particles is added to the development station for the immediately following copy fed. Furthermore, the developer liquid is used at the end of each operation drained from the development station; thereby reduced there is a risk of spillage if the copier is moved or bumped.

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Claims (1)

20A3158 PATENT CLAIMS / 1) ELectrophotographic apparatus with a development station for supplying toner particles dispersed in a carrier liquid to a charge image to be developed which is on electrographic recording material, thereby characterized in that the developing station (D) is a liquid refilling station (R) with at least one container (11, 12, 30, 64, 66) for carrier liquid and / or toner particles. 2) Device according to claim 2, characterized in that the refill station (R) has a liquid storage container (30) has, on the upper side (58) of which a receptacle (63) is provided for a refill container (64) with carrier liquid is. 3) Device according to claim 1 or 2, characterized in that the refill station (R) has a liquid storage container (30), on the upper side (58) of which a receptacle (65) for a refill container (66) with toner particles 4) Device according to claim 2 or 3, characterized in that a pump (31) for conveying the in the storage container (30) liquid is provided to the development station (D). ./Ζ 5) Device according to one of claims 1-4, characterized in that the refill station (R) in the housing (55) of the device is slidably mounted so that they can facilitate the replacement of one or both refill (64 and / or 66) can be at least partially pulled out of the housing (55). 1098 1 p. / U 93 6) Device according to one of claims 3-5 with claim 4, characterized in that the receptacle (65) for the Refill container (66) is arranged with toner particles so that the toner particles of the inlet opening (33) The pump (31) is fed into the reservoir (30) next to it will. 7) Device according to claim 6, characterized by a die Inlet opening (33) of the pump (31) surrounding casing (78) with the receptacle (65) for the refill container (66) is in direct contact with toner particles. 8) Device according to one of claims 3-7, characterized in that that an electrical circuit for controlling the input of toner particles from the refill container (66) is provided in the reservoir (30) and that the circuit is a normally open switch (51, 73 ') for connecting the circuit to a power source and an electromagnet (75) for opening one normally closed toner metering valve (72, 73) of the refill container (66) for toner particles, which through the circuit is excitable. 9) Device according to claim 8, characterized in that the circuit has a memory (74) to which _{a control pulse can be supplied by closing des__S_cha_ltprs__J-_51_ f} 73 ') ι by which the electromagnet (75) can be excited during a subsequent copying process of the device is. 10 9813/1493 20Α3Ί58 -ίδ ιο) device according to one of claims 1-9, characterized in that the development station (D) has a lower and an upper, each arcuately curved trough (12 or 11) which are arranged at a mutual distance from one another, so that a passageway for the passage of a is formed to be developed recording sheet (10) between them, and that a liquid connection (24, 25, 27, 36, 37, 38, 39, 93, _94? 95, 96) between the lower trough ( 12, 86) and the storage container (30) P is provided. 11) Device according to claim 10, characterized in that with the lowest point of the lower trough (12) a liquid distributor (40) is connected and that the distributor (40) means (41-48) for uniform Has a supply line of supplied developer liquid (29) to slots (24) through which the distributor (40) communicates with the top of the lower trough (12). 12) Apparatus according to claim 11, characterized in that * in the distributor (40) as a device for uniform Feeding the liquid to the slots (24) baffles (45, 48) of different lengths, which in the Flow path of the liquid are arranged, are provided and that the length of the deflection walls with increasing Distance from the slots (24) decreases. 13) Apparatus according to claim 12, characterized in that the manifold (40) attached baffles (45) and on The lower trough (12) is provided with deflecting walls (48) which project into the distributor (40). 109813/1493