US3638609A

US3638609A - Electrostatic image developing device

Info

Publication number: US3638609A
Application number: US780673A
Authority: US
Inventors: Sadanao Ando; Funihiro Miyagawa
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1967-12-04
Filing date: 1968-12-03
Publication date: 1972-02-01
Anticipated expiration: 1989-02-01
Also published as: GB1256717A; BE724927A; NL6817371A; DE1817792A1; DE1812729A1

Abstract

An electrostatic image developing device has a photosensitive copy paper transporting body rotatable about a horizontal axis and having a plurality of photosensitive copy paper receiving plates equiangularly disposed and extending radially peripherally of the body. Copy papers bearing electrostatic images are held in position between adjacent receiving plates by hinged holding plates which press them against the receiving plates. Rotation of the transporting body sweeps them through a developing tank.

Description

0 1 Hate States atem 1151 3,638,699

Ando et a1. 1 1 Feb. 1, 1972 [54] ELECTROSTATIC IMAGE [56] References Cited DEVELOPING DEVHCE UNITED STATES PATENTS [72] fi figfzfig gi Miyagaw 467,800 1/1892 Gould, Jr ..117/114 B- y p 2,031,010 2/1936 Simjian....... ..95/89 L [73] Assignee: Kabushiki Kaisha Ricoh, Tokyo, Japan 2,355,278 8/1944 Davis ..1 18/426 383,030 5/1888 White 118/428 X [22] 1968 2,553,014 5 1951 Singer ..95 14 [21 Appl. No.: 780,673 3,417,687 12/1968 Hills 118/426 X 3,511,160 5/1970 Van ReuseL... ..95/89 [30] Foreign Application Priority Data Primary Examiner Morris Kaplan Dec. 4, 1967 Japan ..42/77802 Att0mey-Burgess, Ryan and Hicks Dec. 4, 1967 Japan...

Dec. 13, 1967 Japan... [57] ABSTRACT Dec. 13,1967 Japan....

D 13' 1967 Japan. An electrostatic image developmg device has a photosensitive Dec 13 l967 Japan 42/79951 copy paper transporting body rotatable about a horizontal axis and having a plurality of photosensitive copy paper receiving {52] CL mulls/426 1 18/503 plates equiangularly disposed and extending radially [51] Int. Cl. ..B05c 11/14 peripherally of the ypy P p bearing electrostatic 158] Field 01 Search ..1 18/503, 423-426; images are held in Position between adjacent receiving Plates 95 /39 L, 93; 271/30 by hinged holding plates which press them against the receiving plates. Rotation of the transporting body sweeps them through a developing tank.

3 Claims, 11 Drawing Figures memaum lmz 3.638.609

SHEET 1 0F 4 ATTORNEY 5 PATENTED FEB 1 I972 SHEET 2 0F 4 FI G.4

FIG.5

INVENTORS AqT CN fS FIG.7

PATENIEBFEH W72 3.638.609

SHEET 3 0F 4 FIG.8

ATTORNEY 5 ELECTROSTATIC IMAGE DEVELOPING DEVICE BACKGROUND OF THE INVENTION The present invention relates to a wet-type developing device for developing an electrostatic image produced upon an electrostatic photocopying paper and more particularly a developing device of the type described wherein a plurality of electrostatic images upon copy sheets into which have been cut from a photocopying paper roll, are developed at the same time one by one.

In developing device of the type wherein an electrostatic latent image is produced upon a photosensitive paper (comprised of a photoconductive material such as zinc oxide applied to a suitable insulating material base) and is made visible by applying image-producing particles to the electrostatic latent image, there have been known two types of developing devices; one being the dry-type developing device wherein the electrostatic latent images are developed by contacting the image-producing particles with the latent images; and the other being the wet-type developing device wherein the latent images are developed in a developing solution in which imageproducing particles are suspended in a carrier having a higher electric resistance sufficient to prevent the breakdown of the electrostatic latent images.

Generally, one of the defects of the wet-type developing device is that the developing time is longer as compared with the dry-type developing device. The developing time in the wet-type developing device may be up to times longer as compared with the dry-type developing device even if the image-producing particles are very finely divided and very high-sensitivity developing agent is used. This is especially true when the corona discharge is generated between the corona discharge electrodes and a photocopying sheet which is spaced apart from the electrodes by a considerable distance, in order to give the charges to the photoconductive material upon the photocopying sheet so as to generate a relatively weak surface potential thereupon. It is also especially true when the so called noncharging" method is employed in which the photocopying sheet is not subjected to a corona discharge and an electrostatic latent image is produced by utilizing the photogalvanic effect induced upon exposure of the copy sheet to light and is developed by the wet-type developing method.

Since the exposure time is very short as compared with the developing time, one of the methods to facilitate photocopying, that is to increase the speed of the photocopying process, is to reduce the developing time. However, in case of the wettype developing method, especially in case of the wet-type developing method in which the photocopying sheets whose surface potential is relatively low is to be developed, it is impossible to reduce the developing time during which the photocopying sheets having electrostatic latent images are immersed in the developing solution, because of the inherent characteristics of the wet-type developing method.

In view of the above, one of the objects of the present invention is to provide a developing device for developing an electrostatic latent image which is capable of increasing the photocopying efficiency without reducing the time during which the photocopying sheets are immersed in the developing solution.

SUMMARY OF THE INVENTION According to the present invention, a photocopying sheet transporting rotary body is employed having a plurality of photocopying sheet receiving plates equiangularly radially disposed peripherally of the rotary body so that the photocopying sheets having electrostatic latent images thereupon are advanced between adjacent receiving plates and a plurality of photocopying sheets may be simultaneously developed in sequential order as the photocopying sheets are immersed in the developing solution.

The said rotary body comprises a horizontal rotary shaft and a plurality of photocopying sheet receiving plates equiangularly radially disposed peripherally of the horizontal rotary shaft. A number of photocopying sheet clamping or holding plates equal to that of the receiving plates is provided so as to cooperatively operate with the receiving plates, thereby clamping or holding one photocopying sheet between each plate pair.

BRIEF DESCRIPTION OF DRAWINGS FIG. I is a longitudinal sectional view of one embodiment of an electrostatic image developing device;

FIG. 2 is a perspective view illustrating photosensitive paper transporting rotary body;

FIG. 3 is a longitudinal sectional view of an embodiment of an electrostatic image developing device of the present invention;

FIG. 4 is a perspective view illustrating a photosensitive paper receiving plate and a photosensitive paper clamping or holding plate both of which are adapted to be attached to the photosensitive paper transporting rotary body;

FIG. 5 is a partial enlarged view of an opening member for opening the photosensitive paper clamping or holding plate;

FIG. 6 is a longitudinal sectional view of another embodiment of an electrostatic image developing device of the present invention; and

FIG. 7 is a perspective view illustrating another opening member for opening the photosensitive paper clamping or holding plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring FIGS. 1 and 2, a photosensitive paper transporting rotary body generally indicated by Q has a plurality of photosensitive paper receiving plates 2 which are disposed substantially equiangularly so as to extend radially from a rotary shaft 1. The ends of the rotary shaft I of the rotary body Q are journaled in stationary members such as end plates secured stationarily to a stationary developing solution tank 4 so that the rotary body Q may be rotated in the direction indicated by the arrow a. The developing solution tank 4 has a semicylindrical inner wall surface 4a disposed coaxially with the rotary shaft 1. At the developing solution tank 4 is filled with a developing solution 5 in which image producing particles are suspended in a carrier having a high electric resistance and the lower half of the rotary body Q is immersed in the developing solution 5.

In FIG. I, a photocopying device exclusive of the developing device is schematically shown on the left side of the chain line AA, and a reference numeral 6 designates a device for cutting into a predetermined size a photosensitive paper drawn from a photosensitive paper roll 7; 8, a device for electrostatically charging the cutout photosensitive paper; and 9, a device for exposing the charged paper so as to produce an electrostatic latent image. There is known in the art a photocopying device or machine in which a photosensitive paper roll is automatically cut into a predetermined size and the exposure of the resulting cutout paper is effected in con junction with the paper cutting step. In a photocopying method in which a noncharging" method is employed, the above-described charging device 8 is of course not used.

The exposed photosensitive paper 10 discharged from the exposure device 9 is fed between two adjacent photosensitive receiving plates 2 (which are rotating at low speed) by means of a photosensitive paper feeding device l 3 comprising a pair of rollers 11 and I2. In order that the exposed photosensitive papers sequentially discharged from the feeding device I} may be placed in position one by one in the wedge-shaped spaces between adjacent receiving plates 2, the rotary shaft 1 is interlocked with the roller 12 so that the leading edge of the exposed paper discharged from the exposure device I3 may be permitted to advance just in time into the wedge-shaped space opening in synehronism with the rotation thereof. In order that the exposed paper may be positively fed into the opening of the wedge-shaped space, the peripheral speeds of both the rollers 11 and 12 are fast as possible so that the photosensitive paper may be fed into the wedge-shaped space rapidly when the opening of the wedge-shaped space is located in opposite to the feeding device 1 3.

Now a plurality of exposed photosensitive papers which are sequentially fed into the wedge-shaped space between two adjacent receiving plates one by one and thus carried by the rotary body 3, are immersed in the developing solution and transported away from the feeding device 1 3. Since the rotation of the rotary body 3 is slow, the period of immersion of the exposed papers in the developing solution is sufficiently long.

Projections 14 formed along the inner wall surface of the bottom portion of the developing solution chamber 4 serve to vibrate the photosensitive papers passing through these projections 14 so that the better contact and immersion of the papers with the developing solution may be ensured. it is preferable that each of the receiving plates 2 is made of a plate provided with a multitude of pores for passing the developing solution therethrough or a netlike plate in order to agitate the solution within the chamber 4 and to reduce the resistance of the rotary body encountered when rotated in the solution.

A brush roller 15 is so disposed that th upper surface of the leading edge of the paper after it emerges from the developing solution may abut against the brush roller 15. Both brush roller 15 and a roller 16 are rotated continuously at relative high rpm. in the directions indicated by the arrows. When the outer edge of the paper abuts against the brush roller 15, the brush roller 15 draws out the paper from the wedge-shaped space between the adjacent receiving plates so that the paper propelled out of the developing device by means of the brush roller 15 and the roller 15.

Air is preferably blown from a suitable blower toward the upper half of the rotary body 3 so as to dry the wet receiving plates 2, whereby the resistance to the paper when it was fed into the wedge-shaped space may be reduced.

The rotary member which serves to draw the paper emerging from the solution from the wedge-shaped space is not limited to the brush roller shown in FIG. 1, but any other suitable rotary member may be used such as, a member which is made of a material having a suitable property to exert a frictional force to the paper so as to draw it outwardly. For example, a roller of flexible rubber or synthetic resin, and whose outer surface is provided with suitable projections and recesses, may be advantageously employed.

When the paper has emerged from the developing device, it is fed into a dryer employing a suitable thermal source and/or to the next developing solution treatment chamber (when more than one developing solution is used). In each of such successive treatment chambers, a photosensitive paper transporting rotary body similar to that used in the developing device as described hereinabove may be used. A plurality of treatment devices incorporating the rotary bodies as described above may be disposed in series in such a manner that the rotary member for drawing the treated paper from each treatment device is located in opposite to the paper-feeding portion of the next treatment device.

Next, a second embodiment of present invention will be described hereinafter with reference to FIGS. 3 to 5. A photosensitive paper transporting rotary body generally indicated by 1% is provided with a plurality of photosensitive paper holding elements mg each of which is comprised of a pair of a photosensitive paper receiving plate 102 and a photosensitive paper clamping or holding plate 103. A plurality of photosensitive paper receiving plates 102 and a plurality of clamping or holding plates 103 are equiangularly disposed peripherally of a rotary shaft 101 so as to extend radially therefrom. Both ends of the rotary shaft 101 are journaled by stationary members such as end plates of a stationary developing solution tank 106 respectively so that the rotary body Q15 may be rotated in the direction indicated by the arrow a. As in the case of the first embodiment, in the developing solution tank 106 is filled a developing solution 107 consisting of image-producing particles suspended in a carrier having a high electric resistance, and the lower half of the rotary body is adapted to be immersed in solution 107 in the tank 106.

The structures and operations of the portions indicated by the numerals 108 to 115, shown in FIG. 3 are identical with those of the portions indicated by the numerals 6 to 13 shown in F IG. 1.

The clamping or holding plate 103 is pivoted at ends 1020 and 103a thereof to the shaft 101 so that the holding plate and the receiving plate 102 may be closed or opened as shown in FIG. 4. Furthermore the clamping or holding plate 103 is provided with a spring member so that the clamping or holding plate 103 normally tends to be biased toward the receiving plate 102. When one of the holding mechanisms 11E comprising the pair of receiving and clamping or holding

plates

102 and 103, approaches a feeding device by the slow rotation of the rotary shaft 101, the leading or free end of the clamping or holding plate 103 abuts against a plate-opening member 116 disposed in the vicinity of the feeding device 114. The movement of the clamping or holding plate 103 is thereby retarded temporarily, whereby the clamping or holding plate 103 is rotated about the pivoted end portions 1112b and 1113b against the spring member 115, thereby separating the clamping or holding plate 103 from the receiving plate 102 so as to provide an opening. Thus, the exposed photosensitive paper discharged from the feeding device 114 may be advanced upon the receiving plate 102.

When the movement of the clamping or holding plate 103 is retarded by means of the plate opening member 116 as described above, the clamping or holding plate 103 is retarded with the free outer edge thereof being moved in contact with the inner surface of the opening member 116. When the free outer edge of the holding plate 103 is released from the inner surface of the opening member 116, the clamping or holding plate 103 is again pressed against the receiving plate 102 by the spring member so that the exposed paper advanced between the spaced-apart receiving plate 102 and the clamping plate 103 may be held stationary in position therebetween. When the receiving plates 102 are disposed in closely spacedapart relation with each other, the clamping or holding plate 103 which has been retarded and opened backwardly would be pushed by the following receiving plate 102 before the clamping or holding plate 103 is released from the opening member 116. Therefore, in order to eliminate any mechanical difficulty imposed upon the clamping or holding plate 103 and other members due to the forcible rotation by means of the receiving plate 102 as described above, it is preferably to provide a suitable means to the clamping or holding plate opening member 1 16 so that the clamping or holding plate 103 may be displaced backwardly, that is in the direction remote from the rotary shaft.

When the clamping or holding plate opening member 116 is formed as a stationary member, it is required that the opening member 116 must be adjusted with respect to the advancing speed of clamping or the holding plate 103 due to the rotation of the rotary shaft 101, the strength of the spring member 115 and the time during which the exposed paper fed from the feeding device 114 is advanced toward the receiving plate and held in position in the holding mechanism 104. In this case, as shown in FIG. 5, natural or synthetic resin fibers may be disposed upon the portion of the opening member 116 which engages the clamping or holding plate. A brush 11612 or an elastic rubber or the like may be disposed upon this portion, whereby the best adapted holding plate opening member may be provided.

The operation of the feeding device m is made in synchronism with the rotary shaft 101 so that the leading edge of the exposed paper from the feeding device 121 may be just fed into the opening formed between the receiving and clamping or holding plates in synchronism with the formation of this opening. In order to secure the positive advancement of the paper into the receiving mechanism, it is preferable to make the peripheral speeds of both of

rollers

112 and 113 high so that the paper may be advanced into the opening of the holding mechanism 104 as fast as possible when the opening is located opposite to the feeding device [#1.

A plurality of photosensitive papers 117 which have been secured in position one in each receiving mechanism M are advanced to be immersed into and to pass through the developing solution and transferred to a position opposite to the feeding device 114 as the rotary body 5 rotates. In this case, since the rotation of the rotary body 1% is relatively slow, the time allowed for the papers to be immersed in the developing solution is sufficiently long for proper development.

In order that the developing solution 107 in the chamber 106 may be sufficiently agitated so that the development of the papers may be facilitated and in order that the fluid resistance exerted on the rotary body due to the rotation in the developing solution may be reduced as much as possible, it is advantageous if both the receiving and clamping or holding

plates

102 and 103 are made of screenlike plate or porous plate.

A brush roller 118 is disposed at a position where the upper surface of the outer edge of the photosensitive paper which has emerged from the developing solution abuts against the brush roller 118. Both brush roller 118 and another roller 119 are continuously rotated in the directions indicated by the arrows b at relatively high speed. Therefore, when the outer edge portion of the paper 117 abuts against the brush roller 118, the brush roller 118 draws the paper from the receiving mechanism 11 and propels it out of the developing device in cooperation with the roller 119.

In the second embodiment described above, the shape, the size, the proportion, the position, the material and the like of the spring member 115 are not limited so far as the spring member 115 serves to permit the receiving mechanism w to hold securely therein the paper 117. For example, the spring member 115 may be made of an elastic resin plate. Also the shape, the sizes, the proportion, the material and the like of the holding plate opening member 116 are not limited as long as they serve the purpose. For example, the clamping or holding plate opening member 116 may be made of wire. No special limit is imposed upon the position of the holding plate opening member as long as it can retard the motion of the holding plate as described above.

The third embodiment of the present invention will be described hereinafter with reference to FIGS. 6 and 7. In this embodiment, the length of a clamping or holding plate opening member 116a is made longer than that of the clamping or holding plate opening member 116 in FIGS. 3 and 5. The former is formed in such a manner that it covers the rotary body from the position where the photosensitive paper receiving mechanism emerges out of the developing solution to the position where the mechanism receives the photosensitive paper. Thus, in this embodiment, the clamping or holding plate 103 may be spaced apart from the receiving plate 102 as soon as they emerge from the developing solution so that the opposing surfaces of both of the receiving plate and the clamping or holding plate may be dried by a suitable drying means (not shown), whereby the resistance exerted upon the paper to be fed into the opening of the receiving mechanism 104 may be reduced.

As shown in FIG. 5 and in FIG. 7 wherein the clamping holding plate opening member is designated by 116a, the surface which is made in contact with the clamping or holding plate 103 may be comprised of a brush of natural or synthetic fibers or with a relative soft, but elastic rubber or the like so that the better effect may be attained.

The developed photosensitive papers are sequentially picked up from the developing device at the same rate as the papers are fed into the exposure device.

According to the present invention, there may be provided a developing device or machine in which the developed photosensitive papers may be produced positively at the same rate as they are exposed even for photosensitive papers which are sequentially discharged in large quantities from the exposure device and which require a rather longer developing time for each copy. The great, advantage of the present invention is the higher efficiency in photocopying operation. Especially for the preparation of copies of the registers which are now much utilized in nationalization of the business routines and for the production of photos from positive or negative films, the present invention offers special advantages. The use of the developing device or machine of the present invention is not limited to a developing process as described in the embodiments above, but the device of the present invention is equally useful for fixing the photosensitive papers developed by the developing device or machine of the present invention.

While the principles of the present invention have been made clear in the illustrative embodiments, it will be immediately obvious to those skilled in the art that many modifications in structure, arrangement, proportions, the elements, materials, and components, used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements, are possible without departing from those principles. The appended claims are therefore intended to cover and embrace any such modification, within the limits only of the true spirit and scope of the present invention.

What is claimed is:

1. A device for immersing sheetlike articles in a liquid bath comprising:

a tank adapted to contain a liquid at an intended liquid level;

a transporting structure rotatable in a rotation direction about a nonvertical axis and located at least partially within the tank below the intended liquid level;

a plurality of article-receiving plates on the transporting structure extending parallel to the axis and projecting radially therefrom, said plates being spaced at substantially equal angles around the axis and rotation of the transporting structure moving each plate between a submerged position below the intended liquid level and an elevated position above the liquid level;

a holding plate associated with each article-receiving plate and pivotally mounted on the transporting structure for rotation between a holding position in which the holding plate contacts the trailing surface of the article-receiving plate as the article-receiving plate rotates in the rotation direction and an open position in which the holding plate is rotated away from the article-receiving plate in a direction opposite to the rotation direction whereby an article-receiving gap is defined between the articlereceiving plate and its associated holding plate;

means for resiliently urging the holding plate into the holding position;

retarding means for retarding temporarily the rotation of each holding plate as said plate reaches a loading station and thereby positioning the holding plate at said loading station in the open position;

feed means for feeding an article into the article-receiving gap at the loading station; and

removal means for removing the article from between the article-receiving plate and its associated holding plate after rotation of said plates through the tank beneath the intended liquid level.

2. The device of claim 1 wherein the retarding means comprises a member having a contact surface in the form of an arc of a circle concentric with the axis, said contact surface being disposed in the path of the outer edges of the holding plates for engagement therewith.

3. The device of claim 2 wherein the contact surface of the retarding means extends around the transporting structure above the intended liquid level from a position substantially at the position of the removal means, whereby the holding plates are retarded during substantially all of their passage from the removal means to the loading station.

Claims

1. A device for immersing sheetlike articles in a liquid bath comprising: a tank adapted to contain a liquid at an intended liquid level; a transporting structure rotatable in a rotation direction about a nonvertical axis and located at least partially within the tank below the intended liquid level; a plurality of article-receiving plates on the transporting structure extending parallel to the axis and projecting radially therefrom, said plates being spaced at substantially equal angles around the axis and rotation of the transporting structure moving each plate between a submerged position below the intended liquid level and an elevated position above the liquid level; a holding plate associated with each article-receiving platE and pivotally mounted on the transporting structure for rotation between a holding position in which the holding plate contacts the trailing surface of the article-receiving plate as the article-receiving plate rotates in the rotation direction and an open position in which the holding plate is rotated away from the article-receiving plate in a direction opposite to the rotation direction whereby an article-receiving gap is defined between the article-receiving plate and its associated holding plate; means for resiliently urging the holding plate into the holding position; retarding means for retarding temporarily the rotation of each holding plate as said plate reaches a loading station and thereby positioning the holding plate at said loading station in the open position; feed means for feeding an article into the article-receiving gap at the loading station; and removal means for removing the article from between the articlereceiving plate and its associated holding plate after rotation of said plates through the tank beneath the intended liquid level.