US3840156A

US3840156A - Tuner supply device

Info

Publication number: US3840156A
Application number: US00318457A
Authority: US
Inventors: S Fujimoto
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1971-12-27
Filing date: 1972-12-26
Publication date: 1974-10-08
Anticipated expiration: 1991-10-08
Also published as: DE2262773A1; JPS4878848U; DE2265463C2; JPS52517Y2; DE2262773B2; DE2262773C3

Abstract

A toner supply device comprising a hopper containing a quantity of toner and having a downwardly facing toner supply opening which is blocked by a rotating roller having on its periphery a plurality of axial grooves. As the roller rotates, the toner powder which is packed into the peripheral grooves is carried through the toner supply opening of the hopper and is supplied at a uniform rate to a developing device of a copying machine. Means are provided for scraping off toner powder which may adhere to the groove walls, and for selectively varying the rate at which toner is discharged from the hopper.

Description

Elited States Patent 1 91 Fujimoto Oct. 8, 1974 [5 1 TUNER SUPPLY DEVICE 2,728,308, 12/1955 Nelson... 222/351 x 3,140,016 7/1964 F2 1 ..222/196 [75] Inventor: Sakae Japan 3572.555 3/1971 et a1, 222/342 [73] Assignee: Kabushiki Kaisha Ricoh, Tokyo,

- Japan [22] Filed: Dec. 26, 1972 [21] Appl. No.: 318,457

[30] Foreign Application Priority Data Primary Examiner-Robert B. Reeves Assistant Exan1inerDavid A. Scherbel Attorney, Agent, or Firn1Cooper, Dunham, Clark, Griffin & Moran 5 7 ABSTRACT A toner supply device comprising a hopper containing a quantity of toner and havinga downwardly facing toner supply opening which is blocked by a rotating roller having on its periphery a plurality of axial grooves. As the roller rotates, the toner powder which is packed into the peripheral grooves is carried through the toner supply opening of the hopper and is supplied at a uniform rate to a developing device of a copying machine. Means are provided for scraping off toner powder which may adhere to the groove walls, and for selectively varying the rate at which toner is discharged from the hopper.

10 Claims, 2 Drawing Figures BACKGROUND OF THE INVENTION It is common to apply the same quantity of dry developing agent to a succession of electrostatic latent images to convert these latent images to visible images by the toner adhering thereto. When the same quantity of developing agent is used to develop a succession of latent images, the concentration of toner in the developing agent gradually decreases, so that it is necessary to keep adding toner to the developing agent. The subject invention is directed to devices meeting this requirement of adding toner to the developing agent used in electrostatic copying machines.

In one type of toner supply devices known in the prior art, a toner supply roller is rotatably mounted within the outlet port of a hopper containing a quantity of toner. The roller is rotated continuously or intermittently, as desired, so as to supply toner to the developing device through a slit formed between the periphery of the roller and the outlet port of the hopper.

Some disadvantages are associated with this type of prior art toner supply devices. Since the toner is in the form of very fine powder, it is readily influenced by humidity, and tends to form solid masses which adhere to the periphery of the roller. Toner powder which adheres to the roller tends to build up in quantity and block the slit. As a result, no more toner is supplied, or the toner drops into the developing device in large pieces. Even when there are no difficulties caused by the influence of humidity, the rate at which toner is supplied to the developing device is, of course, a function of the size of the slit, and the setting of the slit size to an optimum level requires a skillful operator and repeated attention.

SUMMARY OF THE INVENTION An object of the invention is to provide a toner supply device which obviates the aforementioned disadvantages of the prior art toner supply devices. This object is accomplished in the present invention by providing a toner supply device that discharges toner at a selected steady rate and is not affected by changes in the humidity and cannot be degraded by buildup of toner adhering to a roller.

In particular, the toner supply device constructed and operating in accordance with the invention comprises a hopper containing a quantity of toner and having a downwardly facing toner supply opening. The toner supply opening of the hopper is blocked by a toner supply roller having a plurality of axial grooves on its periphery. There is substantially no clearance between the toner supply roller and the toner supply opening of the hopper, so that the toner in the hopper is protected from atmospheric humidity. As the roller rotates, the toner powder which is in its peripheral grooves is carried out. through the supply opening of the hopper to be delivered to a developing means. Means are provided to scrape off any toner powder which may remain in the peripheral grooves of the toner supply roller, so that each groove carries out the same amount of toner with each rotation of the toner supply roller, and toner is supplied to the developing means at a steady rate. Means are provided for selectively varying the rate at which toner is supplied to the developing means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a toner supply device comprising one embodiment of the invention;

FIG. 2 is a fragmentary enlarged schematic view of the device shown in FIG. 1;

FIG. 3 is a fragmentary perspectiveview of the device shown in FIG. 1 and illustrates a toner supply roller and toner scraping means;

FIG. 4 is a fragmentary perspective view of another form of toner scraping means;

FIG. 5 is a fragmentary perspective view of still another form of toner scraping means; and

FIG. 6 is a perspective view of means for controlling the quantity of toner supplied by the toner supply device shown in FIG. 1.

DETAILED DESCRIPTION FIG. 1 shows a hopper 2 partially filled with a quantity of toner 1 and having at its right hand end a downwardly facing opening 3 which is blocked by a toner supply roller 4. The quantity of toner 1 in the hopper 2 can be replenished through a top opening 2d which is covered with a hinged lid 20e. The downwardly facing opening 3 in the hopper 2 is substantially rectangular in shape and is formed by the right hand edges 2a and 2b of the top and bottom walls of the hopper, and by the lower right hand edges of the two opposing side walls of the hopper 2 which are parallel to the plane of the drawing but are not shown. The axial cross section of the toner supply roller 4 is approximately equal to the area of the opening 3 in the hopper 2, so that the opening 3 is substantially blocked by the toner supply roller 4, and no toner can seep out of the hopper 2 when the roller 4 is not rotating. The roller 4 is fixedly mounted on a shaft 6 (FIG. 3) and the shaft 6 extends through the two side walls of the hopper 2 which are not shown and is suitably rotatably supported thereby to allow for rotation of the toner supply roller 4. The

. toner supply roller 4 has along its cylindrical periphery a plurality of adjacent grooves 4a which are sawtooth shaped in transverse cross section.

In operation, the toner supply roller is rotated in the clockwise direction by a drive means 11a which rotates at a selected steady speed a sprocket 11 secured to the shaft 6 (FIG. 3). Since the opening 3 of the hopper 2 is substantially blocked by the toner supply roller 4, the only toner powder which can be carried out of the hopper 2 is the powder packed within the grooves 4a. Under most conditions, no toner powder would adhere to the walls of the grooves 4a, and all of the toner powder carried out of the hopper 2 by means of the rotating toner supply roller 4, would fall downwardly toward a developing device (not shown). However, in order to make sure that this is the case, i.e., in order to make sure that no powder is packed into the grooves 4a of the toner supply wheel 4, means are provided to scrape the grooves 4a clean of any toner powder that may have adhered thereto. These means comprise a sheet 7 which is made of a resilient material and has an upwardly bent forward end 7a which is biased to press against the lower portion of the toner supply roller 4 and to scrape off the walls of each groove 4a coming in engagement with it as the toner supply roller 4 rotates in the clockwise direction. The resilient sheet 7 is suitably supported by a bracket 8 affixed to the lower wall 2c of the hopper 2. When mounted as illustrated in FIG. 1, the resilient sheet 7 is biased to press against the toner supply roller 4 with sufficient force to efficiently scrape off any toner powder which may have adhered to the grooves 40 such that no toner powder remains in the grooves 4a which are returned to the hopper 2 as the roller 4 rotates in the clockwise direction.

The toner supply device illustrated in FIG. 1 additionally includes means for agitating the toner powder in the hopper 2 and for making sure that there is a steady and reliable supply of toner powder near the opening 3, so that the toner supply roller 4 can carry out a steady and constant stream of toner powder. These means include a perforated sheet 9 which is disposed immediately above the lower sloping wall 20 of the hopper and has a right hand end extending almost to the toner supply roller 4, and an upwardly extending left hand end 90 which is secured to a piston 10a of a vibrator 10. The piston 10a is suitably mounted in the left hand portion of the wall 2c of the hopper 2 for reciprocating motion against the biasing force of a spring 10b. When the vibrator 10 is turned on, the piston 10a moves in reciprocating motion first leftwardly against the biasing force of the spring 1017. then rightwardly under the biasing force of the same spring 10b, and thus vibrates the perforated sheet 9. With this vibration, the perforated sheet 9 performs two functions: it agitates the toner inside the hopper 2, and it moves the toner toward the toner supply roller 4 to insure an adequate supply of toner thereto.

FIGS. 4 and 5 show two additional and alternate embodiments of scraping means similar to the scraping means 7 illustrated in FIG. 1. The scraping means shown in FIG. 4 comprise a pair of arms 41 (only one arm is shown) which are pivotally supported by a shaft A which is suitably affixed to the hopper 2. The ends of the arms 41 which are opposite the ends pivotally supported by the shaft A support fixedly a bar 42 which corresponds in shape and in function to the upwardly extending portion 7a of the resilient sheet 7. That is, the bar 42 is biased by means of springs S connecting the arms 41 to the hopper 2 such that the bar 42 is always pressing against the lower portion of the toner supply roller 4 to scrape off any toner powder which may have adhered to the grooves 40. FIG. 5 shows scraping-off-means similar to the means shown in FIG. 4, except that the function of the bar 42 is performed by a wire 51, which may be made of a material such as metal or nylon. The wire 51 is urged against the lower portion of the toner supply roller to scrape off any adhering toner powder.

In certain uses of toner supply devices, it may be desirable to regulate the rate at which toner is supplied to the developing device of a copying machine. The toner supply device of the subject invention includes therefore means for selecting the rate at which the toner supply roller 4 discharges toner from the hopper 2. The means are illustrated in FIG. 6 and include a mechanism' for selecting a fast or a slow discharge rate. In particular, the shaft 6 which is affixed to the toner supply roller 4 carries a fixedly secured ratchet wheel 111 which is coaxial with the toner supply roller-4. The means for rotating the ratchet wheel 111, and hence the toner supply roller 4, at either a slow speed or a fast speed correspond to the drive means 11a of FIG. 3 and comprise, referring to FIG. 6, a wheel 613 which rotates at a selected steady speed and drives a gear 612 through a clutch 614. The gear 612 is in meshing engagement with a gear 610 having an offset pin 610a for driving a bell crank arrangement of a lever 611 and a pivotal arm 608. The pivotal arm 608 is rotatably supported near its center by a stub shaft 602 passing through a suitable aperture in the pivotal arm 608, and has at its top end a pivotally mounted pawl 607 which is biased by a spring 609 to engage the teeth of the ratchet wheel 111. The stub shaft 602 is suitably mounted for free rotation and is coaxial with the shaft 6, but is not in contact therewith. The stub shaft 602 supports fixedly a control cam 601 which is parallel to and adjacent the ratchet wheel 111, and a gear 603 which is affixed to a shaft 605 extending through the enclosure (not shown) ofa copying machine and terminating in a control knob 606 which is located outside the enclosure.

The rate at which toner is discharged from the hopper 2 is controlled by setting the control cam 601 to a selected one of two possiblepositions by means of turning the control knob 606. As shown in FIG. 6, the control cam 601 has an arcuate portion 601a and another arcuate cam portion 601b, with the diameter of the portion 601a being greater than that of the portion 60112. In relation to the ratchet wheel 11]. the diameter ofthe portion 601a of the cam 601 is somewhat greater than the addendum circle of the ratchet wheel 11, while the diameter of the arcuate portion 601 of the control cam 601 is somewhat smaller than the diameter of the dedendum circle of the ratchet wheel 111. The

right hand sharp end of the pawl 607 rides over the control cam 601 while engaging the teeth of the ratchet wheel 111. The diameters of the arcuate portions 601a and 601i; and the pertinent dimensions of the bell crank arrangement for converting the rotary motion of the gear 610 into reciprocating motion of the pawl 607 are such that the toner supply roller 4 rotates at one speed when the pawl 607 rides over the arcuate portion 6010, but at another speed when the pawl 607 rides over the arcuate portion 60112 of the control cam 601. For example, the pertinent dimensions may be such that when the pawl 607 rides only over the arcuate portion 601b, one reciprocating motion of the pawl 607 rotates the ratchet wheel 111 along a distance corresponding to four ratchet teeth thereof. However, when the control cam is moved by means of the control knob 606 to a position in which the pawl 607 rides over the arcuate portion 601a of the control cam 601, the pertinent dimensions may be such that one reciprocating motion of the pawl 607 moves the ratchet wheel 111 only along a distance corresponding to three ratchet teeth thereof. In this manner, the speed of rotation of the toner supply roller 4, and hence the rate at which it supplies toner, may be controlled by means of the control knob 606.

What is claimed is:

1. A toner supply device comprising a hopper for containing a quantity of toner, said hopper having a closed and continuous bottom except for a'toner discharge opening in it, a toner supply roller rotatably mounted within said toner discharge opening of the hopper and having a portion disposed within the hopper and a portion extending outwardly of the hopper,

said outwardly extending hopper portion being exposed and freely accessible from outside the hopper, said rolof the hopper.

2. A toner supply device as in claim 1, wherein the scraping means comprise a resilient sheet secured at one end to the hopper and extending therefrom toward the roller, substantially tangentially of the roller, with the end of the sheet opposite the secured end thereof being bent toward the roller to extend substantially radially toward the roller to form a scraping edge for scraping off toner which may have adhered within said grooves, in the portion of the toner supply roller which extends outwardly of the hopper, said resilient sheet being biased to maintain said scraping edge in pressing engagement with the toner supply roller.

3. A toner supply device as in claim 1, wherein the scraping means comprise: an elongated scraper having axially opposite ends, two arms each having an end pivotally connected to the hopper to pivot the arm in a plane perpendicular to the roller axis of rotation, means for connecting the opposite ends of the scraper to the ends of the arms that are opposite their pivoted ciently small to enter the axial peripheral grooves therein for scraping off toner than may have adhered to said grooves.

4. A toner supply device as in claim 3, wherein said scraper is in the form of a wire.

5. A toner supply device as in claim 3, wherein said scraper is in the form of a bar. v

6. A toner supply device as in claim 1, wherein said hopper has a bottom wall sloping toward the opening, and including a sheet mounted in the hopper and disposed in close proximity to said bottom wall of the hopper, said sheet extending along said bottom wall, toward the opening, but terminating before the opening, and means for vibrating said sheet.

7. A toner supply device as in claim 6, wherein said sheet is perforated and has one end disposed in close proximity to the toner supply roller.

8. A toner supply device as in claim 1 wherein the means for rotating the roller comprise means for selectively rotating the roller at a fast and a slow rate to thereby selectively discharge toner at a high and low rate respectively.

9. A toner supply device as in claim 8 wherein the rotating means comprise a ratchet wheel affixed coaxially to the roller to rotate therewith, a pawl, means for reciprocating the pawl along a defined path, said pawl engaging the ratchet wheel when moving along a selected direction of said reciprocating path to thereby rotate the ratchet wheel andthe roller by an amount corresponding to the length of the path, and means for selectively preventing the pawl from engaging the ratchet for a selected portion of the reciprocating path, to thereby selectively rotate the roller at a fast and a slow rate.

10. A toner supply device as in claim 9 wherein the means for selectively preventing the pawl from engaging the ratchet wheel for a portion of the pawl path comprise a cam having a small diameter portion and a large diameter portion, means for supporting the cam in a position in which said pawl engages the ratchet wheel when riding over the small diameter portion of the cam, but does not engage the ratchet wheel when riding over the large diameter portion of the cam, and manually operable setting means selecting the position of the minor and major diameter portions of the cam with respect to the pawl path.

* CERTIFICATE CQRRE-CTIQN Pater'it No. I 3-., ,15 x j Dated oatober 8 197 1 Ifiventofls) Sakae j 130 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1, title page, change "TUNER" to read TONER Signed and sealed this 17th day" of December 1974.

(SEAL) Attest': I

McCOY M. GIBSON JR. c; MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-1050 (10-69) I USCOMM-DC 603764 69

Claims

1. A toner supply device comprising a hopper for containing a quantity of toner, said hopper having a closed and continuous bottom except for a toner discharge opening in it, a toner supply roller rotatably mounted within said toner discharge opening of the hopper and having a portion disposed within the hopper and a portion extending outwardly of the hopper, said outwardly extending hopper portion being exposed and freely accessible from outside the hopper, said roller having a plurality of axial peripheral grooves which are sawtooth shaped in transverse section, means for supporting the roller at an operating position in which the roller at least partially blocks said toner discharge opening in the hopper, means for rotating the roller for discharging toner from the hopper, and means for scraping off discharged toner which may have adhered in the grooves of the exposed portion of the toner supply roller, at the roller portion which eXtends outwardly of the hopper.

3. A toner supply device as in claim 1, wherein the scraping means comprise: an elongated scraper having axially opposite ends, two arms each having an end pivotally connected to the hopper to pivot the arm in a plane perpendicular to the roller axis of rotation, means for connecting the opposite ends of the scraper to the ends of the arms that are opposite their pivoted ends to support the scraper parallel to the roller axis of rotation, and spring means for urging the arms toward the roller to thereby urge the scraper into a pressing engagement with the toner supply roller, said scraper having an edge facing the toner supply roller and sufficiently small to enter the axial peripheral grooves therein for scraping off toner than may have adhered to said grooves.

5. A toner supply device as in claim 3, wherein said scraper is in the form of a bar.

9. A toner supply device as in claim 8 wherein the rotating means comprise a ratchet wheel affixed coaxially to the roller to rotate therewith, a pawl, means for reciprocating the pawl along a defined path, said pawl engaging the ratchet wheel when moving along a selected direction of said reciprocating path to thereby rotate the ratchet wheel and the roller by an amount corresponding to the length of the path, and means for selectively preventing the pawl from engaging the ratchet for a selected portion of the reciprocating path, to thereby selectively rotate the roller at a fast and a slow rate.