US3616969A

US3616969A - Developer replenishing means for an electrostatographic apparatus

Info

Publication number: US3616969A
Application number: US729757A
Authority: US
Inventors: Yutaka Koizumi
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1967-05-25
Filing date: 1968-05-16
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02
Also published as: GB1200986A; DE1772387A1; DE1772387B2; DE1772387C3

Abstract

Apparatus is provided for replenishing developer in an electrostatographic device. The apparatus includes a hopper having discharge apertures and is caused to vibrate above a developing device to replenish same with developer. A pusher plate projects into the hopper to engage the developer and force same through the apertures as the hopper vibrates.

Description

United States Patent [72] Inventor Yutaka Koizumi Tokyo, Japan 21] Appl. No. 729,757

[22] Filed May 16,1968

[45] Patented Nov. 2, 1971 [73] Assignee Kabushiki Kaisha Ricoh Tokyo, Japan [32] Priority May 25, 1967 [33] Japan [54] DEVELOPER REPLENISHING MEANS FOR AN ELECTROSTATOGRAPHIC APPARATUS 7 Claims, 4 Drawing Figs.

[52] 1.1.5. Cl 222/162 [51] Int. Cl 601i 11/00 [50] Field of Search 222/ 1 60,

161, 162,409; l18/D1G. 1

[56] References Cited UNITED STATES PATENTS 2,640,629 6/1953 Thomson et a1. 222/162 X 2,681,169 6/1954 Watson 222/162 2,692,142 10/1954 Hunter 222/162 X 3,387,586 6/1968 Shelffo et a1 118/637 FOREIGN PATENTS 475,645 4/1929 Germany 222/162 Primary Examiner-Robert B. Reeves Assistant Examiner- Frederick R. Handren Attorney-Waters, Roditi & Schwartz ABSTRACT: Apparatus is provided for replenishing developer in an electrostatographic device. The apparatus includes a hopper having discharge apertures and is caused to vibrate above a developing device to replenish same with developer. A pusher plate projects into the hopper to engage the developer and force same through the apertures as the hopper vibrates.

DEVELOPER REPLENISHING MEANS FOR AN ELECTROSTATOGRAPHIC APPARATUS The present invention relates to a means for replenishing toner timely as necessary in an apparatus for developing an electrostatic latent image produced on a sheet of printing paper with toner mixed with iron filings.

It is considerably troublesome generally in the construction of a developing means which includes an iron filing brush using a magnet to replenish said developing means with developer of a mixture of iron filings and toner.

To replenish the developing means with the developer timely as necessary, a means is proposed in which a developer replenishing housing is provided above said developing means and a plurality of holes provided at the bottom of the housing are opened or closed to eject the developer therethrough. In such a simple means, however, it is extremely difficult to control the replenishment of the developer so as to maintain a fixed rate of replenishment. When a magnet is used for the developing means, the developer on the iron filing brush of the developing means and the developer at a developer ejecting portion at the outlet of said housing join together, whereby the replenishment of developer is not only prevented, but the developing means becomes inoperative.

It is the object of the present invention to provide a developer replenishing means wherein the quantity of developer to be replenished is controlled accurately without malfunction in the operation of replenishment.

The developer replenishing means of the present invention comprises a hopper provided for oscillation above the developing means, a developer pushing member with a free end in front of the developer-ejecting portion of said hopper, and an exciting means for oscillating said hopper in the direction in which said developer ejecting portion reciprocates against the free end of said developer pushing member.

In accordance with the means of the present invention, each time the hopper oscillates, a fixed quantity of developer is discharged through the action of the developer pushing member. The developer in the developing means and the developer at the developer ejecting portion of said hopper are not linked, because of the oscillation of the hopper. Since the developer is ejected at a fixed rate each time the hopper oscillates, the quantity of the developer to be replenished is determined by the operation period of the exciting means for oscillating said hopper. The quantity of the developer to be replenished is, therefore, easily adjusted by operating a pushbutton for said exciting means.

For a better understanding of the invention which is advantageous in the above-mentioned points, reference is made to the following detailed disclosure of this invention taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a sectional view of the developer replenishing means indicating an embodiment of the present invention;

FIG. 2 is a perspective view of said means;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1; and

FIG. 4 is a side view of the hopper.

An electrostatographic apparatus has already been proposed wherein a printing paper carrier 3 is mounted on a rail 2 above row of a charging means, an exposure means, (both not shown in the drawings,) a developing means 1, and a fixing means (not shown in the drawings), and wherein a card of printing paper is mounted on the underside of said carrier 3 to obtain a copy. Said developing means 1 comprises a group of magnets 5 supported by a fixed shaft 4 and a nonmagnetic cylinder 6 mounted for rotation around said group of magnets 5. An electrostatic latent image on a sheet of printing paper supported by said carrier 3 is developed by rubbing said printing paper with an iron filing brush 7 which includes toner and is provided on the upper part of the peripheral surface of said cylinder 6.

A hopper 9 mounted for oscillation by a shaft 8 above said developing means 1 contains developer to be replenished.

At the lower part of a sidewall 9a of the hopper 9, there is provided, as shown in FIG. 4, a number of inclined slots 11, parallel to one another, the size of which is determined to be as small as is necessary so that the developer 10 in the hopper 9 does not flow out freely through them. Adjacent to the inside of a developer ejecting portion comprising said slots, there is positioned a free end of a developer pushing member 13 with the other end secured to a fixed member 12. Constituting said developer pushing member 13, is an elastic plate about 0.1 to 0.2 mm. thick.

An arm 14 with the bottom end secured to another sidewall of said hopper 9 is pressed against the top side edge of an operating member 15 owing to the weight of the hopper, and the tip 14a of said arm 14 is extended over a rotating member 17 provided with abutments 16 on its periphery. The operating member 15 is mounted on a pair of supporting

arms

18a and 18b (FIG. 2) so as to be slidable in a direction across said arm 14, by engagement of

fasteners

19a and 19b (FIG. 3) secured to said supporting

arms

18a and 18b in elongated slots 20. At the outer end of said operating member 15, as shown in FIG. 3, there is provided a pushbutton 21, while at the inner end there is an elastic arm plate 22. The operating member 15 is moved in a direction parallel to the hopper outlet against the bias of tension spring 24 when button 21 is pushed, the ends of spring 24 being secured to fastener 19a, and a pin 23 on the operating member 15 respectively. The member 15 has a projection on its upper surface as seen in FIG. 3 formed by a step 15a and an inclined face 15b to provide a camming action when member 15 is moved for raising and lowering of arm 14 as will be explained later.

Said rotating member 17 is secured to a shaft 25 supported for rotation by the supporting

arms

18a and 18b. At one end of said shaft 25, there is provided a sprocket wheel 28 with a chain 27 entrained thereon. Said chain 27 is connected with a drive part of the electrostatographic apparatus and causes member 17 to rotate in the direction of the arrow.

When the pushbutton 21 is depressed in the direction of an arrow against the opposition of spring 24, the projection on the upper surface of member 15 releases arm 14 and the arm 14 becomes disengaged from the operating member 15, wherein the hopper 9 rotates around the fulcrum of the shaft 8, and the tip of the arm 14 descends into the rotational path of the abutment 16 of the rotating member 17. The tip 140, therefore, is subjected to engagement and disengagement with the abutments l6 rotating in the direction of the arrow causing the hopper 9 to oscillate. When the hopper 9 is oscillated, the developer ejecting portion of said hopper 9 is reciprocated against the tip 13a of the developer pushing member 13. Each reciprocation ejects a fixed amount of developer through the outlet in the ejecting portion and the developing means 1 is replenished with the developer.

The cylinder 6 of the developing means 1 stops its rotation when the printing paper carrier is at standstill. If the developer is replenished during the repose period of said cylinder 6, only a part of said cylinder 6 is replenished with developer. In replenishing said cylinder with developer, accordingly, it is desirable to rotate said cylinder 6 and uniformly replenish the peripheral surface of said cylinder with the developer, regardless of the action of said printing paper carrier 3. For that reason when the pushbutton 21 is depressed, the movable contact 26a of a microswitch 26 is depressed through the action of the elastic arm plate 22 provided at the inner end of the operating member 15 and a drive means for rotating cylinder 6 is actuated.

A housing positioned under the developing means 1 is provided for housing the excess developer.

Thereplenishment of the developer is effected continuously when the pushbutton 21 is depressed. When the operator's finger is removed from said pushbutton 21, the arm 14 is first pushed upward by one of the abutments 16 and the operating member 15 is returned to its initial position through the pull of the spring 24. The arm 14 is pushed by inclined face 15b of the operating member 15, and the engagement between the arm l4 and the abutment 16 is released completely. In this manner the replenishment of the developer is stopped.

What is claimed is:

1. Apparatus for replenishing developer in an electrostatographic device, said apparatus comprising in combination a hopper for containing developer, said hopper being provided with apertures for discharging said developer, developing means supported below said apertures in said hopper, means supporting said hopper for oscillation such that said apertures are movable toward and away from said developing means to deposit said developer on said developing means, pushing means supported in said hopper engageable with said developer for forcing said developer through said apertures, said developing means including magnetic means, and an iron filing brush supported between said magnetic means and said apertures in said hopper, said magnetic means and iron filing brush being operatively associated with one another to facilitate the production of images on paper supplied to said developing means, and oscillating means for oscillating said hopper, whereby upon hopper oscillation said pushing means forces said developer through said apertures onto said developing means.

2. Apparatus as claimed in claim 1, wherein said oscillating means includes a plurality of abutments successively engageable with said hopper, and drive means for moving said abutments into engagement with said hopper.

3. Apparatus as claimed in claim 2 including a wheel having a peripheral surface upon which is supported said abutments in spaced circumferential array, said drive means including a rotatable shaft fixedly supporting said wheel, a sprocket wheel fixed on said shaft, and a chain operatively associated with said sprocket wheel for rotating said sprocket wheel, said shaft, and said wheel supporting said abutments.

4. Apparatus as claimed in claim 3 including locking means for preventing said hopper from oscillating, said locking means including a member provided with a projection engageable with said hopper, and depressible means for moving said member and said projection out of engagement with said hopper to free said hopper for oscillation.

5. Apparatus as claimed in claim 4 including resilient means for acting'on said member to return said member to a rest position with said projection engaging said hopper to lock said hopper so as not to oscillate.

6. Apparatus as claimed in claim 5, wherein said hopper includes a projecting member selectively engageable with said abutments and said projection.

7. Apparatus as claimed in claim 1, wherein said pushing means is constituted by a plate projecting internally of said hopper and fixedly supported externally thereof.

Claims

5. Apparatus as claimed in claim 4 including resilient means for acting on said member to return said member to a rest position with said projection engaging said hopper to lock said hopper so as not to oscillate.