JPH0815973A - Image forming device - Google Patents

Abstract

PURPOSE:To efficiently and smoothly carry toner with simple constitution by using a coil spring as a toner carrying means. CONSTITUTION:The endless coil spring 510 is arranged to be able to circulate between a cleaning device 400 and a developing device 300. Since the coil spring 510 is driven to circulate by a driving gear 520, excess toner which is not submitted for development in the toner storage chamber of the developing device 300 is carried to the cleaning device 400, stirred and mixed with the recovered residual toner in the cleaning device 400, and restored to the developing device 300 again. Since the upper end of the coil spring 510 is positioned upper than a sliding part between a developing roller 320 and a regulating blade 330, toner clogging occurring at the exit of the toner storage chamber because overflowing toner gets on the coil spring 510 and is carried excessively, is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus.
More specifically, the present invention relates to an image forming apparatus such as a printer, a copying machine, or a facsimile, which forms an image on a recording paper by using a toner by an electrophotographic method, and particularly, to perform efficient and smooth toner conveyance with a simpler configuration. The present invention relates to an image forming apparatus capable of performing.

[0002]

2. Description of the Related Art As a conventional image forming apparatus, one shown in FIG. 25 is known (Japanese Patent Laid-Open No. 63-2467).
No. 80). The figure (a) is a top view, (b) is a figure (a)
A-A 'sectional view in FIG. 7, (c) is B in FIG.
-B 'sectional view, (d) is CC' sectional view in Fig. (A).

As shown in these figures, the conventional image forming apparatus supplies toner to the surface of the photosensitive drum 3 and develops a latent image on the surface of the photosensitive drum 3 to form a toner image. And a cleaning device F that removes and collects the residual toner adhering to the surface of the photosensitive drum 3 after the toner image formed by the developing device E is transferred to the paper. , A belt-shaped member 4 that is orbitally driven, and a toner detachment that is provided in the developing device E and that removes residual toner that has adhered to the surface of the belt-shaped member 4 inside the cleaning device F from the belt-shaped member 4 inside the developing device E. And means G.

The belt-shaped member 4 is made of a sponge made of a porous elastic body, and a reinforcing core material 5 is embedded in the center thereof. The belt-shaped member 4 includes a main body case 12 of the developing device E and a main body case 14 of the cleaning device F.
And a drive pulley 7a and a driven pulley 7b, which penetrate the inside of the covers 6a and 6b that are installed between
The drive pulley 7 is rotatably supported by 7c and 7d.
It is adapted to be orbitally driven in the direction of arrow 8 by a.

The toner removing means G is provided inside the main body case 12 of the developing device with a plurality of blades 11 facing each other with the strip-shaped member 4 running in the main body case 12 in the direction of arrow 8 being sandwiched therebetween. , A semi-circular cutout 11a at the tip of this blade 11 which engages with the surface of the strip-shaped member 4.
Is engraved.

According to such a conventional image forming apparatus,
The toner is supplied to the surface of the photosensitive drum 3 by the rotation of the developing roller 13 provided inside the developing device E, and the toner is attached to the electrostatic latent image formed on the surface of the photosensitive drum 3. By doing so, a toner image is formed.
After the toner image is transferred to a sheet (not shown), the residual toner adhering to the surface of the photoconductor drum 3 is a cleaning blade provided in the cleaning device F and slid on the surface of the photoconductor drum 3. It is scraped off by 15. The residual toner collected inside the main body case 14 of the cleaning device F by this scraping action adheres to the surface of the belt-shaped member 4. The residual toner adhering to the surface of the belt-shaped member 4 is removed from the inside of the cleaning device F by the cover 6
It is conveyed into the inside of the developing device E through the inside of b and is scraped off by the blade 11 into the inside of the main body case 12 of the developing device E. Strip-shaped member 4 on which residual toner is scraped off
Is orbitally driven in the direction of arrow 8 and heads again to the inside of the cleaning device F.

[0007]

The conventional image forming apparatus described above has the following problems.

(A) The belt-shaped member 4 is composed of a sponge made of a porous elastic body, and has a structure in which the toner is attached to the surface (mainly a large number of holes) and is conveyed. However, there was a problem that the transport efficiency was not always good.

(B) Since the toner adhered to the surface of the belt-shaped member 4 is scraped off by the blade 11,
If the scraping of the toner by the blade 11 is insufficient, the holes in the surface of the belt-shaped member 4 are clogged with the toner, and the transport efficiency is further reduced.

(C) Since the toner adhered to the surface of the belt-shaped member 4 is scraped off by the blade 11,
Since the blade 11 has to be arranged inside the developing device E, there is a problem that the structure is complicated and the developing device becomes large, and thus the image forming apparatus as a whole becomes large.

An object of the present invention is to solve the above problems and to provide an image forming apparatus capable of efficiently carrying toner with a simpler structure.

[0012]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention supplies a toner storage chamber in which toner is stored and toner in the toner storage chamber to the surface of a photoconductor. A developing roller that develops a latent image on the surface of the photoconductor to form a toner image on the surface of the photoconductor, and an amount of toner supplied to the surface of the photoconductor by sliding contact with the surface of the developing roller along the axial direction of the developing roller. A developing device having a regulating blade for regulating, a cleaning device for removing and collecting residual toner adhering to the surface of the photoconductor after the toner image formed by the developing device is transferred onto a recording sheet, and these developing devices The developing device is arranged in a closed loop between the cleaning device and the cleaning device, and moves in the toner storage chamber along the axial direction of the developing roller in the developing device to transfer the toner to the toner storage chamber. As well as incoming and out towards the cleaning device a portion of the excess toner not used for development In the toner storage chamber from the toner reservoir,
A toner transport device having an endless coil spring for transporting the residual toner collected by the cleaning device to the toner storage chamber, and a guide portion slidably contacting the coil spring and guiding the coil spring, and a toner transport device of the toner transport device. A toner replenishing means for replenishing the toner to the toner conveyance path, wherein the upper end surface of the coil spring moving in the toner storage chamber is located above the sliding contact portion between the developing roller and the regulation blade. Characterize.

An image forming apparatus according to a second aspect is the image forming apparatus according to the first aspect.
In the image forming apparatus described above, the coil spring is cyclically driven by a drive gear that engages with the coil spring.

The image forming apparatus according to claim 3 is the image forming apparatus according to claim 2.
In the image forming apparatus described in the above, the drive gear is configured by a helical gear having helical teeth formed in an engaging portion with the coil spring that is inclined in the same direction as the strand of the coil spring. To do.

[0015]

According to the image forming apparatus of the first aspect, the following operational effects can be obtained.

(A) The developing device supplies toner to the surface of the photoconductor, and the toner develops the latent image on the surface of the photoconductor to form a toner image. The residual toner adhering to the surface of the photoconductor after the toner image is transferred to the recording paper is removed and collected by the cleaning device.

Between the developing device and the cleaning device,
The coil springs are arranged in a closed loop shape, and by this coil spring, a part of the excess toner that has not been used for development in the developing device is transferred to the cleaning device,
The residual toner collected by the cleaning device is conveyed to the toner storage chamber of the developing device together with the new toner replenished from the toner replenishing means.

(B) Here, the residual toner, a part of the surplus toner, and the new toner are held between the strands of the coil spring, not by the holes on the surface of the sponge in the above-mentioned conventional apparatus. Because it is transported
It will be efficiently transported.

(C) Since the upper end surface of the coil spring that moves in the toner storage chamber is located above the sliding contact portion between the developing roller and the regulation blade, the toner can be smoothly transported. .

If the upper end surface of the coil spring that moves in the toner storage chamber is located below the sliding contact portion between the developing roller and the regulating blade, the following problem will occur.

That is, the developing device is provided with a developing roller and a regulating blade that regulates the amount of toner supplied to the surface of the photoconductor by sliding contact with the surface of the developing roller along the axial direction of the developing roller. Therefore, a large amount of toner adhered to the surface of the developing roller is thinned by the regulating blade and supplied to the surface of the photoconductor. When the toner is thinned, excess toner overflows from the sliding contact portion between the developing roller and the regulating blade, and the overflowing toner forms a flow perpendicular to the axial direction of the developing roller.

For this reason, when the upper end surface of the coil spring is located below the sliding contact portion between the developing roller and the regulating blade, the toner overflowing from the sliding contact portion (this is called overflow toner). May get on coil springs.

As described above, the coil spring is excellent in the toner carrying ability, and moreover, the residual toner and the new toner are carried into the toner storage chamber of the developing device, and a part of the excess toner in the toner storage chamber is removed. Since the overflow toner is carried out on the coil spring in addition to this, the overflow toner is conveyed by the coil spring and is clogged at the outlet of the coil spring from the toner storage chamber. The phenomenon may occur.

Since such toner clogging acts as a great resistance against the movement of the coil spring,
As a result, smooth coil spring movement, that is,
There arises a problem that smooth toner conveyance cannot be performed.

On the other hand, according to the image forming apparatus of the first aspect, since the upper end surface of the coil spring is located above the sliding contact portion between the developing roller and the regulating blade, the overflow occurs. Toner no longer rides on the coil spring (or becomes extremely difficult to ride).

Therefore, the clogging of the toner at the outlet of the coil spring from the toner storage chamber is eliminated, and as a result, the coil spring is smoothly moved, that is, the toner is smoothly conveyed.

As described above, according to the image forming apparatus of the first aspect, the toner is efficiently and smoothly conveyed.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the coil spring is circulated and driven by a drive gear engaged with the coil spring. Therefore, the following action is further obtained.

(I) At the engaging portion between the drive gear and the coil spring, when a force from the drive gear in the circulating direction acts on the coil spring, the coil spring has a pitch angle. Due to the angle, a component force is generated in the coil spring in a direction different from the circulation direction. Since the coil spring is in sliding contact with the guide portion, as a result, the component force acts so as to rotate the coil spring around its axis.

Therefore, the coil spring circulates while turning around its axis.

(Ii) Since the coil spring circulates while rotating, local catching with the guide portion is prevented, and smooth toner conveyance is obtained. Therefore, the coil spring can be circulated with a small driving force,
The drive motor can be downsized and power consumption can be reduced. Further, since the coil spring comes into uniform contact with the guide portion, local wear is prevented and durability is improved.

(Iii) Since the coil spring circulates while rotating, the toner to be conveyed is agitated, so that the toner blocking occurs together with the expansion and contraction operation of the coil spring itself in the circulation direction. In addition to being prevented, the blocking toner, if present, is destroyed.

According to the image forming apparatus of the third aspect, in the image forming apparatus of the second aspect, the drive gear is
Since the helical gear is formed by the helical gear in which the helical spring is inclined in the same direction as the strand of the coil spring at the engaging portion with the coil spring, the following action is further obtained.

That is, the drive gear may be composed of a spur gear, but when the coil spring is driven by the spur gear, the strands inclined with respect to the circulation direction are formed with tooth flanks perpendicular to the circulation direction. Since the wire is pressed, it cannot be said that there is no risk that the strand will be deformed.

On the other hand, according to the image forming apparatus of the third aspect, the drive gear is formed with a beveled tooth that is inclined in the same direction as the strand of the coil spring at the engaging portion with the coil spring. Since it is composed of tooth gears, the strands will not be deformed. Further, the driving force can be effectively transmitted to the coil spring.

[0036]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view showing an example of a printer using an embodiment of the image forming apparatus according to the present invention, FIG. 2 is a front view, FIG. 3 is a plan view, and FIG. 4 is a sectional view.

In these drawings, reference numeral 100 denotes a printer main body, and a paper feed roller 10 is provided in a case 101.
2, an optical unit 110, an image forming unit 200, a fixing unit 120, and a paper discharge roller 103 are provided. Note that the image forming unit 200 is schematically (schematically) drawn in FIG. 1.

A toner tank 600 serves as a toner replenishing means for replenishing the image forming unit 200 with toner.
The image forming apparatus includes an optical unit 110, an image forming unit 200, and a toner tank 600.

When the toner tank 600 is attached to the main body 100, the upper part of the toner tank 600 is exposed to the outside of the case 101 of the main body 100. In FIG. 3, P2 indicates a recording sheet that is being discharged onto the discharge tray 108, and in FIG. 2, P3 indicates a recording sheet that is discharged onto the discharge tray 108. As is apparent from these figures, the exposed portion 600A of the toner tank 600 is exposed outside the case 101 outside the movement path of the recording paper.

Hereinafter, the main body 100 and the image forming unit 20
0, the toner tank 600 will be described in detail.

First, the overall structure of the main body 100 will be described.

At the back of the case 101, the paper feed tray 10 is provided.
4 is rotatably provided. The paper feed tray 104 is
Base part 1 rotatably supported on the back of case 101
04a and a tray 104b slidably attached to the base portion 104a. When not in use, the tray 104b is stored in the base portion 104a as shown by a broken line in FIG. It is folded so as to be in close contact with the back of the case, and when used, it is opened for use as shown by the solid line.

The recording paper P set in the paper feed tray 104
Are fed one by one by the paper feed roller 102.

The fed recording paper is fed by a paper feed path A formed by the paper guide 105 and the lower surface of the image forming unit 200.
1 and reaches between the photosensitive drum 201 and the transfer roller 106 where a toner image is formed as described later. Here, the recording paper onto which the toner image is transferred from the photosensitive drum 201 passes through the path A2 and the fixing roller 1 of the fixing unit 120.
The toner image is fixed by passing between the pressure roller 122 and the pressure roller 122, and passes through the upwardly curved discharge path A3 and is discharged by the discharge roller 103 from the discharge port 107 to the discharge tray 10.
8 is discharged.

Reference numeral 109 is a cover in which the paper discharge path A3 is formed, and the shafts 109a, 10 are attached to the main body 100.
It can be opened and closed by 9a. The paper discharge port 107
Is formed on the upper surface of the cover 109, and
The fixing unit 120 is attached to the cover 109. The cover 109 is opened to the front side when a paper jam or maintenance is performed.

Next, the image forming unit 200 will be described.

As shown in FIGS. 5 to 8, the image forming unit 200 includes a photosensitive drum 201 which is a photosensitive member, a charging roller 202, a developing device 300, a cleaning device 400, a toner conveying device 500, and a detecting device. By assembling the means 700 and the case 210, the means 700 is configured as a single unit.

The photosensitive drum 201 is constructed by forming a photosensitive layer made of an organic photosensitive body on a conductive base made of an aluminum drum, and is rotatably supported by the case 210.
It is rotationally driven in the direction of arrow a by a drive mechanism (not shown).

The charging roller 202 is pressed against the photosensitive drum 201 by a pressing mechanism (not shown), and charges the photosensitive drum 201 while following the photosensitive drum 201. A bias voltage is applied to the charging roller 202.

The charged photosensitive drum 201 has a laser beam L emitted from the optical unit 110 shown in FIG.
B is scanned, and thereby a latent image is formed on the surface of the photosensitive drum 201.

The case 210 is composed of a lower case 220 and an upper case 230, and a slit 231 for beam scanning is formed in the upper case 230.

The developing device 300 includes a toner storage chamber 301 formed by the lower case 220 in the longitudinal direction thereof,
A supply roller 310 rotatably provided in the toner storage chamber 301, a developing roller 320 rotatably provided in the toner storage chamber 301, and a sliding contact with the surface of the developing roller 320 along the axial direction of the developing roller 320, A regulation blade 330 that regulates the amount of toner supplied to the surface of the photosensitive drum 201 is provided.

Supply roller 310 and developing roller 320
Are rotationally driven in the directions of the arrows in FIG. 6 by drive mechanisms that interlock with the drive mechanism of the photosensitive drum 201.

The regulation blade 330 is made of an elastic body such as a stainless steel plate, and is attached to the upper case 230 by a mounting member 331. Regulation blade 330
Is bent in an L shape, and is in sliding contact with the developing roller 320 at the bent corner.

The supply roller 310 is the toner storage chamber 301.
The toner stored therein is rotated while being stirred to coat the surface of the developing roller 320 with the toner.

The toner coated on the surface of the developing roller 320 is brought into sliding contact with the regulating blade 330 to be thinned and frictionally charged.

A bias voltage is applied to the developing roller 320, the thinned toner is conveyed to the photosensitive drum 201, and is nipped at the nip portion formed by the pressure contact portion between the developing roller 320 and the photosensitive drum 201. The latent image on the photosensitive drum 201 is reversely developed. As a result, the photosensitive drum 20
The latent image on the first surface is developed to form a toner image.

The toner image formed on the surface of the photosensitive drum 201 is the same as that of the transfer roller 106 (see FIG. 4) to which the bias voltage having the opposite polarity to the toner image is applied.
It is transferred to the recording paper P which is sandwiched by and conveyed.

The cleaning device 400 has a cleaning blade 410. Cleaning blade 4
10 is attached to the upper case 230 by the attachment member 420. Lower edge 41 of cleaning blade 410
Reference numeral 1 denotes a peripheral surface of the photosensitive drum 201, and directs the residual toner adhering to the surface of the photosensitive drum 201 after the toner image is transferred to the recording paper to the toner collecting unit 560 of the toner conveying device 500. It is supposed to be scraped off.

Incidentally, the photosensitive drum 201 is cleaned by scraping off the residual toner, and thereafter, the above-mentioned image forming process is carried out again.

The toner conveying device 500 is the developing device 300.
And a cleaning device 400, which are arranged in a closed loop and serve as a toner conveying unit.
0, a drive gear 520 that engages with the coil spring 510 to circulate and drive the coil spring 510, and a coil spring 510.
A substantially groove-shaped guide portion 530 that slidably contacts with and guides
(See FIG. 8).

The coil spring 510 has an endless shape, and is provided inside the cleaning device 400 and the developing device 3.
It is arranged to be able to circulate between the inside of 00.

The drive gear 520 is driven by a drive mechanism (not shown) interlocking with the drive mechanism of the photosensitive drum 201 to circulate and drive the coil spring 510 in the direction of arrow b.

FIG. 8 is a schematic plan view showing the entire image forming unit 200.

As is clear from this figure, the guide portion 53
0 is a shape that guides the coil spring 510, which has an annular shape in a state of being left in a natural state, by correcting the coil spring 510 into an almost elliptical shape in a plan view, and two corner portions C1 formed in an approximately 1/4 arc shape. C2, a corner portion C3 formed in a semi-circular shape, and substantially linear portions L1 and L2 connecting these corner portions.

One of the two straight line portions L1 and L2 is in the toner storage chamber 301 of the developing device 300 as shown in FIG. 6, and the other straight line portion L2 is in the cleaning device 400. Then, for one straight line portion L1, the standing wall 221 of the lower case 220 and the lower surface 232 of the upper case 230 form a guide portion, and for the other straight line portion L2, the concave groove 222 formed on the upper surface of the lower case 220.
It constitutes the guide part. In addition, the toner storage chamber 301
The straight portion L1 in the inside is configured such that the standing wall 221 of the lower case 220 and the lower surface 232 of the upper case 230 guide the outer side and the upper side of the coil spring 510, and as a result, the toner storage chamber 301. On the other hand, an open portion 531 that opens the inner side and the lower side of the coil spring 510 is formed. The lower surface 232 of the upper case 230 is configured so as not to come into contact with the upper end of the coil spring 510 or to come into light contact with the upper end of the coil spring 510, so that it has little resistance to the circulating coil spring 510.

That is, in the toner storage chamber 301, the coil spring 510 is guided only by the upright wall 221 of the lower case 220 and the lower surface 232 of the upper case 230 to the upper side and the outer side, and discharges the toner to the storage chamber 301. Is able to.

As is clear from FIG. 6, the coil spring 510 moving in the toner storage chamber 301.
The upper end surface 515 of the developing roller 320 and the regulating blade 3
It is located above the sliding contact portion 321 with the 30.

On the other hand, in the toner collecting section 560 in the cleaning device 400, the cleaning blade 410
The upper portion is open toward the cleaning blade 410 so that the toner scraped off by the can be received and collected.

The image forming unit 200 as described above operates as follows.

As described above, the developing device 300 supplies toner to the surface of the photosensitive drum 201, and the toner develops the latent image on the surface of the photosensitive drum 201 to form a toner image. After the toner image is transferred to the recording paper P, the residual toner adhering to the surface of the photosensitive drum 201 is the cleaning blade 410 of the cleaning device 400.
And is recovered by the recovery unit 560 in the cleaning device 400.

Cleaning device 400 and developing device 300
An endless coil spring 510 is disposed between the cleaning gear and the developing device so as to circulate between the cleaning gear and the developing device.
Since it is driven to circulate by 0, a part of the excess toner that has not been used for development in the toner storage chamber 301 of the developing device 300 is conveyed to the cleaning device 400 by the coil spring 510 and is collected in the cleaning device 400. The residual toner is transported to the developing device 300 while being agitated and mixed with the excess toner transported by the coil spring 510.

When the toner in the toner storage chamber 301 is consumed and the level surface thereof is lowered, the toner conveyed to the developing device 300 is discharged toward the toner storage chamber 301 by its own weight.

By repeating the above operation, the toner in the image forming unit 200 is gradually consumed, but the consumed toner is in the toner tank 6.
It is replenished from 00 at any time.

As shown in FIGS. 1 and 14, the toner tank mounting hole 101 is provided on the upper surface of the case 101 of the printer body.
a is provided, and the toner tank 600 is configured to be attachable to and detachable from the upper case 230 of the image forming unit 200 through the mounting hole 101a. Mounting hole 1
A guide groove 10 for guiding a convex portion 616 (see FIG. 9) provided on the toner tank described later is provided on the inner wall surface of the groove 01a.
1b is provided.

Next, the structure of the toner tank 600 will be described with reference to FIGS. 9 and 10.

The toner tank 600 includes a transparent tank case 610 filled with toner and the tank case 61.
Agitator 620 rotatably provided in the inside of the tank 0, and shutter portion 630 provided at the bottom of the tank case 610.
And a lid 640.

A shaft hole 612, a toner supply port 613, and a pin 614 are provided in the bottom portion 611 of the tank case 610. Further, the outer peripheral surface 615 is provided with a pair of convex portions 616 that engages and disengages with a pair of dovetail grooves (L-shaped grooves) 242 and 242 provided in a concave portion 240 (see FIG. 12) of the upper case 230 described later. ing.

The agitator 620 is formed integrally with the shaft portion 621, the shaft portion 621, and the scooping blade 622 for scooping up the toner in the tank case, and the scooping blade 622 and the tank case. And a stirring blade 623 for stirring the toner inside.
1 is rotatably attached to a bearing hole 612 at the bottom of the tank case via a seal ring (not shown). When the toner tank 600 is attached to the upper case 230 of the image forming unit as described later,
A groove 625 that engages with the shaft 521 of the drive gear 520 is formed. The stirring blade 623 may be integrally provided with a wiper-shaped cleaning member 626 made of rubber or the like for cleaning the inner wall surface of the tank case 610, as indicated by an imaginary line.

The shutter section 630 includes a sealing member 631 made of an elastic material such as sponge, and a disk-shaped shutter 63.
2 and a guide member 633.

The sealing member 631 has a fan shape and is fitted in a recess 611a of the same shape provided in the tank case bottom portion 611. In the fitted state, the sealing member 631 coincides with the shaft hole 612 in the tank case bottom portion. Shaft hole 631a
And a toner supply port 631b matching the toner supply port 613 at the bottom of the tank case.

In the shutter 632, a shaft hole 632a that matches the shaft hole 612 of the tank case bottom 611, a toner supply port 632b that can match the toner supply port 613, and a pin 614 on the bottom of the tank case are inserted into an arc shape. Slot 632c and the upper case 23 of the image forming unit described later.
An engaging hole 632d that engages with the pin 244 provided at 0 is provided.

The guide member 633 has a ring shape as a whole, and the step portion 6 provided on the tank case bottom portion 611.
It is attached to 11b. In the mounted state, the four square holes 633e are the four engaging claws 611e formed in the step portion.
It is fixed to the bottom portion of the tank case by engaging with the bottom edge portion 633f, and the peripheral edge portion 632f of the shutter 632 is slidably supported by the inner surface (upper surface) of the bottom edge portion 633f. In addition, the guide member 633 has an arc-shaped tongue piece 6 having elasticity.
33g is integrally provided, and a projection 633c that is loosely fitted from the back side (upper surface side in FIG. 10) of the engagement hole 632d of the shutter 632 to the tip end portion of the tongue piece 633g is provided (FIG. 13). The shutter 632 is provided with a tongue piece 63 from the upper surface side of the guide member 633.
It is attached to the guide member 633 so as to pass through 3 g below. The engagement of the projection 633c with the engagement hole 632d prevents the shutter 632 from rotating carelessly, and the toner supply port 632b is aligned with the toner supply port 613 at the bottom of the tank case 610.
The toner inside is prevented from leaking out.

In the toner tank 600 as described above, when the above parts are assembled, the pin 6 at the bottom of the tank case is
14 penetrates the elongated hole 632c of the shutter 632, and the tip end thereof projects from the elongated hole 632c (see FIG. 13). The sealing member 631 is attached to the tank case bottom 611 with its toner supply port 631b aligned with the toner supply port 613 at the bottom of the tank case, and the shutter 6
It is held in a state of being pinched by 32. This improves the adhesion between the sealing member 613 and the shutter 632.
Toner leakage is prevented. The shutter 632 is
Between the tank case bottom portion 611 and the guide member 633, the pin 614 is rotatably slidable in the direction of arrow a or b in the figure within a range in which the pin 614 can relatively move along the elongated hole 632c. That is, in the shutter unit 630, only the shutter 632 is provided in the tank case 610.
It becomes a state in which it can relatively rotate and slide. In a state where the toner tank 600 is not attached to the image forming unit, the toner supply port 632b of the shutter 632.
Does not coincide with the toner supply port 631b of the sealing member 631. That is, the toner supply port 63 of the sealing member 631
1b is in a state of being sealed by the shutter 632.

Next, referring to FIGS. 11 and 12, the toner tank 6 in the upper case 230 of the image forming unit.
The mounting portion 240 of No. 00 will be described.

The mounting portion 240 is formed as a recess into which the lower portion of the toner tank 600 is fitted, and in this recess,
A shutter unit 250 having the same structure as the shutter unit 630 of the toner tank 600 described above is incorporated.

On the bottom surface 241 of the recess, the shaft hole 245 through which the shaft 521 of the drive gear 520 is inserted, and the toner supply facing the engagement start point of the drive gear 520 and the coil spring 510 in the circulation path of the coil spring 510 described above. A mouth 243 (see FIG. 8) and a pin 244 are provided. Further, on the inner peripheral surface of the concave portion, a pair of dovetail grooves (L-shaped grooves) that engage and disengage with the convex portion 616 of the toner tank described above.
242 and 242 are provided. The dovetail groove 242 includes a vertical groove 242a and a horizontal groove 242b.
The upper end of 2a is the mounting hole 10 of the printer body case described above.
It is connected to the lower end of a guide groove 101b provided in 1a (see FIG. 14). Further, the end of the lateral groove 242b constitutes a restricting portion for restricting the end of the rotation operation of the toner tank 600 during the mounting operation of the toner tank described later.

The shutter section 250 includes a sealing member 251 made of an elastic material such as sponge, and a disk-shaped shutter 25.
2 and a guide member 253.

The sealing member 251 is adapted to be fitted and adhered to a recess 241a of the same shape provided on the bottom surface 241 of the recess, and in the fitted state, the shaft hole 2
45 and a shaft hole 251a, and the toner supply port 24
3 and the toner supply port 251b corresponding to No. 3.

The shutter 252 has a shaft hole 252a coinciding with the shaft hole 245, a toner supply port 252b which can coincide with the toner supply port 243, and an arc-shaped elongated hole 252c into which the pin 244 is inserted. The engagement hole 252d that engages with the pin 614 of the toner tank 600 described above is provided.

The guide member 253 has a substantially ring shape and is mounted in the recess (240). In the mounted state, the two engaging claws 253e are fixed in the recess by engaging with the engaging holes (not shown) provided in the wall surface in the recess, respectively, and are fixed on the lower surface of the bottom edge 253f. The peripheral portion 252f of the shutter 252 is supported so as to be slidably rotatable (see FIG. 13). The guide member 253 is integrally provided with an elastic arc-shaped tongue piece 253g, and the engaging hole 25 of the shutter 252 is provided at the tip of this tongue piece 253g.
2d is provided with a protrusion 253c that is loosely fitted from the back side (lower surface side in FIG. 10) (see FIG. 13). The shutter 252 is incorporated under the guide member 253 so that the shutter 252 passes above the tongue piece 253g from the lower surface side of the guide member 253. Protrusion 2 in engagement hole 252d
The engagement of 53c prevents the shutter 252 from rotating carelessly during transportation of the main body, and the toner supply port 252b coincides with the toner supply port 243 so that the toner in the image forming unit 200 leaks. Is prevented.

When the image forming unit 200 is assembled, the pin 244 on the bottom surface of the concave portion becomes the slot 2 of the shutter 252.
The tip of the penetrating portion 52c is projected from the elongated hole 252c (see FIG. 13). The sealing member 251 is held in a state of being sandwiched between the recess bottom surface 241 and the shutter 252. As a result, the sealing member 251 and the shutter 2
Adhesion with 52 is improved and toner leakage is prevented.
The shutter 252 includes a recess bottom surface 241 and a guide member 25.
3, the pin 244 is rotatably slidably held in the direction of arrow a or b in the figure within a range in which the pin 244 can relatively move along the elongated hole 252c. That is, in the shutter part 250, only the shutter 252 is in a state of being relatively rotatable and slidable with respect to the upper case 230. Further, in a state where the toner tank 600 is not mounted, the toner supply port 252b of the shutter 252 has the toner supply port 251 of the sealing member 251 as shown in FIG.
Does not match b. That is, the toner supply port 251b of the sealing member 251 is in a state of being sealed by the shutter 252.

The attachment / detachment operation of the toner tank 600 with respect to the mounting portion 240 as described above is as follows. FIG. 13 is a schematic sectional view showing a state immediately before the toner tank 600 is mounted on the mounting portion 240. The attaching / detaching operation and the operation will be described mainly with reference to this drawing.

First, the toner tank 600 is set to the convex portion 6 thereof.
16 is aligned with the guide groove 101b of the mounting hole 101a (see FIG. 14) of the main body case.
To insert. Then, the convex portion 616 is guided by the guide groove 101b and moves downward in the guide groove 101b, further enters the dovetail groove 242a provided in the mounting portion 240 of the image forming unit, and reaches the lower end thereof. To stop (FIG. 13 shows a state immediately before reaching the lower end). At this time, the shaft 521 of the gear 520 is connected to the shaft portion 621 of the agitator 620 of the toner tank. The pin 614 of the toner tank is attached to the mounting portion 240 of the image forming unit.
The shutter 252 is fitted into the engaging hole 252d, and the projection 253c of the tongue is pushed down to unlock the shutter 252 by the projection 253c. At the same time mounting part 240
The pin 244 on the side is fitted into the engaging hole 632d of the shutter 632 of the toner tank and pushes up the protrusion 633c of the tongue piece to unlock the shutter 632 by the protrusion 633c.

Next, the toner tank 600 is replaced with the arrow b in FIG.
Rotate counterclockwise as shown in. Then, the convex portion 616 of the toner tank enters the lateral groove 242b of the dovetail groove and engages with the lateral groove 242b to prevent the toner tank from coming off.
It will be attached to the. As described above, the pin 614 of the toner tank fits into the engagement hole 252d of the shutter 252 of the mounting portion 240, and the pin 24 on the mounting portion 240 side is attached.
4 is an engagement hole 632d of the shutter 632 of the toner tank
Since the toner tank 600 is rotated in the direction of arrow b in FIG.
52 is the same direction as the toner tank 600, that is, FIG.
1 The toner supply port 252b rotates counterclockwise as indicated by arrow b so as to coincide with the toner supply port 251b of the sealing member 251, and the shutter 632 of the toner tank moves even when the toner tank is rotated in the direction of arrow b. Therefore, the toner supply port 632b is rotated in the clockwise direction as shown by the arrow a in FIG. 9 relative to the tank, and the toner supply port 632b coincides with the toner supply port 631b of the sealing member 631. That is, the toner supply ports 613, 631b, 632b, 252 of all parts
b, 251b, and 243 are in the matched state, and the toner can be supplied from the toner tank 600 to the image forming unit 200.

When the image forming unit 200 operates as described above with the toner tank 600 attached to the image forming unit 200 as described above, the drive gear 52
The agitator 620 is rotationally driven by the zero shaft 521.

The toner contained in the tank case 610 is agitated upward by the scraping blades 622 of the agitator 620.
When the toner in the inside is consumed, the toner is supplied from the toner supply port 613 to the toner supply port and the upper case 23.
Image forming unit 20 through the toner supply port 243 of 0.
The toner will fall freely into 0 and the toner will be replenished in the image forming unit 200.

As shown in FIG. 7, the toner tank 600 is attached on the upstream side of the developing device 300. As shown in FIG. 8, since the toner supply port 243 opens toward the position where the drive gear 520 and the coil spring 510 start to mesh with each other, the toner is not excessively supplied to the toner conveyance path C. Supplied in appropriate amount.

In this way, the toner is replenished to the image forming unit 200 from the toner tank 600, the toner in the toner tank is exhausted, and the tank 600 is replenished.
When the toner is no longer replenished from the image forming unit 2
The amount of toner in 00 decreases, and this is the detection means 7 described later.
00, the toner tank is replaced. Note that the toner in the toner tank is exhausted can be visually confirmed because the tank case 610 is transparent.

The operation for removing the toner tank 600 may be the reverse of the above-described mounting operation. That is,
Grasp the upper part of the tank 600 (exposed part 600A exposed from the main body case 101), and point in the direction of arrow a (clockwise).
After rotating the main body case 101, the main body case 101 may be pulled out from the mounting hole 101a. When the tank 600 is rotated in the direction of arrow a, the shutter 632 of the tank relatively rotates in the counterclockwise direction shown by arrow b in FIG.
At the same time that 13 and 631b are shielded, the shutter 250 of the image forming unit 200 rotates in the direction of arrow a in FIG. 11 to rotate the toner supply ports 243 and 2 of the unit 200.
52b is shielded. Therefore, when the tank 600 is removed, even if some toner remains in the tank 600, it does not scatter and stain the printer and its surroundings. Further, for example, when the printer is transported, the toner in the unit 200 is supplied to the toner supply port 243 even when the printer is transported with the tank 600 removed.
And 252b does not leak and scatter.

Next, the detecting means 700 will be described.

As shown in FIGS. 7 and 8, the detecting means 700 is provided with respect to the toner conveying path R on the downstream side of the developing device 300 and on the upstream side of the cleaning device 400.

FIG. 15 is a partially enlarged view of FIG. 8, and FIG. 16 is FIG.
5 is an XVI-XVI sectional view, and FIG. 17 is an XVII-XVII sectional view in FIG.

The detecting means 700 is, as shown in FIGS. 16 and 17, a detection window 71 provided in the toner conveying path R.
0, an elastic reflection plate 720 provided facing the detection window 710, and a reflection type optical sensor 730 provided in the detection window 710. The optical sensor 730 is provided in close contact with the lower surface of the detection window 710.

The detection window 710 is made of a transparent material such as glass or synthetic resin. Detection window 710
Is a plate-shaped base portion 711, as shown in FIG.
The base portion 711 has a convex portion 713 integrally formed on the upper surface 712, and the upper surface of the convex portion 713 has a protruding surface 7.
Make up 15. As shown in FIG. 18A, the convex portion 713 has a toner transport path R in which the detection window 710 is arranged.
Radius of curvature R1 that is the same as the part (here, corner C3)
Is curved with. As shown in FIGS. 16 and 17,
A recess 223 is formed in the lower case 220 of the image forming unit, and by mounting the base portion 711 in the recess 223, the detection window 710 is closed.
Attached to.

The length L of the protruding surface 715 in the toner conveying direction (see FIGS. 18B and 21A) is equal to or less than 2 pitches (2p) of the coil spring 510.

In FIGS. 16 and 17, reference numeral 224 denotes a smoother made of a low friction material such as fluororesin or polyacetal, and the upper surface 712 of the base portion 711 can be smoothly connected to the smoother 224. To
An arcuate recess 714 is formed (see FIG. 18).

With the detection window 710 attached, the projecting surface 715 of the projecting portion 713 projects somewhat toward the coil spring 510 side from the smoother 224. Therefore, the coil spring 510 has the protruding surface 715.
It will be bent and moved so that it will be pushed up a little by. As a result, the protruding surface 7 of the detection window 710
15 reliably slides in contact with the coil spring 510 by the restoring force due to the elasticity of the coil spring 510 itself, and the toner adhering to the projecting surface 715 is retained by the coil spring 510.
Be wiped by. Note that the protruding surface 715 may be curved upward in conformity with the movement path that is curved slightly upward of the coil spring 510.

The smoother 224 is a coil spring 510.
8 for smoothing the circulation operation of
Corner portions C1, C2, C3 of the guide portion 530 shown in FIG.
Is provided in a gutter shape.

As shown in FIG. 17A, the smoother 224 has a side wall surface 224a that slidably contacts the coil spring 510 and guides it. This side wall surface 224
a is a protruding surface 715 of the detection window as shown in FIG.
And is inclined so as to form an acute angle θ. Therefore, at the contact portion 510a between the inclined surface 224a and the coil spring 510, a component force that urges the coil spring 510 toward the protruding surface 715 is generated. As a result, the coil spring 510 is more surely attached to the protruding surface 715.
It comes into sliding contact with. In this embodiment, θ is set to 86 °.

The reflecting plate 720 is made of a metal plate having spring elasticity. As shown in FIG. 19, a curved portion 721 is formed at the front end and a bent portion 723 is formed at the rear end. . As shown in FIG. 16, a recess 233 is formed in the upper case 230 of the image forming unit, and the bent portion 723 is fitted into the recess 233 to attach the reflection plate 720 to the upper case 230. Has been. In the attached state, the reflection plate 720 biases the coil spring 510 toward the detection window 710 due to its spring elasticity.

Therefore, the coil spring 510 surely comes into sliding contact with the projecting surface 715 of the detection window 710, and the projecting surface 715.
The wiping action of the toner is surely performed. Further, as a result of the reflection plate 720 biasing the coil spring 510, the reflection surface 724 of the reflection plate 720 (see FIG. 17).
The toner adhered to is also wiped off.

The material used for the reflection plate 720 may be any material as long as it has a high reflectance such as a metallic glossy surface with respect to the light of the wavelength emitted by the light emitting element used for the reflection type optical sensor 730. In the example, S having a predetermined spring elasticity
A rolled plate of US304 is used.

At least one of the detection window 710 and the reflection plate 720, preferably the surface in contact with both toners, is
It is made of a material positioned on the same polarity side on the triboelectric charging train with respect to the charging polarity of the toner. In this embodiment, the contact surface of the detection window 710 with the toner is made of a material positioned on the same polarity side on the triboelectric charging column with respect to the charging polarity of the toner. The triboelectrification train measures the polarities of the surface potentials produced by contact charging two kinds of materials arbitrarily selected in an electrically shielded space by a surface electrometer to measure the positive and negative electrodes of the materials. It is required by ordering the relationship of. When the toner is used by being triboelectrically charged to the negative polarity, at least the surface of the transparent detection window 710 that comes into contact with the toner is selected from a material positioned on the negative polarity side in the triboelectric charging column, like the toner, and is equal to the toner. Alternatively, it is preferable to select a material positioned on the negative polarity side. For example, in the case of using a negatively chargeable toner made of a polyester binder, a material positioned on the negative polarity side of PMMA (polymethylmethacrylate), more preferably a polyolefin positioned on the negative polarity side of the toner may be selected. . When the toner is used by being triboelectrically charged to the positive polarity, at least the surface of the transparent detection window 710 that comes into contact with the toner is selected from a material positioned on the positive polarity side on the triboelectrification column, like the toner.
It is preferable to select a material that is equivalent to the toner or is positioned on the positive polarity side. For example, in the case of using a positive charging toner composed of a styrene-acrylic copolymer binder, a material positioned on the positive polarity side of the polyolefin,
More preferably, polyamide or the like positioned on the positive polarity side of the toner may be selected. In this embodiment, since the toner is used by being negatively charged, amorphous polyolefin is used as the detection window 710 as a material located on the negative polarity side of the toner on the triboelectric charging column. Similarly, transparent organic materials such as PMMA, polyamide, melamine resin, polyurethane, SA resin, polystyrene, ABS resin, epoxy resin, polycarbonate, acrylonitrile resin, polyimide, vinyl chloride and inorganic glass such as alumina, diamond, silica, etc. Can be used.

The surface of the reflection plate 720 is preferably coated with a substance selected by the above-mentioned triboelectric series.

The contact surface of the detection window 710 with the toner is made of a material positioned on the same polarity side in the triboelectric charging column with respect to the charging polarity of the toner, so that the toner existing in the toner conveyance path is detected. It becomes difficult to electrostatically adhere to. Therefore, the light that should pass through the detection window 720 is less likely to be blocked by the toner, and the presence or absence of toner in the toner transport path can be reliably detected. In addition, the wiping action of the coil spring 510 on the contact surface of the detection window 710 with the toner is facilitated, so that the presence / absence of the toner in the toner transport path can be detected more reliably.

At least one, and preferably all, of the good conductive members such as the coil spring 510 and the reflection plate 720 are electrically floated. In this embodiment, all are arranged in an electrically floating manner. When the detection window 710 is made conductive, it is also preferable to electrically float it.

The toner carried by the coil spring 510 and circulated and conveyed is frictionally charged by being rubbed against the coil spring 510 and the inner wall of the toner conveying path, and the conductive coil spring 510 and the reflection plate 720 are provided. When this is grounded, an electric charge opposite to that of the toner is supplied, and a strong suction force is generated between the toner and the coil spring 510 or the reflection plate 720, which makes it difficult to wipe the toner. To prevent this, it is electrically floated. When floated, the reflector 72
When the coil spring 510 makes sliding contact with the reflection plate 720, the toner attached to the toner particles is easily wiped off.

To the optical sensor 730, a detection device and a notification device (not shown) are connected.

A toner tank 600 is provided on the toner transport path R.
A predetermined amount of toner is circulated in a state where the toner is being replenished from the device, and is emitted from the reflection type optical sensor 730 at the portion of the detection means 700, transmitted through the detection window 710, and passed through the toner conveyance route R. Reflected by the reflector 720,
The optical path of the detection light that passes through the toner transport path R again, passes through the detection window 710, and is received by the reflective optical sensor 730 is
An output signal corresponding to no reflected light is output from the reflection type optical sensor 730, which is shielded by a predetermined amount of circulating toner.

When the amount of toner in the toner conveying path portion where the detecting means 700 is provided is extremely low or absent, the above-mentioned state where the optical path of the detection light is not blocked by the toner occurs. Since the optical path of the detection light is only temporarily blocked by the coil spring 510 when there is no light, the reflection type optical sensor 7
An output signal corresponding to the detection of the reflected light is output by 30, and a repetitive signal corresponding to the 1/2 pitch of the coil spring 510 is output particularly when there is no toner.

Therefore, the output signal from the sensor 730 is monitored by a detection device (not shown) connected to the sensor 730, and when the repetitive signal is continuously output for a predetermined time with a predetermined probability, the toner signal is detected by this. It is designed to detect that there is no state.

Further, at this time, the user is in the toner-free state (to be exact, the toner in the toner tank 600 is informed by the notification device sounding and / or displaying the message on the display device not shown). That the toner of the developing device 300 is starting to decrease).

According to the printer as described above, the following operational effects can be obtained.

(A) The photoconductor 20 is developed by the developing device 300.
Toner is supplied to the surface of No. 1, and the toner develops the latent image on the surface of the photosensitive drum 201 to form a toner image. After the toner image is transferred to the recording paper P, the photosensitive drum 2
The residual toner adhering to the surface of No. 01 is removed and collected by the cleaning device 400.

Developing device 300 and cleaning device 400
A coil spring 510 is arranged in a closed loop between and, and by this coil spring 510,
Part of the excess toner that has not been used for development in the developing device 300 is transferred to the cleaning device 400, and the residual toner collected by the cleaning device 400 is transferred to the toner tank 60.
The toner is conveyed to the toner storage chamber 301 of the developing device 300 while being agitated and mixed with new toner supplied from 0.

Therefore, a predetermined amount of toner is normally circulated in the developing device 300, the cleaning device 400, and the toner conveying path R, and when toner is consumed in the developing device 300, the consumed toner amount is increased. Will be replenished to the toner storage chamber 301 through the toner transport path R.

FIG. 20 is a schematic sectional view taken along line XX-XX in FIG. 8 and shows the state of the toner T in the toner storage chamber 301.

A predetermined amount of toner circulates in the toner storage chamber 301 and the toner transport path R of the developing device 300. The toner T is conveyed on the toner storage chamber 301 along the longitudinal direction by the coil spring 510, so that the toner is partially consumed in the toner storage chamber 301, and even if the level thereof is lowered, the toner T is lowered. Toner, such as D1 and D2 indicated by imaginary lines, is replenished with toner by free fall (free flow) from the coil spring 510. Therefore, the developing device 30
Even if the toner T is consumed at 0, the consumed toner is replenished to the toner storage chamber 301 through the toner transport path R, and the level of the toner T in the toner storage chamber 301 is normally maintained in a substantially horizontal state. When there are two or more lowered toner levels (for example, D1 and D2), the toner is replenished sequentially from the upstream portion (D1) to be leveled.

According to this embodiment, the above-described toner circulation and transport operation is efficiently performed.

That is, the residual toner, a part of the surplus toner, and the new toner are conveyed not by the holes on the surface of the sponge in the above-described conventional apparatus but by being held between the strands of the coil spring 510. Therefore, it is efficiently transported.

Further, since the toner is supplied to the toner storage chamber 301 by free fall from the coil spring 510, the toner releasing means which is required in the conventional apparatus is not necessary, and the structure is simpler and more efficient. Toner can be conveyed.

(B) As shown in FIG. 6, the upper end surface 515 of the coil spring 510 moving in the toner storage chamber 301 has the developing roller 320 and the regulating blade 330.
By being located above the sliding contact portion 321 with, the toner can be smoothly transported.

For example, as shown in FIG. 21 (a),
If the upper end surface 515 of the coil spring 510 moving in the toner storage chamber 301 is located below the sliding contact portion 321 between the developing roller 320 and the regulation blade 330, the following problem occurs.

That is, since a large amount of toner adhered to the surface of the developing roller 320 is thinned by the regulating blade 330 and supplied to the surface of the photosensitive drum 201, the toner remaining when thinning is indicated by an arrow T5. As shown in FIG. 6, the toner overflows from the sliding contact portion 321 between the developing roller 320 and the regulation blade 330, and the overflowing toner is transferred to the developing roller 320.
Forming a flow (see arrow T5) perpendicular to the axial direction of.

Therefore, the upper end surface 515 of the coil spring 510 has the sliding contact portion 321 between the developing roller and the regulating blade.
If it is located lower than this, the toner (see arrow T5) overflowing from the sliding contact portion will ride on the coil spring 510. The overflow toner flow T5 interferes with the toner flow conveyed by the coil spring 510, and as a result, the overflow toner flows to the coil spring 5
It becomes easier to get on top of 10.

The coil spring 510 is excellent in the toner carrying ability as described above, and further, as shown in FIG.
As shown in (b), the residual toner T1 and the new toner T2 are carried into the toner storage chamber 301, and a part T3 of the excess toner in the toner storage chamber 301 is carried out. In addition, when the overflow toner is placed on the coil spring 501, the overflow toner is transported by the coil spring (the transported toner is indicated as T4), and the coil spring 510
There is a phenomenon that the outlet 301C from the toner storage chamber 301 is clogged.

Since such clogging of toner acts as a great resistance against the movement of the coil spring 510, as a result, the smooth movement of the coil spring 510, that is, the smooth toner conveyance cannot be performed. Occurs.

On the other hand, according to the image forming apparatus of the present embodiment, the upper end surface 515 of the coil spring 510 is located above the sliding contact portion 321 between the developing roller and the regulating blade, and therefore, FIG. As shown in, the overflow toner (see arrow T5) does not ride on the coil spring 510 (or becomes extremely difficult to ride).

Therefore, the toner clogging at the outlet of the coil spring 510 from the toner storage chamber 301 (see reference numeral 301c in FIG. 20) is eliminated, and as a result, the smooth movement of the coil spring, that is, the smooth toner conveyance is performed. Become.

As described above, according to the image forming apparatus of this embodiment, the toner can be transported efficiently and smoothly.

In FIG. 21B, for convenience of explanation, the residual toner is shown as T1, the new toner is shown as T2, and a part of the surplus toner is shown as T3. However, in reality, these toners are agitated and conveyed by the coil spring. It is in a mixed state.

(C) Since the coil spring 510, which is in sliding contact with the guide portion 530, is driven to circulate by the drive gear 520, the following action is further obtained.

(I) As shown in FIG. 23, the drive gear 52
0 and the coil spring 510, the teeth 522 of the drive gear 520 to the coil spring 5 are engaged.
When a force F is applied to the coil 10 in the circulation direction, the coil spring 510 has a pitch angle α as shown in FIG. A component force F1 directed in a direction different from the direction (direction of arrow b) (obliquely upward in FIG. 23A).
And a reaction force F'1 against this occurs. Since the driving gear 520 receives a driving force from a driving source (not shown), the reaction force F′1 acts on the coil spring 510. Then, as a result, this reaction force F′1 is applied to the coil spring 5
This means that 10 is turned around its axis (direction of arrow c in FIGS. 23A and 23B).

Therefore, the coil spring 510 is
It circulates while turning around its axis. It should be noted that in the present embodiment, five turns are made for one circulation.

(Ii) When the coil spring 510 circulates while turning, local catching with the guide portion 530 is prevented, and smooth toner conveyance is obtained. Therefore, the coil spring 510 can be circulated with a small driving force, and the size and power saving of the driving motor can be achieved. In addition, the coil spring 510 includes the guide portion 5
Since it comes into uniform contact with 30, local wear is prevented and durability is improved.

(Iii) When the coil spring 510 circulates while swirling, the toner to be conveyed is agitated, so that the toner blocking occurs together with the expansion / contraction operation of the coil spring 510 itself in the circulation direction. And blocking toner, if present, is destroyed. In addition, the residual toner collected by the collecting unit 560 in the cleaning device 400 and the new toner replenished from the toner tank 600 are well agitated and mixed. Further, the excess toner and the residual toner generated in the developing device 300 are also well mixed by stirring.

(Iv) Since the coil spring 510 circulates while rotating to obtain a smooth circulation operation, the guide portion 530 is sufficient in the circulation path, which is required as in the above-mentioned conventional example. Pulleys 7b, 7
c and 7d are unnecessary.

Therefore, the size of the entire apparatus can be further reduced.

When the driving gear 520 and the coil spring 510 are engaged to drive the coil spring 510 in a circulating manner, the strands 512 of the coil spring 510 are
Enters the groove 523 of the drive gear 520 (see FIG. 23 (c)), and at this time, the strands 512 cause the toner to enter the groove 5
It will be pushed into 23. When the pushed-in toner is gradually aggregated, the groove 523 may be filled, and it may be difficult to drive the coil spring 510. However, such agglomeration of toner can be prevented by making the width e of the tooth bottom larger than the diameter d of the strand 512.

<Modification> This modification is different from the above-described embodiment in that a spur gear is used as a driving gear instead of a helical gear, and other points are the same.

That is, in this modified example, FIG.
As shown in FIG. 3, the drive gear is configured such that the wire 512 of the coil spring 510 is engaged with the coil spring 510.
And a helical gear 524 formed with helical teeth 525 that are inclined in the same direction.

With this structure, the following operation can be obtained in addition to the operation of the above-described embodiment.

That is, as described in the above embodiment, the drive gear 520 can be a spur gear, but
When the coil spring 510 is driven by the spur gear, the strand 512 inclined with respect to the circulation direction is pressed by the tooth surface perpendicular to the circulation direction. Therefore, the strand 512
It can be said that the concentrated load is likely to act on the wire and there is no risk of the strand 512 being deformed.

On the other hand, according to this modification, since the drive gear is composed of the helical gear 525, the wire 51
2 is pressed by the entire tooth surface of the helical gear 525. Therefore, the transmission loss of the driving force is reduced and the wire 51
The concentration of the force acting on 2 is alleviated, and the strand 512 is not deformed. Along with this, the turning force of the coil spring 510 due to the torsional moment becomes smaller, and in this example, the coil spring 510 turns twice for one circulation.

Regardless of whether the drive gear is a spur gear or a bevel gear, by setting the shape of the tooth bottom 526 to be the deepest in the central portion as shown in FIG. 24 (b). , Vertical direction of coil spring 510 (especially upward direction)
It is possible to obtain a stable drive state by restricting the movement to.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be appropriately made within the scope of the present invention.

[0159]

According to the present invention, the toner can be transported efficiently and smoothly with a simpler structure.

[0160]

[Brief description of drawings]

FIG. 1 is an external perspective view of a printer using an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a sectional view of the same.

FIG. 5 is a partially omitted perspective view showing an image forming unit and a toner tank.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a schematic plan view showing an image forming unit and a toner tank.

FIG. 8 is a schematic plan view showing the entire image forming unit.

FIG. 9 is a perspective view of the toner tank as viewed from below.

FIG. 10 is an exploded perspective view of a toner tank.

FIG. 11 is a plan view of the image forming unit.

FIG. 12 is an exploded perspective view of a toner tank mounting portion of the image forming unit.

FIG. 13 is a schematic cross-sectional view showing a state immediately before the toner tank is mounted on the mounting portion.

FIG. 14 is a partial perspective view of a main body case.

FIG. 15 is a partially enlarged view of FIG.

16 is a sectional view taken along line XVI-XVI in FIG.

FIG. 17 (a) is XVII-XVII in FIG.
Sectional drawing, (b) is a partially enlarged view of FIG.

FIG. 18 is a diagram showing details of a detection window, (a) is a front view,
(B) is a left side view and (c) is a bottom view.

FIG. 19 is a perspective view of a reflection plate.

FIG. 20 is a schematic cross-sectional view taken along the line XX-XX in FIG. 8, illustrating the operation of the toner in the toner storage chamber.

FIG. 21A and FIG. 21B are explanatory views of the action in proportion to each other.

FIG. 22 is an explanatory view of the operation of this embodiment.

23 (a), (b) and (c) are explanatory views of the operation of the present embodiment.

FIG. 24A is an explanatory view of a modified example, and FIG. 24B is a sectional view showing another modified example of the drive gear.

FIG. 25 is a view showing a conventional device, (a) is a plan view,
(B) is an AA 'sectional view in FIG. (A), (c) is a BB' sectional view in FIG. (A), (d) is a CC 'sectional view in FIG.

[Explanation of symbols]

 R toner transport path 201 photosensitive drum 224a inclined surface 300 developing device 400 cleaning device 500 toner transport device 510 coil spring 520 drive gear 524 bevel gear 530 guide part 600 toner tank

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 21/10

Claims (3)

[Claims] 1. A toner storage chamber in which toner is stored, and a developing roller that supplies toner in the toner storage chamber to the surface of a photoconductor to develop a latent image on the surface of the photoconductor and form a toner image on the surface of the photoconductor. A developing device having a regulating blade that slidably contacts the surface of the developing roller along the axial direction of the developing roller to regulate the amount of toner supplied to the surface of the photoconductor, and a toner image formed by the developing device. A cleaning device that removes and collects the residual toner adhering to the surface of the photoconductor after the transfer to the recording paper, and a cleaning device that is arranged in a closed loop between the developing device and the cleaning device. Excess toner that has moved in the chamber along the axial direction of the developing roller to carry the toner into the toner storage chamber and is not provided for development in the toner storage chamber. An endless coil spring that carries a part of the toner from the toner storage chamber toward the cleaning device and conveys the residual toner collected by the cleaning device to the toner storage chamber, and slides the coil spring to guide it. And a toner replenishing means for replenishing the toner to the toner conveying path of the toner conveying device, and the upper end surface of the coil spring moving in the toner storage chamber is regulated to the developing roller. An image forming apparatus, which is located above a sliding contact portion with a blade. 2. The image forming apparatus according to claim 1, wherein the coil spring is cyclically driven by a drive gear that engages with the coil spring. 3. The drive gear is configured as a helical gear having helical teeth formed in an engaging portion with the coil spring that is inclined in the same direction as the strand of the coil spring. Item 2. The image forming apparatus according to item 2.