JPS6361667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner supply device for an electrostatic recording device such as an electrophotographic copying machine.

In an electrostatic recording device, an electrostatic latent image of an image to be recorded is formed on a member made of a photosensitive material or a dielectric material, and this electrostatic latent image is developed with a developer containing toner to make it visible. After forming an image, it is melted and fixed onto recording paper to obtain the final recorded image. A developing device is provided to develop the electrostatic latent image into a visible image, and a developer containing toner is stored in the developing device. The developer consists of a two-component developer consisting of a magnetic powder called a carrier and colored resin fine particles called a toner, and a single component consisting of a magnetic toner containing a magnetic substance and, if necessary, a colorant in the resin. In the former, only the toner is consumed, and in the latter, the entire developer is consumed, and as a result, the density of the recorded image changes, so in both cases, the developer must be replenished. There is a need to. Regarding replenishment of developer, there is no problem with single-component developers because you only need to replenish the amount of developer that has decreased, but with two-component developers, as the toner is consumed, the ratio of toner to carrier, that is, the developer Since the concentration of the developer changes, it is necessary to know the concentration of the developer when replenishing the developer, which requires a concentration detection means, which is not as simple as in the case of a one-component developer. Various methods have been proposed for detecting toner concentration, including an optical method that uses the transmittance or reflectance of developer by attaching it to transparent glass, and an optical method that uses the transmittance or reflectance of the developer, and an optical method that uses the electrical properties of the developer, such as resistivity and magnetic permeability, to determine the toner concentration. Electrical methods and physical methods that take advantage of changes depending on quantity are known. The conventional toner replenishment method detects the toner concentration, and when the toner concentration drops below a predetermined reference value, drives the toner replenishment mechanism to replenish the toner to the developing device, which makes the mechanism complicated.
An electrical circuit is required. The time when the toner density drops below the standard value varies depending on the amount of toner consumed and the number of recordings, so it is necessary to constantly monitor the toner density in order to maintain the ideal toner density. be.

In view of the above points, the present invention uses a simple mechanism to replenish a fixed amount of toner for each recording operation. According to the present invention, since toner is not replenished according to the toner concentration, there is no need for a toner concentration detection means or an electric circuit for processing a detection signal, and moreover, the amount of toner consumed is only approximately equal to the amount consumed. Because it is quickly replenished, the average developer density is always maintained at a value closer to a constant value than in conventional toner density control systems. In particular, when the recording target is relatively thick standard paper (so-called ticket paper) such as postcards, book cards, microconvert cards, etc., and the amount of information contained therein is fixed, the recording operation is required only once. Since the amount of toner consumed is fixed, the method of the present invention in which toner is replenished for each recording operation is convenient and advantageous in maintaining the toner concentration of the developer constant.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Although the illustrated embodiment is an electrophotographic copying machine for copying paper tickets, the present invention is of course not limited to this type of copying machine.

FIG. 1 shows, as an example, a schematic configuration of an electrophotographic copying machine for copying ticket sheets with a movable document table. In the figure, reference numeral 1 denotes a document table that can reciprocate on the top surface of the copying machine main body 2. A document M placed on the document table 1 is irradiated by an irradiation lamp 3 as the document table 1 moves, and the reflection from the document M is The light passes through mirrors 4, 5 and lens 6 and is projected onto photoreceptor 7a on rotating drum 7. The rotary drum 7 is rotated in the direction of the arrow in synchronization with the copying operation, and the photoreceptor 7a is uniformly charged by the charging electrode 8 and then exposed to light reflected from the document M, so that a static image corresponding to the document image is formed on its surface. A latent image is formed. Reference numeral 9 denotes a developing device for converting the electrostatic latent image thus formed into a visible image. In this embodiment, a magnetic brush type developing device is used and has a magnetic sleeve 9a inside. Reference numeral 10 denotes a toner replenishing device for replenishing toner to the developing device 9, which is constructed according to the present invention. A paper feed tray 11 is attached to the outside of the copying machine main body 2, and the ticket sheets K stacked and stored on the paper feed tray 11 are fed one by one from the bottom by a paper feed roller 12, and are further fed by a feeding device 13 and a conveying device 14. The image is transported to the transfer position.
At the transfer position, the visible image on the photoreceptor 7a is transferred to the ticket paper K by the transfer electrode 15, and the transfer device 1
6, the sheet is thermally fixed by a fixing device 17, and then discharged onto a paper discharge tray 18.

Now, the toner replenishing device 10 in the above-mentioned copying machine
The drive mechanism is shown in detail in Figure 2 and below.

The toner replenishing device 10 is fixed to the upper part of the developing device 9, and both side plates 20a, 20b of the toner storage device 20 are composed of side plates 20a, 20b whose width gradually becomes narrower toward the bottom, and an upper lid 20c. A toner supply shaft 22 is rotatably held by an end plate 20d in the longitudinal direction of the toner storage device 20 in a gap 21 formed at the lowermost end of the toner storage device 20. A notch 22a is formed on the surface of the toner supply shaft 22, and toner is stored in this notch 22a. The number of notches 22a can be determined arbitrarily, but in the illustrated example, it is two. In order to prevent toner from leaking from around the toner supply shaft 22 in the bottom gap 21 of the toner storage device 20, the edge of the backing plate 20e made of thin metal or resin is applied to the surface of the toner supply shaft 22 from the outside of the bottom of the side plates 20a and 20b. is lightly touched. Also,
A toner scraping plate 20 made of a thin plate with spring properties is installed from the outside of the bottom of the side plate 20b of the toner storage device 20.
f is lightly pressed against the surface of the toner supply shaft 22.

The drive mechanism of the toner replenishing device 10 is best shown in FIGS. 3 and 4. Toner supply device 10
A drive arm 24 is provided at one end that can rotate around a column 23 installed in a part of the copying machine main body 1. This drive arm 24 has three arms, and one arm 24a has a A notch 25 is formed,
One end of a spring 26 for always biasing the arm 24 counterclockwise is hung on the other arm 24b, and the other arm 24c stands up from the plane of the arm 24 and has a roller 27 at its tip. On the other hand, a one-way clutch 28 is fixed to a part of the copying machine main body 1, and a drive shaft 28 for driving the toner supply shaft 22 is provided.
9 is engaged with this one-way clutch 28. A pin 29 is provided at the tip of the drive shaft 29 at right angles to the drive shaft 29.
a is fixed, and this pin 29a is connected to a coupling member 2 fixed to one end of the toner supply shaft 22.
It engages with a groove formed in 2b. A relay arm 30 is fixed to the end face of the one-way clutch 28, and a pin 30a is implanted near one end of the relay arm 30, and this pin 30a engages with a notch 25 formed in one arm 24a of the drive arm 24. ing.

An opening 11a is formed in a part of the paper feed tray 11, and a part of the paper feed roller 12 is inserted into this opening 1 when feeding paper.
A solenoid 31 is provided for inserting into 1a. The feeding device 13 includes a pair of feeding rollers 13.
a, 13b, both rollers 13
a and 13b are not in contact with each other and are separated by an interval slightly narrower than the thickness of one sheet of ticket paper K.
The feed roller 13a is made of rubber, for example, and is rotationally driven by a drive mechanism (not shown), but the feed roller 13b is driven only when the ticket paper K is held between both rollers. Rotating shaft 3 of driven feed roller 13b
An eccentric cam 33 is fixed to the roller 2, and the rotation of the feed roller 13b also rotates the eccentric cam 33. The roller 27 of the drive arm 24 is in contact with the peripheral edge of the eccentric cam 33 due to the action of the spring 26.

A toner supply amount scale plate 34 is provided on the paper feed side of the copying machine main body 1, and a supply amount adjustment arm 35 can be manually moved up and down along this scale plate 34. As can be seen from FIG. 4, when the adjustment arm 35 is moved up and down, the downward movement of the arm 24b of the drive arm 24 is restricted at the stop position, so the amount of rotation of the drive arm 24 is limited, and as a result, the drive arm Since the contact position between the rollers 26 of 24 and the eccentric cam 33 is displaced, the amount of rotation of the relay arm 30 via the pin 30a can be changed.

Next, the operation of the toner supply device will be explained.

When the copying operation is started by pressing the copy start button, the solenoid 31 is energized in synchronization with the copying operation, and a part of the paper feed roller 12 enters the opening 11a of the paper feed tray 11, and the lowest part of the ticket paper is energized. contact with the sheet and send it out. This ticket paper is sent to feeder 1
When the rollers 13a and 13b are fed between the pair of rollers 13a and 13b, the rotation of the roller 13a, which is rotationally driven by a drive device (not shown), is transmitted to the other feed roller 13b via the ticket sheet, and the feed roller 13b also rotates. be rotated. Feed roller 13b
When the cam 33 rotates, the coaxial eccentric cam 33 rotates, and the roller 27 of the drive arm 24 that is in contact with the periphery of the cam 33 rotates, and the drive arm 24 moves toward the column 23.
It rotates clockwise against the spring 26 around the center.
As a result, the relay arm 30 is rotated counterclockwise via the pin 30a as shown in FIG. 29. The rotation of the drive shaft 29, which engages with the pin 29a, is transmitted to the toner supply shaft 22 via the coupling member 22b. In this way, the toner supply shaft 22 is rotated by a predetermined rotational angle each time one sheet of ticket paper is sent out. The rotation angle of the toner supply shaft 22 can be determined by the shape of the eccentric cam 33, the position of the pin 30a, etc. For example, the shape of the eccentric cam 33 and the shape of the pin 30 are such that the toner supply shaft 22 rotates 180 degrees each time one sheet of ticket paper is sent out.
If you choose the planting position a, two notches 22a are formed symmetrically on the toner supply shaft 22, so
The toner accumulated in the notch 22a for each ticket sheet is replenished into the developing device 9 from the bottom gap 21 of the toner storage device 20.

When the ticket paper finishes passing through the feeding device 13, the feeding roller 13b rotates freely, so the eccentric cam 33
The drive arm 24 can also rotate freely.
is rotated counterclockwise about the support post 23 by the spring 26 and returns to its original position. At this time, the relay arm 30 is also rotated clockwise via the pin 30a and returned to its original position, but the relay arm 30
0 rotation is blocked by the one-way clutch 28 and is not transmitted to the drive shaft 29, so the toner supply shaft 2
2 is never rotated in the opposite direction.

In synchronization with the copying operation, the next ticket sheet is sent to the feeder 13.
, the toner supply shaft 22 is further rotated 180 degrees in exactly the same manner as described above, and the toner accumulated in the opposing notch 22a is discharged from the bottom gap 21 of the toner reservoir 20 into the developing device 9. will be supplied to.

In this way, toner is replenished each time a sheet of ticket paper is sent out. The amount of toner supplied at one time can be adjusted by changing the width and depth of the notch 22a formed in the toner supply shaft 22.

In the above embodiment, a thick regular recording paper, that is, a ticket paper is used, and the toner replenishment operation is started via the ticket paper, but the present invention is not limited to the ticket paper, and the toner replenishment operation can be performed not only on the ticket paper but also on general thin recording paper. Of course, this may be started via a microswitch or the like operated in synchronization with the copying operation. Further, if the number of notches 22a formed in the toner supply shaft 22 is two or more, for example four, the rotation angle of the toner supply shaft may be 90 degrees for each copying operation, and the notches 22a can be formed in this way. The number of notches can be arbitrarily selected, and by selecting the number of notches and the rotation angle of the toner supply shaft that rotates during one copying operation, it is possible to copy several times instead of every single copying operation. It is also possible to perform toner replenishment once for each operation.

As explained above, in the present invention, the amount of toner consumed per copying operation is preferably replenished, so even if the developer used is a two-component developer, the toner concentration can be measured. The toner concentration can be maintained at a nearly constant value at all times without the need to perform different measurements or compare it with a reference toner concentration, eliminating the need for a toner concentration measuring device or an electric circuit. Furthermore, the configuration shown in the embodiment of the present invention is advantageous in practice because it can be easily realized with a purely mechanical configuration.

[Brief explanation of drawings]

FIG. 1 of the accompanying drawings is a schematic diagram of the entire electrophotographic copying machine employing the toner replenishing device according to the present invention;
Figure 2 is a side view of the toner supply device, and Figure 3 is a side view of the toner supply device.
FIG. 4 is a plan view of the drive mechanism of the toner replenishing device taken along the line AA in the figure, and FIG. 4 is a side view of the drive mechanism taken along the line BB in FIG. DESCRIPTION OF SYMBOLS 1... Original table, 2... Copying machine main body, 3... Irradiation lamp, 7... Rotating drum, 7a... Photoreceptor, 8
...Charging electrode, 9...Developing device, 9a...Magnetic sleeve, 10...Toner supply device, 11...Paper feed tray, 12...Paper feed roller, 13...Feeding device, 1
4, 16... Conveyance device, 15... Transfer electrode, 17
... Fixing device, 18 ... Paper discharge tray, 20 ... Toner storage device, 22 ... Toner supply shaft, 24 ... Drive arm, 25 ... Notch, 28 ... One-way clutch, 29 ... Drive shaft , 30... Relay arm, 33
...Eccentric cam.

Claims (1)

[Claims] 1. A toner storage device, a drive means driven by a driven roller that rotates only while the recording paper is being fed by the drive roller, and a drive means that supplies an amount of toner according to the size of the recording paper. and a toner supply means for supplying the toner from the storage to the developing device,
The driving means includes an eccentric cam that rotates together with the driven roller, an arm that is rotated by the eccentric cam, and a one-way clutch that transmits rotation of the arm in one direction to the toner supply means. A toner replenishing device for an electrostatic recording device, characterized by: