JP2659706B2 - Image forming device - Google Patents

Description

Description: Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus such as an electronic copying machine, and more particularly, to an image forming apparatus using a two-component developer composed of a toner and a carrier. The present invention relates to an improvement in an image forming apparatus that makes a latent image on a body visible.

(Prior Art) In a conventional image forming apparatus of this type, the toner density of a two-component developer stirred in a developing apparatus during an image forming operation is detected by a toner density detecting means, and the detection output is detected. When the toner absence level is indicated, the image forming operation is not performed, and at the same time, a message indicating that the toner cartridge of the toner replenishing device should be replaced or that the toner cartridge should be inserted into the toner replenishing device is displayed. In this state, when the toner cartridge loaded in the toner replenishing device is replaced or toner is supplied to the toner replenishing device, this is detected and the image forming operation is enabled.

However, if the image forming operation is immediately enabled only by replacing the toner cartridge or charging the toner, the amount of toner supplied from the toner replenishing device to the developing device when the image forming operation is restarted. Insufficiently, and the incomplete stirring of the two-component developer in the developing device results in poor visualization of the latent image on the image carrier. Accordingly, there is a problem that a copy whose density is indistinct is obtained at the beginning of the restart of the image forming operation.

(Problems to be Solved by the Invention) Conventionally, as described above, since the image forming operation can be immediately performed in a state where the toner concentration of the two-component developer is low, a copy having indistinct shading often occurs. Was. Therefore, in order to obtain a copy having an appropriate density, the paper is often wasted, and as a result, the time required to make a substantial copy is often increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to surely obtain a copy having an appropriate density from the beginning after replacing a toner cartridge of a toner replenishing device or after supplying toner to the toner replenishing device. To provide an image forming apparatus capable of performing such operations.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention comprises a two-component developer comprising a toner and a carrier, and forms a latent image on an image carrier. Developing means for developing the latent image by supplying toner to the developing means; stirring means provided inside the developing means for stirring the contained two-component developer; provided inside the developing means; A toner density detecting means for detecting a toner specific density in the contained two-component developer; and a toner specific density in the two-component developer contained in the developing means by the toner density detecting means is equal to or less than a predetermined density. The toner supply means for replenishing toner to the developing means; and when the toner replenishment means supplies toner to the developing means, the toner concentration Until the degree detecting means detects that the specific toner concentration of the two-component developer contained in the developing means has reached the predetermined density, the developing operation by the developing means is prohibited and Control means for controlling the stirring means so as to stir the two-component developer.

(Operation) In the image forming apparatus according to the present invention, a two-component developer including a toner and a carrier is stored, and the latent image is developed by supplying the toner to the latent image on the image carrier. When the developing means is performing the developing operation, the two-component developer is stirred by the stirring means, and at the same time, the toner specific concentration of the two-component developer is detected by the toner concentration detecting means. Then, when the toner density detecting means detects that the specific toner concentration in the two-component developer is equal to or lower than the predetermined density, toner is supplied to the developing means by the toner replenishing means. When the toner is supplied, the control unit inhibits the developing operation by the developing unit until the toner concentration detecting unit detects that the toner specific concentration in the two-component developer has reached a predetermined concentration. At the same time, the stirring means is controlled so as to stir the two-component developer in the developing means. Therefore, the developing means performs the developing operation only when the toner specific concentration of the two-component developer is at the predetermined concentration, and when the concentration is lower than the predetermined concentration, the developing operation is prohibited.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of an image forming apparatus to which the present invention is applied.

In the figure, reference numeral 1 denotes a copying machine main body. An automatic or manual paper feed cassette 2 is loaded on the right side of the main body 1 of the copying machine, and a discharge tray 3 is loaded on the left side of the main body 1 of the copying machine. A document table 4 is provided on the upper surface document placing plate on which the document table 4 is placed so as to be reciprocally movable in the left-right direction (the direction of arrow a). In the figure, 5
Reference numeral 6 denotes an operation display section such as a display 6, a numeric keypad 7, an exposure setting volume 8, and a print key 9 provided at the front end of the upper surface of the copying machine body 1.

Next, the internal mechanism of the copying machine main body 1 will be described with reference to FIG.

In the drawing, reference numeral 10 denotes a drum-shaped photosensitive member as an image carrier rotatably supported at a substantially central portion in the copying machine main body 1 in a direction indicated by an arrow b in synchronization with the document table 4 by a driving mechanism (not shown). It can be driven to rotate. This photoconductor 10
Are uniformly charged by the charger 11 and the exposure lamp 12
An image of the original uniformly illuminated is formed on a photoreceptor 10 by a converging light transmitter (trade name: SELFOC lens array) 13 to form an electrostatic latent image. The developing device applies a developer (hereinafter, referred to as toner) to develop the electrostatic latent image, and sends an image of the developer (hereinafter, referred to as toner image) to the transfer charger 14 side.

The transfer charger 14 is formed on the photoreceptor 10 on copy paper P or P 'which is fed from a paper feed cassette 2 which is automatically or manually fed through a paper feed roller 15 and a pair of registration rollers 16, 16. In transferring the toner image, the copy paper P or P 'after the transfer is peeled off from the photoreceptor 10 by the peeling charger 17 by the AC corona discharge, and the toner image is melted and fixed by the fixing device 19 through the transport path 18, The sheet is discharged onto the sheet discharge tray 3 by the pair of discharge rollers 20 and 20.

On the other hand, the residual toner on the photoconductor 10 after the transfer of the toner image onto the copy paper P or P ′ is cleaned by the cleaning device 21, and the potential on the photoconductor 10 is reduced to a certain level or less by the discharging lamp 22, and the next Make the copy operation possible.

In the copier main body 1, an upper frame and a lower frame (not shown) are pivotally supported so as to be openable and closable at a desired angle (for example, 30 °) with each other.
0, and a charger 11, an exposure lamp 12, a converging light transmitter 13, a cleaning device 21, and a static elimination lamp
22 and other devices such as a developing device described later are attached by appropriate means to constitute an upper unit. On the other hand, a transfer charger 14, a peeling charger 17, a fixing device 19, a discharge roller pair 20, 20 and the like are mounted on the lower frame. Each unit and other mechanisms such as a power supply unit (not shown) are attached to form a lower unit, and both units can be opened and closed with the transport path 18 of the copy paper P or P 'as a boundary, thereby facilitating repair and inspection. I have to.

Further, in the drawing, reference numeral 23 denotes a developing device which is located in contact with the periphery of the photoconductor 10. The developing device 23 includes a supply unit main body 24 that supplies a toner T supplied from a toner cartridge, which will be described later, onto the surface of the photoreceptor 10 in a brush shape.
In the supply body 24, the toner T
Roller 25 composed of a non-magnetic rotating sleeve and a fixed magnet positioned in contact with each other to attach and supply
A doctor 26 for regulating the layer pressure of the toner T attached on the magnet roller 25 and a stirring roller 27 for stirring the toner T are provided.

Further, a toner level sensor 30 using a magnetic sensor is provided behind the stirring roller 27 on the sensor shaft 31 to detect the toner density.

Reference numeral 32 denotes a toner cartridge, 33 denotes a hopper, 34 denotes a supply port, and 35 denotes a developer supply roller. T is a toner.

Next, a control circuit for controlling the amount of toner from the replenisher 32 to the developing device 23 based on the detection output of the toner concentration detector 30 is shown in FIG.

The control circuit shown in FIG. 3 uses a microcomputer 41 of the image forming apparatus as a control center, and a detection signal of the toner level sensor 30 is input to the input side of the microcomputer 41 via an A / D converter 42. In addition, a solenoid 43 for opening and closing the supply port 34 connected to the output side of the microcomputer 41, an analog switch 44,
A predetermined output is sent to the display panel 45 or the like.

Then, in such a configuration of the control circuit, the microcomputer 41 executes a fourth
The processing as shown in the figure is executed.

First, when the power supply of the image forming apparatus is turned on, initialization is performed (step 401), and at this time, data of the toner density which is the toner-less level stored in the memory is read. Next, the detection signal of the toner level sensor 30 is received (Step 402), and it is confirmed that the toner density of the developer of the developing device 23 is at an appropriate density level. (Step 403).

During the normal copying operation, the toner level sensor 30 is functioning (step 404),
Steps 403 to 405 are repeated until copying for the set number of sheets is completed (No at Step 405), and when copying is completed (Yes at Step 405), a standby state is set.

Steps 402 and 404 of such main processing
In each of the processes described above, a subroutine process as shown in FIG. 5 is executed to detect the level of the toner concentration of the developer of the developing device 23.

This subroutine process is started when the toner level sensor is turned on, and controls the toner density using the sensitivity curve X given to the output characteristic of the toner density (weight ratio density) level sensor as shown in FIG. Perform In FIG. 6, A is a proper toner density value, B is a density value treated as if there is no toner, A 'is a proper density level corresponding to the proper toner density value A, and B' is a density treated as no toner. This is the toner absence level corresponding to the value B. The area between the appropriate density levels A 'and B' is the appropriate density limit level area.

First, it is determined whether or not the output of the toner level sensor 30 is the tonerless level B '(step 501). If the toner density is higher than the tonerless level (step 50).
(1 No), it is determined whether or not the density level is lower than the appropriate level A '(step 502).

If it is the appropriate level A '(No at step 502), the fourth
It returns to the main routine of the figure. If it is the appropriate density limit level lower than the appropriate level A '(step 502)
Affirmative), since the supply port 34 is opened by driving the solenoid 43, the toner T is supplied from the toner cartridge 32 to the developing device 23.
The stirring roller 27 is rotated while the machine operation is stopped (hereinafter, referred to as idle rotation of the stirring roller) (step 503). When the process of step 503 is completed, the process returns to step 501, and the determination of step 502 is executed again.
1 to 503 are repeated.

On the other hand, if the output of the toner level sensor 30 is the toner-out level B '(Yes at step 501), a process for temporarily stopping the machine operation is performed (step 504), the transfer charger 14 and the peeling charger 17 are turned off, and the exposure lamp is turned off. 12,
The charger 11 is turned off, the charge removing lamp 22, the motor is turned on, and the fixing lamp is turned on (step 505). Next, at the same time as the 30-second timer is turned on (step 506), the supply port 34 is opened by driving the solenoid 43.
When the toner 32 is newly loaded, the toner T is supplied once to the developing device 23 (step (507)).

If the toner concentration of the two-component developer stirred in the developing device 23 is lower than the appropriate density level A 'at the time when the toner T is supplied to the developing device 23 for one time (Yes at step 508). ), Until the timer of Step 504 expires (No at Step 509), Step 507
Step 509 is repeated. When the timer times out (Yes at Step 509), a toner empty display is displayed on the display panel 45 (Step 51).
0), the machine operation is stopped (step 511).

However, in step 508, the appropriate density level A '
If the process returns to step (5), the process goes to the standby state (step 513) after the process of step 512, and returns to the main routine of FIG.

As described above, in one embodiment of the present invention, even if the output toner level of the toner level sensor 30 does not reach the toner-absent level (No at Step 501), if the density is at the appropriate density limit level lower than the appropriate density level. (Yes at Step 502), at Step 503, the toner supply operation and the stirring roller 27
Is performed, and this operation is repeated until the density reaches the appropriate density level. Therefore, the toner cartridge 32
Can be reliably obtained from the beginning even if a new is loaded.

In the above-described embodiment, the case where the toner cartridge is used has been described. However, the present invention can be realized even in a case where the toner is supplied to the toner supply device.

Further, when the output of the toner level sensor 30 becomes the toner-less level, the toner replenishing operation and the idling operation of the stirring roller 27 are performed, and the operation is repeatedly performed until the density reaches the appropriate density level. After replacing the toner or after supplying toner to the toner supply device,
It is possible to reliably obtain a copy having an appropriate density from the beginning.

[Effects of the Invention] As described above, according to the present invention, if the toner concentration of the two-component developer stirred by the developing device is lower than the appropriate value, the process is repeated until the toner concentration reaches the appropriate value. Since the replenishment and the idle rotation in the developing device are performed, a copy having an appropriate density can be obtained from the beginning of the replacement of the cartridge or the beginning of the supply of the toner.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an image forming apparatus to which the present invention is applied, FIG. 2 is a view showing a mechanical structure of the image forming apparatus, and FIG. 3 is a main part of one embodiment of the present invention. FIG. 4 is a flowchart showing a main routine of one embodiment of the present invention, FIG. 5 is a flowchart showing an operation of a main part of the configuration of the present invention, and FIG. 6 is a characteristic of toner density-sensor output. FIG. 23 developing device 27 stirring roller 30 toner level 32 toner cartridge 33 hopper 34 supply port 41 microcomputer 43 solenoid

Claims (1)

(57) [Claims] A developing means for housing a two-component developer comprising a toner and a carrier, and for developing the latent image by supplying toner to the latent image on the image carrier; Stirring means provided inside the means and for stirring the contained two-component developer; and toner concentration detection provided inside the developing means and detecting the concentration of the toner in the contained two-component developer. Means for containing toner and supplying a predetermined amount of toner to the developing means by one replenishing operation, wherein the toner concentration detecting means accommodates the toner contained in the developing means. When it is detected that the toner concentration in the component developer is equal to or lower than the first reference concentration, a toner replenishing operation for the developing unit is performed once, and the toner concentration detecting unit stores the toner in the developing unit. When it is detected that the toner density in the two-component developer is equal to or lower than a second reference density lower than the first reference density, the toner replenishing operation for the developing unit is continuously performed a plurality of times for a predetermined time. A toner replenishing means for performing the toner replenishing operation on the developing means by the toner replenishing means. And controlling the stirring means so as to continuously stir the two-component developer in the developing means until it is detected that the reference density of the developing means has been reached. If the toner density detecting means does not detect that the toner density has reached the first reference density, it is determined that the toner in the toner replenishing means has run out, and Image forming apparatus characterized by comprising a control means for stopping the stirring operation by the supplying operation and the stirring means by the toner replenishing means.