JPH09325595A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure time for a preliminary rotation, to execute a sensing operation in the stable state of the concn. of toner and to supply the toner by providing a control part for executing a mode for attaining a toner supplying operation, after or simultaneously with the sensing operation. SOLUTION: A microprocessor 510 executes a real-time mode or a delay mode. This device executes the sensing operation for setting toner supplying conditions, based on output signals from toner concentration sensors L1-L4, after the preliminary rotational operation of previously stirring a developer, for stabilizing the concn. of the toner in a developing unit, based on the result of the detection of the size of a recording paper or an original. At this time, in the real-time mode, the operation of supplying the toner from a toner hopper is successively executed after the sensing operation. In the delay mode, the toner is supplied from the toner hopper, simultaneously with the sensing operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit of an image forming apparatus for driving and rotating a plurality of developing units and supplying toner to replenish toner.

[0002]

2. Description of the Related Art Each developing device used in a color image forming apparatus contains a developer of a specific color and is driven individually in accordance with the timing of developing each toner image. As a driving power source, one driving motor is used as a common power source for the purpose of downsizing and cost reduction of the device, and the developing devices specified by switching the power transmission system are individually used. It has a working structure.

Although a toner replenishing device is also provided in each of these developing devices, the motor is also used as a power source for the toner replenishing operation, and by switching the replenishing power transmission system similarly to the driving of the developing device. The structure is such that toner is supplied to the specified developing device. An image forming apparatus equipped with such a toner replenishing mechanism pre-rotates a stirring roller in order to stabilize the toner concentration in the developing device when detecting the toner concentration in the developing tank, and then performs a sensing operation following the preliminary rotation. And a toner replenishing operation is executed based on the sensing result. Such a series of operations is a so-called real-time mode that is performed within the time when the developing device is continuously driven by the motor.

[0004]

However, the above-mentioned real-time mode cannot be applied to a small size printing operation represented by a postcard. Specifically, in the small-size printing operation, the printing operation is shortened, and therefore the rotation time of the developing device per print is shortened, so that the toner replenishing operation cannot be performed from the preliminary rotation in real time. Therefore, it is possible to reduce the preliminary rotation time in order to secure a sufficient toner replenishing operation, but an accurate sensing operation cannot be performed because the toner concentration is unstable.

Further, since small-sized postcards and the like have a high printing rate, the toner consumption amount during the printing operation also increases. For this reason, the toner supply time may be insufficient. In order to solve such a problem, it is conceivable to lengthen the drive time of the engine unit per print. This has a problem that the number of copies per unit time is reduced.

Since the developer coagulates due to temperature and humidity, the detection output of the L-detection sensor generally changes depending on the condition of the developer around the L-detection sensor, and an accurate toner concentration may not be detected.

In view of the above technical problems, a first object of the present invention is to provide an image forming apparatus capable of securing sufficient pre-rotation time and performing a sensing operation in a state where the toner density is stable to replenish the toner. Especially.

In view of the above technical problems, a second object of the present invention is to secure a sufficient time for preliminary rotation without reducing the number of copies per unit time, and to perform a sensing operation with a stable toner density. An object of the present invention is to provide an image forming apparatus capable of performing toner supply by replenishing toner.

In view of the above technical problems, a third object of the present invention is to provide an image forming apparatus capable of supplying an appropriate amount of toner in consideration of the toner supply amount and process conditions.

[0010]

The above object can be achieved by the following constitutions.

(1) A toner density sensor for detecting the toner density in the developing device, a toner density calculating section for calculating the toner density from an output signal from the toner density sensor, and a toner density calculated by the toner density calculating section. An image forming apparatus that replenishes toner from a toner replenishing means to a developing device based on the above, and a toner density in the developing device based on the size detection means for detecting the size of the recording paper and the detection result of the size detection means. In order to stabilize the toner, a sensing operation for determining the toner replenishment condition based on the output signal from the toner concentration sensor is performed after the pre-rotation operation for premixing the developer, and the toner replenishment operation is performed after the sensing operation by the toner replenishing section. Real-time mode that is sequentially executed and pre-rotation operation that agitates the developer in advance to stabilize the toner concentration in the developing unit One of a delay mode in which a sensing operation for subsequently determining a toner replenishment condition based on an output signal from the toner concentration sensor is sequentially performed, and a toner replenishment operation is performed from the toner replenishment unit in parallel with the sensing operation. An image forming apparatus comprising: a control unit that executes the above. By providing such a configuration, it is possible to secure a sufficient time for preliminary rotation even in a small-size printing operation, and perform the sensing operation in a state where the toner concentration is stable to replenish the toner.

(2) A toner density sensor for detecting the toner density in the developing device, a toner density calculating section for calculating the toner density from an output signal from the toner density sensor, and a toner density calculated by the toner density calculating section. An image forming apparatus that replenishes toner from a toner replenishing means to a developing device based on a size detection means for detecting the size of recording paper or the size of a document, and a unit time based on the detection result of the size detection means. An image forming apparatus comprising a control unit for increasing a replenishment amount per hit. With such a configuration, since the printing rate is high, the pre-rotation time is sufficiently secured without reducing the number of copies per unit time even during the printing operation, and the sensing operation can be performed in the state where the toner density is stable. You can go and replenish toner.

(3) A toner density sensor for detecting the toner density in the developing device, a toner density calculating section for calculating the toner density from an output signal from the toner density sensor, and a toner density calculated by the toner density calculating section. An image forming apparatus that replenishes toner from a toner replenishing means to a developing device based on the above, and indicates a reception detecting means that detects reception of toner replenishment data from a print controller and a toner replenishing amount received by the reception detecting means. An image forming apparatus comprising: a control unit that replenishes an appropriate amount of toner from the toner replenishing unit based on the data. By providing such a configuration, it is possible to replenish an appropriate amount of toner in consideration of the toner replenishment amount and the process condition without being affected by environmental conditions.

[0014]

FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus according to the present embodiment, and FIG. 2 is a sectional view showing each cartridge according to the present embodiment.

The image forming apparatus according to the present embodiment has a main body 2 in which a cartridge containing various process members is loaded.
00, a double-sided paper feeding device 400 and a recording paper feeding device 600 are optionally provided. Prior to describing each component configuration, an image forming process of the image forming apparatus according to the present embodiment will be described.

The microprocessor 510 (see FIG. 7) grounds the photoconductor drum 10 having the OPC photoconductor coated on the drum and drives and rotates it clockwise. The microprocessor uses a scorotron charger 12 to uniformly charge VH on the peripheral surface of the photosensitive drum 10 by corona discharge by a grid and a corona discharge wire whose potential is held at VG. Prior to the charging by the scorotron charger 12, in order to eliminate the history of the photoconductor up to the previous print, exposure is performed by the PCL 11 using a light emitting diode or the like to eliminate the charge on the peripheral surface of the photoconductor.

Writing device 2 after uniformly charging the photosensitive member
Image exposure is performed by 30 based on the image signal. The writing device 230 is a device in which an optical path is bent by a reflection mirror through a polygon mirror, a fθ lens, etc., which rotates using a laser diode (not shown) as a light source, and scanning is performed.
A latent image is formed by rotation (sub-scanning) of the photosensitive drum 10. In the present embodiment, a character portion is exposed to form a reversal latent image such that the character portion has a lower potential VL.

At the periphery of the photosensitive drum 10, there are provided developing units 14 each containing a developer containing toner such as yellow (Y), magenta (M), cyan (C) and black (K) and a carrier. First, the development of the first color is performed by the developing sleeve 141 which contains a magnet and holds the developer and rotates. The developer consists of a carrier in which ferrite is used as a core and is coated with an insulating resin around it, and a toner whose main component is polyester and pigments according to the color and charge control agents, silica, titanium oxide, etc. are added. The agent is regulated by the layer forming means to have a layer thickness (developer) of 100 to 600 μm on the developing sleeve 141 and is conveyed to the developing area.

The gap between the developing sleeve 141 and the photosensitive drum 10 in the developing area is set to 0.2 to 1.0 mm, which is larger than the layer thickness (developer), and the AC bias of VAC and the DC bias of VDC are superposed between them. Applied. V
Since DC, VH, and toner charge have the same polarity, VAC
The toner that has been triggered to separate from the carrier does not adhere to the VH portion having a higher potential than VDC,
The toner adheres to the VL portion having a lower potential than VDC and visualization (reversal development) is performed.

After the visualization of the first color is completed, the image forming process for the second color is started, the uniform charging is performed again by the scorotron charger 12, and a latent image based on the image data for the second color is formed by the writing device 230. It At this time, the charge elimination by the PCL 11 performed in the image forming process of the first color is not performed because the toner attached to the image portion of the first color scatters due to the sudden decrease in the potential around the image.

Again, a latent image similar to that of the first color is formed and developed on the portion of the photosensitive member having the potential of VH all over the peripheral surface of the photosensitive drum 10 without the image of the first color. However, in the portion where the portion where the image of the first color is present is developed again, the latent image of VM ′ is formed by the light shielded by the toner attached to the first color and the electric charge of the toner itself.
Development is performed according to the potential difference between DC and VM '. This one
When the first color is developed by forming a VL latent image in the overlapping portion of the images of the first color and the second color, the balance between the first color and the second color is lost, so that the exposure amount of the first color is reduced and VH> V
There may be an intermediate potential where M> VL.

For the third and fourth colors, the same image forming process as that for the second color is performed, and 4 steps are performed on the peripheral surface of the photosensitive drum 10.
A visible color image is formed.

On the other hand, the paper feeding roller 20 from the paper feeding cassette 15
The recording paper conveyed through 2 is temporarily stopped, and when the transfer timing is adjusted, it is fed to the transfer area by the rotation operation of the registration roller 209.

In the transfer area, a transfer roller 216 is pressed against the peripheral surface of the photosensitive drum 10 in synchronism with the transfer timing, and the supplied recording paper is nipped and a multicolor image is transferred at once. .

Next, the recording paper is discharged at almost the same time by a separating brush 217 which is brought into a pressure contact state, and the photosensitive drum 10 is discharged.
After being separated by the peripheral surface of the sheet, the sheet is conveyed to the fixing device 220, and the toner is fused by heating and pressurizing the heat roller 221 and the pressure roller 222, and then discharged to the outside of the apparatus through the paper discharge roller 21. The transfer roller 216 and the separation brush 21
After the recording paper has passed, 7 is retracted and separated from the peripheral surface of the photosensitive drum 10 to prepare for the next toner image formation.

On the other hand, the photosensitive drum 10 from which the recording paper is separated
Removes and cleans the residual toner by pressing the blade of the cleaning device 22, receives the charge removal by the PCL 11 and the charge by the charger 12 again, and starts the next image forming process. The blade moves immediately after the cleaning of the photoconductor surface and retracts from the peripheral surface of the photoconductor drum 10.

First, the structure of each cartridge will be described with reference to FIGS.

As shown in FIGS. 1 and 2, the drum mount 30 includes a photosensitive drum 10 and a PCL 1 arranged on the peripheral surface thereof.
1. The charger 12, the developing devices 14, and the cleaning device 22 are housed and integrated. As shown in FIG. 2, the equipment accommodated in the drum stand 30 includes a drum cartridge 40 incorporating the photosensitive drum 10 and others, a developing cartridge 50 incorporating each developing device 14 containing Y, M, and C developers, and a K cartridge. The cartridge is separately stored in a developing cartridge 50A in which only the developing device 14A containing a developer is incorporated.

The drum cartridge 40 is the photosensitive drum 1.
In addition to 0, a PCL 11, a charger 12, and a cleaning device 22 are incorporated, and the openings 40A, 40B, and 40 corresponding to the areas of exposure, development, and transfer on the surface of the photoconductor are provided.
It covers all photoreceptor surfaces except C. In the drum cartridge 40, the bearing portion 41 of the photosensitive drum 10 is brought into contact with the vertical groove 30A of the drum base 30, and the bottom portion is brought into contact with the pair of position regulating pins P1 provided on both inner side surfaces of the drum base 30. As a result, the respective equipments that are housed with their positions in the horizontal and vertical directions being restricted while being prevented from rotating are set to predetermined image forming positions.

The opening 40A, which is the exposure area of the drum cartridge 40, is provided with a sliding type shielding plate 42 in a narrow slit hole having a width sufficient for the writing beam to pass therethrough, so that the surface of the photoreceptor cannot be touched. It has become.

On the other hand, the developing cartridges 50 and 50A
Are biased by the compression springs 52 in a state where the position regulating pins P2 of the respective developing devices projectingly engage with the elongated holes on both side surfaces. The developing cartridges 50 and 50A are pressed to the left by the pressing pin P3 or P4 provided on the side door 34 forming the right side surface of the drum base 30, and the abutting rollers (not shown) coaxial with the developing sleeves 141 are provided. The gap between the peripheral surface of each developing sleeve 141 and the peripheral surface of the photoconductor drum 10 is set by pressing the peripheral surface of the photoconductor drum 10 against the surface of the photoconductor drum.

The drum base 30 is a base 30 installed above.
A plurality of toner replenishing means 300 for replenishing toner to each developing unit are provided integrally on the upper surface of B.

Each toner replenishing means 300 comprises a toner hopper 310 connected to each developing device by a toner carrying pipe (not shown) and a loading section 330 for mounting the toner cartridge 320 in a horizontal position. The toner replenishing means 300 are arranged adjacent to each other on the same plane in the axial direction of the developing sleeve 141 of the developing device 14. The developing sleeve 141 includes a power source 152 for applying a DC bias and an AC bias set for each color.
The DC bias and the AC bias can be individually turned on / off under the control of the microprocessor 510.

The connection portion between the toner conveying pipe (not shown) and each developing device is released and connected in accordance with the withdrawal and insertion of each developing device. In other words, when the drum cradle 30 is pulled out for jam processing, replacement of the drum cartridge, or the like, the connecting portion between the toner conveying pipe and the developing device does not separate, and the connecting portion separates only when each developing device is taken out. Reductions have been made. Further drum stand 3
When taking out 0, the toner replenishing means 300
The fact that there is no need to separate the device simplifies the configuration of these devices and simplifies the handling operation.

Further, by disposing the toner cartridge 320 and the toner hopper 310 on the same plane, the height of the space occupied by the toner replenishing means 300 can be reduced and the apparatus can be made compact.

As shown in FIG. 1, the image forming apparatus is provided with a recording paper passage detection sensor 70 for detecting the recording paper between the transfer roller 216 and the cleaning device 22.

The transfer roller 216 includes a power source 216E capable of applying a positive or negative transfer bias, and is switched by the control of the microprocessor 510. When the recording paper exists at the transfer portion, the polarity of the bias voltage to the transfer roller 216 is set to the opposite polarity to the polarity of the toner. When the recording paper passes through the transfer roller and the photosensitive drum 10 and the transfer roller 216 come into direct contact with each other at the transfer portion, the polarity of the bias voltage applied to the transfer roller 216 is made the same as the charge polarity of the toner. . When the recording paper is not present at the transfer portion, the polarity of the bias voltage to the transfer roller 216 is set to be the same as the polarity of the toner. By determining the operation of the transfer roller in this manner, when performing continuous image formation, the transfer roller 216 can be quickly cleaned during a period between adjacent recording sheets. Such a control method is also effective when the size of the transfer material in the traveling direction is not known in advance, for example, for manual feeding.

As shown in FIG. 1, the main body 200 is provided with a manual paper feed mechanism 270. The manual paper feed mechanism 270 has an insertion hole 271 into which a recording paper is inserted and a recording paper inserted into the insertion hole 271. A detection member for detecting the paper is provided. The leading end of the inserted recording paper hits the built-in paper feed roller 272 and stops. The recording paper is conveyed by the rotation of the paper feed roller 272, and is conveyed toward the registration rollers 209 via the conveyance path 273. The manual feed mechanism 270 is the main body 2
The shaft is fixed to the shaft at 00 and is slightly movable outward.
Further, a part of the outer member is supported by the shaft, and the insertion hole can be opened.

A paper feed cassette 203 containing a plurality of recording papers in the main body 200 is detachably provided as shown in FIG. A half-moon-shaped paper feed roller 202 for feeding recording paper is provided on the paper feed cassette 203, and the paper feed cassette 2
A push-up plate 204 for pressing the uppermost recording sheet against the separation claw 205 is provided in the inside of the sheet. The recording paper placed on the push-up plate 204 is constantly pushed upward by a spring (not shown), the leading end of the recording paper is locked by the separation claw 205, and the recording paper is fed by the operation of an electromagnetic clutch (not shown). Roller 202
Is driven, and the uppermost sheet of recording paper is separated by the separation claw 205 and fed. The fed recording sheet is driven and conveyed by the intermediate sheet feeding roller 206, and is guided to the registration roller 209. A registration shutter 215 that opens and closes the registration unit according to a control signal from the microprocessor is provided on the downstream side of the registration rollers 209 in the sheet feeding direction. The detection member 219 is operated by the microprocessor 510, and when the detection member 219 detects the recording paper, the recording paper directly enters the registration roller 209 and is stopped by the registration shutter 215. A sensor 189 for detecting the transparency of the recording paper surface is provided upstream of the registration rollers 209 in the paper feed.
Is provided. At that time, the leading end of the recording paper abuts on the upper part of the guide member 213 to a protrusion provided on a part of the transmission sensor 199 rotatably attached to a part of the main body 200.
After the transmission sensor 199 is arranged at a predetermined position along the image forming surface of the recording paper, the transparency of the image forming surface formed on the recording paper is detected.

A detection member for detecting the recording paper is provided above the paper feed cassette 203. Intermediate paper feed roller 20
Reference numeral 6 denotes a sheet cassette 203 and a curved reversing guide member 212.
It is provided between and.

The recording paper guide member 210 is the registration roller 2
The recording paper having passed through the transfer roller 09 is guided toward the transfer roller 216 which can be pressed and separated from the photosensitive drum 10.

The fixing device 220 is a device for fixing the image transferred on the recording paper, and comprises a fixing heating roller 221 and a pressure roller 222. The discharge roller 223 is connected to the fixing device 22.
The recording paper is discharged from 0, and the discharged recording paper is conveyed upward by the conveying roller 224. The recording paper conveyed upward by the conveyance rollers 224 is transferred to the main body 200 by paper discharge rollers 225 provided in a paper discharge passage formed in the main body 200.
The recording surface is discharged onto a discharge tray 210 provided on almost the entire upper surface with the recording surface facing downward. A paper ejection detection sensor 229 is provided in the paper ejection path of the fixing device 220.

The motor 99 drives a paper feed roller 202 and an intermediate paper feed roller 20 via a speed reduction mechanism (not shown).
The driving force is transmitted to 6 via the toothed pulley and the intermediate gear group. The paper feed roller 202 is intermittently driven by an electromagnetic clutch (not shown). On the other hand, the registration roller 209 and the intermediate sheet supply roller 206 are configured to be driven and rotated at all times.

FIG. 3 shows a developing device driving device and a toner replenishing driving device connected thereto, and FIG. 4 is a cross-sectional view showing a connection state of the developing device and the toner carrying pipe.
5 and 6 show the main part of the toner replenishing drive device.

The gear G10 of the motor 79 (see FIG. 7) meshes with the gear G11 and is further coaxial with the gear G11.
The rotation is transmitted to the gear G13 via 12.

As shown in FIG. 3, the gear G13 meshes with a pair of driven gears G14A and G14B, and each of the gears G14A and G14B is a pair of gears G15A.
Alternatively, disks 60A and 60B having G15B as a shaft are provided coaxially and rotatably.

When the gear G10 is rotated in the clockwise direction by the forward rotation of the motor 79 while the one locking claw S1 of the actuator is separated from the notch 61A of the one disk 60A by the action of the solenoid SOL1, the gear G14A is rotated. Rotates counterclockwise, whereby the disk 60A rotates counterclockwise and the gear G15A meshes with the gear G2 shown in FIG. 4 to power the developing device 14 containing the specified magenta developer. To convey. On the other hand, the gear G on the disk 60B is prevented from rotating by the engagement of the other locking claw S2.
15B idles and does not transmit power.

When the motor 79 is switched to the reverse rotation in this state, the rotation of the gear G14A is rotated clockwise, and as a result, the disk 60A is rotated clockwise and the gear G15A is of the developing device 14 containing the yellow developer, for example. It meshes with the gear G2 (see FIG. 4) to transmit power.

On the other hand, by the action of the solenoid SOL1, the other locking claw S2 of the actuator is disengaged from the notch 61B of the other disk 60B and the engagement of the locking claw S2 with the disk 60B is released. The forward rotation, that is, the clockwise rotation of the gear G14B causes the gear G14B to rotate in the counterclockwise direction, and the disk 60B rotates in the counterclockwise direction. (See FIG. 4) meshes with the power of the motor 79 and when the motor 79 is switched to reverse rotation, the disk 60
B rotates clockwise, and as a result, the gear G15B meshes with the gear G2 of the developing device 14 containing the cyan developer, for example, to transmit power. In this case, the locking claw S1 is the disc 60A.
The gear G15A is kept idle by engaging with the notch 61A.

In this way, by switching the rotation direction of the motor 79 and switching the operation of the solenoid SOL1, the developing devices 14 containing the yellow, magenta, cyan and black developers start their developing operations sequentially in accordance with the timing of development. To be done.

The rotation of the gear G25 (see FIG. 5) is transmitted to the gear G26 arranged in the right angle direction through the deflection gear pair 80, and further, as a sun gear 4 via a plurality of intermediate gears G27.
It is transmitted to the individual gears G28 and G28A. Each gear G
28 and G28A are provided with support levers 64 and 64A that freely rotate about their rotation centers as fulcrum restricting means of the planetary gear, and have a protrusion 65 formed at one end and each gear at the other end. A gear G29 that is a planetary gear that meshes with G28 and G28A is provided.

The gear G30 of the motor 89 (see FIG. 7) for toner replenishment control rotates counterclockwise in response to the toner replenishment signal, as shown in FIG.
The gear 33 is driven and rotated in the counterclockwise direction via G32 and G32. The gear 33 meshes with a gear G34 that is axially attached to a support plate 66 that freely rotates about its rotation center as a fulcrum.
As the gear G33 rotates counterclockwise, the gear G34 is rotated leftward to transmit power to the gear G34.

The gear G34 is a cam mechanism shown in FIGS.
As shown in FIG. 6, four cam members 70Y, 70M, 70C and 70K for sequentially changing the phase of the cutout portion by, for example, one-fifth circumference are provided on the coaxial shaft 70 as shown in FIG. The control motor rotates a predetermined number of times according to the color of the toner, and each cam member rotates one fifth. As a result, for example, when a toner replenishment signal is input to the developing device 14 containing a magenta developer, the cam member 70M is rotated by the drive of the motor 89, and the cutout portion 170M faces the protrusion 65 of the support lever 64. As a result, the gear G29 revolves around the gear G28,
The toner is started to be conveyed to the developing device 14 by meshing with a gear G40M provided in the magenta toner conveying screw 121 which is a driven gear. On the other hand, the cam member 7 other than the cam member 70M
No gears 0Y, 70C, and 70K face the protrusions 65 of the respective support levers 64, so that the gears G29 do not mesh with the gears G40Y, 40C, or 40K of the toner conveying screws 121. Therefore, toner is not supplied to the yellow, cyan and black developing devices 14. Thus, the cam member 70
By sequentially switching the phases of the notch portions of Y, 70M, 70C, and 70K, the replenishment of toner to each developing device 14 is alternately performed.

As described above, since the power for toner replenishment is reliably transmitted by the meshing of gears, it is possible to obtain a stable toner replenishment function as compared with the transmission method using the clutch mechanism.

In forming a single color image by the specified developing device 14, the rotation direction of the motor 79 described above is temporarily reversed at the time when a predetermined amount of toner has been replenished so that the gear G18 as shown in FIG. At the same time as setting the neutral state in which none of the gears G19A or G19B is engaged, the solenoid SOL2 is turned off and the locking claw S3 serving as a blocking means is provided in the notch 62A of the support member 62.
When the gear G18 is held in the neutral state, the toner replenishing operation can be interrupted.

Further, the shaft 70 serves as a means for returning to the reference phase, and a spring hooking pin 9 is provided in the groove at the end on the gear G34 side.
0A and a rotation restricting member 90 formed with a protrusion 90B on the peripheral surface portion.
It is equipped with.

The rotation restricting member 90 rotates in the direction opposite to the rotation direction of the shaft 70 by the action of the tension spring 92 stretched between the spring hooking pin 90A and the spring hooking pin 91 on the apparatus main body side. So that the protrusion 90B
By contacting the stopper 93 on the apparatus main body side, rotation is restricted and each cam member is set to the initial position.

The rotation of the gear G30 (see FIG. 3) of the motor 89 causes the shaft 70 to sequentially rotate by a fifth cycle against the tension of the tension spring 92 to replenish each developing device with toner. Then, replenishment of toner to each developing device is completed,
When the gear G30 rotates in the reverse direction, the engagement between the gear G33 and the gear G34 is released, the shaft 70 automatically rotates in the opposite direction by the biasing force of the tension spring, and the protrusion 90B abuts the stopper 93 as shown in FIG. Each cam member is returned to the reference phase again.

Therefore, the rotation angle of each cam member can be accurately set by adjusting the number of rotations of the motor 89 from the angle of the above-mentioned reference phase so as to supply each toner. .

The above is the schematic mechanism of the image forming apparatus according to the present embodiment.

Next, the schematic structure of the engine controller employed in the image forming apparatus of this embodiment will be described with reference to FIG.

FIG. 7 is a block diagram showing the main structure of the engine controller according to the present embodiment.

The engine controller 500 receives page data and print parameters from an external device such as a personal computer, and determines the drive timing of the writing device 230, the scorotron charger 12, the developing device 14, the transfer roller 216, and the cleaning device 22. To control
The paper feeding device 400, the paper feeding cassette 203, and the manual paper feeding mechanism 2
70 controls the paper feed timing of the recording paper from the microprocessor 70, the SRAM 520, and the RA.
M530, a developing device drive system 540, a transfer cleaning drive system 550, a paper feed drive system 560, and the like. The configuration of each part will be described below.

The microprocessor 510 is the SRAM 5
20 executes the sequence program for executing the electrophotographic process using REGIST_PS which is an external signal as a trigger.
The drive state of the 544, 552, 562 and the solenoid SOL1 is controlled, and the passage detection sensors 70, 189, 219,
Based on the detection signal from 229, the conveyance state of the recording paper is controlled, and the purge process corresponding to the recovery process from the jammed state is executed. As described above, the microprocessor 510 switches the polarity of the transfer bias of the transfer roller 216 to adhere the toner or the like adhered to the transfer roller 216 to the photosensitive drum 10. Microprocessor 5
The unit 10 has a function of detecting a color mode input from the operation unit 580.

The microprocessor 510 has an operating section 58.
The recording size is detected from the signal generated by pressing the button for designating the recording paper size set from 0.

The microprocessor 510 is the I / O 590.
It is connected to a print controller such as a personal computer via. The I / O 590 corresponds to the reception detecting means described in the claims.

The microprocessor 510 can also calculate the toner consumption amount from the print information received from a print controller (not shown), the rotation speed of the developing device, and the laser power, and can also calculate the replenishment time from the toner consumption amount. Here, the toner consumption amount is calculated as toner printing rate × developing device rotation rate × laser power rate. The developing device rotation rate is calculated as the developing device rotation number / reference developing device rotation number (1473 rpm). Next, Table 1 shows the relationship between the toner consumption amount and the replenishment time (sec).

[0068]

[Table 1]

The SRAM 520 has a warm-up process, a multi-color print process, a mono-color print process, a letter size print sequence, a postcard size print sequence, a first purge process and a second purge process.
The programs corresponding to the paper feeding process including the purging process, the manual paper feeding process, and the double try sequence are written.

The RAM 530 stores parameters necessary for executing various print sequences.

The developing device drive system 540 controls the gate circuit 541 for selecting the driving state of the driving mechanism of the developing device, the control lines for controlling the driving states of the motor driver 542 and the solenoid SOL1, and the operation of the driving mechanism of the toner replenishing device. It comprises a gate circuit 543 for controlling and a motor driver 544. The gate circuit 541 sends to the motor driver 542 a forward / reverse rotation signal that indicates the rotation direction of the motor 79 and an on / off signal that specifies either rotation or stop, based on the timing signal from the microprocessor 510. is there. The motor driver 542 sends a pulse signal for giving a predetermined rotation speed to the motor 79. Thereby, the motor 7
9 is forward or reverse at a predetermined speed. By turning on / off the solenoid SOL1 in response to a control signal from the microprocessor 510, one of the ends of the regulating member 173 described above comes into contact with the locking claws S1 and S2. The gate circuit 543 sends, to the motor driver 542, a forward / reverse rotation signal for instructing the rotation direction of the motor 89 and an on / off signal for designating either rotation or stop by a timing signal from the microprocessor 510. is there. Further, the microprocessor 510 sends the internal clock CLOCK to the motor driver 544. The motor driver 544 sends a pulse signal that gives a predetermined rotation speed to the motor 89. This allows
The motor 89 will rotate normally or reversely at a predetermined speed.
The motor 89 is 295 rp by the motor driver 544.
Rotate at m-2021 rpm. The setting of the rotation speed is performed by the microprocessor 510.

The transfer cleaning drive system 550 is for instructing the pressing / releasing state of the cleaning blade and the transfer roller 216 to the photosensitive drum 10 in the various sequences described above, and is composed of a gate circuit 551 and a motor driver 552. It is a thing. The transfer cleaning drive system 550 can change the speed and timing of the pressure contact / release operation between the cleaning blade and the transfer roller 216 during continuous printing and during other printing. The gate circuit 570 sends a SAVE signal and an ENABLE signal for controlling the driving state of the motor driver 552 to the motor driver 552 according to the print size and the print sequence. Also, the microprocessor 5
10 is two drive clocks CLOCK from the internal clock
A and CLOACKB are supplied to the motor driver 552. Therefore, the motor driver 552 rotates the motor 59 at a speed according to various sequences. As a result, the transfer / cleaning drive mechanism performs the pressure release operation of the transfer roller 216 and the cleaning blade at a predetermined speed.

The paper feed drive system 560 controls the conveyance speed of the recording paper according to the print size, print mode, etc., and comprises a gate circuit 561 motor driver 562. The gate circuit 561 is the microprocessor 51.
The SAVE signal and the ENABLE signal for controlling the drive state of the motor driver 562 according to the control signal from 0, and the clock signals CLOCKA, CL for giving the drive timing.
OCKB is sent to the motor driver 562. Therefore, the motor driver 562 rotates the motor 99 at a speed according to various sequences. This allows
The recording paper is fed at a speed according to various sequences.

The frequency selector 571 selectively oscillates the oscillating outputs from the toner density sensors L1 to L4 provided in the developing units loaded with the yellow, magenta, cyan, and black developers with a selection signal from the microprocessor 510. It is sent to 572.

The timer counter 572 counts a predetermined number of counts by the trigger signal from the microprocessor 510 and outputs the output signal when the count is completed.
It outputs to the reset terminal of 72.

The frequency counter 573 counts the oscillation frequency of the oscillation output input from the frequency selector 571 by counting the pulses at the predetermined time set by the timer counter 572. The count value is referred to by the microprocessor 510. The microprocessor 510 calculates the toner density from the oscillation frequency and outputs a toner replenishment signal.

The above is the schematic configuration of the engine controller in the present embodiment.

FIG. 9 is a time chart showing the real time mode and the delay mode.

In the real-time mode shown in FIG. 9A, the stirring roller is preliminarily rotated from the time when the driving force of the motor 79 can be transmitted to the stirring roller in order to make the toner concentration in the developing tank uniform. This is a mode in which the sensing operation is performed subsequently to and the toner replenishing operation is performed based on the sensing result. Preliminary rotation is a stirring operation for stabilizing the toner concentration in the developing device when the toner concentration is detected. Such a series of operations is performed within the time when the developing device is continuously driven by the motor 79.

The delay mode shown in FIG. 9B is common in that the stirring roller is preliminarily rotated from the time when the driving force of the motor 79 can be transmitted to the stirring roller, and the sensing operation is performed following the preliminarily rotation. However, the difference is that the toner replenishing operation is executed in parallel with the sensing operation. Such a replenishment operation is not performed based on the sensing operation performed concurrently, but is performed based on the preceding sensing operation. Such a delay mode is adopted to cope with postcard size copy or the like in which toner consumption is intense.

FIG. 8 is a flowchart showing the toner replenishing operation of the image forming apparatus according to this embodiment.

The microprocessor 510 compares the size of the recording paper conveyed by the paper supply mechanism with the reference paper size (step 21). The toner consumption is great when a small-sized original such as a postcard is continuously copied. Therefore, the reference paper size is selected as a size that can identify a small size such as a postcard. If the microprocessor 510 determines in step 21 that the size is smaller than the reference paper size, the microprocessor 510 performs the replenishing operation in the delay mode (step 24).

The microprocessor 510 executes step 21.
If it is determined that the size is larger than the reference paper size, the rotation speed of the drive mechanism of the developing device is compared with the reference rotation speed (step 22). The microprocessor 510 performs step 2
If it is judged from the judgment of No. 2 that it is lower than the reference number of revolutions, the replenishing operation is carried out in the delay mode (step 24).

The microprocessor 510 executes step 2
If it is judged from the judgment of No. 2 that it is higher than the reference number of revolutions, the replenishing operation is carried out in the real mode (step 23).

FIG. 10 is a flow chart showing the process from the L detection sensing to the forced replenishment operation in the present embodiment.

The microprocessor 510 sends a select signal to the frequency selector 571 to output the oscillation output from each of the L detection sensors L1 to L4 in the order of yellow, magenta, cyan and black in the frequency counter 573 and the timer counter 57.
The oscillation frequency is detected at 2 (step 11). Here, it is assumed that the oscillation frequency from the developing device loaded with the yellow developer is detected.

The microprocessor 510 executes step 1
The toner replenishment time is calculated from the oscillation frequency obtained by the sensing operation No. 1 (step 12).

The microprocessor 510 compares the toner supply time in the real time mode shown in FIG. 9 with the toner supply time calculated in step 12 (step 13).

The microprocessor 510 executes step 1
If it is determined that the toner replenishment time calculated in 3 is within the standard replenishment time in the real-time mode, the replenishment operation is executed as it is (step 17).

The microprocessor 510 executes step 1
If it is determined that the toner replenishment time calculated in 3 exceeds the standard replenishment time in the real-time mode, the replenishment time is set to the maximum (step 14) and the replenishment operation is executed (step 15). Steps 14 and 15 are the forced replenishment operation.

The microprocessor 510 executes step 1
When the replenishment operation of No. 5 is completed, it is necessary to execute steps 12 to 13 based on the oscillation output from the L detection sensor provided in the developing device loaded with magenta, cyan and black to perform the forced replenishment operation. It is confirmed whether there is any (step 16).

Microprocessor 510 proceeds to step 16
If it is determined that it is necessary to forcibly replenish another developing device, the replenishment operation is executed (step 15), and if the microprocessor 510 determines in step 16 that there is no other developing device that requires forced replenishment. , This routine ends.

[0093]

According to the first aspect of the present invention, by providing the above configuration, the pre-rotation time is sufficiently secured even in the printing operation of a small size, and the sensing operation is performed in the state where the toner density is stable. To replenish toner.

According to the second aspect of the present invention, by providing the above configuration, the printing rate is high, and therefore the number of copies per unit time is not reduced even during the printing operation.
It is possible to replenish the toner by performing the sensing operation in a state where the toner density is stable by sufficiently securing the time for preliminary rotation.

According to the third aspect of the present invention, by providing the above configuration, it is possible to replenish a proper amount of toner in consideration of the toner replenishment amount and the process condition without being affected by the environmental conditions.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment.

FIG. 2 is a cross-sectional view showing each cartridge according to the embodiment.

FIG. 3 shows a developing device driving device and a toner replenishing driving device connected thereto.

FIG. 4 is a cross-sectional view showing a combined state of a developing device and a toner transport pipe.

FIG. 5 shows a main part of a toner replenishing drive device.

FIG. 6 shows a main part of a toner replenishing drive device.

FIG. 7 is a block diagram showing a main configuration of an engine controller according to the present embodiment.

FIG. 8 is a flowchart showing a toner supply operation of the image forming apparatus according to the present embodiment.

FIG. 9 is a time chart showing a real-time mode and a delay mode.

FIG. 10 is a flowchart showing L detection sensing to forced replenishment operation in the present embodiment.

[Explanation of symbols]

 10 Photoreceptor Drum 14,14A Developing Device 141 Developing Sleeve 30 Drum Stand 40 Drum Cartridge 50,50A Developing Cartridge 300 Toner Replenishing Means 310 Toner Hopper 320 Toner Cartridge 510 Microprocessor 590 I / O L1 to L4 L Detection Sensor

Claims (3)

[Claims] 1. A toner concentration sensor for detecting a toner concentration in a developing device, a toner concentration calculation unit for calculating a toner concentration from an output signal from the toner concentration sensor, and a toner concentration calculated by the toner concentration calculation unit. In an image forming apparatus that replenishes toner to a developing device from a toner replenishing device based on the size detection device, the size of the recording paper is detected, and the toner density in the development device is stabilized based on the detection result of the size detection device. In order to perform a sensing operation for determining the toner replenishment condition based on the output signal from the toner concentration sensor after the preliminary rotation operation for premixing the developer, the toner replenishment for replenishing the toner from the toner replenishing section after the sensing operation is sequentially performed. Real-time mode to execute and preliminary rotation to stir the developer in advance to stabilize the toner concentration in the developing unit After the operation, a sensing operation for determining the toner replenishment condition based on the output signal from the toner concentration sensor is sequentially performed, and in parallel with such a sensing operation, a delay mode for replenishing the toner from the toner replenishing section is executed. An image forming apparatus, comprising: 2. A toner density sensor for detecting a toner density in a developing device, a toner density calculation section for calculating a toner density from an output signal from the toner density sensor, and a toner density calculated by the toner density calculation section. An image forming apparatus that replenishes toner from a toner replenishing means to a developing device based on the size detection means for detecting the size of a recording sheet or the size of an original, and replenishment per unit time based on the detection result of the size detection means. An image forming apparatus comprising a control unit for increasing the amount. 3. A toner density sensor for detecting a toner density in a developing device, a toner density calculation section for calculating a toner density from an output signal from the toner density sensor, and a toner density calculated by the toner density calculation section. In the image forming apparatus that replenishes toner to the developing device based on the toner replenishing means, the reception detecting means for detecting the reception of the toner replenishing data from the print controller and the data for instructing the toner replenishing amount received by the reception detecting means are provided. An image forming apparatus comprising: a control unit that replenishes an appropriate amount of toner from the toner replenishing unit based on the above.