JP2000267441A - Developing device and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of reducing a stress on a user by shortening a time for dissolving the one sided state of replenished developer at a set-up time, or when the developer exceeding a reference quantity is consumed within a unit time. SOLUTION: When the toner is replenished in a state where the storing chamber 122 of a developing unit 120 is empty, the rotating speed of each screw driving motor M1 and M2 is set double for a five minutes. Thus, the rotating speed of each screw 123 and 124 is increased double. Thus, the carrying ability of each screw 123 and 124 for carrying the replenished toner T from the replenishing position to one side in the rotary shaft direction is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device having a developer replenishing function and an image forming apparatus using the same. The technology relates to the technology of transporting along different directions.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
For example, an electrostatic latent image obtained by exposing and scanning the peripheral surface of a photosensitive drum that is driven to rotate is transferred from a developing device to a developer (toner).
Is supplied to form a visible image, and the toner image is transferred to a recording sheet to form an image. The developing device includes a screw disposed in a toner storage chamber and a developing roller disposed opposite to the photosensitive drum, and rotates the screw to stir the toner in the storage chamber in a direction parallel to the developing roller. The toner is spread over the entire area of the developing roller surface in the axial direction corresponding to the image forming width of the photosensitive drum, and the developing roller is rotated to transport the toner to a developing area between the photosensitive drum and the developing roller. (The width in the axial direction of the surface of the developing roller corresponding to the image forming width of the photosensitive drum is hereinafter referred to as “developing width”.)

In particular, in a commercial image forming apparatus,
Since a large amount of images are formed at a high speed, toner runs out frequently. For this reason, the capacity of the storage chamber is formed large so that a large amount (for example, 1 kg) of toner can be stored. In recent years, the developing device has been unitized so as to be detachable from the image forming apparatus so that a user can easily perform maintenance (this unitized developing device is hereinafter referred to as a “developing unit”). The toner can be supplied to the storage chamber of the developing unit via the supply port.

Conventionally, a developing unit is shipped from a factory with toner stored in a storage chamber.
The weight (for example, 1 kg) of the toner in addition to the weight of the developing unit itself is also weighted, so that the weight becomes heavy. As a result,
It was difficult to attach the developing unit to the main body. Further, there is a possibility that the toner may spill from the developing unit during transportation.

Therefore, in recent years, the developing unit has been shipped with the storage chamber empty, and the user mounts the developing unit and the toner supply bottle on the image forming apparatus main body. When the developing unit and the toner supply bottle are mounted, a predetermined amount (for example, one bottle) of toner is supplied from the toner supply bottle to the storage chamber via a supply port provided in the developing unit. The replenished toner accumulates near the replenishing port and is unevenly distributed, so that the toner is corrected by being transported along a direction parallel to the rotation axis of the developing roller while being stirred by the rotation of the screw, The developing roller extends over the entire area from the surface of the developing roller near the supply port to both ends of the developing width.

Note that mounting a developing unit on the image forming apparatus main body and replenishing a predetermined amount of toner from a toner replenishing bottle through a replenishing port to an empty storage chamber of the developing unit is hereinafter referred to as "setup". The time from the start of the setup until the toner spreads over the entire area between both ends of the developing width on the surface of the developing roller, that is, the time from the completion of the setup is hereinafter referred to as “setup time”. After the set-up time has elapsed, an image can be formed in the image forming apparatus. When the setup is completed, the toner supply bottle used at the time of the setup is empty, so that the user replaces the empty toner supply bottle with a new toner supply bottle.

[0007]

However, in the conventional developing device, when replenishing toner, the rotation speed of the screw is always kept constant without considering the toner replenishment state at all. As a result, for example, when 1 kg of toner is replenished at the time of setup as described above, the setup time is required as long as 10 minutes, and there is a problem that a user waiting for the completion of the setup is stressed. Further, when the developer exceeding the reference amount is consumed within a unit time, the amount of toner in the storage chamber is reduced, and uneven development occurs due to the area in the axial direction of the developing roller. The development is stopped until the toner spreads over the entire area between both ends of the developing width on the surface of the developing roller. As a result, the same problem as that at the time of set-up occurs when the developer exceeding the reference amount is consumed within a unit time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it has been found that the bias of the replenished developer is reduced in the case of set-up or when a developer exceeding a reference amount is consumed within a unit time. It is an object of the present invention to provide a developing device capable of shortening the time for solving the problem and reducing the stress given to the user.

[0009]

In order to solve the above-mentioned problems, a developing device according to the present invention supplies a developer supplied to a developer storage chamber through a supply port from a replenishing position to a developing roller. A developing device having a conveying unit that conveys the developer in a direction parallel to a rotation axis, wherein the developer storage chamber is empty, or when a developer exceeding a reference amount is consumed within a unit time. And a control means for controlling the transport means so as to increase the transport ability of the developer in the direction for a predetermined time.

Further, in the developing device according to the present invention,
The transport unit has a rotary transport unit that transports the developer along a direction parallel to the rotation axis by being rotated in a predetermined direction, and the control unit increases a rotation speed of the rotary transport unit. By controlling so that the developer is conveyed, the carrying capacity of the developer is increased.

Further, in the developing device according to the present invention,
A first conveying unit configured to convey the supplied developer from a replenishing position thereof in a direction parallel to the rotation axis;
And conveying means for conveying the developer in a direction opposite to the conveying direction of the first conveying means, wherein the control means controls the conveying direction of the developer by the second conveying means. Is controlled to be the same as the transport direction of the first transport means, thereby increasing the transport capability of the developer.

Further, a developing apparatus according to the present invention is an image forming apparatus for forming an image by supplying a developer to an image on a conveyed sheet via an image carrier or directly, wherein the developer is supplied. The above-mentioned developing device is used as a developing means. In the specification of the present application, “increase the transfer capacity” is used to mean that the amount of the developer passing through a predetermined unit area in a rotation axis direction during a predetermined unit time is increased. .

"Conveying the developer from the replenishing position in a direction parallel to the rotation axis" means that the developer replenishing port is located near the axial center of the developing roller. This is intended to include the case where the sheet is conveyed separately from the replenishing position in the direction of both ends of the rotation shaft of the developing roller.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Hereinafter, an example in which Embodiment 1 of a developing device according to the present invention is applied to a single-color digital copying machine (hereinafter, simply referred to as "copier") will be described. I do.

(Overall Configuration of Copying Machine) FIG. 1 is a diagram showing the overall configuration of the copying machine 1. As shown in FIG.
Is composed of an image reader unit 10 for reading a document image, a printer unit 20 for printing and reproducing the read image on a sheet P, and a control unit 300 for controlling these.

The image reader section 10 reads an image of a document placed on a platen glass by moving a scanner, and reads the read document image via a reading lens by a CCD.
It is a known device that converts the signal into an electric signal by an image line sensor.

This electric signal is supplied to the control unit 300 by A
After the / D conversion, the image data is converted into image data representing an image density of, for example, 8 bits and 256 gradations. The obtained image data is used as a drive signal for the laser diode.

The printer section 20 forms an image by an electrophotographic method, and includes an exposure scanning unit 30 and
It comprises an image forming unit 40, a paper feeding unit 60, a fixing unit 70 and the like.

The exposure scanning unit 30 includes a laser diode (not shown), a polygon mirror, a scanning lens, and the like therein. The laser diode is connected to the control unit 3
Receiving the driving signal output from the laser beam LB
Is emitted. The laser beam LB is deflected by a polygon mirror, and the main scanning speed is made constant by a scanning lens to expose and scan the surface of the photosensitive drum 41 of the image forming unit 40 in the main scanning direction.

The image forming section 40 includes a photosensitive drum 41, a cleaner 42 disposed around the photosensitive drum 41, a static elimination lamp (not shown), a charging brush 44, a developing device 100 of a non-magnetic one-component developer system, and a transfer device. It is composed of a roller 46 and the like. The photosensitive drum 41, the charging brush 44, and the transfer roller 46 have arrows a, a so that the peripheral speed thereof becomes a predetermined system speed.
It is rotationally driven in each of the b and c directions.

The paper feeding section 60 is provided with a recording sheet P of a predetermined size.
Paper cassette 61 for stacking and housing
A half-moon-shaped feeding roller 62 for feeding out the upper recording sheet P one by one, and a timing roller 63 for setting a timing for feeding out the recording sheet P to a transfer position between the photosensitive drum 41 and the transfer charger 46. , Paper feed roller 6
The sheet P fed out by the roller 2 is fed to the timing roller 63.
And a pair of guide members 65 for transporting the recording sheet P fed from the timing roller 63 to the transfer position.

The fixing unit 70 includes a pair of fixing rollers 7.
1 and a discharge roller 72 and the like.
Then, the paper discharge roller 72 is driven to rotate in the directions of arrows d and e, respectively, so that the peripheral speed thereof becomes a predetermined system speed.

Before the photosensitive drum 41 is exposed to the laser beam LB, the residual toner on the surface of the photosensitive member is removed by a cleaner 42 before being irradiated with an eraser lamp (not shown) to eliminate the charge. The photosensitive drum 41 is uniformly charged, and when exposed in such a uniformly charged state, an electrostatic latent image is formed on the photosensitive member on the surface of the photosensitive drum 41. This electrostatic latent image is transferred to the photosensitive drum 41
In the developing area between the developing device 100 and the developing roller 125, the developer (toner) is supplied from the developing device 100 to be visualized as a toner image. The toner image is transferred onto the recording sheet P fed from the sheet feeding unit 60 at the transfer position by applying electrostatic force between the drum and the transfer roller in synchronization with the image forming operation. The recording sheet P on which the toner image has been transferred is conveyed at a system speed to a fixing device 70 via a guide 66, and after the toner is thermally fixed by a fixing roller 71, the recording sheet P is discharged from a discharge roller 72 onto a discharge tray 80. Then, the image formation based on the image data of the document is completed.

An operation panel 90 is provided at an easy-to-operate position on the upper front side of the housing of the image reader section 10, so that the user can set a copy mode such as the number of copies and the copy density, or A copy start instruction can be given.

(Structure of Developing Device Main Body 100) FIG. 2 is a sectional view taken along line AA in FIG. 1, and the structure of the developing device 100 will be described with reference to FIGS. FIG. 1 shows a state in which a new toner supply bottle is installed and toner is being supplied from this bottle after setup is completed, and FIG. 2 shows a state in which toner is supplied during setup. Α, β, and γ indicate changes in the free surface of the toner T from the start of setup to the completion of setup.

As shown in FIGS. 2A and 2B, the developing device 100 includes a toner supply bottle 110 for storing the toner T, and a toner supply bottle 110 disposed below the toner supply bottle 110.
The toner replenishing bottle 110 and the developing unit 120 are configured to be detachable so that the user can easily replace the toner replenishing bottle 110 and the developing unit 120.

A toner supply port 111 is provided near the one end of the toner supply bottle 110. The toner supply bottle 110 is provided on a drive shaft of the toner supply motor M3 with the toner supply port 111 facing upward. Coupler 16
3 is mounted on the copying machine 1.

The developing unit 120 includes a housing 121
And two screws 123 and 124 for stirring and transporting the toner T in the storage chamber 122 formed in the housing 121 in the axial direction, and a developing roller arranged so that a part of the outer peripheral surface is exposed from the housing 121. 125,
A supply roller 126 that is arranged to be in contact with the peripheral surface of the developing roller 125 or with a slight space therebetween to supply toner to the surface of the developing roller 125;
The toner thinning blade 127 having an elastic force in the direction toward the 25-axis, the static elimination sheet 128 disposed immediately below the developing roller 125, and the front end of the storage chamber 122 in FIG. Part) Toner supply port 129 formed at a position above housing 121, thermal fuse 140
The screws 123 and 124, the developing roller 125, and the supply roller 126 are rotatably fixed to the housing 121 in a state parallel to each other.

Couplings 123a, 124a are provided at the inner ends (left side in FIG. 2) of the rotary shafts of the screws 123, 124.
And couplings 161 and 162 are provided on the drive shafts of the screw drive motors M1 and M2 attached to the main body frame of the copying machine 1, respectively. These couplings 123a, 124a and the couplings 161, 162 are engaged with each other when the developing unit 120 is mounted, and the driving force of the screw driving motors M1, M2 is transmitted to the screws 123, 124. In the f direction, the screw 124 is driven to rotate in the direction of the arrow g opposite to the screw 123. The driving force of the screw driving motor M2 is also transmitted to the supply roller 126 and the developing roller 125 via a driving force transmission mechanism (not shown). , Respectively.

The toner supply port 1 of the toner supply bottle 110
11 is set upward as described above, but is rotated downward by the toner supply motor M3 at the time of toner supply, and when the toner supply port 111 and the toner supply port 129 communicate with each other, the toner The rotation of the supply motor M3 is temporarily stopped for a predetermined time. At the time of this stop, the toner T stored in the toner supply bottle 110 is supplied to the storage chamber 122 of the developing unit 120. After a lapse of a predetermined time, the toner supply port 111 is turned upward by the rotation of the toner supply motor M3.

The predetermined time during which the toner supply motor M3 is stopped during one rotation (the predetermined time is hereinafter referred to as "supply time") is at most a maximum in order to prevent the toner T from being clogged in the toner supply port 111. For example, it is set within one second, and 50 g of toner is supplied during this maximum supply time. When toner replenishment exceeding 50 g is required, the toner replenishment motor M3 is rotated several times, and the toner replenishment amount is adjusted by the total replenishment time during this rotation. When toner replenishment of less than 50 g is required, the replenishment time is adjusted to less than one second to adjust the toner replenishment amount. Also, the toner supply bottle 11
On the inner peripheral surface of the toner supply bottle 110, a spiral convex portion indicated by a dotted line in FIG. 1 is formed. So that no toner remains inside.

The toner T supplied to the storage chamber 122 contacts the blades of the screw 124 rotated by the screw drive motor M2, and is stirred from the near side of the storage chamber 122 in FIG. To the side (left side in FIG. 2) in the direction of arrow o, contacts the blades of the screw 123 rotated by the screw drive motor M1, and is agitated from the back side (left side in FIG. 2) to the front side (right side in FIG. 2).
Is transported in the direction of arrow p1. On the front side of the storage chamber 122, the powder pressure of the toner T is lower on the screw 124 side than on the screw 123, so that the toner T is conveyed from top to bottom in the direction of arrow q. Since the pressure is lower on the screw 123 side than on the screw 124, the pressure is conveyed from the bottom to the top in the direction of the arrow r. As a result, the toner T supplied to the storage chamber 122 is stored in the storage chamber 1
It is circulated in 22.

The toner T agitated and conveyed by the screws 123 and 124 is supplied to the screw 124 and the supply roller 12.
6 and the supply roller 126
And the rotation of the developing roller 125, the supply roller 12
6 to the developing roller 125. During this supply,
The toner T is negatively charged by friction with the developing roller 125. The negatively charged toner T is applied to the toner thinning blade 1
27 so that the elastic force of the developing roller 125 with respect to the developing roller 125 and the force of the toner T pushed between the developing roller 125 and the toner thinning blade 127 to push up the toner thinning blade 127 are balanced. A certain amount of the toner layer is applied to the surface of the developing roller 125. Toner T applied on developing roller 125
Is transported to the developing area between the photosensitive drum 41 and the developing roller 125 by the rotation of the developing roller 125.

The surface of the photosensitive drum 41 is uniformly negatively charged by the charging brush 44, and the portion (image area) exposed to the laser beam LB has a charge of "0", and the image area is negatively charged. The so-called reversal development for attaching the toner T is performed. When the toner T is applied, a bias voltage is applied by the control unit 300 so that an electric field is generated from the developing roller 125 toward the photoconductor 41, so that so-called jumping development is performed. The bias voltage has a frequency of 1 to 10 kHz.
z, a voltage difference of 1 to 3 kv, and a DC offset voltage of -100 to -800 v superimposed on an AC voltage of 10 to 90% duty.

The residual toner T on the surface of the developing roller 125 is
The rotation of the developing roller 125 returns to the inside of the developing unit 120, the charge is removed by the charge removing sheet 128, and the charge is temporarily separated from the developing roller 125. Then, after the toner T collected by the rotation of the supply roller 126 and the toner T supplied from the screws 124 and 125 are mixed, the toner T is used again for development.

The rotations of the screw drive motors M1 and M2 and the toner supply motor M3 are appropriately controlled by the control section 300, whereby toner supply from the toner supply bottle 110 to the developing unit 120, agitation and conveyance of the supplied toner, and the like are performed. Is performed.

(Structure of Control Unit 300) FIG.
FIG. 2 is a block diagram showing a configuration of a 00. As shown in the figure, the control unit 300 mainly includes a CPU 310, an image processing unit 320, an image memory 330, a laser diode driving unit 340, a motor driving unit 350, a bias voltage supply unit 360, a temperature fuse, Drive section 370 and ROM 38
0, a RAM 390 and the like.

The image processing section 320 A / D converts an electric signal obtained by scanning the original to generate image data composed of a multi-valued digital signal, and further performs correction processing such as shading correction and edge enhancement processing. After performing a scaling process, an image shift process, an erase process, an image rotation / compression / expansion process, a gradation conversion process, etc. according to a copy mode, image data of a reproduced color is generated and stored in the image memory 330. Output.

The image memory 330 has a storage area for temporarily storing the image data for a plurality of pages, and outputs image data of a necessary page to the laser diode driving section 340.

The laser diode drive section 340 sends a drive signal to the laser diode based on the image data sent from the image memory 330 and drives it to emit a laser beam LB.

The motor drive section 350 drives the screw drive motors M1 and M2, the toner supply motor M3, and the like based on instructions from the CPU 310.

The bias voltage supply section 360 is connected to the CPU 31
Based on the instruction of “0”, a necessary bias voltage is supplied to the developing roller 125 and the like.

The temperature fuse driving section 370 is connected to the CPU 31
Based on the instruction of 0, a predetermined voltage (for example, DC 12 V) is applied between both ends of the thermal fuse 140, and whether or not the thermal fuse 140 is conductive is detected based on whether or not a current flows through the thermal fuse 140. . In addition, the thermal fuse driving unit 370 increases the applied voltage and causes an overcurrent to flow through the thermal fuse 140 to blow the thermal fuse 140.

The ROM 380 stores in advance programs for controlling the respective parts of the copying machine, initial values of control variables, and the like.

The RAM 390 temporarily stores the copy mode set by the operation panel 90 and the current value of the control variable, and provides a work area when the program is executed.

The CPU 310 reads out a necessary program from the ROM 380, controls the operations of the image reader unit 10 and the printer unit 20 in a unified manner while taking timing, and executes a smooth copying operation. In particular, the screw drive motors M1, M
2 to control the rotation speed to shorten the setup time.

(Control Operation in Control Unit 300) FIG.
5 is a flowchart illustrating a main routine of a control operation by a CPU of a control unit. When the power is turned on, the CPU 310 of the control unit 300 executes the initial processing (step S1), starts a routine timer, and performs time management of the main routine (steps S2 and S8). Then, the key input receiving process (step S
3) Original image reading processing (Step S4), paper feeding / image forming processing (Step S5), developer supply processing (Step S4)
6) Other processes (step S7) other than the above are sequentially and repeatedly executed at predetermined time intervals.

In the initial processing of step S1, the CP
U310 initializes the internal registers of the CPU 310,
Initialization of work area of AM390, image memory 330
After the initialization of the printer, a work area such as a copy enable flag 391 indicating whether copying is possible in the RAM 390 and a toner supply flag 392 indicating whether toner is supplied from the toner supply bottle 110 to the developing unit 120 is secured. I do. It should be noted that "1" indicating that copying is possible is set as an initial value in the copy enable flag 391, and "0" indicating no toner supply is set as an initial value in the toner supply flag 392.

In the key input receiving process of step S 3, CPU 310 receives the key input of various keys input from operation panel 90 and stores the set copy mode in RAM 390.

In the original image reading process in step S4, when CPU 310 detects that the copy start key has been operated in step S3, CPU 310 reads the original image in accordance with the copy mode stored in RAM 390, and stores the image data in image memory 330. To be stored.

In the paper feed / image forming process in step S5, when the CPU 310 detects that the copy start key has been operated in step S3, the CPU 310 refers to a copy available flag in the RAM 390, and this flag is "1". Then, the recording sheet P is transported to the transfer position, and the image memory 33
A predetermined image is read from 0 and transferred to the laser diode driving unit 340, and the above-described image forming operation is executed to transfer the toner image to the recording sheet P. This step S
In 5, the CPU 310 instructs the motor driving section 350 in synchronization with the formation of the latent image, and
M2 is driven at a steady speed to develop the latent image.

In the developer replenishment process of step S6, the CPU 310 issues an instruction to the motor drive unit 350 in accordance with the toner replenishment amount, thereby causing the toner replenishment motor M3
Alternatively, the screw drive motors M1 and M2 are driven. Thus, the toner T is supplied from the toner supply bottle 110 to the developing unit 120, and the supplied toner T is agitated and conveyed. Details of this processing will be described later.

In the other processing of step S7,
The CPU 310 controls the temperature in the fixing unit 70 and the like.

Next, the details of the toner supply process will be described. FIG. 5 is a flowchart showing a subroutine of the toner supply process (step S6) shown in FIG. First, the CPU 310 determines whether or not the development unit is set up (step S101). This determination is made by obtaining a detection result as to whether or not the thermal fuse 140 is conductive from the thermal fuse driving unit 370. If the thermal fuse 140 is conductive, the CPU 310 determines that the developing unit is set up, that is, the storage chamber 122 is empty (Y in step S101).
An instruction is issued to the thermal fuse driving unit 370, and the thermal fuse 14
An overcurrent is passed to 0 to blow the thermal fuse 140 (step S102).

When the thermal fuse 140 is blown, CP
In U310, since the toner cannot be supplied from the developing roller 125, the copy enable flag 391 is reset to “0” (step S103), and the toner supply flag 392 for supplying toner from the toner supply bottle 110 is set to “1”. Is set (step S104),
The toner supply time is set (step S105). The toner replenishment time is a time required for replenishing one toner T (for example, 1 kg) contained in the toner replenishment bottle 110 at the time of setting up the developing unit, and more specifically, one second as described above. Since 50 g of toner is supplied, the time required for 1 kg of supply is set to 20 seconds.

The CPU 310 controls the motor drive unit 3
50 is instructed to drive the toner supply motor M3 (step S106), and the toner supply time is decremented with the lapse of time (step S107), and it is determined whether or not the toner supply time has become "0" (step S108). Until the toner supply time becomes “0”, the toner supply motor M3
Is continued (N in step S108), and when the toner supply time reaches “0” (Y in step S108), the drive of the toner supply motor M3 is stopped (step S10).
9). As a result, one toner T stored in the toner supply bottle 110 is stored in the storage chamber 12 of the developing unit 120.
Replenish to 2.

Next, CPU 310 determines whether or not toner supply flag 392 is "1" (step S110).
If it is "1" (Y in step S110), the drive time of the screw drive motors M1 and M2 is set (step S111). The driving time of the screw drive motors M1 and M2 is set such that the toner T1kg contained in the toner supply bottle 110 when the developing unit is set is stirred and conveyed to spread the toner over the entire printing width of the developing roller 125. This is the time required, and specifically, is set to 5 minutes as a result of measurement by the actual machine.

Then, CPU 310 determines whether or not copy enable flag 392 is "0" (step S112).
If it is "0" (Y in step S112), it instructs the motor drive unit 350 to drive the screw drive motors M1 and M2 at double speed (step S113). Thereby, the screws 123 and 124 are driven to rotate at double speed. After the instruction to the motor drive unit 350, the CPU 310 decrements the drive time of the screw drive motors M1 and M2 (step S114), determines whether the drive time has become “0” (step S115), The drive speed of the screw drive motors M1 and M2 is doubled until the drive time reaches "0" (N in step S115). An instruction to stop driving M2 is issued (step S116).

After this instruction, CPU 310 determines whether or not copy enable flag 391 is "0" (step S11).
7) If it is “0” (Y in step S117), since the toner T supplied to the storage chamber 122 has spread over the entire developing width of the developing roller 125, the copy enabled flag 39
"1" is set to 1 (step S118), and the process returns to the main routine of FIG.

Since "1" is set in the copy enable flag 391, the user can start copying. When the setup is completed, the user replaces the empty toner supply bottle 110 with a new toner supply bottle 110 because the toner supply bottle used for the setup is empty. Thus, toner can be supplied from the new toner supply bottle 110.

Next, the above steps S101 to S11
The behavior of the toner T replenished into the storage chamber 122 by the process of No. 8 will be described with reference to FIG. In addition, in order to clarify the difference in effect from the conventional one, the transport amount per unit time when the screws 123 and 124 are rotated at a constant speed is set to the same V1 as the conventional one.
It will be described as.

Before the start of the setup, the toner T is not contained in the storage chamber 122 in the developing unit 120, and the user mounts the empty developing unit 120 and the toner supply bottle 110 in the copying machine 1 body. I do. Thereby, the toner supply bottle 110 is moved from the developing unit 12
0 is supplied with toner to the storage chamber 122,
3, 124 is rotated at double speed to start setup. At this stage, most of the replenished toner T stays near the toner replenishing port 129 (see α in FIG. 2).

In the conventional developing device, the screw 1
The toner T that has come into contact with the blade of the screw 123 is transported in the direction of arrow o at V1 and
Is transported in the direction of arrow p1 at V1. Therefore, the toner T staying in the vicinity of the toner supply port 129 is transported to the back side, the free surface of the toner T reaches the smooth free surface γ via the line β, and the toner T It took 10 minutes to reach the whole area in between.

On the other hand, in the developing device 100 according to the first embodiment, the toner T contacting the blade of the screw 124 is conveyed at 2V1 in the direction of the arrow o, and the toner T contacting the blade of the screw 123. Is transported in the direction of arrow p1 at 2V1. That is, the screw 12
The transport capacity of 3,124 is doubled. As a result, the toner T staying near the toner supply port 129 is removed.
Is transported to the back side, the free surface of which reaches the smooth free surface γ via the line β, and the toner T
It took only 5 minutes, half the time required to reach the entire development width. Therefore, the set-up time is remarkably shortened by the control for increasing the transfer capability of the screws 123 and 124, and the set-up can be performed without the user feeling stress. Further, since the setup time is short, the delay of the start of image formation can be shortened accordingly.

In the control for increasing the transfer capacity of the screw 124, the transfer capacity of the screw 123 is also increased. However, the screw 123 may be rotated at a constant speed. Thereby, the screw 124
Can be relatively further increased, and the setup time can be further reduced.

If the developing unit is not set up in step S101, the CPU 310 proceeds to step S5.
It is determined whether or not the developing process has been executed (step S
121), when the developing process is executed (step S121)
Y), since the toner T has been consumed, the toner consumption is estimated (step S122). This toner consumption is 1
This is performed every time one image is formed, and is estimated by integrating the gradation data for each pixel of this image for one image. When the estimation of the toner T consumption is completed, the CPU 310
Based on the estimated value, a predetermined unit time (for example, 2
It is determined whether or not the toner T exceeding the reference amount (for example, 50 g) has been consumed within (minute) (step S123). The state exceeding the reference amount occurs when an image such as a photograph having many black solid portions is continuously copied. If the amount exceeds the reference amount (Y in step S123), the toner consumption is large, and the free surface of the toner T in the storage chamber 122 becomes γ.
, The toner T needs to be replenished from the toner replenishing bottle 110 by the consumed amount. When the toner T is replenished, the toner T is deposited near the toner replenishing port 129. Therefore, the CPU 310 determines in step S
Proceeding to step 103, the above-described steps S103 to S118 are executed. The toner supply time set in this case (step S105) and the screw drive motor M
The drive times of M1 and M2 (step S111) are set according to the toner supply amount.

Therefore, even when the reference amount is exceeded, the screw drive motors M1 and M2
Since the 3,124 is driven at a double speed, the time for eliminating the bias of the replenished developer can be reduced, the stress applied to the user can be reduced, and the delay in the start of image formation can be reduced by the reduced time. Can be shorter.

If the reference amount is not exceeded in step S123 (N in step S123), the replenished toner T is supplied to the toner replenishing port 129 because the toner T consumption is small.
It will not be deposited nearby. Therefore, the CPU 310
Skips step S103, proceeds to step 104, and roughly executes steps S103 to S118 described above. The toner supply time set in this case (step S105) and the drive time of the screw drive motors M1 and M2 are set according to the toner supply amount. On the other hand, since step S103 is skipped, the toner supply flag 392 is maintained at "1". As a result, the CPU 310 proceeds from step S112 to step S112.
Proceeding to 131, the motor drive unit 350 is instructed to drive the screw drive motors M1 and M2 at a constant speed. For this reason, the carrying capacity of the screws 123 and 124 is not increased. Therefore, similarly to the conventional developing device, the toner T contacting the blade of the screw 124 is transported in the direction of arrow o at V1, and the toner T contacting the blade of the screw 123 is transported in the direction of arrow p1 at V1. And the storage room 122
It is circulated inside.

If the developing process has not been executed in step S121, the toner T is not consumed, and the CPU 310 returns to the main routine via step S110.

(Embodiment 2) Next, a copying machine according to Embodiment 2 of the present invention will be described. In the first embodiment, the screw drive motors M1 and M2 are driven at double speed to set up the screws 123 and 12 in the case of setup or when the toner T exceeding the reference amount is consumed within a unit time.
4 is doubled, but in the second embodiment,
The difference is that the rotation direction of the screw drive motor M1 in these cases is reversed from that in the normal case. Since the configuration of the copying machine 1 and the developing device 100 are the same as those of the first embodiment, only the control specific to the second embodiment will be described below.

That is, instead of the double speed drive in step S113 shown in FIG.
50, the screw drive motor M2 is driven to rotate at a constant speed in the same direction as normal, but the screw drive motor M1 is driven to rotate at a constant speed in the opposite direction to the normal speed. As a result, the screws 123 and 124 are driven to rotate in the same direction, the conveying direction of the toner T of the screw 123 is reversed, and the toner T is conveyed in the same direction as the screw 124. As a result, the ability to transport the toner T is increased.

Next, the behavior of the toner T supplied to the storage chamber 122 by the processing according to the present embodiment will be described with reference to FIG. In addition, in order to clarify the difference in effect from the conventional case, the description will be made assuming that the transport amount per unit time when the screws 123 and 124 rotate at a constant speed is V1 which is the same as the conventional case. In the developing device 100 according to the second embodiment,
The toner T in contact with the blade of the screw 124 is transported in the direction of arrow o at V1, and the toner T in contact with the blade of the screw 123 is transported in the direction of arrow p2 at V1. That is, the carrying capacity of the screws 123 and 124 is increased about 1.5 times. As a result, the toner T staying in the vicinity of the toner supply port 129 is conveyed to the back side, and its free surface reaches the smooth free surface γ via the line β, and the toner T It took about two-thirds of the time it took to reach the entire area, eight minutes.
Therefore, by the above-described control for increasing the transport capacity of the screws 123 and 124, the time for eliminating the bias of the toner T is significantly reduced in the case of setup or when the toner T exceeding the reference amount is consumed within a unit time. Thus, setup and the like can be performed without the user feeling stress, and the delay in starting the image formation can be shortened by the shortened time.

The toner supply time set in this case (step S105) and the screw drive motor M
The drive times of the first and M2 (step S111) are set according to the conveying capacity of the screws 123 and 124 and the toner supply amount, but the drive of the screw drive motors M1 and M2 is continued beyond these set times. Then, storage room 1
22, the powder pressure at the back side of the screw 22 increases, and the torque of the screw drive motors M1 and M2 increases,
The shafts of 23 and 124 may be crushed. Therefore, when these set times elapse, the CPU
310 immediately instructs the motor drive unit 350 to stop driving the screw drive motors M1 and M2.

(Modification) The developing device and the image forming apparatus using the same according to the present invention have been described based on the embodiments. However, the contents of the present invention are not limited to the above embodiments. Of course, the following modified examples are conceivable.

In the first and second embodiments, the screw 1
23, 124, the conveyance speed was increased by changing the rotation speed and the rotation direction of this screw. Instead, a propeller was attached to the rotation shaft at a predetermined interval, and in the case of setup or black solid copy. In this case, the propeller may be changed in angle by a well-known variable propeller angle mechanism to increase the transfer capacity.

In the first and second embodiments, the screws 123, 124 are connected to the screw driving motors M1, M2.
, But may be driven by one motor. In this case, in the second embodiment, the driving force of the motor may be transmitted to the screw 123 via a reverse rotation mechanism such as a gear.

In the first and second embodiments, the toner supply amount is determined by the supply time. However, the toner supply amount may be measured by a measuring roller or the like.

In the first and second embodiments, the non-magnetic one-component developer type developing device is used. However, the magnetic one-component developer type developing device and the two-component developer type developing device are also used. Applicable.

In the first and second embodiments, the toner supply port 129 is provided near the front end of the developing roller 125. However, the toner supply port 129 is provided in other places, for example, near the axial center of the developing roller. May be provided. In this case, the direction of the teeth of the screws 123 and 124 may be changed in the vicinity of the center, and the screws 123 and 124 may be conveyed separately from the replenishment position toward both ends of the rotating shaft of the developing roller.

In the first and second embodiments, the image forming apparatus of the electrophotographic type is used. However, a plurality of needles are arranged in a row in opposition to the developing roller 125, and the The present invention is also applicable to a so-called direct recording type image forming apparatus in which a toner image is formed directly on the recording sheet P by applying a voltage corresponding to the image data to the needle when the recording sheet P passes through the needle.

Further, in the first and second embodiments, the present invention is applied to a digital copying machine. However, the present invention is applied to an image forming apparatus such as an analog copying machine, a printer, a facsimile, a micro reader print, and a multifunction machine thereof. Can also be applied.

[0082]

As described above, according to the developing device of the present invention, the developer replenished into the developer storage chamber via the replenishing port is moved from the replenishing position to the direction parallel to the rotation axis of the developing roller. A developer transporting means for transporting the developer along the direction, wherein when the developer storage chamber is empty, or when a developer exceeding a reference amount is consumed within a unit time, the developer is discharged in the direction for a predetermined time. Control means for controlling the transport means so as to increase the transport capacity of the developer to the
For example, even if 1 kg of toner is replenished at the time of set-up, the set-up time does not take a long time as in the conventional case, and when the developer storage chamber is empty or within a unit time, When the developer in excess of the amount is consumed, the time for eliminating the bias of the supplied developer can be reduced, and the stress applied to the user can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire configuration of a copying machine 1;

FIG. 2 is a cross-sectional view illustrating a configuration of the developing device 100 illustrated in FIG.

FIG. 3 is a block diagram showing a configuration of a control unit 300 shown in FIG.

FIG. 4 is a flowchart showing a main routine of a control operation by a CPU 310 of the control unit 300.

FIG. 5 is a flowchart showing a subroutine of a toner supply process (step S6) shown in FIG.

FIG. 6 is a cross-sectional view illustrating a behavior of a toner T supplied to a storage chamber 122 in the developing device 100 according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier 100 Developing device 110 Toner supply bottle 111 Toner supply port 120 Developing unit 122 Storage chamber 123, 124 Screw 125 Developing roller 129 Toner supply port 300 Control unit 310 CPU T Toner P Recording sheet

Continued on the front page F-term (reference) 2H077 AA33 AB02 AC02 AC04 AD06 AD13 AD17 AD31 AD35 AE04 BA01 CA08 DA16 DB25 EA01 EA13 EA14 EA16

Claims (4)

[Claims] 1. A developing device having a conveying means for conveying developer supplied to a developer storage chamber through a supply port from a replenishing position thereof in a direction parallel to a rotation axis of a developing roller. When the developer storage chamber is empty, or when a developer exceeding a reference amount is consumed within a unit time, the transport is performed so as to increase the transport ability of the developer in the direction for a predetermined time. And a control unit for controlling the unit. 2. The method according to claim 1, wherein the transport unit includes a rotary transport unit configured to transport the developer along a direction parallel to the rotation axis by rotating the shaft in a predetermined direction. The developing device according to claim 1, wherein the developer conveying capacity is increased by controlling the rotational speed of the developer to increase. 3. The transporting means includes: a first transporting means for transporting the supplied developer from a replenishing position thereof in a direction parallel to the rotation axis; and a transporting means for transporting the developer by the first transporting means. A second conveying unit that conveys the developer in a direction opposite to the direction, wherein the control unit reverses a conveying direction of the developer by the second conveying unit and conveys the developer by the first conveying unit. 2. The developing device according to claim 1, wherein the control unit controls the developer to be transported in the same manner as described above, thereby increasing the developer conveyance capacity. 4. An image forming apparatus for supplying a developer via an image carrier or directly onto a conveyed sheet to form an image, wherein the developing means for supplying the developer comprises:
An image forming apparatus using the developing device according to claim 1.