JP2952902B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine and a laser printer, and more particularly to an image forming apparatus with an improved toner supply operation.

[Conventional technology]

Copying machine developers include one-component developers and two-component developers. The two-component developer is composed of a toner and a carrier having different polarities, and the toner as a colorant is adsorbed on the photoreceptor, and the electrostatic latent image on the photoreceptor is visualized. Therefore, the carrier is not consumed, but the toner is always consumed.

In a conventional copying machine, toner is supplied by a toner container, and the toner is supplied to a developing device by a supply unit. Then, the presence or absence of the toner in the toner container is detected, and when the toner runs out, the toner empty lamp is turned on to notify the operator that there is no toner, and to urge the operator to replace the toner container.

[Problems to be solved by the invention]

However, in the conventional copying machine, even if the toner empty lamp is turned on, the copying operation can be performed as it is. If the copying is continuously performed after the toner empty lamp is turned on, the toner density in the developing device gradually decreases. There is a problem in that the image density is reduced and the image density of the copy is reduced. This problem does not directly detect the presence or absence of toner in the toner container, but indirectly detects the presence or absence of toner in the toner container using a toner concentration sensor in the developing tank.
Since there is a time delay from when the toner in the toner container actually runs out to when the toner concentration decreases, the detection of the toner empty is delayed, and this is particularly noticeable when copying is continuously performed after the toner empty lamp is turned on. When the toner container is replaced after the image density becomes low and copying is performed by a normal toner replenishing operation, a time delay until the toner density reaches the predetermined density causes a delay in the first few copies copied during that time. There is a problem that the image density is low and the image quality deteriorates.

The present invention has been made in view of such circumstances, and detects the presence or absence of toner in a toner container and detects the toner concentration in a developing device. When the value is lower than the value, the information is stored, and when the toner container filled with the toner is newly mounted, the toner is continuously replenished based on the stored information until the toner concentration is restored. It is an object of the present invention to provide an image forming apparatus capable of obtaining an image having an appropriate image density even when the toner container is replaced after the density has decreased.

[Means for solving the problem]

The image forming apparatus according to the present invention supplies the toner from the toner container detachably mounted to the main body to the developing unit by the developer supplying unit, and forms the toner on the photoreceptor by the developer containing the supplied toner. In an image forming apparatus for visualizing a latent image, a toner concentration detecting unit for detecting a toner concentration contained in a developer in the developing unit, a unit for detecting the presence or absence of toner in the toner container, and the presence or absence of the toner If the detecting means determines that there is no toner in the toner container, and the detected toner concentration is lower than a predetermined value, the memory stores information indicating that toner replenishment is necessary after toner container replacement. Means for supplying a predetermined amount of toner to the developing means based on the information stored in the storage means when the toner container filled with toner is mounted on the main body. Characterized in that it comprises a means for controlling the developing agent supply means.

[Action]

In the present invention, when the toner in the toner container runs out, it is detected, and in this case, when the toner concentration in the developing unit becomes lower than a predetermined value, information on toner replenishment is generated and stored in the storage unit. You. When the information is stored in the storage unit when a toner container filled with toner is mounted, the developer supply unit is controlled to supply a predetermined amount of toner to the development unit.

As a result, more toner is supplied to the developing device than usual, and the toner concentration in the developing device rapidly increases. Conversely, if the toner in the toner container is empty, but the toner is only the predetermined value in the developing means, the image forming operation can be re-established immediately after the toner container is replaced, without the need to forcibly replenish the toner. It becomes possible.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment.

FIG. 1 is a schematic longitudinal sectional view showing the internal structure of a copier (hereinafter, referred to as the present invention) as an image forming apparatus according to the present invention, and FIG. 2 is a schematic perspective view of the copier showing an attached / detached state of an image forming unit. It is. In the figure, reference numeral 1 denotes a copying machine main body, and a glass platen 15 is provided on the upper surface of the main body 1. The document placed on the document table 15 is scanned by the optical scanning device 10 driven by a scan motor (not shown), and the image is formed on the photosensitive drum 2 as an electrostatic latent image.

The optical scanning device 10 includes an exposure lamp 9, movable mirrors 17, 18a, and 1
8b, a lens 8, and optical systems such as fixed mirrors 19a and 19b. The reflected light from the original which is reflected or transmitted in this order exposes the photosensitive drum 2 at a predetermined exposure position E. In addition, a second lamp equipped with an exposure lamp 9 and movable mirrors 18a and 18b is provided.
The slider is moved in the direction of arrow b by the scan motor. At this time, the first slider moves at twice the speed of the second slider and scans the original. FIG. 1 shows the positions when the first slider and the second slider perform the maximum scanning.

A cover 16 is pivotally supported on the document table 15 at the rear side so as to be vertically rotatable, and the document table 15 is opened and closed by vertically moving the front end. The cover 16 is opened to place a single-leaf or bound book document on the document table 15 with the image facing downward, and then closed to copy the document.

As shown in FIG. 2, a front cover 110 is pivotally supported on the front side of the main body 1 so as to be able to rotate back and forth on the lower surface side, and the main body 1 is opened and closed by moving the upper front part back and forth. The attachment and detachment of the operation unit 40 described later is performed. The power of the main body 1 is turned on and off by opening and closing the cover 110.

The photoconductor drum 2 has a photoconductive layer on the outer peripheral surface, and can be driven to rotate in a counterclockwise direction indicated by an arrow. A charge 5 is disposed above the photosensitive drum 2, and applies a charge of a constant potential to the surface of the photosensitive drum 2.

The peripheral speed V of the photosensitive drum 2 is constant, and the moving speeds of the first slider and the second slider of the optical scanning device 10 are V and V / 2, respectively.

A developing device 4 is provided downstream of the exposure position E of the photosensitive drum 2 in the rotation direction. The developing device 4 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 2 by a magnetic brush method into a toner image. A transfer charger 6 is provided below the photoreceptor drum 2, and the transfer charger 6 applies an electric field to the copy paper P conveyed from a cassette 120 described later from the back surface thereof, and applies the electric field to the developing device 4. The toner image formed on the surface of the photosensitive drum 2 is
Transfer to the top.

A cleaning device 3 is provided in the rotation direction of the photosensitive drum 2 of the transfer charger 6. The cleaning device 3 removes toner remaining on the surface of the photosensitive drum 2 by a blade method. An eraser lamp 7 is provided between the cleaning device 3 and the charger 5.
The eraser lamp 7 removes electric charges remaining on the surface of the photosensitive drum 2 by light irradiation in order to prepare for the next copying process.

Further, the photosensitive drum 2, the eraser lamp 7, the developing device 4, the cleaning device 8, and the charging charger 5 are integrated as an image forming unit 40, and the image forming unit 40 is detachable from the main body 1. In addition, a transport conveyor 12 that transports the developer is disposed facing the opposite side of the photosensitive drum 2 of the developing device 4 in the image forming unit 40. Conveyor 12
Is used to agitate the developer by the rotation thereof and supply it to the developing device 4 of the magnetic brush type.

The developer supply device 11 is provided above the image forming unit 40. The developer supply device 11 supplies a fixed amount of the developer to the conveyor 12. The image forming unit 40 has an E ² PROM for storing information such as toner empty and the number of times of image formation.
(Electrically Erasable & Programmable ROM) 203 is provided, and a toner density and a sensor 13 for detecting the toner density are provided below the conveyor 12. The toner density indicates the composition ratio of the toner and the carrier, and the carrier, which is a magnetic material, is detected by a toner density sensor 13 using a magnetic sensor, and the composition ratio is detected.

Figure 3 is a diagram showing memory content of the E ² PROM, E ² PROM20
3 has an address space of 2 ⁶ (= 3F _H ).
The 00-01 _H to hold the count value of image formation counter which increments for each copy in order to detect the service life of the image forming unit 40, 02 _H for detecting the toner empty the toner concentration at the time of copying a predetermined value or less In the case of, 03 is used to hold the count value of the toner empty counter that counts up.
_H indicates that the toner density is 4% or less when the toner empty flag is set in the area of the toner empty flag, and 04 _H indicates that toner replenishment is necessary after replacement of the toner container 141 described later. Each is used for the area of the toner supply flag. In addition, predetermined data is stored in a specific area at the time of shipment, and whether the image forming unit 40 is used or not can be determined by detecting the data.

As described above, in this embodiment, the image forming counter, the toner empty flag, the toner empty counter, and the toner replenishment flag are stored in the E ² PROM 203 which is a nonvolatile memory provided in the image forming unit 40. 40
Is removed from the main body 1 and the life, the toner empty information and the toner replenishment information are retained without being reset even if the main body 1 is attached again.

FIG. 4 is a perspective view showing the structure of a developer supply container (hereinafter referred to as a toner container), and FIG. 5 is a longitudinal sectional view showing the structure of the developer supply device. In the figure, reference numeral 141 denotes a toner container, which comprises a cylindrical body 142 having one end opened and the other end closed, and a lid 150 detachably provided at an open portion of the cylindrical body 142. Note that the other end of the cylindrical body 142 may be closed with a lid.

The cylindrical body 142 is integrally formed by blow molding using a thermoplastic resin, and a ridge 143 projecting inward is formed in a spiral strip along the inner peripheral surface, and the ridge 143 and the ridge 143 are formed. A spiral groove 144 is formed between them. Further, on the open side of the cylindrical body 142, an opening 146 is formed near the terminal end 145 of the spiral groove 144.
Is provided.

The lid 150 has an inner surface that bulges toward the closed side of the cylindrical body 142, and is provided with a conical restricting portion 151 having an apex on a central axis of the cylindrical body 142. Recess 15
Two are provided. Note that the restricting portion 151 may have a hemispherical or semi-elliptical spherical shape.

The toner container 141 having the above configuration covers the opening 146 of the cylindrical body 142 with a sealing tape or the like (not shown), is loaded with toner, and is sealed with the lid 10. Note that, instead of the toner, a starter, which is a developer including a toner and a magnetic carrier, may be loaded.

Next, in FIG. 5, reference numeral 160 denotes a holding unit of the toner container 141, 170 denotes a conveying unit, and 180 denotes a driving unit.

The holding portion 160 has a cylindrical portion 161 having one end opened, and the inner diameter of the cylindrical portion 161 is slightly larger than the outer shape of the cylindrical body 142. The open side of the cylindrical portion 161 has an inner diameter that is enlarged to serve as the guide portion 16, and a hole 163 is formed at the center of the closed side. The holding section 160 is supported by the transport section 170 in a substantially horizontal state.

The transport section 170 is provided with transport blades 172 on the transport conveyor 12 connected to the developing device 4 as described above, and the transport blades 172 are driven to rotate by a motor (not shown) or the like. Further, a drop port 173 is formed at a connection portion with the holding portion 160. Further, seal members 174, 174 are provided on the inner peripheral surface on the inner side of the cylindrical portion 161 sandwiching the dropout port 173 and the inner peripheral surface on the near side.

The drive section 180 includes a motor 181, and a drive shaft 182 is inserted into a hole 163 of the cylindrical section 161.

In the developer supply device 11 having the above configuration, the toner container
141, the seal tape of the opening 146 is peeled off and the opening 146 is turned upward, and the inside of the cylindrical portion 161 is provided from one end side having the lid 150, and is driven into the engaging recess 152 as shown in FIG. axis
182 are fitted, and are supported by the drive shaft 182 and the cylindrical portion 161.

The toner container 141 supported by the holding unit 160 includes a motor 181.
Is rotated in the direction of arrow c by the rotation of the drive shaft 182 based on the drive of.

Accordingly, the toner in the toner container 141 moves to the lid side along the spiral groove 144. Then, when being carried to a space 143 (hereinafter referred to as “regulation space”) between the regulation portion 151 of the lid 150 and the inner surface of the toner container 141, the space cross-section of the regulation space 143 is reduced toward the opening side. Therefore, the movement of the developer or toner toward the open side is regulated, and the amount of toner reaching the open side end is constant.

When the toner reaches the open side along the spiral groove 144 and the opening 146 is located down with the rotation of the toner container 141, the toner is conveyed to the conveyor 12
Is supplied. That is, the toner is stored in the toner container 141
Is supplied to the conveyer 12 by a fixed amount each time it rotates once. Then, the toner supplied to the conveyor 12 is
The developer is transported to the developing device 4 based on the rotation of the transport blade 172.

On the other hand, in FIG. 1, reference numeral 120 denotes a cassette for storing the copy paper P, which is detachable from the main body 1 and provided with a paper feed roller 31 for feeding out the paper. I have. The paper feed roller 31 is connected to a motor (not shown) provided therein and is driven to rotate. Copy paper P sent out from cassette 120
Is sent to the timing roller 33 via the intermediate roller 32, and is sent out between the photosensitive drum 2 and the transfer charger 6 at a timing by the timing roller 33.

Here, the copy paper P on which the toner image has been transferred is sent to the fixing device 34 via the transport path 22. The fixing device 34 fixes the toner image on the copy paper P by heat. The copy paper P on which the image has been fixed is discharged to the discharge tray 121.

FIG. 6 is a plan view showing an operation panel provided on a front portion of the document table 15. A print key 71 for starting a copying operation is provided at a right corner of the operation panel 790, and a display 72 for the number of copies made up of two 7-segment LEDs is provided at substantially the center.

Numeric keys 80 to 89 arranged on the left side of the print key 71 are mainly used for input setting of the number of copies. Numeral 90 denotes a clear stop key (C / S key) for releasing the numeral and for interrupting copying. The density of the copied image can be continuously set by an exposure volume 92 provided below the display 72. On the left side of the exposure volume 92, an exposure automatic / manual switching key 93 for selecting whether or not to perform automatic exposure, and an LED 9 which is turned on when automatic.
4 are arranged.

Above the automatic / manual switching key 94, an image forming unit replacement display LED 95 for instructing replacement of the image forming unit 40 according to the life (= number of times of image forming) of the image forming unit 40 is provided, and a paper jam or other failure is provided on the left side thereof. A jam / trouble display LED 96 to be displayed is provided. Above that, copy paper P is placed in cassette 120.
A paper empty LED 98 indicating that there is no paper and a toner empty LED 99 indicating that the toner container 141 is empty are arranged, and the left side of the paper jam is divided into two parts, the main body 1 and the cassette 120. Jam indicator 97
Is arranged. In addition, above the print key 71, a copy prohibition LED 10 that indicates a copy prohibition during a trouble, a jam, etc.
0 and a copy waiting display LED 101 for displaying various types of copy waiting are arranged.

FIG. 7 is a block diagram showing the configuration of a control circuit of a copying machine according to the present invention, which is provided with a microcomputer (hereinafter referred to as CPU) 200 for controlling the copying machine. The CPU 200 has a switch matrix 201 composed of keys of the operation panel 70 and switches of various sensors, and a display 7 for the number of copies.
2. LEDs 94 to 101 for various displays are connected. Also,
Drive circuits (not shown) for the main motor 27, a developing motor (not shown), a timing roller clutch, a charger 5, a transfer charger 6, and other devices are connected to an output boat unit for controlling copying operation and operation operation. ing. Further, a chip select terminal CS1, CS2, a serial clock terminal SCK, and a data input / output terminal SI, SO are provided on the main body side, and an E ² PROM 202 for storing various information such as mode information and number information.
And a corresponding terminal of the E ² PROM 203 which stores information indicating the state of the image forming unit 40 provided in the image forming unit 40. Furthermore, a RAM 204 for temporarily storing a control program of the main unit 1 and a flag indicating the state of the main unit 1 is connected.

Next, referring to the flowcharts of FIGS.
The control procedure by 200 will be described. Before describing the flowchart, the terms on-edge and off-edge used therein will be defined.

The on-edge is defined as an on-edge when a state of a switch, a sensor, a signal, or the like changes from an off state to an on state.

The off edge is defined as an off edge when a state of a switch, a sensor, a signal, or the like changes from an on state to an off state.

FIG. 8 is a flowchart of a main flow of the apparatus of the present invention, and the overall schematic operation will be described with reference to this flowchart.

First, when the power is turned on, the reset of the CPU 200 is released and the CPU 200 is initialized (step # 1). Next, E ² PROM 2
Initial settings of 02 and 203 are performed (step # 2). Connection of the initialization and E ² PROM 202, 203 are checked and E ² PROM 202,2
Read out the data stored in 03. When the initial setting of the E ² PROM is completed, the operation mode of the copying machine is set using the data read from the E ² PROM 202, 203 (step # 3). For example, when the imaging unit 40 is not used, E ² PROM
Upon detection of specific data in a predetermined area 202, a developer (starter) set mode is set.

Next, input processing for reading the state of each key, switch, and each sensor on the operation panel 70 connected to the outside of the CPU 200, A / D input processing for reading the level of the analog input terminal of the CPU 200, and CPU 200 Various input / output processes such as an output process for setting the level of the output terminal are performed (step # 4). Next, reading from the E ² PROMs 202 and 203,
A serve routine for the writing process is executed (step # 5). The read / write processing for the E ² PROMs 202 and 203 is performed when it is necessary to read and write the E ² PROMs 202 and 203 for each control program. When this is done, step # 6
Then, an operation panel key input process for determining input of keys on the operation panel 70 and performing control processing for each key is performed.

Next, in step # 7, display data for setting display contents of the display 72 of the operation panel 70 is created. When this is completed, it is checked whether or not a trouble such as a paper jam in the copying machine body 1 or an abnormal temperature of the fixing device 34 has occurred (step #).
8) If a trouble occurs, do not perform the following control.
Wait until the main routine times out. If no trouble has occurred, each device such as the photosensitive drum 2 and the developing device 4 around the image forming unit 40 is controlled. (Step # 9). Incidentally, when this subroutine is determined that the toner supply flag is set in the E ² PROM initial setting subroutine (step # 2), control of the toner supply when the container is exchanged. When this is completed, the toner density is detected, and the toner density control is performed at a predetermined timing of the copy cycle (step # 10). Then, when the toner density during copying becomes low, toner replenishment is performed. A normal toner supply control subroutine to be performed is executed (step # 11).

Next, in step # 12, it is determined whether or not a predetermined time of one loop of the main routine has elapsed, and the process waits until the predetermined time elapses.

Next, among the subroutines, subroutines related to the present invention will be described.

FIG. 9 is a flowchart showing the procedure of the E ² PROM initial setting subroutine of step # 2. First, a read / write test of a predetermined address of the E ² PROM 202 provided in the main body 1 is performed (step # 201), and then the image forming unit 40
A read / write test is performed at a predetermined address of the E ² PROM 203 provided in the program (step # 202). These tests show that E
² Detects whether the connection status of PROMs 202 and 203 is abnormal. Next, data of a second address (for example, the address of the image forming counter) different from the above address of the E ² PROM 202 is read, and an initial check of the E ² PROM 202 is performed based on the content of the data (step # 203). When the E ² PROM 202 is initial, initial data is written to the E ² PROM 202 in step # 204. E ² PROM 202 when not initial
The data of the various modes and flags stored in the RAM 204 are read and written into the RAM 204 (step # 205). Next, the E ² PRO mounted on the imaging unit 40 in the same manner as in step # 203
An initial check of M203 is performed (step # 206).
When the E ² PROM 203 is initial, the E ² PRO
Write initial data to M203. If the E ² PROM 203 is not an initial, information such as the life of the developing device 4 and the toner empty flag stored in the E ² PROM 203 is read and written to the RAM 204 (step # 208).

Then, in step # 209, it is checked whether or not the toner supply flag is set. If the toner supply flag is set, the toner supply mode request flag is set. If not, the process returns to the main routine.

FIG. 10 is a flowchart showing a read / write processing subroutine of the E ² PROM, and includes steps # 501 to # 5.
If there is a data write command in each control program in 03, detect it, write the data, read it again, compare it with the data for writing, and check whether the writing was done correctly .

Next, a control procedure around the image forming unit will be described. FIGS. 11A to 11F are flowcharts showing this subroutine. 1 0 _H to 24 _H in this subroutine
The equipment around the imaging unit is controlled in eight states.

In state = _0H , it is checked whether or not copying can be started by a copy start check subroutine described later.
If so, set the state to _1H , stop the timing roller, and set a timer to turn on the main motor. In the copy start check subroutine, it is determined that the toner supply mode is set. It is set to the state = 20 _H. Perform next state = 1 startup control of _H main motor in performs state = 2 _H in on the transfer charger 6 and the exposure lamp 9, a paper feed permission by the sheet feeding roller 31.

State = 3 sets the confirmation and the toner density check request _H in the sheet feeding, sets the timer for scanning started at State = 4 _H, turns on the charging charger 5 in the state = 5 _H, sets the toner density check flag I do. Then detecting the rear end in the copy sheet fed to the transfer charger 6 in state +6 _H, check the scanning end after timeout in state = 7 _H, turns off the main charger 5. In state = _8H , when the end of scanning is confirmed, the scanning end flag is reset and the exposure lamp 9 is turned off.

Performs copy stop check by copying stop checking subroutine will be described later in the state = 9 _H, when the copying stop, i.e. turns off the exposure lamp 9 when the carry flag is set, when not a copy stop, i.e. carry flag If it has been cleared, it is determined whether or not the scanning has been completed. If it has not been completed, the exposure lamp 9 is turned on, the state returns to _3H , and the next scanning is performed. In State = A _H to D _H performs various stop working. Particularly when state = A _H-optical scanning device 10, is in the home position (FIG. 1 right), state = until the C _H is the main motor stops, the copy start checking the copy start check subroutine shown respectively Figure 12 And constantly monitor the copy operation.

FIGS. 11 (e) and 11 (f) are flowcharts relating to the toner supply mode which is the gist of the present invention. When the start of the toner supply mode is detected, step # 9 of state = _20H is performed.
After the time-up at 01, the toner supply flag on the E ² PROM 203 is cleared (step # 902), and the supply motor 181 is turned on (step # 903). Next, an interval timer is set, the state is incremented by 1 (step # 904), and the routine returns. After the time-up in state = 21 _H At step # 911 (step # 911), sets the toner density check request flag (step # 91
2) Then, set the stirring time by the conveyor 12 and
The state is incremented by 1 (step # 913), and the process returns.

In state = _22H , after time-up (step # 92)
1) It is checked whether the toner low density flag is set (step # 922). If the flag is set, the toner replenishment counter is incremented by one (step # 923). It is checked whether the count value is 31 (step # 924). If the count value is smaller than 31, the state is incremented by 1, the timer for the interval is set (step # 925), and the routine returns. Also, when replenishing number becomes 31 times, it sets a timer (step # 926), clears the toner supply counter (Step # 927), is set to 24 _H state (Step # 928).

On the other hand, if the toner low-density flag is not set in step # 922, the toner empty detection counter of the E ² PROM 203 is cleared (step # 929). Then, it is determined whether the count value of the toner supply counter is 0 or not. That is, it is detected whether or not replenishment has not yet been performed (step # 930).
If no replenishment has been performed (= 0), state =
The process proceeds to step # 942 of 24 _H. Also if supplemented even once returns to step # 926, the process proceeds to the timer and sets the state 24 _H for agitating the supplied toner.

In the next state = 23 _H, performs timer count in the step # 931, until the count-up, step # 933
Turns on the toner supply clutch (not shown) for engaging and disengaging the output of the motor 181 and returns to the main routine. After the time is up, it turns it off in step # 932. Then step # 934
In setting the toner density check request flag, and sets a timer to turn off the toner supply clutch (Step # 935), the state is returned to 22 _H (step # 930),
Return to the main routine.

Advances to state = 24 _H when or toner density toner replenishment becomes 31 times is increased. When the timer expires in step # 941 of this state, the flag is cleared during operation (step # 942), the toner supply request flag is cleared (step # 943), and the SD12 operation is started.
That proceeds to the routine of the machine stops operation of the state = C _H.

As mentioned above has been described, in the state = 20 _H to 24 _H, it is performed to force the toner replenishment. Then, the toner supply and the stirring are repeated a predetermined number of times, or during that time, the toner supply is performed until it is detected that the toner concentration in the developing device 4 becomes higher than a predetermined value. As a result, when the toner empty is detected, the toner concentration becomes 4% or less,
When the toner becomes low in density, open the cover 110 to replace the toner container 141, turn off the power, attach a new toner container 141 containing toner to the developer supply device 11, close the cover 110, and turn on the power. Then, a predetermined amount of toner is replenished in these states or the toner is replenished until a predetermined density is reached.
Even at the time of the first copy after replacement, low-density copying is not performed, and erroneous copying can be prevented.

Then the above state = 0 _H, State A _H, described copy start check subroutine performed by the C _H. In the copy start check subroutine shown in FIG. 12, first, the copy start flag is checked in step # 951, and if the copy start flag is set, the state is set to 1 _H (step # 952). From the next state starts at _1H . Next, the in-operation flag is set (step # 953), the carry flag used for branch determination is set (step # 954), and the process returns.

If the copy start flag is not set in step # 951, it is checked whether warming up is in progress (step # 955). If warming up is in progress, operation is not performed to protect the fixing device 34. If not, it is checked whether the toner supply mode request has been set, that is, whether the toner supply set flag has been set and whether there has been a toner supply mode operation request (step # 956).
If the toner supply mode request flag is not set, the carry flag is cleared (step # 957),
Return to the main routine. Also, when the toner supply mode request flag is set, the state 20 _H so as to perform the toner replenishing mode from the state = 20 _H as described above
(Step # 958), and then proceed to Step # 953.

The toner replenishment mode request flag is a toner replenishment flag that is set when the toner density is 4% or less when a toner empty is detected in step # 1020 of a toner density detection control subroutine (step # 10) described later. It is determined in step # 209 of the E ² PROM initial setting subroutine (step # 2) when the power is turned on.
The flag is set in step # 210 to check for and forcibly replenish the toner. That is, when the toner concentration is 4% or less when the toner empty is detected, which is the gist of the present invention, the toner can be forcibly supplied at the next power-on after the toner container 141 is replaced. I have.

Next, the copy stop check subroutine shown in FIG. 13 will be described. First, it is checked in step # 961 whether or not the copy start flag is set. If not, the copying operation must be stopped. Therefore, the operation flag is cleared (step # 962), and the carry flag is set. Is set (step # 963) and the routine returns to the original routine. If the copy start flag is set, the carry flag is cleared to return to the original routine in order to continue the copy operation. Here, the carry flag is used as an index for determining copy continuation / stop in the original routine.

Next, the toner concentration detection control subroutine in step # 10 of the main routine will be described. FIG. 14 is a flow chart of this subroutine. In normal copying, the toner density in the developing device 4 is detected, and an index for controlling the internal toner density to be constant is obtained. Here, control is performed separately for states 0 and 1, preparation for detection is performed in state 0, and detection of an experiment is performed in state 1.

First, a state branch check is performed in step # 1001, and when the state is 0, whether or not a toner density check request is made is detected by setting a toner density check request flag (step # 1002), and a request is made. If not, the process returns to the main routine without doing anything. If a request has been made, step # 1003
Clears the toner density check request flag.
Subsequently, in step # 1004, the value of the 6% detection counter which is a normal density is set to 8, and in step # 1005, the value of the 4% detection counter indicating that the toner density is too low is set to 8, and in step # 1006 To set the value of the detection counter to 16. The 6% or 4% detection counter is a counter which is decremented every time the toner density is detected to be low when the toner density is detected in the next state 1, and when it is finally set to 0. It is determined that the toner density is low overall. The detection number counter is a counter indicating the number of times the toner density level is determined, and is decremented each time the level is determined. When the detection number counter becomes 0, that is, when the toner density is detected 16 times, it is determined whether the 6% or 4% detection counter is 0, that is, when the toner density is lower than 8 times. It is determined whether or not the toner density is low depending on whether or not the determination is made. When the setting of these counters is completed, the process proceeds to the next state, so that the state is incremented by 1 (step # 1007).

In the state 1, first, the detection number counter is decremented by 1 and it is determined whether or not the result is 0 (step # 100).
8) If the number-of-times-of-detection counter is not 0, that is, if 16 detections have not been completed, the flow proceeds to the toner density check subroutine of step # 1022. Detection counter is 0
In other words, when the toner density is detected 16 times, it is checked whether the 6% detection counter is 0, that is, whether the toner density is low (step # 1009). The detection counter is 0
, That is, when the density is low, the toner low density flag is set (step # 1010). If it is not 0, that is, if the toner density is high, the process proceeds to step # 1016, where the toner empty detection counter is set to 0, and the E ² PROM 203
The count value is written into (step # 1017).

On the other hand, if the toner low density flag is set in step # 1010, it is next determined whether or not the toner supply mode is set by the toner supply mode request flag (step # 101).
1) If the mode is not the toner supply mode, the number of toner supply is set (step # 1012), and the toner empty detection counter is counted up (step # 1013). The toner empty detection counter is a counter for detecting whether or not the toner is empty. When the toner density is lower than 6% and 15 copies are continuously performed, it is determined that the toner is empty. Next, in step # 1014, it is determined whether or not the counted value of the counted-up toner empty detection counter is larger than 15, and if it is larger, it is determined that the toner is empty, and a toner empty flag is set (step # 1015). Steps # 1016 to # 1017 described above are performed.

On the other hand, if the mode is the toner supply mode in step # 1011, the process proceeds to step # 1021. If the count value of the toner empty detection counter is smaller than 15 in step # 1014, no processing is performed, and the process proceeds to step # 1017.

When the value of the toner empty detection counter is written to the E ² PROM 203 in step # 1017, it is determined whether the toner empty flag is set (step # 1018). It is checked whether the value is 0, that is, whether the toner density is 4% or less (step # 1019). If the toner density is 4% or less,
The toner supply flag is set (step # 1020), the state is returned to 0 (step # 1021), the process ends, and the process returns to the main routine. This setting of the toner supply flag is used to determine the forced supply of toner when the power is turned on. If the toner empty flag is not set in step # 1018, or if the toner density is 4% or more in step # 1019, the process skips to step # 1012.

Next, the toner concentration check subroutine shown in FIG. 15 will be described. In this subroutine, it is determined whether the toner density is lower than 6% or 4% based on whether the output voltage from the toner density sensor 13 is higher than a predetermined threshold. Since the output voltage of the toner density sensor decreases as the toner density increases, when the detected output voltage is higher than the first threshold value, the toner density is determined to be 6% or less, and the first
When it is higher than the second threshold, which is higher than the threshold, it is determined to be 4% or less. First, in step # 1023, it is checked whether or not the toner density is 6% or less. If the toner density is more than 6%, the process returns to the main routine without doing anything. If it is less than 6%, it is checked whether the value of the 6% detection counter is 0 (step # 102).
4) If not 0, that is, if it is not determined to be 6% or less, the value of the 6% detection counter is decremented by 1 (step # 1025). If the value is 0, that is, if it is determined that it is 8% or more and 6% or less, step # 1025 is skipped because it is determined to be 6% or less. Then step # 10
At 26, it is checked whether the toner density is 4% or less, and if it is more than 4%, nothing is returned, and if it is 4% or less, it is checked whether the value of the 4% detection counter is 0 (step #). 1027). If it is not 0, that is, if it is not determined to be 4% or less, the value of the 4% counter is decremented by 1 (step # 1027), and the process returns to the main routine and returns to 0.
, Ie, when it is determined to be 4% or less, step #
Skip 1028 and return to the main routine.

Next, the toner supply control subroutine (step # 11) shown in FIG. 16 will be described. This subroutine controls the normal toner reinforcing operation during the copying operation. When the toner replenishing condition is satisfied, the toner replenishing operation and the stirring operation of the replenished toner are repeated a predetermined number of times.

First, it is checked in step # 1101 whether or not the toner supply mode is requested. If the toner supply mode request flag is set, this subroutine does not perform the toner supply operation and returns to the main routine. If not, the routine proceeds to the next step # 1102 to perform normal tonneau replenishment, and checks the state of the control state. If the state is 0, it is checked in step # 1103 whether or not the number of toner replenishments has been set, and if it has been set, the process proceeds to step # 1104.
To turn on the toner supply clutch. Then, a supply timer is set, the state is incremented by 1 (step # 1105), and the process returns to the main routine. If the toner supply count is not set, the process returns without performing any processing.

If the state is 1, no processing is performed until the time is up. After the time is up (step # 1106), the toner supply clutch is turned off (step # 1107), and a timer for stirring is set (step # 1108). Increment by 1 (step # 1109) and return.

In the next state = 2, no processing is performed until the time is up. After the time is up (step # 1110), the number of times of replenishment is decremented by 1 (step # 1111), and the state is set to 0.
(Step # 1112), and the routine returns.

In this embodiment, the presence or absence of the toner in the container, that is, the toner empty is indirectly determined by the output of the toner density sensor, but the present invention is not limited to this.
It goes without saying that the toner empty may be detected by directly monitoring the toner supply from the container or by other means of measuring the weight of the container.

Further, in this embodiment, the necessity of the toner replenishing operation at the time of replacing the toner container is determined based on the toner replenishment flag. However, the present invention is not limited to this, and the toner empty flag and the toner density are 4% or less. May be stored in the E ² PROM as storage means, and whether or not the toner supply operation is necessary may be determined by setting and resetting the flags.

Further, in this embodiment, when the power is turned on by closing the cover, the replacement of the toner container is detected, and the toner replenishing operation is checked, but the present invention is not limited to this.
It goes without saying that the toner supply operation may be checked by directly detecting the replacement of the toner container.

〔effect〕

As described above, in the present invention, when the toner concentration in the developing unit is low (for example, 4% or less) when there is no toner in the toner container, a toner supply flag which is information of toner supply is set. This is stored in the storage means, and when the toner container is replaced, the toner is quickly replenished based on the toner replenishment flag, so that an image having an appropriate density can be obtained from the beginning of the replacement. Even when there is no toner in the toner container, toner is present in the developing means, and when forced toner replenishment is not necessary, an excellent effect is obtained such that image formation can be resumed immediately.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing the structure of a copying machine which is an image forming apparatus according to the present invention, FIG. 2 is a schematic perspective view of the copying machine showing an attached / detached state of an image forming unit, and FIG. In the unit
FIG. 4 is a diagram showing the contents of the memory of the E ² PROM, FIG. 4 is a perspective view showing the structure of the developer supply container, FIG. 5 is a longitudinal sectional view showing the structure of the developer supply device, and FIG. Fig. 7
The figure is a block diagram showing the configuration of the control circuit.
5 is a flowchart illustrating a control procedure of a copying operation by a CPU. DESCRIPTION OF SYMBOLS 1 ... Copier main body, 2 ... Photoconductor, 4 ... Developing device, 11
... developer supply device, 13 ... toner concentration sensor, 40 ...
Image forming unit, 141: developer supply container, 200: CPU, 2
03 …… E ² PROM

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tsuneo Kitagawa Osaka International Building Minolta Camera Co., Ltd. 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka (56) References JP-A-63-212970 (JP, A) JP-A-62-105172 (JP, A) JP-A-62-78579 (JP, A) JP-A-54-96047 (JP, A) Fully open 63-101949 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) G03G 15/08

Claims (1)

(57) [Claims] A developer supply means for supplying toner from a toner container detachably mounted to the main body to the developing means, and developing the latent image formed on the photoreceptor by the developer containing the supplied toner; In the image forming apparatus for forming an image, a toner concentration detecting unit for detecting a toner concentration contained in a developer in the developing unit; a unit for detecting the presence or absence of toner in the toner container; and a unit for detecting the presence or absence of the toner A storage unit for storing information indicating that toner replenishment is necessary after replacing the toner container when the detected toner concentration is lower than a predetermined value when it is determined that there is no toner in the toner container; When the toner container filled with the toner is mounted on the main body, the developer supply unit supplies a predetermined amount of toner to the developing unit based on the information stored in the storage unit. An image forming apparatus comprising: means for controlling a feeding means.