JP2914513B2 - Toner density control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner density control device for controlling a toner density of a developing device for visualizing an electrostatic latent image.

[Conventional technology]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine that develops an electrostatic latent image formed on a photoreceptor with a toner, in order to maintain a proper toner density, when the toner density in a tank of the developing apparatus falls below a certain control level. The toner is supplied from the hopper 371 to the tank 373 (see FIG. 3). In such an image forming apparatus, for example, in a case where a document is continuously copied, the developed image may be thinned because the toner supply amount cannot keep up with the toner consumption amount.

For this reason, a second control level is set between the control level and the empty level, and when the toner density falls below the second control level, the copying operation is temporarily stopped to supply toner, and the toner density is reduced to a certain level. A toner density control device has been proposed in which the copying operation is restarted after the toner concentration is recovered (see JP-A-62-105173 and JP-A-Hei.
-156782).

[Problems to be solved by the invention]

However, in the above-described toner density control device, it takes a long time after the copying operation is stopped to recover to the predetermined level, and the copying operation is stopped for a long time. In other words, when continuous copying is performed at intervals of several seconds in a case where the toner consumption is large, such as continuous copying of a document having a large black solid area, the user may stop for several tens of seconds to several minutes. May cause anxiety. On the other hand, when the amount of toner remaining in the hopper 371 becomes small, the amount of toner supplied to the tank 373 decreases. In this case, it is necessary to notify the user at an early stage that the toner needs to be supplied to the hopper 371, and to prevent continuous copying at a low density for a long time.

SUMMARY OF THE INVENTION The present invention solves the above-described problems, and provides a toner density control device that shortens a stop time for recovering toner density when performing continuous printing and that prevents continuous printing at a low density for a long time. The purpose is to provide.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, in an image forming apparatus in which continuous recording is performed while toner is supplied while a detected toner density is between a control level and an empty level, setting switching to a high consumption mode is performed. Mode setting means for performing, a rest level setting means for setting a rest level between the control level and the empty level, a first density discriminating means for discriminating whether the toner density is equal to or less than the rest level, and recording. A recording operation pausing unit for pausing the recording operation for a preset time each time one sheet is completed; and a recording operation pausing unit when the toner density changes below the pause level when the multi-consumption mode is set. Control means for setting a detection level between the halt level and the empty level; and a detection level setting means for setting a detection level between the pause level and the empty level. A second density discriminating means for discriminating whether or not the toner density is equal to or lower than the detection level, and a display means for displaying an empty display when the toner density changes below the detection level when the multi-consumption mode is set. It is a thing.

In addition, a stopping means for stopping the recording operation when the toner density changes below the detection level is provided.

Furthermore, the present invention further comprises a canceling unit for canceling the driving of the recording operation suspending unit if the toner density does not change to the suspending level or more during the driving of the recording operation suspending unit.

According to a fourth aspect of the present invention, a third density determining means for determining that the toner density is equal to or higher than the control level, and the recording operation halt means when the toner density becomes equal to or higher than the control level while the printing operation halt means is being driven. And second release means for releasing the drive of the motor.

According to a fifth aspect of the present invention, the mode setting means includes a consumption detecting means for calculating a toner consumption per sheet, a consumption determining means for determining that the toner consumption is equal to or larger than a predetermined amount, Switching means for switching the setting to the multi-consumption mode when the toner consumption is equal to or greater than a preset amount.

Further, according to the present invention, the pause time for changing the pause time of the recording operation based on the obtained toner consumption amount per sheet and the toner supply amount per time so as to match the toner consumption amount and the toner supply amount. Change means were provided.

[Action]

According to the toner density control device having the above configuration, when the multi-consumption mode is set and the toner density changes below the pause level set between the control level and the empty level, the recording operation is paused for a preset time, After the elapse of the above time, the recording operation is restarted. This pause of the recording operation is recording 1
It is carried out every time a sheet is finished. When the multi-consumption mode is set and the toner density changes below the detection level set between the pause level and the empty level, an empty display is performed.

Further, according to the toner density control device of the second aspect, when the toner density changes below the detection level, the recording operation is stopped.

Furthermore, according to the toner density control device of the third aspect, if the toner concentration does not change to a level higher than the pause level while the recording operation is suspended every time one recording is completed, the suspension of the recording operation is released, Normal recording is performed.

Further, according to the toner density control device of the present invention, if the toner concentration becomes equal to or higher than the control level while the recording operation is suspended every time one recording is completed, the suspension of the recording operation is canceled and the normal operation is stopped. A record is made.

Furthermore, according to the toner concentration control device of the fifth aspect,
The toner consumption per sheet is obtained, and if the toner consumption is equal to or greater than a preset amount, the setting is automatically switched to the multi-consumption mode.

Further, according to the toner density control device of the present invention, the idle time can be changed based on the toner consumption amount per sheet and the toner supply amount per time so that the toner consumption amount and the toner supply amount coincide. . That is, when the toner consumption is large, the pause time is changed to be longer, and when the toner consumption is small, the pause time is changed to be shorter.

〔Example〕

FIG. 2 is a configuration diagram of a digital copying machine (image forming apparatus) to which the toner density control device according to the present invention is applied.

The copying machine 21 has a contact glass 22 and a document holder 23 on its upper surface, and has an optical mechanism L and an image forming means P inside.

The optical mechanism L includes a light source including a halogen lamp 24 and a reflection plate 25, reflection mirrors 26, 27, and 28, a lens unit 29, and a solid-state imaging device (hereinafter, referred to as a CCD) 30. And
When the recording (copy) operation is started, the light from the light source is reflected by the original placed on the contact glass 22, and the reflected light is guided to the lens unit 29 via the reflecting mirrors 26.27 and 28. Later, it is read by CCD30.

The image forming means P includes a laser generator 31 and a polygon mirror.
32, reflector 33, photoconductor 34, charging device 35, blank lamp
36, a developing device 37, a transfer device 38, a separating device 39, a cleaning device 40, and the like. Then, laser light corresponding to the read original is emitted from the laser generator 31.
On the other hand, the surface of the photoreceptor 34 is uniformly charged by the charging device 35, is exposed to the laser light passing through the polygon mirror 32 and the reflection mirror 33, and an electrostatic latent image is formed. Thereafter, the electrostatic latent image developed with the toner by the developing device 37 is transferred to the transfer device.
After being transferred to the paper by 38, the photoreceptor is
Separated from 34.

Further, as a paper feeding mechanism, a paper feeding cassette 41, a paper feeding roller 42, and a registration roller pair 43 are arranged in this order from the upstream in the feeding direction, whereby the paper is fed to the photoconductor 34, and the transfer is performed. Done. A transport belt 44, a fixing device 45, a discharge roller 46, a discharge tray 47, and the like are provided as a fixing and discharging mechanism for the sheet after the transfer. Note that an automatic document feeder (not shown) may be provided to automatically and sequentially feed a plurality of documents between the contact glass 22 and the document holder 23.

Next, a configuration example of the developing device 37 will be described with reference to FIG.

The hopper 371 stores toner. The supply roller 372 supplies toner from the hopper 371 to the tank 373. The stirring rollers 374 and 375 stir and mix the toner and the carrier in the tank 373 and frictionally charge the toner. The developing roller 376 supplies toner to the photoconductor.

Then, the frictionally charged toner is supplied to the photoconductor, and the electrostatic latent image on the photoconductor is developed with the toner. Also,
The hopper 371 can be appropriately replenished with toner.

Subsequently, a block configuration showing an example of the control system will be described with reference to FIG.

The toner density sensor 1 is provided at an appropriate position around the stirring roller 375 (see FIG. 3), detects the toner density, and outputs a voltage corresponding to the toner density to a central control unit (hereinafter referred to as CPU) 11.
Is output to Note that the voltage from the toner density sensor 1 (hereinafter, referred to as a sensor voltage) decreases as the toner density increases and increases as the toner density decreases. The operation unit 2 starts copying,
This is for setting the mode, setting the magnification, setting the number of copies, and the like. Further, the operation unit 2 has a display area in which an empty signal is received from the CPU 11 and an empty display is performed. The AD converter 3 converts an image signal from the CCD 30 into a digital signal and outputs the digital signal to the image memory 4. The image memory 4 stores the digital signal and outputs the stored content to the CPU 11.

The optical system motor 5 drives the light source of the optical mechanism L and the reflecting mirrors 26, 27, 28 and the like in accordance with a control signal from the CPU 11. The toner supply motor 6 drives the supply roller 372 in response to a control signal from the CPU 11. The toner stirring motor 7 is driven by a stirring roller 374,3 in response to a control signal from the CPU 11.
It drives 75. The paper feed roller motor 8 is connected to the CPU 11
The sheet feed roller 42 and the pair of registration rollers 43 are driven in response to a control signal from the CPU. In addition, the above-mentioned motor 5
Instead of 8, the driving force may be transmitted from the main motor by a clutch.

The RAM 9 and the ROM 10 store a processing program and processing contents of the CPU 11 and other sensor voltages set in advance. That is, the ROM 10 has a sensor voltage V _C corresponding to a toner density at a control level at which a copy operation can be performed without supplying toner, a sensor voltage V ₂ at an empty level at which a copy operation cannot be performed, and a ROM between the control level and the empty level. made copy operation there to store each time the predetermined time t _X only sensor voltage V ₁ of the quiescent level to pause _{(V C <V 1 <V} 2) and the paper said predetermined time determined by size t _X ing. Also, the ROM 10 displays V ₃ (V ₁ <V ₃ <) for displaying an empty display when the multi-consumption mode is selected.
V ₂ ) and the sensor voltage V ₄ (V ₄ = V ₂ or V ₄ = V ₃ may be stored) that causes the empty display to be performed when the high-consumption mode is not selected, that is, in the normal mode. It has been made to be.

The CPU 11 controls the motors 5 to 8 (ON / OFF of the clutches when a clutch is provided instead of the motors 5 to 8), and performs a scaling process on the image signal read by the CCD 30 as necessary. Then, the laser generator 31 irradiates a laser beam corresponding to the image signal after the scaling process. Further, CPU 11 along with (or when the clutch is provided the clutch instead of the motor 7) for driving the stirring roller 374 and 375 outputs a control signal to the toner stirring motor 7, the sensor voltage is equal to or higher than the voltage V _C A control signal is output to the toner supply motor 6 (or a clutch when a clutch is provided instead of the motor 6) to drive the supply roller 372.

Further, the CPU 11 determines whether the sensor voltage is the voltage V ₁ , V _C or V ₃
The function of determining whether or not the above is the case, the function of suspending the copy operation for the time t _{X at the} end of each copy operation during continuous copy, and the manual instruction from the operation unit 2
Or when automatic sensor voltage when the multi-consumption mode is set will be voltages V ₁ or more based on the later-described pre-scan, functions to provide a dwell time as discussed above, when the sensor voltage is below the voltage V _C, When function and sensor voltage to release the pause time is less than the voltage V _3, and has a function to perform the empty display. Further, CPU 11 detects the paper size has a function of setting the t _X time by the paper size detecting sensor (not shown) provided around the sheet feed cassette 41.

Next, a first embodiment of the toner density control according to the above configuration will be described with reference to the flowchart of FIG.

In the first embodiment, the switching setting to the multi-consumption mode is manually performed by the operation unit 2.

First, the number of copies is set by the operation unit 2 (or a plurality of documents are set in the automatic document feeder).
When continuous recording (copy) is started, the sensor voltage V in step S ₁ is whether the following voltage V _C, namely whether the optimum toner density or higher is determined. Then, the sensor voltage V is less than or equal to the voltage V _C (YES in Step S _1),
The toner supply motor 6
(When the clutch instead of the motor 6 is provided with the clutch) without toner supply by driving the is performed, recorded as normal mode in step S ₂ (copies)
The operation is performed. That is, the original is read and the photoconductor
After the electrostatic latent image is formed on the developing device 37, the electrostatic latent image is
And the toner is transferred to a sheet, and the transfer sheet is fixed and discharged. Subsequently, step whether a copy of the number of copies set by the S ₃ is completed is determined, the copy setting number of sheets has been completed (step S
₍ YES in ₃ ), the process of this flowchart ends.

On the other hand, NO> in step S ₃ that remains number to be copied in (step S _3, it is determined whether the sensor voltage V is less than or equal to the voltage V _C returns to step S ₁ again. Then, Step S ₁ in the sensor voltage V is equal to or higher than the voltage V _C (NO in step S _1), whether it is set to the multi-consumption mode is determined by the operation unit 2 in step S ₄ because it is less toner concentration optimum. at this time, if it is not set in multiple consumption mode (NO in step S _4), the sensor voltage V is whether the voltage V ₄ or less is determined in step S _5.

Then, the sensor voltage V is the voltage V ₄ or less (YES in step S _5), while performing the toner replenishment by the driving of the toner supply motor 6 (or clutch) at Step S ₆ to maintain the toner concentration, the step S ₂ And the copy operation is performed. Then whether a copy of the set number of sheets in step S ₃ is completed is judged, when there remains a number to be copied back to step S _1.

On the other hand, a sensor voltage V in step S ₅ is the voltage V ₄ or more (NO in step S _5), the toner empty display (hereinafter, referred to as empty display) in step S ₇ is carried out, and the continuous copying in step S ₈ The mode is prohibited and the mode is switched to the single copy mode, so that the copy operation as the single copy can be continued (step S ₂ ). Whether copy setting number of sheets in step S ₃ after this has been completed is determined, if there remains a number to be copied back to step S _1.

On the other hand, that it is set to the multi-consumption mode in step S ₄ (YES in step S _4), i.e., the toner consumption per one sheet in the multi-consumption mode, for example, since pre greater than or equal to the specified amount, first, step sensor voltage V in S ₉ is discriminated whether voltages V ₁ or less, (YES in step S ₉₎ and the sensor voltage V is voltages V ₁ or less, the toner replenishment in step S ₁₀ to maintain the toner density while performing toner supply by driving the motor 6 (or clutch), a copying operation is performed in step S _2. Whether copy setting number of sheets in step S ₃ after this has been completed is determined, if there remains a number to be copied back to step S _1. On the other hand, when the sensor voltage V is changed to voltages V ₁ or in step S ₉ (NO in step S _9), the sensor voltage V is whether the voltage V ₃ or less is determined in step S _11.

That is, when the sensor voltage V is the voltage V ₃ or more (NO in step S _11), although the toner concentration has not decreased until empty level, the toner concentration by continuing the copying operation can not normal copy further reduced At the same time, the carrier deteriorates. Therefore, the toner density in order to perform the toner replenishing before empty level, namely that the sensor voltage V becomes a voltage V _2, the sensor voltage V is changed to the voltage V ₃ or more, empty display is made in step S _16, step waits hopper 371 in S ₁₇ until the toner is replenished. Then, if it is the toner replenishment (YES in step S _17), the flow returns to step S _1.

On the other hand, since the toner consumption is large in the multi-consumption mode as described above, if the copying operation is continuously performed in the multi-consumption mode, the toner supply cannot catch up and the toner density gradually decreases. Therefore, when the sensor voltage V becomes a voltage V ₁ or more, pausing only copy operation t _X time each time one copy is completed while the toner replenishment, thereby achieving recovery of toner concentration. That is, the sensor voltage V in step S ₁₁
There as being voltage V ₃ or less (YES in step S _11), in order to recover in a short period of time the toner density shortage, while performing toner supply by driving the toner supply motor 6 (or clutch) in step S _12, preset It has been t _X time, halting only copying operation, for example, several seconds. Then, after the t _X time, the copy operation is performed in step S _13, step S
_It is determined in step ₁₄ whether the set number of copies have been completed, and if the set number of copies have been completed (step S
₍ YES in ₁₄ ), the process of this flowchart ends. It should be noted that the toner replenishment during the pause of the copy operation is performed at a time t _X between the time when the voltage V ₁ or more is detected and the time when the voltage V _C is detected.
The replenishment is performed for a time, and the replenishment is stopped when the voltage is lower than the voltage V _C.

On the other hand, (NO in step S ₁₄₎ Step S that remains number to be copied at _14, the sensor voltage V in step S ₁₅
There is discriminated whether the following voltage V _C, the sensor voltage V is equal to or higher than the voltage V _C (NO in step S _15), it is determined whether the sensor voltage V is the voltage V ₃ or less returns to step S ₁₁ again You. Then, the sensor voltage V is unless the voltage V ₃ or more, pause copying operation t _X time is continued (step S _12). On the other hand, the sensor voltage V in step S ₁₅
If There becomes below the voltage V _C (YES in step S _15), i.e., the toner concentration by the toner supply is restored to the control level, rest of the copying operation the copying operation is performed is released in the normal mode (step S ₂₎ .

Here, the sensor voltage V in a multi-consumption mode according to the present invention will be described with reference to FIG. 5, the operation of when it becomes voltages V ₁ or more.

First, when the continuous copying operation in the normal mode is started at a time point t _{1 of} the sensor voltage V of the voltage V _C , the toner density gradually decreases and the sensor voltage V increases from the voltage V _C. Then, the sensor voltage V at t ₂ point exceeds the voltage V _1, is resting only copying operation t _X times for each termination 1 copies, toner replenishment is performed by the drive during this period the toner supply motor 6 (or clutch) . Thus, the t _X time, so that the sensor voltage V is decreased as shown.
After this copy operation is resumed, the next copy operation is completed, it is performed toner supply again t _X time. Then, the toner density is gradually increased, the sensor voltage V at t ₃ time becomes equal to or lower than the voltage V _C (YES in step S _15), is released pause copying operation, the copy operation without pause back to normal mode Is performed (step S ₂ ).

Thereafter, been carried out continuous copying in the normal mode (the loop of steps S ₁ ~ Step S _3), t the hopper 3 at the ₄ time
When the amount of toner remaining in 71 decreases, the amount of toner supplied to the tank 373 decreases, the toner concentration gradually decreases, and the sensor voltage V gradually increases. When reaching voltages V ₁ at t ₅ the time is paused only copying operation t _X time per one copy end again, during which the toner supply according to the driving of the toner supply motor 6 (or clutch) is performed.

Furthermore, the toner density decreases, and reaches the voltage V ₃ at t ₆ time, empty display is performed to wait until the further toner hopper 371 is replenished (step S _18,
S ₁₇ ).

Next, a second embodiment of the toner density control will be described with reference to the flowchart of FIG.

In the second embodiment, the sensor voltage V becomes the voltages V ₁ or more intensive mode, when the rest of the copying operation t _X time is being performed, the sensor voltage V is changed to voltages V ₁ or again In this case, the pause operation of the copy operation is released, and normal copying is performed.

That is, start continuous copying, the sensor voltage V is less than or equal to the voltage V _C (YES in step S _21), the copy operation without the toner replenishment is performed is performed (step S
_22), and a copy of the set number of sheets is completed (YES at step S _23), the processing of this flowchart is terminated. On the other hand, that remains the number to be copied (at step S ₂₃
NO), the process returns to step S _21, a sensor voltage V is equal to or higher than the voltage V _C (NO in step S _21), whether it is set to the multi-consumption mode is determined, if not set in the multi-consumption mode (NO in step S _24), the sensor voltage V is whether the voltage V ₄ or less is judged (step S _25).

Then, the sensor voltage V is the voltage V ₄ or less (YES in step S _25), while performing the toner replenishment by the driving of the toner supply motor 6 (or clutch), Step S ₂₂
Migration to the copying operation is performed (at step S ₂₃ NO) and there remain sheets to be copied back to step S _21.
On the other hand, a sensor voltage V is the voltage V ₄ or more in the step S ₂₅ (in step S ₂₅ NO), empty display is performed,
Switched to mode of single copy continuous copying is prohibited (step S _27, S _28), the copy operation as single copies are still available (step S _22). Number to be copied after this remaining with (at step S ₂₃ NO) returns to step S _21.

On the other hand, if the multi-consumption mode is set (step S
YES _24), the sensor voltage V in step S ₂₉ is discriminated whether voltages V ₁ or less, the sensor voltage V is voltages V ₁ or less (YES in step S _29), the toner supply motor 6 (or clutch) while performing the toner replenishment by the driving of the copying operation is performed (step S _30, S _22), and there remains a number to be copied later returns to (step S ₂₃ NO) step S _21. On the other hand, when the sensor voltage V is changed to voltages V ₁ or more in the step S ₂₉ (NO in step S _29), whether the sensor voltage V is the voltage V ₃ or less is determined in step S _31, the sensor voltage V is the voltage V ₃ If it is above (step S
₍ NO at ₃₁ ), an empty display is performed to replenish the toner before the toner concentration reaches the empty level (step _S36 ), and the process waits until the toner is replenished (step _S37 ). (YE in step S ₃₇
S), returns to the step S _21.

On the other hand, a sensor voltage V is the voltage V ₃ or less in step S ₃₁ (YES at step S _31), in order to promote the recovery of the toner density, while performing the toner replenishment by the driving of the toner supply motor 6 (or clutch), only t _X times to pause the copying operation, after this copy operation is performed, or it is judged whether a copy of the set number of sheets is completed (step S ₃₂
-Step _S34 ). Then, the copy setting number of sheets and has ended (YES in step S _34), the processing of this flowchart is terminated. The toner replenishing dormant copying operation is from the first embodiment similarly to voltages V ₁ or more detection time to the detection time of the voltage V _C is performed supplementation t _X time, when the following voltage V _C Supply is stopped.

On the other hand, if the number of copies to be copied remains (step S
NO _34), step sensor voltage V in S ₃₅ is discriminated whether voltages V ₁ or less, the sensor voltage V is voltages V ₁ or less (at step S ₃₅ YES), the flow returns to step S _32. That is, since the toner density when the sensor voltage V is voltages V ₁ or less is not recovered, subsequently the toner supply motor 6
(Or clutch) while performing the toner replenishment by the driving of, t _X time copy operation is paused. Then, the sensor voltage V in resting step S ₃₅ of the copying operation voltage V
Unless _one or more, is performed one by one copy end until the copy of the set number is completed (step S ₃₂ ~ Step S _35).

On the other hand, the sensor voltage V in step S ₃₅ is becomes the voltages V ₁ or more (NO in step S _35), the sensor voltage V is whether the voltage V ₂ or less is determined in step S _38. Then, N and sensor voltage V is a voltage V ₂ or more (in step S ₃₈
O), the toner density is in the empty level, as toner replenishment, empty display is performed, waiting in the hopper 371 until the toner is replenished (step S _39, S _40), the toner replenishment (Step S
₄₀ YES), the flow returns to step S _21.

On the other hand, a sensor voltage V is a voltage V ₂ or less in the step S ₃₈ (YES at step S _38), the toner supply motor 6
(Or clutch), and at the same time, a copy operation is performed while toner supply is performed (step S ₄₁ ,
_S42 ). In other words, despite resting and toner replenishing copying operation (step S _32, S ₃₃₎ is performed,
Since the toner density decreases, such the toner in the hopper 371 is insufficient, the toner density is short perform normal copying without pause copying operation in order to perform early empty display (step S ₃₉₎ Between empty levels.

Then, it is determined whether the copy of the configuration number of sheets in step S ₄₃ is completed, and there remain sheets to be copied (at step S ₄₃ NO), the flow returns to step S _38. That is, unless the set number of copies are completed (step S
₄₃ YES), the sensor voltage V is a voltage V ₂ or more (step S ₃₈
In until empty display becomes NO) (step S ₃₉₎ is performed, step S _38, step S ₄₁ ~ step S
₄₃ loop is repeated for the copy set number of sheets is completed (YES at step S _43), the processing of this flowchart is terminated.

Here, the operation according to the present invention, is set in multiple consumption mode in the second embodiment, the sensor voltage V when the sensor voltage V is performing dormant copying operation becomes voltages V ₁ or more
There will be described with reference to FIG. 7 to vary the voltages V ₁ or more again.

First, the sensor voltage V is the continuous copying operation in t ₇ when the voltage V _C is started, the toner concentration gradually decreases, the sensor voltage V is increased from the voltage V _C. Then, the sensor voltage V at t ₈ point becomes the voltage V ₁ or more, is only a copy operation pause t _X time per one copy end, toner replenishment by the driving of the toner supply motor 6 (or clutch) is performed. Then, the copy of the resting and the toner replenishment set number of copying operation is continued in the copy operation each terminated until the end (loop of steps S ₃₂ ~ Step S _35), the toner density is gradually increased. When the toner concentration becomes equal to or higher than the control level, the toner supply is stopped, and when the toner concentration becomes equal to or lower than the control level, the toner supply is started again.

On the other hand, during the processing of the loop of steps S ₃₂ ~ step S _35, for example, made toner running low in the hopper 371 at t ₉ time, since the toner density decreases gradually reduces the amount of toner supplied to the tank 373, sensor voltage V gradually rises again become voltages V ₁ or more t ₁₀ time. At this time, the pause of the copy operation is released and the operation returns to the normal copy. Subsequent copying further reduces the toner density,
Upon reaching the voltage V ₂ at t ₁₁ time, empty display is performed (step S _36), and waits without performing copying operation until the toner is replenished into the hopper 371 (Step S
₃₇ ).

Next, a third embodiment of the toner density control will be described with reference to the flowchart of FIG.

In the second embodiment, when the sensor voltage V is voltages V ₁ or less in the step S ₃₅ (YES at step S _35), but so as to proceeds to step S _32, in the third embodiment, steps S ₆₅
When the sensor voltage V is voltages V ₁ or less (step S ₃₅₎ (YES at step S _65), the sensor voltage V in step S ₇₄
There determines whether the following voltage V _C. When the sensor voltage V is equal to or lower than the voltage V _C , the process returns to the normal copy operation,
When the sensor voltage V is equal to or greater than the voltage V _C is obtained to perform the pause and toner replenishing copying operation.

That is, the multi-consumption mode is set (at step _S54) .
YES), and, when the sensor voltage V is voltages V ₁ or more (NO in step S _59), if the sensor voltage V is the voltage V ₃ or less (at step S ₆₁ YES), only the copying operation t _X time pause is while the toner replenishment is performed by, t _X time after the copying operation is performed (step S _62, S _63). Then, when the copying operation is suspended, the sensor voltage V is changed to the voltage V again.
If less than or equal to ₁ (YES at Sutedzubu S _65), the sensor voltage V in step S ₇₄ whether the following voltage V _C, namely whether the toner density control level or higher is determined. And
Pause of copy operation and toner supply (steps _S62 and _S63 )
By, (YES in step S ₇₄₎ and the toner density are recovered to over control levels increase, the normal copying operation without pauses copying operation is performed is performed (step S _52). On the other hand, when the toner concentration is less than the control level, the process returns to step S _61.

That is, the sensor voltage V is the voltage V ₃ or more (step S
₆₁ NO) or less voltage V _C (YES in step S _74), or a copy of the set number is completed (YES at step S ₆₄₎
Unless until the sensor voltage V is changed to voltages V ₁ or more (NO in step S _65), resting and toner supply copying operation t _X times for each copying operation ends is continued (step S _62, S ₆₃₎ .

Here, the operation according to the present invention, is set in multiple consumption mode in the third embodiment, the sensor voltage V when the sensor voltage V is performing dormant copying operation becomes voltages V ₁ or more
There will be described with reference to Figure 9 a case where the voltages V ₁ or more again.

When the sensor voltage V is continuous copying operation at t ₁₂ when the voltage V _C is started, the sensor voltage V toner concentration gradually decreases rises from the voltage V _C, the driving of the toner supply motor 6 (or clutch) The copy operation is performed while toner is being supplied. When the sensor voltage V exceeds the voltage V ₁ at t ₁₃ time, is only a copy operation pause t _X time per one copy completion, the toner concentration gradually is the toner replenishment t _X time of the copying operation ends each elevated, sensor voltage V drops to the voltage V _C (t ₁₄ time).

Thereafter, for example, when the toner in the hopper 371 at t ₁₅ the time is running low, and decreased toner concentration gradually decreases the amount of toner supplied to the tank 373, the sensor voltage V is gradually increased, the voltage V at t ₁₆ time _{Be 1} or more. At this time,
The rest is just copying operation again t _X time. However,
Can not toner density increases sufficiently by a reduction in the toner supply amount, the sensor voltage V becomes voltages V ₁ or again at time t ₁₇ which is the next copying operation. For this reason, the pause of the copy operation is released and the operation returns to the normal copy, and the toner density further decreases in accordance with the subsequent copy operation. Then, empty display reaches the voltage V ₂ at t ₁₈ the time is carried out, a hopper 3
Toner 71 waits without performing copying operation until it is replenished (step S _39, S _40).

Next, a fourth embodiment of the toner density control will be described with reference to the flowchart of FIG.

In the fourth embodiment, first, a pre-scan is performed to calculate a toner consumption amount T per sheet, and when the calculation result exceeds a predetermined amount Tx, the mode is automatically switched to the multi-consumption mode. , FIG. 4, FIG. 6, or FIG. The setting of the black-and-white inversion mode and the magnification is performed by the operation unit 2.

Step S ₈₁ prescanning is started, the document is read while being scanned by the CCD 30, is converted to digital (image) signal are sequentially stored in the image memory 4. In step _S82 , the document size is detected. The document size may be set by the operation unit 2 or may be calculated automatically. As a method for automatically calculating the document size, it is conceivable to calculate the document size because at least the four corners of the document are white. That is, the back side of the document presser 23 is set to an intermediate color such as gray, the four corners (white) of the document are identified by pre-scanning, and the document size is calculated from the four corners. It is also conceivable to scan an original with a detection unit in which a plurality of photosensors are arranged, and detect the size of the original based on the presence or absence of reflected light from the original.

Subsequently, in step _S83 , the number of black pixels is counted from the image signal stored in the image memory 4 according to the scan,
In step _S84 , it is determined whether the pre-scan has been completed. If the pre-scan has not been completed (step S84).
₍ NO at ₈₄ ), the process returns to step _S82 , and the document size is detected. When the prescanning is completed (YES at step S _84), whether it is set to black and white inversion mode is determined in step S _85. Are not set in the tone reversal mode (NO in step S _85), step S ₈₆
Then, the toner consumption amount T per sheet is calculated as in the following equation. The amount of toner consumption per black pixel is omitted for the sake of explanation.

T = one (magnification) × (number of black pixels), (YES in step S ₈₅₎ and are set to black and white inversion mode in step S _85, the toner consumption T per sheet in step S ₈₇ is of the formula It is calculated as follows.

T = (magnification) × {(total number of pixels of document) − (number of black pixels)} In step _S88 , the toner consumption amount T calculated in step _S86 or step _S87 is set to a predetermined amount Tx.
It is determined whether the toner consumption amount T is larger than the amount Tx.
And greater than (YES in step S _88), is set in multiple consumption mode in step S _89, FIG. 4 described above after the sixth
The process proceeds to the flowchart of FIG. 8 or FIG. on the other hand,
In step S ₈₈ the toner consumption T is less than the amount Tx (NO in step S _88), without being set to the multi-consumption mode shifts Figure 4, the flowchart of FIG. 6 or FIG. 8.

That is, when the multi-consumption mode is set, the determination at step S 4 in FIG. ₄ (step S _{24 in} FIG. 6, step S _{54 in} FIG. 8) is YES, and step S ₉ (6
Step S ₂₉ in the figure, in Figure 8 proceeds to step S _59), whereas, NO next in branch are not set in the multi-consumption mode the four view Step S ₄ (step S _24, step S ₅₄₎ , Step S ₅ (Step S _{25 in} FIG. 6,
In FIG. 8, the process proceeds to step _S55 ).

Further, as a fifth embodiment of the toner density control, when the toner consumption is relatively small in the multi-consumption mode, the time t _X is changed to be short to stabilize the toner density (see the broken line in FIG. 5). Alternatively, the toner density may be stabilized, and the time until the copy is completed may be shortened. In other words, calculates the toner consumption T per sheet was calculated in the flowchart of FIG. 10, the toner supply amount per predetermined time, the t _X time toner consumption and toner supply amount and the match. As a result, when the toner consumption T increases, the time t _X increases, and when the toner consumption T decreases, the time t _X decreases.

In the digital copying machine using the image memory 4, the pre-scan is not particularly required, and the mode can be set based on the image signal in the image memory 4 obtained by the main scan, and the image can be formed. . Also,
In the above description, the toner density control device is applied to a digital copying machine, but may be applied to an image forming device such as a printer.

Further, FIG. 4, in the flowchart of FIG. 6 and FIG. 8, step S ₁₇ (sixth step S ₃₇ in the figure, 8 in FIG step S ₅₇₎ solving steps S which is the toner replenished in
_17, YES in step S ₃₇ or step S _57), step S ₁ (sixth step S ₂₁ in FIG., In the Figure 8 and returns to the step S _51), when the toner replenished, step S ₁₁ ( step S ₃₁ in FIG. 6, in the FIG. 8 may return to the step S _61).

Further, in the flowchart of FIG. 6 and FIG. 8, step S ₃₈ or the sensor voltage V in (step S ₆₈ in FIG. 8) performs empty display to determine whether the voltage V ₂ or less, pause copying operation and it has been adapted to select whether to perform toner replenishment, to determine the sensor voltage V instead of the voltage V ₂ if the voltage V ₃ below, may be performed the selection. In this case, since the time point at which the empty display is performed due to the decrease in the toner density is earlier (for example, at time t _{19 in} FIG. 7 and at time t _{20 in} FIG. 9), it is possible to notify the necessity of toner replenishment earlier. it can.

Moreover, by delaying the copy start time for a predetermined time may be given time t _X one by one copy end. Further, the detection of the toner density may be performed after the copying operation is stopped, or may be performed after the copying operation is completed.

(Effects of the Invention) According to the present invention, when the toner concentration to be replenished at the time of setting the multi-consumption mode changes below a preset pause level, the recording operation is suspended for a preset very short time each time one recording is completed. Therefore, toner replenishment can be performed at the same time as recording, and even if the toner consumption is large, recording is performed at equal intervals, and irregular operations such as a long pause during continuous recording can be prevented as in the related art. A sense of security can be given to the user. Also, when the toner density changes below the detection level set between the pause level and the empty level when the multi-consumption mode is set, an empty display is displayed, so that the user is immediately notified of the need for toner replenishment, and the low density , It is possible to prevent continuous recording and prevent deterioration of the carrier.

Further, when the toner density changes below the detection level, the recording operation is stopped, so that it is possible to prevent continuous recording at a low density for a long time before replenishing the toner, and it is possible to reliably prevent the deterioration of the carrier. .

Further, if the toner concentration does not change to a level higher than the pause level while the recording operation is suspended, the suspension of the recording operation is canceled. Therefore, when the toner replenishment amount decreases, the toner concentration decreases to the display level. And the user can be notified of the need for toner replenishment earlier.

If the recording level becomes equal to or higher than the control level while the printing operation is stopped, normal printing is performed without the printing operation being stopped. Shortening can be achieved.

Further, the toner consumption amount is obtained, and when the toner consumption amount is equal to or larger than a preset amount, the multi-consumption mode is automatically set. Therefore, even when the toner consumption amount is large, recording is performed at equal intervals without fail. In addition, it is possible to prevent the toner concentration from excessively decreasing.

Further, since the pause time is changed based on the toner consumption amount per sheet and the toner supply amount per time, the minimum pause time can be obtained, and a stable toner density can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control system of the toner density control device according to the present invention, FIG. 2 is a block diagram of an image forming apparatus to which the toner density control device according to the present invention is applied, and FIG. FIG. 4 is a flow chart showing a first embodiment of the operation of the toner density control device, FIG. 5 is a timing chart for explaining the operation of the flow chart of FIG. 4, and FIG. Second operation of the concentration control device
FIG. 7 is a flowchart showing the embodiment, FIG. 7 is a timing chart for explaining the operation of the flowchart in FIG. 6,
FIG. 8 is a flowchart showing a third embodiment of the operation of the toner density control device, FIG. 9 is a timing chart for explaining the operation of the flowchart of FIG. 8, and FIG. It is a flowchart which shows 4 Example. DESCRIPTION OF SYMBOLS 1 ... Toner density sensor, 2 ... Operation part, 11 ... Central control part (CPU), 34 ... Photoconductor, 37 ... Developing device, 371 ...
Hopper, 372 ... Supply roller, 373 ... Tank.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Ueda 1-2-28 Tamazo, Chuo-ku, Osaka City, Osaka Prefecture Inside Mita Industries Co., Ltd. (72) Inventor Yasuhiro Kawai 1-2-2, Tamazo, Chuo-ku, Osaka City, Osaka Prefecture No. 28 Inside Mita Kogyo Co., Ltd. (56) References JP-A-1-157682 (JP, A) JP-A-62-105173 (JP, A) JP-A-63-8766 (JP, A) 161383 (JP, A) JP-A-63-8770 (JP, A) JP-A-63-8767 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 21/00 370- 540 G03G 15/00 303 G03G 13/08-13/095 G03G 15/08-15/095

Claims (6)

(57) [Claims] 1. An image forming apparatus in which continuous recording is performed while replenishing toner while a detected toner density is between a control level and an empty level, a mode setting means for switching setting to a multi-consumption mode; Pause level setting means for setting a pause level between the control level and the empty level; first density determination means for determining whether the toner density is equal to or lower than the pause level;
Recording operation pausing means for pausing the recording operation for a preset time each time a sheet ends, and when the toner concentration changes below the pause level when the multi-consumption mode is set,
Control means for driving the recording operation suspending means; detection level setting means for setting a detection level between the pause level and the empty level; and a second for judging whether or not the toner density is below the detection level. A toner density control device comprising: a density discriminating means; and a display means for performing an empty display when the toner density changes below the detection level when the multi-consumption mode is set. 2. A toner density control device according to claim 1, further comprising a stop means for stopping a recording operation when the toner density changes below a detection level. 3. The toner density control device according to claim 1, wherein the driving of the recording operation pausing unit is released if the toner density does not change to a level higher than the pausing level during the driving of the recording operation pausing unit. A toner concentration control device comprising: 4. A toner density control device according to claim 1, wherein said third density discrimination means for discriminating that the toner density is equal to or higher than a control level, and said toner concentration control means stops the recording operation. A second canceling means for canceling the driving of the recording operation suspending means when the density becomes equal to or higher than the control level. 5. A mode setting unit comprising: a consumption detecting unit for calculating a toner consumption per sheet; a consumption determining unit for determining that the toner consumption is equal to or larger than a predetermined amount; 5. The toner density control device according to claim 1, further comprising a switching unit configured to switch a setting to a multi-consumption mode when the toner consumption is equal to or more than a preset amount. 6. A toner density control apparatus according to claim 5, wherein said toner consumption amount and said toner supply amount are made coincident with each other based on the obtained toner consumption amount per sheet and toner supply amount per time. A toner density control device comprising a pause time changing means for changing a pause time of an operation.