JP3126814B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electrophotography in which a developer is attached to a latent image formed on a recording medium (image carrier) based on an input image signal to visualize the latent image. Image forming apparatus such as a copying machine and a printer of a recording method or an electrostatic recording method, and in particular, an image in which the density of a developer is controlled by a control signal obtained by arithmetically processing an image signal used in a digital copying machine or the like. The present invention relates to a forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer for forming an image by attaching a developer to a latent image formed on a recording medium, a proper supply of the developer requires a good image output. It is a necessary function to maintain. In particular, in a color copying machine, due to the problem of color reproducibility, a two-component developer (a two-component developer) containing a magnetic powder called a carrier separately from the toner as a colorant is often used. . In the case of an image forming apparatus using this two-component developer, maintaining a constant mixture ratio of toner and carrier (hereinafter referred to as a mixture ratio of developer) is an important factor in maintaining image quality. For this reason, the mixture ratio of the developer in the developing device is detected as needed using a developer concentration control device (ATR), and toner is replenished according to the change.
It is necessary to keep the mixture ratio of the developer constant so as to maintain the image quality.

Conventionally, such a developer concentration control apparatus includes (1) a reflectance (absorption rate) of a toner (for example, magenta M, cyan C, and yellow Y toners) and a light in a near infrared region of a carrier. By utilizing the difference between the two, a two-component developer carried on a developer carrier such as a developing sleeve of a developing device is irradiated with near-infrared light from a light source, for example, an LED (light emitting diode), and the reflected light is emitted. Light is received by a light receiving element, for example, a photodiode (white light may be emitted, and a near-infrared component of the reflected light may be extracted by a filter and received). The arithmetic control means calculates the mixture ratio of the developer in the developing device, compares the calculated mixture ratio of the developer with a preset reference value, and controls the toner supply amount according to the comparison result. Optical reflected light Those that use the knowledge system, (2)
In the case of a toner, such as a carbon black toner, in which the ratio of the amount of light reflected by the toner and the amount of absorption by the carrier is not determined, a patch-shaped electrostatic latent image corresponding to a predetermined density is carried on an image bearing member such as a photosensitive drum. Formed on the body, developed to form a patch-like visible reference image (toner image), and irradiates this reference image with infrared light from the LED as in the case of the reflected light amount detection method described above, The reflected light is received by a photodiode to detect the density of the reference image. Since this density corresponds to the toner density of the two-component developer in the developing device, the detection result is compared with a reference value, and the comparison result is obtained. There has been proposed a device using a patch reference image forming method in which a toner supply amount is controlled in accordance with the condition.

[0004] Further, as one that is particularly frequently used in digital image forming apparatuses, (3) an analog image signal of a document image read by an image sensor such as a CCD is converted into a digital image signal, and all of the digital image signals are converted. Alternatively, a so-called video count type developer concentration control device is proposed in which a video count is calculated by integrating the output level of each pixel for each pixel and the video count is converted into a toner supply amount to supply toner. Have been.

[0005]

However, the above-mentioned (1) in which the near-infrared reflected light from the developer on the developer carrier is received to detect the mixing ratio of the developer or the toner concentration.
When a black toner using normal carbon black is used, the light absorption region of the developer concentration control device of the optical reflection light amount detection method extends to the near infrared region, so that it can be determined as a carrier component. Therefore, since the measurement accuracy is extremely low, there is a disadvantage that the toner density cannot be controlled in the case of a black toner.

Further, in the patch reference image forming type developer concentration control apparatus of the above (2), which receives the reflected light from a certain reference visible image formed on the image carrier and detects the toner density, The light-emitting surface of the light-emitting element and the light-receiving surface of the light-receiving element are contaminated by the developer scattered on the surface, which directly results in measurement errors, and prevents accurate toner replenishment. Is disadvantageous in that the transfer medium is soiled.

Further, a video count is calculated by accumulating the image data or a part thereof, the video count is converted into a toner supply amount to calculate a toner consumption amount, and a toner corresponding to this is supplied. In the video count type developer density control device of (3), since the difference in toner consumption according to the image characteristics (average density, image type, spatial frequency, etc.) as shown in FIG. 15 is not considered, There is a drawback that a replenishment error is likely to occur and the error is accumulated so that stable and high-precision toner replenishment cannot be performed.

The characteristics shown in FIG. 15 are brought about by factors such as the effect of enhancing the edge of the portion to be developed in the electrophotographic image forming apparatus and the deterioration in following the very small dot pattern. It is believed that.

Further, in the developer concentration control of the video count method of the above (3), the amount of developer consumption is estimated not by the actual amount of toner consumption but by the accumulated value of digital image data. Even when an abnormal state occurs and the toner is not consumed, image data is accumulated, so that there is a problem that an error occurs in the replenishment amount.

Accordingly, it is an object of the present invention to normally estimate the toner consumption by weighting and adding the image data value by an appropriate coefficient corresponding to the characteristic of the image data group, to supply the toner, and to reduce the toner supply error. An object of the present invention is to provide an image forming apparatus capable of detecting toner by a patch reference image forming method and correcting the excessive supply amount to an integrated value of data when oversupply is performed so that toner can be supplied with high accuracy.

Another object of the present invention is to estimate and replenish the amount of toner consumed by weighting and adding the image data values by an appropriate coefficient which normally corresponds to the characteristics of the image data group. An object of the present invention is to provide an image forming apparatus capable of replenishing toner with high accuracy by stopping the addition count.

Still another object of the present invention is to provide a method of estimating and replenishing toner consumption by weighting and adding an image data value by an appropriate coefficient corresponding to a characteristic of a group of image data, and replenishing the toner when an abnormal condition occurs. An object of the present invention is to provide an image forming apparatus capable of replenishing toner with high accuracy by replenishing toner by a patch reference image forming method.

[0013]

The above object is achieved by an image forming apparatus according to the present invention. In summary, according to a first aspect, the present invention provides a developing unit for developing a latent image formed on an image carrier based on image data with a developer, and a coefficient corresponding to a feature of the image data group. The image forming apparatus includes a developer replenishing control unit that estimates the amount of developer consumed and controls the replenishment of the developer. The image forming apparatus is provided with a count start / stop unit capable of stopping the count, and when an abnormal state occurs, the count start / stop unit is operated to stop the count.

[0014] In a second aspect, the present invention provides:
Developing means for developing the latent image formed on the image carrier based on the image data with a developer, and counting and weighting the image data values by coefficients corresponding to the characteristics of the image data group, A first developer supply control unit for estimating the amount and controlling the supply of the developer; and a second developing unit for detecting the concentration of the developer using light reflection from the reference image and controlling the supply of the developer. In the image forming apparatus having the developer supply control means, when an abnormal state occurs, the supply of the developer by the first developer supply control means is stopped, and after returning to the normal state, the second development is performed first. An image forming apparatus characterized in that a developer is supplied by a developer supply control unit.

[0015]

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

In the following embodiment, a case where the present invention is applied to an electrophotographic full-color digital copying machine will be described. However, the image forming apparatus to which the present invention can be applied is, for example, a photosensitive member, a dielectric member, or the like. A latent image corresponding to an image signal is formed on an image carrier (recording medium) by an electrophotographic method, an electrostatic recording method, or the like, and the latent image is formed using a two-component developer mainly composed of toner particles and carrier particles. Any configuration may be used as long as it forms a visible image (toner image) by developing with a developing device.

First, an overall configuration of an electrophotographic full-color digital copying machine to which the present invention is applied will be described with reference to FIG.

As shown in FIG. 1, this digital copying machine includes first, second, third and fourth four image forming stations P _M , P _C , P _Y and P _K in the apparatus body. Further, an endless circulating transfer medium transporting unit that carries and transports the transfer medium (paper) fed from the paper feed cassettes 270, 271, 272 or the manual paper feed table 273 of the paper feed unit, for example, an endless transfer belt 274 is stretched between the rollers in a known manner. The transfer belt 274 is driven in the direction indicated by an arrow, bearing the transfer medium fed through the paper feed unit, the image forming stations P _M described above, P _C, sequentially conveyed to P _Y and P _K I do.

Each of the image forming stations P _M , P _C , P _Y
And P _K have substantially the same configuration, includes a photosensitive drum 241, 242, 243 and 244 is typically an image bearing member which is rotated in the arrow direction as shown in, around each photosensitive drum A charger (corona charger) for uniformly charging the photosensitive drum, a developing device for developing the electrostatic latent image formed on the photosensitive drum with a two-component developer, a developed visible image (toner image) ) Onto a transfer medium,
Drum cleaners and the like for removing toner remaining on the photoconductor drums are sequentially arranged in the drum rotation direction, and further, each of the photoconductor drums 241, 242, 243, and 244 is provided.
Are provided with image exposure devices for forming an electrostatic latent image based on color image data, respectively. In the figure, developing devices 251, 252, 253, 254 related to the present invention are provided. Only the toner hoppers 261, 262, 263, 264 for replenishing the color toners, and the image exposure apparatus including the semiconductor lasers 221, 222, 223, 224 and the polygon mirrors 231, 232, 233, 234. The developing device 251 and the toner hopper 261
Magenta toner M, developing device 252 and toner hopper 262 cyan toner C, and developing device 25
3 and the toner hopper 263
However, the developing device 254 and the toner hopper 264 contain black toner K, respectively.

On the other hand, a color original (not shown) placed between the original platen 201 on the glass and the original platen 202 is scanned by the motor 209 in the direction of arrow V while being illuminated by the lamp 203 and reflected from the original. The resulting color light image is reflected by mirrors 204, 205, and 206, enters lens 207, is condensed, and forms an image on CCD element 208, which is an image reading unit that has been subjected to RGB three-color filters. The CCD element 208 separates the incident light into colors,
(Red), G (green), and B (blue) are photoelectrically converted into electric signals corresponding to the respective colors. These electric signals are input to the image processing circuit unit 212, where they are subjected to image processing so that an appropriate image is obtained, and the four colors of magenta (M), cyan (C), yellow (Y), and black (K) are obtained. Is generated, and the image data of each color is converted into a pulse width modulated (PWM) laser drive signal such that each image data value is a signal proportional to the pulse width. The processing up to this point is performed by the image processing circuit unit 212. The lamp 203 and the mirror 204
Is driven mechanically at a speed V by a motor 209, and a second mirror unit 211 including mirrors 205 and 206 is
9 is mechanically driven at a speed of 1/2 V to scan the entire surface of the original.

In the following process, similar processing is performed for each color of magenta M, cyan C, yellow Y, and black K. Therefore, the case of magenta M will be described as a representative example.

The semiconductor laser 221 is driven based on the magenta M image data subjected to the pulse width modulation, and the semiconductor laser 221 emits a temporal light pulse corresponding to the image data, and the polygon mirror 2 rotates the optical pulse at a high speed.
31 spatially scans. By exposing the photosensitive drum 241 rotating in the direction of the arrow in the figure with a light beam corresponding to the image data scanned spatially, an electrostatic latent image corresponding to a magenta color image of a document is formed on the photosensitive drum 241. Is formed. The electrostatic latent image is developed by the developing device 251 to form a magenta M visible image.

On the other hand, the transfer medium is supplied to the sheet cassettes 270 and 2
71 or 272 or a manual feed tray 273, and the transfer belt 5
The transfer belt 5 is conveyed along with the transfer belt 5 moving in the direction of the arrow shown in the figure. During this time, the synchronization is taken and the paper feed timing, the photosensitive drum 241 of the first image forming station P _M visible image of magenta toner, second
The visible image cyan toner on the photosensitive drum 242 of the image forming station P _C is, a visible image of the third yellow toner on the photosensitive drum 243 of the image forming stations P _Y is, and the fourth image forming station P _{On the K} photoconductor drum 244, a visible image of black toner is shared and formed sequentially. These visible images are transferred medium is conveyed to the first to the direction of the fourth image forming station P _M to P _K of the photosensitive drum fuser 275 by sequentially passing through the lower part of the movement of the transfer belt 5 Between,
A transfer charger (not shown) of each image forming station sequentially transfers the images onto a transfer medium in a superimposed manner, and a color image corresponding to the document is synthesized. Since the toner of each color is carried away from each of the developing devices 251 to 254 to the transfer medium in this way, the toner in each of the developing devices is consumed. Therefore, the consumed toner is transferred to each toner hopper 261.
Replenish from ~ 264. In addition, hoppers 261-264
Supply screws 281 to 284 for replenishing the respective color toners in the hopper to the respective developing devices are provided in the replenishing opening portions, respectively. Each time rotation is given by a motor (not shown), a certain amount of toner is supplied. Is supplied into the developing device. 291 to 294 are developing units 251 to 251.
254, the toner of the two-component developer is
244 is a developing sleeve that is attached to the electrostatic latent image formed on 244 to develop it. (Supplementally, the developer concentration control of the optical reflection light amount detection method of the prior art (1) described above was performed by measuring the reflectance of infrared rays on the developing sleeve.) after passing through the fourth image forming station P _K, it is separated from the transfer belt 5 is fed to the fixing unit 275, after the transferred composite color image superimposed in the fixing device is fixed, to the discharge tray 276 And one copy cycle is completed.

FIG. 2 shows a detailed circuit configuration of the image processing circuit section 212 of the digital copying machine shown in FIG. 1. The processing from processing of color image data of a document read by the CCD 208 as an electric signal to output as a print signal is described. 5 shows a flow of an image signal.

The color image data received by the CCD 208 is color-separated and converted into electric signals corresponding to R, G, and B colors, and the R, G, and B electric signals are sampled by the analog processing circuit 51. After being held, the analog
The digital signals are converted into digital signals of three colors of RGB. The digital signals of these colors are subjected to shading correction and black correction by a shading correction circuit 52 as is well known,
After being SC-corrected and further subjected to scaling processing such as enlargement and reduction in a scaling processing circuit 54, the image data is sent to an image data companding section 55. In the image data companding unit 55, the image data is first compressed by the encoder unit 56, and the compressed image data is stored in the next memory unit 57. The image data stored in the memory unit 57 is expanded and read by the decoder unit 58, and the M, C, Y, and K color signals corresponding to the toner signals used in the printer are generated. The read color signals of M, C, Y, and K are subjected to under color removal and masking processing in a masking and UCR processing circuit 59, and subsequently to γ correction in a γ correction circuit 60, and further to an edge enhancement circuit. At 61, the edge is emphasized and sent to the printer unit as M, C, Y, K image signals used in the printer.

FIG. 3 shows the flow of image data in the printer unit. The M, C, Y, and K image signals sent from the image processing circuit unit 212 in FIG. 2 are subjected to γ correction by the γ correction circuit 62 according to the sensitivity of each photoconductor. afterwards,
The image signals M and C pass through a FIFO (first-in first-out) circuit 63, are converted into a pulse width according to the gradation data by a pulse width modulation circuit 64, and are supplied to a laser driver 65. Laser 6
6M and 66C are driven to emit light. On the other hand, after the image signals Y and K are γ-converted, the Y and K lasers 66Y and 66K are changed to the M and C lasers 66.
Since scanning is performed with mirror images of M and 66C, the data of the main scanning is inverted by a LIFO (last-in first-out) circuit 67 and then sent to a pulse width modulation circuit 68 to be converted into a pulse width corresponding to gradation data. Laser driver 69
Supplied to The laser driver 69 drives the lasers 66Y and 66K according to the pulse width to emit light.

FIG. 4 schematically shows the video counting method used in this embodiment. The video counting method in the present embodiment divides an image into a plurality of determination regions, sequentially extracts these determination regions, averages the density of the image in each region, the image type distinguished from the edge pattern of the image in the region, and the space of the image. The frequency and the like are measured from the image data, and the amount of the consumed developer is estimated. Then, the estimated amount of the consumed developer is supplied by the toner supply motor.

FIG. 5 schematically shows a second developer concentration control device used in this embodiment. This is used for toner replenishment control in which the ratio between the amount of light reflected by the toner and the amount of absorption by the carrier is not obtained, as in the case of carbon black toner. As shown in FIG. A patch-like electrostatic latent image is formed on a photosensitive drum 244 for black toner, and is developed by a developing device 254 to form a patch-like visible reference image (toner image) 504. The light source 504 irradiates infrared light from a light source, for example, an LED 501, and the reflected light is received by a first light receiving element, for example, a photodiode 503.
Is received by the second photodiode 502.

Here, the output signal from the second photodiode 502 for directly receiving light is Ere, and the output signal from the first photodiode 503 for receiving reflected light is Esi.
And the initial signals which are the target values of these signals are E
If rein and Esiin are used, the toner supply amount H is represented by the following equation.

[0031]

(Equation 1) Here, α is a coefficient indicating the ratio between the calculated value and the actual supply amount.

Next, the basic sequence of the developer supply control in this embodiment will be described with reference to the flowchart of FIG. In this embodiment, until the copy count number reaches the specified number, the toner amount is controlled by a control amount obtained by weighting the image data value by an appropriate coefficient corresponding to the feature of the image data group by the video count method. When the replenishment is performed and the number of sheets reaches a specified number, a patch-like visible reference image is formed on the photosensitive drum by the patch reference image forming method, and the toner concentration of the developer (mixing ratio of the developer) is detected. The amount is calculated and toner is supplied. The following processing is performed for each copy.

First, in step S1, it is determined whether or not the number of copy counts has reached a specified number. If the number of copies has not reached the specified number (NO), in step S2 a video count method is used to deal with the characteristics of the image data group. The toner is replenished by a control amount obtained by weighting the image data value by the appropriate coefficient thus obtained, and the copy count is increased by one in step S3. This process is repeated until the number of copy counts reaches the specified number. Next, when the copy count number reaches the specified number in step S1 (YES), in step S4 a toner replenishment error is detected by the video count method using the patch reference image forming method, and the toner replenishment amount is calculated from the detection result. The toner is supplied according to the calculated value. Then, in step S5, the copy count number is cleared to 0, and the basic sequence of the developer supply control ends.

Next, as described above, the toner replenishment amount is calculated by the patch reference image forming method, the toner is replenished according to the calculated value, and the data values obtained by weighting the image data values are integrated. FIG. 7 shows a sequence of the developer supply control of the present embodiment for estimating the toner supply amount.

First, in step S11, the toner supply amount is calculated by the patch reference image forming method, and toner supply is performed according to the calculated value. Next, step S12
In the step S13, it is determined whether or not the toner amount is in the oversupply state as a result of the toner supply by the patch reference image forming method. If the toner amount is not the excessive supply state (NO), the image data value is obtained by weighting in step S13. The integrated counting of data is started, and toner is supplied based on the counted value. Then, the sequence of the developer supply control ends.

On the other hand, if it is determined in step S12 that the toner is in an excessively replenished state, (YE
S), the integrated counting of the data obtained by weighting the image data values in step S14 is started, and the counting is continued until the count value corresponding to the excess supply is reached (step S15). When the counter value has been counted up to the count value corresponding to the excess supply (YES in step S15), the count value of the counter is cleared to 0 in step S16,
Thereafter, in step S13, an integrated count of data obtained by weighting the image data values as usual is started, and toner is supplied based on the count value.

In the first embodiment, when it is determined that toner replenishment by the patch reference image forming method is excessive replenishment, the integrated counting of data obtained by weighting the image data values is started, and the amount corresponding to the excessive replenishment is started. Counting is continued until a count value is reached, and after the count is completed, the count value is cleared to 0, and then an integrated count of data obtained by weighting the image data value is started as usual. After replenishing the toner by the patch reference image forming method, the data values are integrated, and after subtracting the count value corresponding to the oversupply from the integrated count value of the data values, The toner may be supplied based on the count value. FIG. 8 is a flowchart showing a sequence of the developer replenishment control according to the second embodiment of the present invention configured as described above.

First, in step S21, the toner replenishment amount is calculated by the patch reference image forming method, and toner replenishment is performed according to the calculated value. Next, step S22
, An integrated count of data obtained by weighting image data values is started to estimate a toner supply amount. It is determined in step S23 whether or not the image formation has been completed, and if not completed (NO), step S2 is performed.
In step 4, the integrated counting of data obtained by weighting the image data values is continued. If it is determined in step S23 that the image formation has been completed (YES), it is determined in step S25 whether or not the previous toner replenishment by the patch reference image forming method was excessive replenishment. (NO), toner is supplied in step S26 based on the count number as it is, and the developer supply control sequence ends. On the other hand, if it is determined in step S25 that the toner has been excessively replenished (YES), the count corresponding to the excessive replenishment is subtracted from the counter integrated value in step S27, and based on the subtracted count. Step S2
At 6, the toner is supplied, and the sequence of the developer supply control ends.

In the second embodiment, the toner amount corresponding to oversupply is converted into a count value and subtracted from the accumulated count value. Needless to say, the toner supply may be performed by subtracting the toner amount corresponding to the oversupply from the estimated toner supply amount based on the count value.

As described above, in the first and second embodiments, the video data value to be estimated by replenishing the toner count by estimating the toner consumption by weighting and adding the image data value by an appropriate coefficient corresponding to the feature of the image data group. The toner is replenished up to a specified number of sheets, a replenishment error due to the replenishment is detected by the patch reference image forming method, the toner corresponding to the error is replenished, and the image data of the video count method is supplied according to the detected toner replenishment amount. Since the integrated value is appropriately corrected, the toner can be replenished with high accuracy, and the mixing ratio of the toner and the carrier can be constantly controlled.

Next, third to fifth embodiments of the present invention will be described with reference to FIGS. In these embodiments, means for arbitrarily starting and stopping the counting of data obtained by weighting the image data values is provided, and the image data values calculated by the video counting method are usually used for image counting. The control amount obtained by weighting with an appropriate coefficient corresponding to the characteristics of the data group is used to supply the toner, and when an abnormal state occurs, the toner supply and the count based on the image data are stopped. Is reduced.

Since these embodiments are also applied to the electrophotographic full-color digital copying machine shown in FIG. 1, the overall configuration, the detailed circuit configuration of the image processing circuit section 212, and the image in the printer section The flow of data and the like are the same and have already been described, so that the description thereof is omitted here. Also, the video counting method is the same as in the first and second embodiments schematically shown in FIG. That is, the image is divided into a plurality of determination regions, and these determination regions are sequentially taken out, and the average density of the image in each region, the image type distinguished from the edge pattern of the image in the region, the spatial frequency of the image, and the like are determined from the image data. Measure,
It estimates the amount of developer consumed. further,
The basic sequence of the developer supply control is the same as that of the first and second embodiments, and has already been described with reference to FIG. 6, so that the description is omitted here.

First, a description will be given of a developer supply control sequence according to a third embodiment of the present invention when a recording material jam occurs.

FIG. 9 is a flow chart showing the sequence of the developer supply control in this embodiment. First, when the copying operation is started and the image forming operation is started, in step S31 an appropriate operation corresponding to the characteristics of the image data group is started. A counter operation for integrating data obtained by weighting image data values by various coefficients is started. next,
In step S32, it is determined whether or not a jam of the recording material has occurred during image formation. If no jam of the recording material has occurred (NO), an appropriate process corresponding to the characteristics of the image data group is performed in step S33. The operation of integrating the data obtained by weighting the image data values by the coefficients is continued. Then, it is determined whether or not the image forming operation has been completed in step S34. If the image forming operation has not been completed (NO), the process returns to step S32 to check again for occurrence of a recording material jam. On the other hand, step S3
If it is determined in step 4 that the image forming operation has been completed (YES), the amount of toner replenishment is estimated based on the integrated data value in step S35, and the estimated amount of toner is supplied to the developing device. The sequence of the medicine supply control ends.

On the other hand, if it is determined in step S32 that the recording material has jammed (YE
S), the toner development is immediately stopped in step S36,
At the same time, in step S37, the counter operation for integrating data obtained by weighting the image data values by appropriate coefficients corresponding to the features of the image data group is stopped. Thereafter, in step S35, the toner replenishment amount is estimated based on the data integrated value integrated until the counter operation is stopped, and the estimated amount of toner is replenished to the developing device.

As described above, according to this embodiment, even if the recording material is jammed during the image forming operation, the toner development and the data accumulation operation are stopped at the time when the jam is detected.
The toner replenishment amount is estimated based on the integrated value of the data, and when replenishing the toner to the developing device, an error does not occur in the toner replenishment amount due to a jam of the recording material, and the advantage is that the toner replenishment can be performed with high accuracy. is there.

In the third embodiment, the developer replenishment control sequence when a jam occurs in the recording material is shown. Next, the BD cannot be detected due to fluctuations in the power of the laser.
A developer supply control sequence according to the fourth embodiment of the present invention when a BD error occurs will be described. When a BD error occurs, the laser power fluctuates, so that the consumption of the developer is different from the normal consumption. Therefore, in the present embodiment, a developer supply control sequence as shown in the flowchart of FIG. 10 is executed.

First, when the copying operation is started and the image forming operation is started, in step S41, a counter operation for integrating data obtained by weighting the image data values by an appropriate coefficient corresponding to the characteristics of the image data group. To start. Next, in step S42, it is determined whether a BD error has occurred during image formation. If no BD error has occurred (NO), step S4 is performed.
At 3, the operation of integrating data obtained by weighting the image data values with appropriate coefficients corresponding to the features of the image data group is continued. Then, it is determined whether or not the image forming operation is completed in step S44, and if the image forming operation is not completed (NO), step S42 is performed.
To check again for the occurrence of a BD error. on the other hand,
If it is determined in step S44 that the image forming operation has been completed (YES), the toner supply amount is estimated based on the integrated data value in step S45, toner is supplied to the developing device, and developer supply is performed. The control sequence ends.

On the other hand, in step S42, the BD
If it is determined that an error has occurred (YE
S), the toner development is immediately stopped in step S46,
At the same time, in step S47, the counter operation for integrating the data obtained by weighting the image data value by an appropriate coefficient corresponding to the feature of the image data group is stopped. Thereafter, in step S45, the toner replenishment amount is estimated based on the integrated data value until the counter operation is stopped, and the estimated amount of toner is replenished to the developing device.

As described above, according to this embodiment, even if a BD error occurs during the image forming operation, the toner development and the data accumulation operation are stopped at the time of detection of the BD error.
When the toner replenishment amount is estimated based on the integrated data and the toner is replenished to the developing device, no error occurs in the toner replenishment amount due to a BD error, so that there is an advantage that highly accurate toner replenishment can be performed.

In the fourth embodiment, the developer supply control sequence when a BD error occurs is shown.
A developer supply control sequence according to the fifth embodiment of the present invention when a charger has failed will be described. When the charger fails, the charge amount of the photosensitive drum and the carrier of the two-component developer fluctuate, so that the consumption amount of the developer is different from the normal amount.
Therefore, in the present embodiment, a developer supply control sequence as shown in the flowchart of FIG. 11 is executed.

First, when the copying operation is started and the image forming operation is started, in step S51, a counter operation for integrating data obtained by weighting the image data values by appropriate coefficients corresponding to the characteristics of the image data group. To start. Next, it is determined in step S52 whether a charger failure has occurred during image formation. If no charger failure has occurred (NO), step S5 is performed.
At 3, the operation of integrating data obtained by weighting the image data values with appropriate coefficients corresponding to the features of the image data group is continued. Then, it is determined whether or not the image forming operation is completed in step S54, and if the image forming operation is not completed (NO), step S52 is performed.
And check again for the occurrence of charger failure. on the other hand,
If it is determined in step S54 that the image forming operation has been completed (YES), the amount of toner supply is estimated based on the integrated data value in step S55, toner is supplied to the developing device, and developer supply is performed. The control sequence ends.

On the other hand, if it is determined in step S52 that a charger failure has occurred, (YE
S), the toner development is immediately stopped in step S56,
At the same time, in step S57, the counter operation for integrating the data obtained by weighting the image data values by an appropriate coefficient corresponding to the feature of the image data group is stopped. Thereafter, in step S55, a toner supply amount is estimated based on the data integrated value integrated until the counter operation is stopped, and the estimated amount of toner is supplied to the developing device.

As described above, according to the present embodiment, even if a charger failure occurs during the image forming operation, the toner development and data integration operations are stopped at the time of detection of the charger failure.
The toner replenishment amount is estimated based on the integrated data value, and when replenishing the toner to the developing device, there is no advantage in that the toner replenishment amount causes an error due to the failure of the charging device, and there is an advantage that the toner can be replenished with high accuracy. .

In the third to fifth embodiments, when a recording material jam occurs, a typical case is the BD.
The toner consumption estimation and replenishment control sequence based on the image data when an error occurs and when a charger failure occurs is shown. However, even when other abnormal conditions occur, the same It is needless to say that the same operation and effect as those of these embodiments can be obtained by estimating the toner amount and supplying the toner.

Next, sixth to eighth embodiments of the present invention will be described with reference to FIGS. In these embodiments, means for stopping toner development is provided, and control obtained by weighting an image data value calculated by a video count method by an appropriate coefficient corresponding to a feature of the image data group is provided. When an abnormal state occurs, the toner development is immediately stopped, and after returning to the normal state, the toner is replenished by the patch reference image forming method first to reduce the estimation error of the toner replenishment amount. It is like that.

Since these embodiments are also applied to the electrophotographic full-color digital copying machine shown in FIG. 1, the overall configuration, the detailed circuit configuration of the image processing circuit section 212, and the image in the printer section The flow of data and the like are the same and have already been described, so that the description thereof is omitted here. Also, the video counting method is the same as in the first and second embodiments schematically shown in FIG. That is, the image is divided into a plurality of determination regions, and these determination regions are sequentially taken out, and the average density of the image in each region, the image type distinguished from the edge pattern of the image in the region, the spatial frequency of the image, and the like are determined from the image data. Measure,
It estimates the amount of developer consumed. further,
The basic sequence of the developer supply control is the same as that of the first and second embodiments, and has already been described with reference to FIG. 6, so that the description is omitted here.

First, a description will be given of a developer supply control sequence according to a sixth embodiment of the present invention when a recording material jam occurs.

FIG. 12 is a flowchart showing the sequence of the developer supply control in this embodiment. First, when the copying operation is started and the image forming operation is started, in step S61, an appropriate operation corresponding to the characteristics of the image data group is performed. A counter operation for integrating data obtained by weighting image data values by various coefficients is started. Next, at step S62, it is determined whether or not a recording material jam has occurred during image formation. If no recording material jam has occurred (NO), at step S63, the image data group corresponds to the feature of the image data group. The operation of integrating the data obtained by weighting the image data values by the appropriate coefficient is continued. Then, it is determined in step S64 whether or not the image forming operation has been completed. If the image forming operation has not been completed (NO), the process returns to step S62 to check again for occurrence of a recording material jam. On the other hand, if it is determined in step S64 that the image forming operation has been completed (YES), the toner replenishment amount is estimated based on the integrated data value in step S65, and the estimated amount of toner is supplied to the developing device. Then, the developer supply control sequence ends.

On the other hand, if it is determined in step S62 that a recording material jam has occurred (YE
S), the toner development is immediately stopped in step S66,
Perform jam processing. After jam clearance, first step S
At 67, the toner supply amount is calculated by the patch reference image forming method. At step S68, the toner of the calculated toner supply amount is supplied to the developing device, and the sequence of the developer supply control ends.

As described above, according to the present embodiment, even if the recording material is jammed during the image forming operation, the toner development is stopped immediately upon detection of the jam, and after the jam is cleared, the patch reference image is firstly obtained. The toner supply amount is calculated by detecting the toner concentration (mixing ratio) of the developer according to the forming method, and the toner supply is performed. Therefore, an error does not occur in the toner supply amount due to a jam of the recording material, and high accuracy is achieved. There is an advantage that the toner can be supplied.

In the sixth embodiment, the developer supply control sequence when a jam occurs in the recording material has been described. Next, the main power of the apparatus is turned off by a user or a power failure during the image forming operation. A developer supply control sequence according to the seventh embodiment of the present invention will be described.

FIG. 13 is a flowchart showing a developer supply control sequence according to the seventh embodiment of the present invention.
When the copying operation is started and the image forming operation is started, in step S71, a counter operation for integrating data obtained by weighting image data values by an appropriate coefficient corresponding to the characteristics of the image data group is started. Next, it is determined in step S72 whether or not the main power supply has been turned off during image formation. If the main power supply has not been turned off (NO), an appropriate response corresponding to the characteristics of the image data group is made in step S73. The operation of integrating data obtained by weighting the image data values by various coefficients is continued. Then, it is determined in step S74 whether or not the image forming operation has been completed. If the image forming operation has not been completed (NO), the process returns to step S72 to check again whether the main power supply has been turned off. On the other hand, if it is determined in step S74 that the image forming operation has been completed (YES), the toner replenishment amount is estimated based on the data integrated value in step S75.
This estimated amount of toner is supplied to the developing device, and the sequence of the developer supply control ends.

On the other hand, if it is confirmed in step S72 that the main power supply has been turned off (YES), toner development is immediately stopped in step S76. After the main power is restored, first, in step S77, the toner replenishment amount is calculated by the patch reference image forming method.
At 78, the toner of the calculated toner supply amount is supplied to the developing device, and the sequence of the developer supply control ends.

As described above, according to the present embodiment, even if the main power supply of the apparatus is turned off during the image forming operation, the toner development is stopped immediately at the time when the main power supply is detected to be off. The toner supply amount is calculated by the patch reference image forming method to supply the toner to the developing device. Therefore, even if the main power supply is turned off during the image forming operation due to a user error, a device failure, a power failure, or the like. There is an advantage that an error does not occur in the toner supply amount, and the toner supply can be performed with high accuracy.

In the seventh embodiment, the developer replenishment control sequence when the main power supply is turned off is shown. However, the BD cannot be detected due to the fluctuation of the laser power.
The developer supply control sequence according to the eighth embodiment of the present invention when a BD error occurs will be described. When a BD error occurs, the laser power fluctuates, so that the consumption of the developer is different from the normal consumption. Therefore, in the present embodiment, a developer supply control sequence as shown in the flowchart of FIG. 14 is executed.

First, when the copying operation is started and the image forming operation is started, in step S81, a counter operation for integrating data obtained by weighting the image data values by an appropriate coefficient corresponding to the characteristics of the image data group. To start. Next, in step S82, it is determined whether a BD error has occurred during image formation. If no BD error has occurred (NO), step S8 is performed.
At 3, the operation of integrating data obtained by weighting the image data values with appropriate coefficients corresponding to the features of the image data group is continued. Then, it is determined whether or not the image forming operation is completed in step S84, and if the image forming operation is not completed (NO), step S82 is performed.
To check again for the occurrence of a BD error. on the other hand,
If it is determined in step S84 that the image forming operation has been completed (YES), a toner replenishment amount is estimated based on the integrated data value in step S85, and the estimated amount of toner is replenished to the developing device. The developer supply control sequence ends.

On the other hand, in step S82, the BD
If it is determined that an error has occurred (YE
S), the toner development is immediately stopped in step S86,
Perform BD error processing. After the processing, first, step S8
At 7, the toner supply amount is calculated by the patch reference image forming method, and at step S88, the toner of the calculated toner supply amount is supplied to the developing device, and the sequence of the developer supply control ends.

As described above, according to the present embodiment, even if a BD error occurs during the image forming operation, the toner development is stopped immediately upon detection of the BD error, and after the BD error processing,
First, the toner concentration (mixing ratio) of the developer is detected by the patch reference image forming method to calculate the toner replenishment amount, and the toner replenishment is performed. Therefore, an error occurs in the toner replenishment amount due to the occurrence of a BD error. And there is an advantage that toner can be supplied with high accuracy.

In the above-described sixth to eighth embodiments, typical examples are the toner based on image data when a recording material jam occurs, when the apparatus power supply is turned off, and when a BD error occurs. Although the consumption estimation / supply control sequence has been described, even when other abnormal conditions occur, the same developer supply control sequence estimates the toner consumption and performs toner supply to achieve the same effect as in these embodiments. Needless to say, the effect of the invention can be obtained.

The embodiments described above are merely examples of the present invention, and it goes without saying that various modifications and changes can be made as necessary. INDUSTRIAL APPLICABILITY The present invention is applicable to all image forming apparatuses that treat an image as digital value data and use a developer to form the image on a recording medium, such as a digital copying machine.

[0072]

As described above, according to the present invention, a developing means for developing a latent image formed on an image carrier based on image data with a developer and a coefficient corresponding to the characteristics of the image data group are provided. In an image forming apparatus having a developer replenishment control unit that counts and counts image data values, estimates a developer consumption amount, and controls developer replenishment.
A count start and stop means for arbitrarily starting and stopping the count during the count is provided, and when an abnormal state occurs, the count start and stop means is operated to stop the count. A control amount obtained by weighting the image data value calculated by the method with an appropriate coefficient corresponding to the feature of the image data group is used, and further, the developer amount is proportional to the estimated cumulative developer supply value based on the image data. If any abnormal condition such as a recording material jam, a BD error, or a charger failure occurs during the replenishment of the developer, the weighted addition counting is arbitrarily started during the counting by the image data. And the stop can be performed, so that the error in estimating the developer replenishment amount can be reduced. Therefore, when the developer is replenished to the developing device, an error occurs in the developer replenishment amount due to the occurrence of an abnormal state, thereby providing an effect that highly accurate toner replenishment can be performed.

Further, according to the present invention, a developing means for developing a latent image formed on an image carrier based on image data with a developer, and an image data value by a coefficient corresponding to a feature of the image data group. Counting with weighting, estimating the amount of consumption of the developer, first developer supply control means for controlling the supply of the developer, and detecting the concentration of the developer using light reflection from the reference image, and In the image forming apparatus having the second developer supply control unit for performing the supply control of the developer, when an abnormal state occurs, the supply of the developer by the first developer supply control unit is stopped, and the normal state is restored. Thereafter, since the developer is first supplied by the second developer supply control means, the patch reference image formation by measurement using the light reflection from the developer of the reference image developed on the image carrier is used. Type developer Control the developer as much as possible in proportion to the estimated cumulative value of developer replenishment based on image data, and perform replenishment of developer proportional to the estimated cumulative value of developer replenishment based on image data. Jam, recording material jam, device power off, BD
When any abnormal state such as an error occurs, the developer is first supplied by the patch reference image forming method after returning to the normal state, so that contamination in the apparatus can be prevented as much as possible. In addition, the developer supply amount estimation error can be reduced. Therefore, there is an effect that the toner can be replenished with high accuracy, and the mixing ratio of the toner and the carrier can always be controlled to be constant.

[0074]

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing the entire configuration of an electrophotographic full-color digital copying machine to which the present invention is applied.

FIG. 2 is a block diagram showing a detailed circuit configuration of an image processing circuit unit of the digital copying machine shown in FIG.

FIG. 3 is a block diagram showing a flow of image data in a printer unit of the digital copying machine shown in FIG.

FIG. 4 is an explanatory diagram schematically showing a method of estimating a developer consumption amount according to the first embodiment of the present invention.

FIG. 5 is a conceptual diagram for explaining a developer concentration control device of an optical reflected light amount detection type used in the present invention.

FIG. 6 is a flowchart illustrating a basic sequence of developer supply control according to the first embodiment of the present invention.

FIG. 7 is a flowchart illustrating a sequence of developer supply control according to the first embodiment of the present invention.

FIG. 8 is a flowchart illustrating a sequence of developer supply control according to a second embodiment of the present invention.

FIG. 9 is a flowchart illustrating a sequence of developer supply control according to a third embodiment of the present invention.

FIG. 10 is a flowchart illustrating a sequence of developer supply control according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart illustrating a sequence of developer supply control according to a fifth embodiment of the present invention.

FIG. 12 is a flowchart illustrating a sequence of developer supply control according to a sixth embodiment of the present invention.

FIG. 13 is a flowchart illustrating a sequence of developer supply control according to a seventh embodiment of the present invention.

FIG. 14 is a flowchart illustrating a sequence of developer supply control according to an eighth embodiment of the present invention.

FIG. 15 is a characteristic diagram illustrating a relationship between a spatial frequency as an image feature and a toner consumption amount.

[Explanation of symbols]

Reference Signs List 51 analog processing circuit 52 shading correction circuit 53 input masking circuit 54 scaling processing circuit 55 image data companding section 59 masking and UCR processing circuit 60, 62 γ correction circuit 61 edge emphasis circuit 63 FIFO circuit 64, 68 pulse width modulation circuit 65 , 69 laser driver 66M~K semiconductor laser 67 LIFO circuit 208 CCD 212 image processing circuit 241 to 244 the photosensitive drum 251 to 254 developing devices 261 to 264 toner hopper P _M to P _K image forming stations

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI B41J 29/20 B41J 3/00 M

Claims (2)

(57) [Claims] 1. A developing means for developing a latent image formed on an image carrier based on image data with a developer, and image data values are counted and weighted by coefficients corresponding to characteristics of the image data group. , Estimating developer consumption,
An image forming apparatus having developer supply control means for performing developer supply control, wherein count start and stop means capable of arbitrarily starting and stopping the count during the counting are provided; An image forming apparatus, wherein counting is stopped by operating a start / stop unit. 2. A developing means for developing a latent image formed on an image carrier on the basis of image data with a developer, and image data values are weighted and counted by coefficients corresponding to characteristics of the image data group. , Estimating developer consumption,
First developer supply control means for performing developer supply control;
Detecting the concentration of the developer using light reflection from the reference image,
In an image forming apparatus having a second developer supply control unit for performing developer supply control, when an abnormal state occurs, the supply of the developer by the first developer supply control unit is stopped and the normal state is returned. An image forming apparatus characterized in that, after returning, the developer is first supplied by the second developer supply control means.