JP4904982B2 - Developing device, image forming apparatus, and program. - Google Patents

Description

The present invention relates to a developing device, and in particular, a developing device and an image forming device that use a developer containing toner and a carrier and attach the toner to an electrostatic latent image formed on a predetermined image holding member for development. And the program .

  Conventionally, as an example of a developing device that circulates and conveys a developer including toner and a carrier and uses a part of the toner for development in the conveying process, one shown in FIG. 8 has been proposed.

  In this developing device, a developer supply path 502 and a developer stirring path 504 are formed in the axial direction of the developing sleeve 500, and the developer accommodated therein passes through passages 506 and 508 by conveying members 510 and 512 such as screws. Circulated and conveyed in the direction of arrow 516. Further, a part of the developer conveyed through the developer supply path 502 is held on the outer peripheral portion of the developing sleeve 500, and the toner is used for development at a portion facing the photoreceptor 520.

  The toner concentration of the developer, that is, the mixing ratio of the toner with respect to the carrier is detected by a toner concentration detection sensor 518 provided in the developer stirring path 504, and the toner is replenished from the replenishing port 514 in accordance with the decrease in the toner concentration.

  However, in this type of developing device, when the image forming apparatus incorporating the developing device is installed in an inclined state, the developer water level changes due to the inclination of the developing device, and the toner concentration detection sensor In some cases, the correct toner density cannot be detected. In addition, even when the amount of developer in the developing device suddenly decreases or increases due to some abnormal operation or the like, the toner concentration detection sensor may not detect the correct toner concentration. As described above, if the toner density cannot be detected correctly, the toner density becomes too high or too low, resulting in print fogging, afterimages, white spots, dirt in the apparatus, and the like. Cause.

As a technique that can be applied to solve this problem, Patent Document 1 discloses a light of a latent image medium of a recording apparatus that forms an electrostatic latent image on a latent image medium and visualizes the latent image with toner of a developing device. A light reflectance sensor that detects reflectance, a toner concentration sensor that detects toner density of the developing device, a toner supply unit that supplies toner to the developing device, and a detection value of the light reflectance sensor at a predetermined timing A toner density control device comprising a toner supply control means for calculating a toner density reference value and supplying and energizing the toner supply means in correspondence with the toner density reference value and the detected density of the toner density sensor. The toner density reference value is compared with the toner density reference value calculated so far to detect the change direction of the toner density reference value. When the same change direction is detected several times in succession, the toner density reference value is detected. Technology characterized by having a toner concentration sensor abnormality detecting means for generating information indicating the abnormality of the over concentration sensor is disclosed.
Japanese Patent No. 2820265

  However, in the technique disclosed in Patent Document 1, it is necessary to newly provide a light reflectance sensor for detecting the light reflectance of the latent image medium, which increases the cost and increases the size of the apparatus. There was a problem that.

The present invention has been made to solve the above-described problems, and a developing device , an image forming apparatus, and an image forming apparatus capable of detecting an abnormality in a toner density detection result without causing an increase in cost and an increase in size of the apparatus. And to provide a program .

In order to achieve the above object, the developing device according to claim 1 is directed to an electrostatic latent image formed on a predetermined image holding member in a state where a developer including toner and a carrier is circulated and conveyed inside. A developing means for developing the toner by attaching the toner; a replenishing means for replenishing the toner into the developing means from a toner storage; a detecting means for detecting the density of the toner inside the developing means; and the replenishing a metering means for metering the supply amount of the toner by means, said supply amount which is metered counting means for counting the number of pixels of the developed image, by the weighing means by the developing unit, counted by the counting means The difference between the ideal value indicating the ideal value of the toner replenishment amount with respect to the cumulative number of pixels and the abnormal lower limit threshold and the abnormal upper limit threshold is that the cumulative pixel number is equal to or less than a predetermined value. If the said supply amount which is metered by the metering means based on whether the case of more than the predetermined value at a constant outside the larger as a predetermined allowable range in accordance with the larger is the cumulative number of pixels Based on the number of pixels counted by the counting unit, it is determined whether or not the detection result of the toner density by the detection unit is abnormal. If it is determined that the detection result is not abnormal, the detection result is the function of the image forming apparatus. A determination unit that determines whether the difference is within an allowable range determined according to at least one of the difference and an error due to an installation environment of the image forming apparatus; and the determination unit determines that the detection result is abnormal the detection result executes the process for notifying an abnormal if the detection result by the determining means is determined not to be abnormal, and if the Ru allowable outside the scope And a, a process execution means for executing a processing for approximating the ideal amount replenishment amount of the toner by the supply means when it is constant.

Generally, the toner replenishment amount is determined based on the number of pixels of the image developed by the developing unit and the actual toner density detection result inside the developing unit. Therefore, when the toner replenishment amount deviates greatly from the amount corresponding to the number of pixels, it is considered that the toner density detection result is abnormal.

  The present invention focuses on this point and determines whether or not the detection result of the toner density is abnormal based on the toner replenishment amount and the number of pixels. Note that the toner replenishment amount and the number of pixels can be obtained without providing a new member such as a sensor, so that the cost is not increased and the apparatus is not enlarged.

  Thus, according to the developing device of the first aspect, since it is determined whether or not the toner density detection result is abnormal based on the toner replenishment amount and the number of pixels of the developed image. Therefore, it is possible to detect an abnormality in the detection result of the toner concentration without causing an increase in cost or an increase in the size of the apparatus.

  According to the present invention, as in the second aspect of the present invention, the developing unit adjusts the replenishing time in a state where the replenishing amount of the toner per predetermined time is constant. The toner replenishment amount may be determined, and the metering unit may measure the replenishment amount by measuring the toner replenishment time by the replenishment unit.

In particular, in the invention described in claim 1 or 2 , as in the invention described in claim 3 , the toner replenishment amount T by the replenishing means is such that P is an object of image formation by the image carrier. The number of pixels of the image to be actually formed for each sheet of paper is set, M is a target value corresponding to the target toner density that indicates the toner density detected by the detection means, and S is the actual value by the detection means. of the detected value, when the predetermined coefficients α and beta, are those obtained by the following equation, the processing for approximating the supply amount of the toner to the ideal amount, the replenishment amount of pre Symbol toner When T is larger than the ideal amount, the target value M is decreased by a predetermined value, and when the toner replenishment amount T is smaller than the ideal amount, the target value M is increased by a predetermined value to thereby increase the toner replenishment amount T. Said The adjustment may be performed so as to approach the ideal amount. As in the invention according to claim 4 , the processing for bringing the toner replenishment amount close to the ideal amount is performed by using the toner replenishment amount T as the ideal amount. When larger, the coefficient β is decreased by a predetermined value, and when the toner replenishment amount T is smaller than the ideal amount, the coefficient β is increased by a predetermined value so that the toner replenishment amount T approaches the ideal amount. It is good also as processing to do.

T = (α × P) + {β × (MS)}
In order to achieve the above object, the image forming apparatus according to claim 5 is formed on the image carrier by the developing device according to any one of claims 1 to 4 and the developing device. And transfer means for transferring a toner image obtained by developing the toner by attaching the toner to the electrostatic latent image.
The program according to claim 6 is applied to an electrostatic latent image formed on a predetermined image holding member in a state where a developer containing toner and a carrier is circulated and conveyed from a toner storage unit. A measuring means for measuring the replenishment amount of the toner by the replenishing means for replenishing the toner in the developing means for developing the toner, a counting means for counting the number of pixels of the image developed by the developing means, and the measuring means The replenishment amount measured by means of an ideal value indicating an ideal value of the toner replenishment amount with respect to the cumulative number of pixels counted by the counting means to an abnormal lower limit threshold and an abnormal upper limit threshold. The difference deviates from a predetermined allowable range so that the difference is constant when the cumulative pixel number is less than or equal to a predetermined value and increases as the cumulative pixel number increases when the cumulative pixel number is greater than or equal to the predetermined value. Based on the number of pixels counted by the metered the supply amount and the counting means by the metering means based on whether, of the toner by detecting means for detecting the concentration of the toner in the interior of the developing unit It is determined whether or not the density detection result is abnormal. When it is determined that the density detection result is not abnormal, the detection result is determined according to at least one of a difference between image forming apparatuses and an error due to an installation environment of the image forming apparatus. A determination unit that determines whether the detection result is within the allowable range, and a process for notifying that the detection result is abnormal when the determination unit determines that the detection result is abnormal, wherein the detection result by the determining means is determined not to be abnormal, and the ideal amount of replenishment of the toner by the supply means when the is determined Ru unacceptable der It was assumed for causing a computer to function as process execution means for executing a process for characterizing.

  As described above, according to the present invention, there is an excellent effect that it is possible to provide a developing device capable of detecting an abnormality in a toner density detection result without causing an increase in cost or an increase in size of the device. can get.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of an image forming apparatus 10 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 10 includes an engine unit 12, and a paper feeding unit 14 is provided below the engine unit 12.

  The paper feed unit 14 includes a paper tray 22 on which paper is stacked, and a paper feed roll 24 that feeds paper from the paper tray 22, and the paper delivered by the paper feed roll 24 is The paper passes through the paper feed path 30 via the transport rolls 26 and 28 and is transported to the transfer roll 74 described later.

  After the toner image is transferred onto the paper by the transfer roll 74 and fixed by the fixing roll 32A of the fixing unit 32, the toner image is provided on the upper portion of the engine unit 12 by the discharge roll 36 or the discharge roll 38 depending on the position of the switching claw 34. The discharged first discharge tray 16 or the second discharge tray 18 is discharged.

  Here, in the case of double-sided printing, after the printing of the front surface is completed in the order as described above, before the paper is completely discharged to the first discharge tray 16, the discharge roll 36 is reversed and the paper is reversed. Supplied to the line 40. The paper is then returned to the paper feed path 30 through the transport rolls 42, 44, 46, and 48, and the back side of the paper is printed. In the case of manual printing, by placing paper on the manual feed tray 20, the paper is transported from the manual feed roll 49 to the paper feed path 30 via the transport roll 48 and printed.

  Meanwhile, on the right side of FIG. 1 of the image forming apparatus 10, four developer cartridges 64 filled with a developer for each color (made of toner and magnetic carrier) are arranged. The developer cartridge 64 is connected to developing units 60Y, 60M, 60K, and 60C, which will be described later, arranged in order from the top of FIG. 1 through a developer supply path 65, and the developer in the developer cartridge 64 is stored in the developer cartridge 64. Supplied to developing devices 60Y, 60M, 60K, and 60C.

  Here, in each developer supply path 65, a spiral auger (not shown) that stirs the developer supplied from the corresponding developer cartridge 64 and conveys it to the corresponding developer is rotatably supported. In addition, motors 152 each having a rotation shaft mechanically connected to the shaft of the spiral auger are provided. Therefore, the developer can be supplied from the developer cartridge 64 to the corresponding developing device by rotating the rotating shaft of the motor 152.

  An exposure unit 62 is arranged on the left side of the developer cartridge 64 in FIG. 1, and four laser beams L (Y), L (M), and L (K) corresponding to the image signal are provided from the exposure unit 62. , L (C) is emitted toward the photoconductor 52 constituting the photoconductor unit 50 arranged on the left side of the exposure unit 62 in FIG. 1 to form a latent image on the photoconductor 52.

  The photoconductor unit 50 includes four photoconductor drums 52 (52Y, 52M, 52K, and 52C) arranged in the vertical direction. For example, yellow (52Y), magenta (52M), black (52K), and the like from the top. For cyan (52C).

  The exposure unit 62 includes Y (yellow), M (magenta), C (cyan), and K (black) laser beams L (Y), L (M), L (K), and L (C) (hereinafter, generic names). A light source unit that outputs a laser beam L), a modulation processing unit that modulates and scans the laser beam L, an fθ lens that corrects the scanning speed on the exposure surface, and a lens power in the scanning direction. And an optical system composed of a cylindrical lens for surface tilt correction and the like.

  In the exposure unit 62, the laser light L of each color emitted from the light source unit enters the modulation processing unit, is modulated according to the image information for each color, and is scanned by the polygon mirror 67 rotated by the polygon motor 63. (Main scanning). The laser light L of each color scanned by the polygon mirror 67 is reflected by the mirror group 69 in the arrangement direction of the photoconductor 52 corresponding to each color and is imaged on each photoconductor 52.

  The photoconductor unit 50 includes a charging roll 56 and a refresh roll 54 corresponding to each photoconductor 52, and is provided so as to rotate in contact with the photoconductor 52. In the charging roll 56, the photosensitive member 52 is uniformly charged, and toner flying from a magnet roll 80 provided in the developing unit 58 described later is attached to the surface of the photosensitive member 52. On the other hand, the refresh roll 54 discharges the photosensitive member 52 to remove residual toner adhering to the surface of the photosensitive member 52, thereby preventing ghosts and the like caused by the toner remaining on the surface of the photosensitive member 52.

  Here, the developing unit 58 is arranged on the lower right side in FIG. 1 of each photosensitive unit 50, and four developing units 60 corresponding to the respective photosensitive drums 52 (52Y, 52M, 52K, 52C). (60Y, 60M, 60K, 60C) are arranged in the vertical direction.

  The developing device 60 is in a trickle developing system (in order to prevent the charging performance of the developer from being lowered and to extend the interval for changing the developer, the developer is gradually replenished in the developing device, but becomes excessive ( (Developing system that contains a lot of deteriorated carriers) and develops while discharging the deteriorated developer) is adopted, and the deteriorated developer is collected in a collection container (not shown).

  On the other hand, an intermediate transfer unit 66 is arranged on the left side of the photoconductor unit 50 in FIG. 1, and three drum-shaped intermediate transfer bodies 68, 70, and 72 are provided. The two first intermediate transfer members 68 and 70 are arranged vertically in the vertical direction, and the upper first intermediate transfer member 68 is arranged on the two photoconductors 52Y and 52M arranged at the upper portion of the photoconductor 52. The lower first intermediate transfer member 70 rotates in contact with the two photoconductors 52K and 52C disposed in the lower portion. Further, the second intermediate transfer member 72 is rotated in contact with both the first intermediate transfer members 68 and 70, and the transfer roll 74 described above is rotated in contact with the second intermediate transfer member 72.

  Accordingly, the toner images are transferred from the photoconductors 52Y and 52M to the first intermediate transfer body 68, and the toner images are transferred from the photoconductors 52K and 52C to the first intermediate transfer body 70, respectively. The two color toner images transferred to the first intermediate transfer bodies 68 and 70 are transferred to the second intermediate transfer body 72 to form four colors, and the four color toner images are transferred onto the sheet by the transfer roll 74. Will be.

  A cleaning roll 76 and a cleaning brush 78 are disposed in the vicinity of the intermediate transfer members 68, 70, and 72, respectively, and the residual toner on the surface of the intermediate transfer members 68, 70, and 72 is scraped off.

  As shown in FIG. 2, the developing device unit 58 includes four developing devices 60, and each developing device 60 includes a box-shaped housing 110 and a lid 120 that closes the housing 110. Includes a magnet roll 80 (developer carrier) for supplying toner to the photoconductor 52, a spiral auger 112 (supply member) and a spiral auger for stirring the developer in the developing device 60 and supplying the developer to the magnet roll 80. 114 (stirring member) is rotatably supported. Note that an opening for supplying a developer to the inside of the developing device 60 is provided at a substantially central portion of the lid 120 of each developing device 60, and the developer supply path 65 and the developer supplying path 65 from the corresponding developer cartridge 64 are provided. The developer is supplied (supplemented) through the opening.

  Further, a toner concentration detection sensor 150 for detecting the toner concentration (the mixing ratio of the toner with respect to the carrier) inside the developing device 60 is provided near the lower surface of the portion where the spiral auger 114 is provided in each developing device 60. Is provided.

  Here, each developing device 60 can move between a position where the magnet roll 80 contacts the photoreceptor 52 and a position where the magnet roll 80 is retracted from the photoreceptor 52, and the magnet roll 80 moves to the photoreceptor 52 during image formation. It comes to contact. As a result, toner adheres to the photoconductor 52 corresponding to the latent image formed on the photoconductor 52. However, when image formation is not performed, the developing unit 58 is retracted from the photoconductor 52. It is supposed to be.

  A developing bias voltage in which a DC component is superimposed on an AC component is applied to the magnet roll 80, whereby toner is electrostatically attached only to the electrostatic latent image (image portion) of the photoconductor 52, thereby causing a toner image. Is formed.

  FIG. 3 is a block diagram of a control system for image formation in the engine unit 12.

  The main power management unit 200 is connected to a commercial power source (not shown), generates low voltage power and high voltage power, and supplies driving power to each unit via a power supply line.

  A user interface unit 204 is connected to the main controller 202, and an instruction relating to image formation or the like is given by a user's operation, and information such as image formation is notified to the user.

  The main controller 202 is connected to a network line with an external host computer (not shown) so that image data is input.

  When the image data is input, the main controller 202 analyzes, for example, the print instruction information included in the image data and the image data, and converts them into a format suitable for the engine unit 12 (for example, bitmap data). The image data is sent to the image forming process control unit 206.

  The image formation processing control unit 206 controls the optical scanning system control unit 208, the drive system control unit 210, the charger control unit 212, the developing device control unit 214, and the fixing device control unit 216 based on the input image data. Synchronous control is performed to execute image formation.

  Further, a toner density detection sensor 150 provided in each developing device 60 is connected to the main controller 202. Therefore, the main controller 202 can detect the toner density inside each developing device 60.

  Here, in the main controller 202 according to the present embodiment, when the image forming process control unit 206 executes the image forming process, as shown in FIG. 4 as an example, a value (hereinafter referred to as the value output from the toner density detecting sensor 150). , Referred to as “sensor output value”) The amount of toner replenished from the developer cartridge 64 to the developing device 60 so that S becomes a value corresponding to a predetermined target toner density (hereinafter referred to as “target value”) M. Is derived by the following equation (1), and the motor 152 is controlled via the image forming processing control unit 206 so as to be the replenishment amount.

Toner replenishment amount = (α × P) + {β × (MS)} (1)
Here, P is the number of pixels of the image actually formed for each sheet of the image formation target, and α and β are predetermined according to the characteristics of the developer, the sheet of the image formation target, and the like. It is a coefficient.

  As an example, the developing device 60 according to the present embodiment circulates and conveys the developer in the same manner as the conventional developing device shown in FIG. The sensor output value S changes continuously and periodically. Therefore, as a result of calculating the toner replenishment amount obtained by the above equation (1) as a continuous and periodic change, the toner replenishment amount from the developer cartridge 64 to the developing device 60 is also continuously and periodically. Controlled to change. The toner replenishment amount can be controlled by increasing or decreasing the rotation time or rotation speed of the motor 152 provided in the corresponding developer supply path 65, but the image forming apparatus according to the present embodiment. 10, the rotation speed of the motor 152 is constant at a predetermined rotation speed, and only the rotation time is increased or decreased. Therefore, the coefficient α and coefficient β in the above equation (1) are determined in advance so that the toner replenishment amount is calculated as the toner replenishment time (rotation time of the motor 152).

  Incidentally, in the image forming apparatus 10, when the apparatus main body is installed in an inclined state, the developer water level changes due to the inclination of the developing device 60, and the correct toner concentration is detected by the toner concentration detection sensor 150. There are cases where it is not possible. Even when the amount of the developer in the developing device 60 suddenly decreases or increases due to some abnormal operation or the like, the toner concentration detection sensor 150 may not be able to detect the correct toner concentration. As described above, if the toner density cannot be detected correctly, the toner density becomes too high or too low, resulting in print fogging, afterimages, white spots, dirt in the apparatus, and the like. Cause.

  Therefore, the image forming apparatus 10 according to the present embodiment is equipped with an abnormality detection function for detecting an abnormality in the toner density detection result. Here, the abnormality detection function according to the present embodiment can cope with a case where the detection result of the toner density is clearly abnormal and a case where the detection result is abnormal, but by adjusting the toner supply amount. Two types of abnormalities can be detected in the case of a degree of abnormality. For this reason, in the memory 202A built in the main controller 202 of the image forming apparatus 10, information (hereinafter, referred to as various threshold values in the relationship between the cumulative number of pixels and the cumulative toner replenishment time, schematically shown in FIG. 5 as an example) , "Abnormality determination information") is stored in advance.

  As shown in the figure, the abnormality determination information according to the present embodiment is clearly abnormal in the ideal value indicating the ideal value of the cumulative toner replenishment time with respect to the cumulative number of pixels and the detection result of each toner density. The upper limit threshold and the lower limit threshold indicating the threshold value, and the allowable upper limit value and the allowable limit value indicating the range when the detection result of the toner density is within the error range due to the machine difference of the image forming apparatus 10 or the installation environment. And a lower limit value. Here, the ideal value, the abnormal upper limit threshold value, the abnormal lower limit threshold value, the allowable upper limit value, and the allowable lower limit value are values obtained when the image forming apparatus 10 is used in an ideal state. Those obtained in advance by computer simulation or the like based on the design specifications or the like can be applied.

  In the figure, the area outside the first area sandwiched between the line indicating the abnormal upper limit threshold and the line indicating the abnormal lower limit threshold is an area where the toner density detection result is clearly abnormal, and the allowable upper limit in the first area. An area between the line indicating the value and the line indicating the allowable lower limit value is an area where the toner density detection result is within the above error range. In the image forming apparatus 10 according to the present embodiment, as the abnormality determination information, information schematically illustrated in FIG. 5 as an example is stored in the memory 202A in the form of a table. A function that can calculate a line indicating various values shown in the figure may be stored in the memory 202A.

  Next, with reference to FIG. 6, the operation at the time of execution of the abnormality detection function of the image forming apparatus 10 according to the present embodiment will be described. FIG. 6 is a flowchart showing the flow of processing of an abnormality detection processing program executed by the main controller 202 during a predetermined period of the image forming process, and the program is built in the main controller 202. Previously stored in the memory 202A. Further, here, in order to avoid complications, a case where the abnormality detection processing program is executed assuming that it corresponds to only one developing device 60 (hereinafter referred to as “processing target developing device”) in the developing device unit 58 will be described. However, in practice, the same processing is executed for all the developing devices 60.

  In step 300 in the figure, the cumulative value of the pixel number P of the image being formed is counted as the cumulative pixel number L, and the cumulative value of the toner replenishment time obtained from the image formation processing control unit 206 is calculated as the cumulative toner replenishment time T. As timed. In the next step 302, it is determined whether or not the number of formed images (number of printed sheets) is equal to or greater than a predetermined number (1000 sheets in the present embodiment). If the determination is negative, the process returns to step 300. On the other hand, if the determination is affirmative, the routine proceeds to step 304.

  In step 304, an abnormal upper limit threshold, an abnormal lower limit threshold, an allowable upper limit value, an allowable lower limit value, and an ideal value corresponding to the cumulative number of pixels L in the abnormality determination information (see also FIG. 5) are read from the memory 202A. In 306, it is determined whether or not the cumulative toner replenishment time T has exceeded the read abnormality upper limit threshold value. If the determination is negative, the process proceeds to step 308. If the determination is affirmative, step 310 described later is performed. Migrate to

  In step 308, it is determined whether or not the cumulative toner replenishment time T is less than the read abnormality lower limit threshold value. If the determination is negative, the process proceeds to step 312. If the determination is affirmative, the process proceeds to step 310. To do.

  In step 310, a predetermined abnormality notification process is executed, and then the abnormality detection process program is terminated. Note that in the abnormality detection processing program according to the present embodiment, as the predetermined abnormality notification process, the notification screen shown in FIG. 7 as an example is displayed on the display unit 204A provided in the user interface unit 204. The processing to be applied is applied. In the notification screen shown in FIG. 7, a message indicating that there is a possibility that the toner concentration detection sensor 150 is abnormal is displayed. As described above, the image forming apparatus 10 according to the present embodiment notifies that the detection result of the toner density is abnormal by the display on the display unit. Of course, it is possible to adopt other forms such as notification by outputting a sheet on which an image showing a notification screen as shown in FIG. 7 is printed.

  On the other hand, in step 312, it is determined whether or not the cumulative toner replenishment time T is a value within the range of the read allowable lower limit value and allowable upper limit value. This abnormality detection processing program is terminated assuming that there is no particular problem within the range of errors due to machine differences of the image forming apparatus 10 and the installation environment. On the other hand, if a negative determination is made, Although the detection result is outside the range of the error due to the machine difference of the image forming apparatus 10 and the installation environment, the detection result is regarded as being able to be dealt with by adjusting the toner replenishment amount, and the process proceeds to step 314. Then, a predetermined toner density correction process is executed.

  In the abnormality detection processing program according to the present embodiment, a process for adjusting at least one of the target value M and the coefficient β in the equation (1) is applied as the predetermined toner density correction process.

  Here, when adjusting the target value M, when the accumulated toner replenishment time T is larger than the ideal value read out by the processing of step 304, the target value M is set to a predetermined value (in this embodiment, the target value M at the normal time). When the cumulative toner replenishment time T is shorter than the ideal value, the target value M is set to a predetermined value (in this embodiment, one tenth of the normal target value M). Make adjustments to increase only.

  When adjusting the coefficient β, when the cumulative toner replenishment time T is longer than the ideal value, the coefficient β is decreased by a predetermined value (in this embodiment, a value that is one fifth of the normal coefficient β). When the cumulative toner replenishment time T is shorter than the ideal value, the coefficient β is adjusted to be increased by a predetermined value (in this embodiment, a value that is one fifth of the normal coefficient β).

  That is, in the toner density correction process executed here, if the cumulative toner replenishment time T is larger than the ideal value, it is assumed that the toner replenishment amount is larger than the toner replenishment amount when the toner density detection result is normal. If the cumulative toner replenishment time T is shorter than the ideal value, the toner replenishment amount is considered to be smaller than the toner replenishment amount when the toner density detection result is normal. As a result, it is possible to prevent occurrence of abnormality in the amount of toner replenishment due to erroneous detection of the toner density.

  When the toner density correction process as described above ends, the abnormality detection process program ends.

  As described above in detail, in the present embodiment, it is determined whether the toner density detection result is abnormal based on the toner replenishment amount and the number of pixels of the developed image. Abnormalities in the detection result of the toner concentration can be detected without causing an increase in cost or an increase in the size of the apparatus.

  In this embodiment, the replenishing means (here, the motor 152) adjusts the replenishing time in a state where the toner replenishing amount per predetermined time is constant, thereby developing means (here, The amount of toner replenished to the inside of the developing device 60) is determined, and the toner replenishment amount is measured by measuring the toner replenishment time by the replenishing means. Can be weighed.

  Further, in the present embodiment, since the predetermined processing is executed when the detection means determines that the detection result is abnormal by the determination means (here, the main controller 202), the detection result is abnormal. Specialized processing can be performed in some cases.

  In particular, in the present embodiment, as the predetermined process, a process for notifying that the detection result is abnormal is applied, so that the user can be made aware of the abnormality.

  Further, in the present embodiment, it is further determined whether or not the detection result is within a predetermined allowable range based on the measured supply amount and the counted number of pixels, and the detection result is the allowable range. When it is determined that the toner supply amount is outside and is not abnormal, a process for making the toner supply amount by the supply means close to the ideal amount is executed as the predetermined process. The amount can be made small.

  In particular, in the present embodiment, the toner replenishment amount is obtained by the equation (1), the processing for bringing the toner replenishment amount close to the ideal amount, the target value M, and the toner replenishment amount Since the process for adjusting the toner amount to approach the ideal amount and the process for adjusting the coefficient β so that the toner replenishment amount approaches the ideal amount, the toner replenishment amount can be easily brought close to the ideal amount. it can.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such changes or improvements are added are also included in the technical scope of the present invention.

  The above embodiments do not limit the invention according to the claims (claims), and all the combinations of features described in the embodiments are essential for the solution of the invention. Is not limited. The above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in the above embodiment, the case where the abnormality detection function is realized by software has been described. However, the present invention is not limited to this, and for example, the function can be realized by hardware. . In this case, the speed of the function can be expected to be higher than that in the above embodiment.

  In addition, the configuration (see FIGS. 1 to 3) of the image forming apparatus 10 described in the above embodiment is merely an example, and unnecessary portions are deleted or new portions are within the scope not departing from the gist of the present invention. Needless to say, you can add.

  The flow of processing of the abnormality detection processing program described in the above embodiment (see FIG. 6) is also an example, and unnecessary steps can be deleted or new steps can be added without departing from the scope of the present invention. Needless to say, they can be added or the processing order can be changed.

1 is a side view illustrating a configuration of an image forming apparatus according to an embodiment. It is an enlarged view showing a configuration of a developing unit according to the embodiment. 3 is a control block diagram illustrating a configuration of a control system for image formation in an engine unit of the image forming apparatus according to the embodiment. FIG. 6 is a graph for explaining control of a toner replenishment amount by the image forming apparatus according to the embodiment. It is a schematic diagram which shows an example of the data structure of the abnormality determination information which concerns on embodiment. It is a flowchart which shows the flow of a process of the abnormality detection process program which concerns on embodiment. It is the schematic which shows an example of the display state of the alerting | reporting screen which concerns on embodiment. FIG. 10 is a diagram for explaining the problems of the conventional technology, and is a schematic plan view illustrating a configuration example of a conventional developing device.

Explanation of symbols

10 Image forming apparatus 60 Developer (Developing means)
64 Developer cartridge (toner storage)
150 Toner concentration detection sensor (detection means)
152 Motor (replenishment means)
202 Main controller (measuring means, counting means, determination means, processing execution means)

Claims (6)

Developing means for developing the toner by attaching the toner to an electrostatic latent image formed on a predetermined image holding member in a state in which a developer including toner and a carrier is circulated and conveyed inside;
Replenishing means for replenishing the toner from the toner storage unit into the developing means;
Detecting means for detecting the density of the toner inside the developing means;
Weighing means for weighing the amount of toner replenished by the replenishing means;
Counting means for counting the number of pixels of the image developed by the developing means;
From the ideal value indicating the ideal value of the replenishment amount of the toner to the cumulative number of pixels counted by the counting unit, the replenishment amount measured by the measurement unit, from the abnormal lower limit threshold and the abnormal upper limit threshold Whether or not the difference between each of the above is out of a predetermined allowable range such that the difference is constant when the cumulative number of pixels is equal to or less than a predetermined value and increases as the cumulative number of pixels increases when the cumulative number of pixels is equal to or greater than the predetermined value. Whether or not the detection result of the toner density by the detection means is abnormal, and if it is determined that the detection result is not abnormal, the detection result is a difference between image forming apparatuses and an installation environment of the image forming apparatus. Determining means for determining whether or not the tolerance is determined according to at least one of the errors by;
When the determination means determines that the detection result is abnormal, a process for notifying that the detection result is abnormal is executed, the determination means determines that the detection result is not abnormal, and the tolerance and processing execution means for executing a processing for approximating the ideal amount replenishment amount of the toner by the supply means when it is determined that the out of range Ru,
A developing device comprising: The replenishing means determines the toner replenishment amount inside the developing means by adjusting the replenishment time in a state where the toner replenishment amount per predetermined time is constant.
The developing device according to claim 1, wherein the measuring unit measures the replenishment amount by measuring a replenishment time of the toner by the replenishing unit. The toner replenishment amount T by the replenishing means is defined by P being the number of pixels of an image actually formed for each sheet of paper to be image-formed by the image carrier, and M being detected by the detecting means. When the target value corresponding to the target toner density is a value indicating the toner density, S is an actual detection value by the detecting means, and α and β are predetermined coefficients, the following formula is obtained. Yes,
T = (α × P) + {β × (MS)}
When the toner supply amount T is larger than the ideal amount, the target value M is decreased by a predetermined value, and the toner supply amount T is set to the ideal amount. 3. The developing device according to claim 1, wherein when it is smaller, the target value M is increased by a predetermined value to adjust the toner replenishment amount T so as to approach the ideal amount. 4. The toner replenishment amount T by the replenishing means is defined by P being the number of pixels of an image actually formed for each sheet of paper to be image-formed by the image carrier, and M being detected by the detecting means. When the target value corresponding to the target toner density is a value indicating the toner density, S is an actual detection value by the detecting means, and α and β are predetermined coefficients, the following formula is obtained. Yes,
T = (α × P) + {β × (MS)}
In the process for making the toner replenishment amount close to the ideal amount, when the toner replenishment amount T is larger than the ideal amount, the coefficient β is decreased by a predetermined value, and the toner replenishment amount T is smaller than the ideal amount. 3. The developing device according to claim 1, wherein the processing is performed so that the toner replenishment amount T is adjusted to approach the ideal amount by increasing the coefficient β by a predetermined value. A developing device according to any one of claims 1 to 4,
Transfer means for transferring a toner image obtained by developing the electrostatic latent image formed on the image carrier by the developing device by attaching the toner to the electrostatic latent image; and
An image forming apparatus including: Computer
A developer containing toner and a carrier is circulated and conveyed from the toner storage unit to the inside of the developing means for developing the toner by attaching the toner to an electrostatic latent image formed on a predetermined image carrier. Metering means for metering the toner replenishment amount by the toner replenishment means;
Counting means for counting the number of pixels of the image developed by the developing means;
From the ideal value indicating the ideal value of the replenishment amount of the toner to the cumulative number of pixels counted by the counting unit, the replenishment amount measured by the measurement unit, from the abnormal lower limit threshold and the abnormal upper limit threshold Whether or not the difference between each of the above is out of a predetermined allowable range such that the difference is constant when the cumulative number of pixels is equal to or less than a predetermined value and increases as the cumulative number of pixels increases when the cumulative number of pixels is equal to or greater than the predetermined value. Based on the above, it is determined whether or not the detection result of the toner density by the detection means for detecting the toner density inside the developing means is abnormal. A determination unit that determines whether or not the difference is within an allowable range determined according to at least one of an apparatus difference and an error due to an installation environment of the image forming apparatus
And when the determination means determines that the detection result is abnormal, executes a process of notifying that the detection result is abnormal, and the determination means determines that the detection result is not abnormal, and program for functioning as a process execution means for executing a processing for approximating the ideal amount replenishment amount of the toner by the supply means when it is determined that the Ru unacceptable der.

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