JP5919927B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Some image forming apparatuses such as copiers, printers, and facsimiles are detachably mounted with a replaceable toner cartridge in the main body of the image forming apparatus. In such an image forming apparatus, for example, toners of four colors of Y (yellow), M (magenta), C (cyan), and K (black) are filled in the respective toner cartridges and consumed by image formation. When the toner cartridge that has become empty is detected or predicted, and the toner cartridge is detected to be empty, the printing operation of the image forming apparatus is stopped, and a notification that the toner cartridge has become empty is displayed or sounded. Thus, the replacement of the toner cartridge is urged.

  Since such an image forming apparatus has four color toner cartridges, when a toner cartridge of a certain color (for example, magenta) becomes empty, even if a new magenta toner cartridge is mounted and the printing operation is resumed, Immediately thereafter, toner cartridges of other colors (for example, cyan) may become empty, and the replacement work is complicated.

  For solving such problems, for example, the image forming apparatuses of Patent Documents 1 and 2 have been proposed. In the image forming apparatuses disclosed in Patent Documents 1 and 2, when it is detected that a toner cartridge of a certain color is empty, the toner in the toner cartridge of another color is forcibly moved to a reserve tank such as an intermediate hopper. The other color toner cartridges are also urged to be replaced at the same time.

JP 2002-148926 A JP 2009-210743 A

  However, in the image forming apparatuses disclosed in Patent Documents 1 and 2, a reserve tank, a toner supply / conveyance unit that supplies toner from the toner cartridge to the reserve tank, and a toner supply / conveyance unit that supplies toner from the reserve tank to the developing device. There is a problem that the apparatus has a complicated configuration.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can reduce the number of toner cartridge replacement operations with a simple configuration.

In order to achieve the above object, the present invention provides the following means.
(1) An image forming apparatus having a plurality of detachable and replaceable toner cartridges, a notification unit for notifying replacement of a toner cartridge detected as empty, and a count of image pixels at the time of image formation for each toner cartridge A pixel count unit that stores the pixel count value, a toner discharge unit that discharges the toner in the toner cartridge, a dispense count unit that counts the discharge drive amount of the toner discharge unit and stores it as a dispense count value, and a pixel count A detection unit that detects an empty state of the toner in the toner cartridge based on the value and the dispense count value. When the detection unit detects an empty state of one toner cartridge of the plurality of toner cartridges, the detection unit Pixel toner of other stored toner cartridges Referring to preparative value, detects the pixel count of the other toner cartridges when it exceeds the number of image pixels corresponding to the image formable sheets of nominal other toner cartridges, the other toner cartridges and empty image A forming apparatus is provided.

( 2 ) The image forming apparatus according to (1), further including a control unit that controls the toner discharge unit to discharge the toner in the other toner cartridge that has detected an empty state from the other toner cartridge based on the dispense count value. Providing equipment.
(3) control unit, the toner in the other toner cartridge detects the empty state, dispense count value to control the toner discharging portion so as to discharge from the other toner cartridges reaches a predetermined value according to (2) An image forming apparatus is provided.

(4) The toner discharge unit is to provide an image forming apparatus according to discharging the toner in the toner cartridge to the developing device (1).
( 5 ) a developing unit and a density acquisition unit that acquires toner density in the developing unit, and the control unit is configured to allow the toner to be allowed in the developing unit and the toner density in the developing unit acquired by the density acquisition unit. The image forming apparatus according to ( 3 ), wherein the predetermined value is determined based on the above.
( 6 ) The control unit provides the image forming apparatus according to ( 5 ), wherein the control unit determines a predetermined value according to at least one of the environmental correction and the temporal correction.

  According to the present invention, it is possible to provide an image forming apparatus that can reduce the number of toner cartridge replacement operations with a simple configuration.

1 is a schematic diagram illustrating a configuration example of an electrophotographic image forming apparatus according to the present invention. It is a figure explaining the cross section of the developing device arrange | positioned at the image development unit shown in FIG. FIG. 3 is a block diagram illustrating an example of a control configuration in the image forming apparatus according to the embodiment of the present invention. FIG. 6 is a dispense count value-pixel count value diagram used when estimating a remaining capacity of a toner cartridge. 6 is a flowchart illustrating toner cartridge empty detection processing. FIG. 4 is a diagram illustrating a toner cartridge consumption determination area and a toner discharge area. It is a figure explaining calculation processing of compulsory discharge possible regulation value N. 6 is a chart in which environmental correction values according to room temperature and humidity are recorded for an allowable density of toner that can be supplied to a developing device. 6 is a chart in which correction values with time due to changes over time in the developing roll are recorded for the allowable density of toner that can be supplied to the developing device.

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

  FIG. 1 is a schematic diagram showing a configuration example of an electrophotographic image forming apparatus 10 according to the present invention. The image forming apparatus 10 shown in FIG. 1 employs a rotary type including a rotary developing unit 46u, but the present invention is not limited to the rotary type image forming apparatus 10.

  The image forming apparatus 10 includes a paper storage unit 31 that stores recording media P for printing in a stacked state, a paper supply unit 35 that takes out the recording media P from the paper storage unit 31 one by one, and a paper supply unit 35. The vertical conveyance unit 36 that vertically conveys the recording medium P fed by the top to bottom, and the registration unit 37 that feeds the recording medium P conveyed by the vertical conveyance unit 36 to the transfer unit 28 in accordance with the transfer time. Including. The image forming apparatus 10 forms an unfixed toner image based on the image data, and transfers the toner image to the recording medium P that has been transported, and a recording that carries the unfixed toner image. By pressing and heating the medium P, the fixing device 29 that fixes the toner image, the discharge unit 41 that discharges the recording medium P that has finished printing, and the discharged recording medium P are stored in an overlapping manner. And a discharge accommodating portion 42 to be kept.

  The image forming unit 13 is a part that forms and transfers a toner image using an electrophotographic system. Specifically, a photosensitive drum 20 that rotates in the direction of the arrow is provided. Around the photosensitive drum 20, a charger 44 for charging the image holding surface of the photosensitive drum 20, and a laser beam LB based on image data is applied to the charged surface of the photosensitive drum 20 to cause electrostatic potential having a potential difference. An exposure device 45 that forms a latent image and a cleaner 47 that removes and cleans toner remaining on the surface of the photosensitive drum 20 after transfer are provided.

  The image forming unit 13 includes a rotary developing unit 46u including four developing units 46 (see FIG. 2) that form toner images corresponding to the colors Y, M, C, and K. The rotary developing unit 46u is disposed so as to be rotatable about a rotation center 46c. Further, the image forming unit 13 has conveyed a primary transfer roll 24 corresponding to the photosensitive drum 20, an endless intermediate transfer belt 27 serving as an intermediate transfer member, and a toner image primarily transferred to the intermediate transfer belt 27. And a transfer unit 28 for transferring to the recording medium P.

  The photosensitive drum 20 is formed by forming an image holding surface of a photoconductive layer (photosensitive layer) made of an organic photosensitive material on a cylindrical substrate. As the charger 44, for example, a charging roll that rotates in contact with the surface of the photosensitive drum 20 may be a contact charging type that applies a predetermined charging voltage to be charged. The exposure device 45 is a device composed of a semiconductor laser scanning device or the like. The exposure device 45 inputs image data obtained by performing predetermined image processing on image data input from an image reading device or a communication device such as a computer connected to the image forming device 10, and outputs an electrostatic latent image Form.

  An ADC (Auto Density Control Sensor) sensor 60 detects the density of each color toner image formed on the photosensitive drum 20 using an optical sensor or the like. It is also possible to employ a configuration in which the ADC sensor 60 is disposed in the vicinity of the intermediate transfer belt 27 and the toner density of each color transferred to the intermediate transfer belt 27 is detected. As a density detection target, one or more types of patches on which density detection patterns for each color of Y, M, C, and K are drawn can be used depending on the density.

  In the developing unit 46u, Y, M, C, and K developing units 46 (see FIG. 2 described later) are arranged, and each developing unit 46 has a plurality of units corresponding to the respective colors. Toner cartridges 19 (Y, M, C, K) are arranged. The toner cartridge 19 is configured to be detachable and replaceable.

  The intermediate transfer belt 27 is stretched around a plurality of stretching rolls. The intermediate transfer belt 27 is configured to circulate around a primary transfer portion including the photosensitive drum 20 and the primary transfer roll 24, a transfer portion 28 for transferring the toner image to the recording medium P, and a belt cleaner. Yes.

  Next, the configuration of the developing device 46 will be described with reference to FIG. FIG. 2 is a diagram for explaining a cross section of one of the four developing units 46 arranged in the developing unit 46u shown in FIG.

  As shown in FIG. 2, a toner cartridge 19 containing toner T is attached to each developing device 46 adjacently. The developing unit 46 is provided with a supply port 46 b that receives supply of the toner T from the toner cartridge 19 and a toner discharge unit 46 e that performs driving for discharging the toner T from the toner cartridge 19. The toner discharging means 46e can be disposed inside the toner cartridge 19, or a helical conveying rib is formed on the inner periphery of the toner cartridge 19, and the toner cartridge 19 is rotated to discharge the toner T. A configuration to be performed can also be adopted. Each toner discharge means 46e is driven at a predetermined timing for a predetermined time, so that the toner T (including the carrier Q) of any one of Y, M, C, K stored in each toner cartridge 19 is included. May be discharged into the developing device 46. Further, an admix auger 46f and a supply auger 46g for stirring and mixing the toner T and the carrier Q, and a developing roll 46a for supplying the toner T and the carrier Q to the photosensitive drum 20 are disposed in the developing device 46. .

  Note that a toner sensor 64 that detects the supply of the toner T may be disposed in the supply port 46 b of the developing device 46. The toner sensor 64 may be disposed inside the toner cartridge 19 to detect the remaining amount of toner T. By disposing the toner sensor 64 for each color, it is possible to directly detect that the toner T in the toner cartridge 19 has been consumed. However, with the arrangement of the toner sensor 64, the price of the entire apparatus increases and the image forming apparatus 10 becomes larger.

  Further, a toner concentration detection TC sensor (Toner Concentration Sensor) 61 may be disposed inside the developing device 46. The TC sensor 61 is, for example, a magnetic permeability sensor that is arranged inside each color developing device 46, can measure the magnetic permeability in the developer, and can obtain a voltage value corresponding to the magnetic permeability. . The detected magnetic permeability can be converted into a toner concentration by the print control unit 50 described later. However, the TC sensor 61 is generally expensive and needs to be arranged for each developing unit 46. For example, the TC sensor 61 is difficult to adapt to the demand for downsizing and cost reduction of the image forming apparatus 10. Have

  Next, a schematic process of image formation using the image forming apparatus 10 will be described. First, the photosensitive drum 20 is rotated in the image forming unit 13. Then, after the surface of the rotating photosensitive drum 20 is charged to a predetermined potential by the charger 44, the surface of the charged photosensitive drum 20 is irradiated with light based on image data from the exposure device 45. An electrostatic latent image having a predetermined latent image potential is formed for the first color.

  Subsequently, the electrostatic latent image is moved along with the rotation of the photosensitive drum 20, and the toner T supplied from the developing roll 46a of the developing unit 46u is electrostatically attached to the latent image portion. In this way, the development of the toner image on the photosensitive drum 20 is completed for the first color.

  When superimposing other colors, the developing unit 46u is rotated about the rotation center 46c, and the developing roller 46a of the other color is moved to a position facing the photosensitive drum 20. Then, a toner image is formed on the surface of the photosensitive drum 20 in the same manner as in the case of the first color. For example, when forming a full-color image, the charging, exposure, and development processes are repeated four times for each of the colors Y, M, C, and K.

  The toner images of the respective colors thus formed are transferred to the intermediate transfer belt 27 using the primary transfer roll 24. The toner image formed on the intermediate transfer belt 27 is conveyed to the transfer unit 28 in accordance with a preset transfer time while being held on the intermediate transfer belt 27. In parallel with the transfer and conveyance of the toner image, the recording medium P is conveyed to the transfer unit 28 in accordance with a preset transfer time.

  The toner image on the intermediate transfer belt 27 is electrostatically transferred to the recording medium P in the transfer unit 28. The surface of the intermediate transfer belt 27 after the transfer of the toner image is cleaned by a cleaner.

The recording medium P on which the toner image is formed in the image forming unit 13 is conveyed to the fixing device 29. In the pressure contact fixing unit of the fixing device 29, the recording medium P is conveyed while being sandwiched and pressed between the pressure rolls. At that time, the unfixed toner image is fixed on the recording medium P by applying pressure and heating. The recording medium P after fixing is discharged from the fixing device 29 and then transported by a pair of transporting rolls or the like, and is discharged to the discharge storage portion 42 via the discharge portion 41.
In this way, an image of the toner T is formed on one side of the recording medium P.

  An object generally used as the recording medium P of an object for forming an image is a sheet-like object such as a recording sheet, a cardboard, a transparent sheet, a plastic sheet such as an OHP sheet. In addition to these, a bag-like object represented by an envelope can also be used. These recording media P are stored in advance in the paper storage unit 31, taken out using the paper supply unit 35 during image formation, and conveyed to the registration unit 37 by driving a pair of conveyance rolls. Thereafter, the sheet is conveyed to the transfer unit 28 of the image forming unit 13 at a predetermined timing.

  Next, the control configuration of the image forming apparatus 10 will be described. FIG. 3 is a block diagram illustrating an example of the print control unit 50 in the image forming apparatus 10.

  The print control unit 50 is a part that comprehensively controls processing operations of the entire image forming apparatus 10. The print control unit 50 is configured by a computer or the like in which a calculation unit such as a CPU (Central Processing Unit), a storage unit such as a memory, an I / O, a timer, and various communication units are connected via a bus. Can be used. The print control unit 50 is connected to an operation panel 52, an image processing unit 53, a paper detection sensor 54, a paper feed motor 55, a conveyance motor 56, and a toner discharge unit 46e for each color.

  Further, the print control unit 50 includes an ADC sensor 60 that detects the density of each color toner image formed on the photosensitive drum 20, a TC sensor 61 that detects the toner density inside the developing device 46, and the image forming apparatus 10. Are connected to a temperature sensor 62 that measures the temperature in the environment where the toner is installed, a humidity sensor 63 that measures humidity, and a toner sensor 64 that detects the supply of toner T to the developing device 46.

  The operation panel 52 is a user interface through which a user who uses the image forming apparatus 10 inputs various information, displays various information to the user, and emits sound. The operation panel 52 includes an input unit having various buttons, switches, keys, and the like, a display unit including a liquid crystal display with a touch panel, and a speaker that emits a warning sound or the like. The operation panel 52 functions as a notification unit that notifies the user of a request to replace the toner cartridge 19 detected as being empty.

  The image processing unit 53 performs predetermined image processing on image data sent from an external communication device, thereby converting the image data into printing data.

  The paper detection sensor 54 detects the passage of the leading edge and the trailing edge of the recording medium P (paper) on the paper conveyance path of the paper conveyance device 14. The paper detection sensor 54 is disposed at an appropriate position on the paper transport path as required. As the sheet detection sensor 54, for example, a reflection type photosensor in which a light emitting element and a light receiving element are arranged on the same surface can be used. For example, the sheet detection sensor 54 is turned on when the recording medium P is present at a sensor detection position in a predetermined range that is close to and opposed to the sensor surface, and is turned off when the recording medium P is not present. In this case, the output of the sheet detection sensor 54 is switched from the OFF state to the ON state when the leading edge of the recording medium P flowing in the downstream direction passes the sensor detection position, and then the recording medium P conveyed downstream. When the rear end passes through the sensor detection position, the on state is switched to the off state.

  The paper feed motor 55 supplies driving force for individually feeding the recording medium P from each paper storage unit 31 in the image forming apparatus main body 15. The conveyance motor 56 has a driving force for conveying the recording medium P fed from the sheet storage unit 31 to the fixing device 29 via the vertical conveyance unit 36, the registration unit 37, and the transfer unit 28 in this order. Supply. The toner discharging means 46e for each color drives to discharge the toner T of each color from the toner cartridge 19 of each color to the developing device 46 arranged for each color. A plurality of each of the motors 55 and 56 and the toner discharging means 46e can be arranged as necessary.

  The print control unit 50 functions as a detection unit 50a, a pixel count unit 50b, a dispense count unit 50c, a toner discharge control unit 50d, and a toner density acquisition unit 50e. After the replacement of the toner cartridge 19, the pixel count unit 50b accumulates and counts the number of image pixels at the time of image formation for each toner cartridge 19, and stores the pixel count value.

The pixel count value is temporarily stored in a storage unit such as a nonvolatile memory in the print control unit 50. The life of the toner cartridge 19 must be capable of printing the nominal printable number (100%) when printing is performed under the conditions defined in the standards such as ISO. The amount of toner T required for printing varies depending on the temperature and humidity during printing and the secular change of the developing roll 46a. Therefore, in order to maintain the nominal printable number of sheets in any environment, the toner cartridge 19 is generally filled with the toner T more than the nominal printable number of sheets. For this reason, the pixel count value exceeds 100% when the toner T in the toner cartridge 19 is exhausted and becomes empty.
After the replacement of each toner cartridge 19, the dispense count unit 50c accumulates and counts the toner discharge drive amount by the toner discharge means 46e and stores it as a dispense count value.

As the discharge drive amount of the toner T, a value obtained by integrating the drive time of the toner discharge means 46e can be used. When the toner discharging means 46e uses a discharging means using a spiral auger, a value obtained by integrating the rotation speed of the auger can be used as the discharge driving amount. The dispense count value is temporarily stored in a storage unit such as a nonvolatile memory in the print control unit 50. By converting the accumulated discharge driving amount of the toner T, the mass of the toner T discharged from the toner cartridge 19 can be calculated. The discharge amount of the toner T calculated based on this dispense count value is highly likely to be a value close to the actual discharge amount.
The detection unit 50 a detects an empty state of the toner in each toner cartridge 19. The detection unit 50a may perform the empty detection using the pixel count value or the dispense count value when detecting the empty of the first toner cartridge 19 that first detects empty, or the sensor 50a may detect the empty inside of the toner cartridge 19 without using these. The toner may be physically measured.
When detecting the first toner cartridge 19 using the pixel count value and the dispense count value, the detection unit 50a uses the wear determination area determined by the relationship between the pixel count value and the dispense count value to empty the first toner cartridge 19. Detect state.

  The toner discharge control unit 50d controls the toner discharge unit 46e to discharge the toner from the toner cartridge 19. The toner concentration acquisition unit 50e acquires the toner concentration in the developing device 46.

  Next, an example of determining the consumption of the toner T by the detection unit 50a will be described with reference to FIG. FIG. 4 is a dispense count value-pixel count value line diagram used when estimating the remaining capacity of the toner cartridge 19.

  The horizontal axis shown in FIG. 4 is the dispense count value (%) obtained by accumulating the driving amount for discharging the toner T by the toner discharging unit 46e. This value corresponds to a ratio of a value obtained by estimating the mass of the toner T discharged from the toner cartridge 19 to the mass of the toner T accommodated in the toner cartridge 19.

  The vertical axis shown in FIG. 4 is a pixel count value (%) obtained by accumulating the number of printing pixels using the toner T of the toner cartridge 19. This value corresponds to the ratio of the cumulative value up to the present with respect to the nominal number of printable sheets. Ideally, it is preferable that the pixel count value = 100% when the dispense count value = 100%.

  The black areas shown in FIG. 4 are toner cartridge consumption determination areas, which are areas determined by the relationship between the dispense count value and the pixel count value. When the relationship between the current dispense count value and the pixel count value is in the wear determination area (for example, when the dispense count value = 101% and the pixel count value = 101%), the detection unit 50a It is determined that the toner T in the cartridge 19 is consumed and empty, and the printing process is interrupted. Then, a message indicating that the toner T in the toner cartridge 19 has been consumed and a replacement request (toner empty) are displayed on the display unit of the operation panel 52, and a warning sound is emitted to notify the user.

  As shown in FIG. 4, when the relationship between the current dispense count value and the pixel count value is “Point A” (when the dispense count value = 36% and the pixel count value = 44%), “Point At “Point Ai” on the extension line of “A”, it is predicted that the wear determination area will be entered. Therefore, the current consumption rate of the toner T can be calculated as 40%. Formula 1 below shows a calculation formula for calculating the toner consumption rate TR at “Point A”. The symbol “^” represents a power.

TR = ((36 ^ 2 + 44 ^ 2) / (90 ^ 2 + 110 ^ 2)) ^ (1/2) (Formula 1)

  By using Expression 1 above, it is possible to notify the user of a warning (near empty) that the toner capacity has decreased. For example, when the current toner consumption rate TR exceeds 80%, a warning (pre-warning) that the preparation of the next replacement toner cartridge 19 is necessary is displayed on the display unit of the operation panel 52. I can keep it.

  As described above, the detection unit 50a can estimate the remaining amount of toner without using the special toner sensor 64 by using the dispense count value-pixel count value diagram shown in FIG. When the toner sensor 64 is disposed in the developing unit 46 or the toner cartridge 19, the print control unit 50 determines that the toner T in each toner cartridge 19 has been consumed based on the output result of the toner sensor 64. can do.

When the detection unit 50a detects the empty state of the first toner cartridge 19, the detection unit 50a further refers to the pixel count value of the other toner cartridge 19 stored in the pixel count unit 50b, and the pixel count value of the other toner cartridge 19 And another toner cartridge 19 is additionally detected as empty based on a predetermined pixel threshold (for example, 100%).
In detecting the empty state of the other toner cartridges 19, the detection unit 50 a detects the empty state of the other toner cartridges 19 using a wear determination area determined by the relationship between the pixel count value and the dispense count value.
Then, the toner discharge control unit 50d controls the toner discharge unit 46e to forcibly discharge the toner in the other toner cartridge 19 additionally detected as empty into the developing device 46.
Thereafter, the user is requested to replace the toner cartridge 19 that is first detected as empty and the toner cartridge 19 that is additionally detected as empty.
Details of this processing will be described later with reference to FIGS.

  The toner density acquisition unit 50e acquires the current toner density in the developing device 46, and performs process control to detect the current density of the toner T of each color. For example, the print control unit 50 performs process control every predetermined printing interval or every predetermined time, detects the density of the toner T of each color, and corrects the toner density. In the process control, for example, one or more types of toner image patches on which density detection patterns of Y, M, C, and K are drawn are formed on the photosensitive drum 20. The toner image is read using the ADC sensor 60, and the density of each color toner image formed on the photosensitive drum 20 is detected. A toner density correction amount is calculated from the density of the toner image. When it is determined that the toner density is low, the toner discharging means 46e is driven for a predetermined time, and the toner T is supplied from the toner cartridge 19 to the developing unit 46, thereby increasing the toner density in the developing unit 46. I do.

  When the TC sensor 61 is disposed in each developing device 46, the toner density can be calculated from the value of the TC sensor 61 without performing process control. When the TC sensor 61 is provided, the toner concentration acquisition unit 50 e acquires the toner concentration from the TC sensor 61.

  The toner discharge control unit 50d determines a predetermined value of the toner that can be supplied to the developing unit 46 based on the allowable density of the toner T allowed by the developing unit 46 and the current toner concentration acquired by the toner concentration acquiring unit 50e. decide. Since the allowable density of toner allowed to the developing device 46 is generally 5% to 10%, the development is performed based on the allowable density of toner, the current toner density, and the capacity of the developing device 46. A predetermined value of the toner T that will not significantly affect the color balance during printing even if it is supplied into the container 46 is calculated.

  The toner density acquisition unit 50e also acquires the allowable toner density allowed for the developing device 46 according to at least one of the temperature, humidity, and cumulative number of times the developing roll 46a is used. The allowable density of the toner that can be supplied to the developing device 46 can be appropriately changed depending on the room temperature, humidity, and aging of the developing roll 46a.

Next, the process up to the determination of the toner T consumption and the replacement time in the toner cartridge 19 and the subsequent notification of the replacement request will be described with reference to FIGS.
FIG. 5 is a flowchart for explaining empty detection processing of the toner cartridge 19.

The toner cartridge empty detection process shown in FIG. 5 is a process executed by the print control unit 50 after polling, printing, or before printing.
When the process executed by the detection unit 50a branches to the toner cartridge empty detection process shown in FIG. 5, the process executed by the detection unit 50a proceeds to step S102.

In step S102, the detection unit 50a acquires the dispense count value and the pixel count value of all the toner cartridges 19 from the dispense count unit 50c and the pixel count unit 60b, respectively.
Then, the process proceeds to the next step S104.

In step S104, the detection unit 50a applies the dispense count value and the pixel count value acquired in step S102 to the dispense count value-pixel count value diagram for estimating the remaining capacity of the toner cartridge shown in FIG.
Then, the consumption rate of the toner T is estimated for all the toner cartridges 19.
When it is determined that the toner T consumption rate is less than 100% in all the toner cartridges 19 (at least one of the dispense count value and the pixel count value is out of the toner cartridge consumption determination area shown in FIG. 4). In the case where there is an error, the process executed by the detection unit 50a branches to step S106, the printing operation is permitted, and the process returns to step S102 again.

  If it is determined in step S104 that the consumption rate of the toner cartridge 19 exceeds 80%, for example, a warning (pre-warning) that the preparation of the next replacement toner cartridge 19 is necessary is performed. It can be displayed on the display unit of the operation panel 52.

  On the other hand, when it is determined in step S104 that the toner T consumption rate exceeds 100% in at least one toner cartridge 19 (the dispense count value and the pixel count value are in the toner cartridge consumption determination area shown in FIG. 4). ), The process executed by the detection unit 50a proceeds to step S108.

  In step S <b> 108, the detection unit 50 a determines an empty state due to the consumption of the toner T for the first toner cartridge 19 in which the consumption rate of the toner T exceeds 100%. When the process in step S108 ends, the process executed by the detection unit 50a proceeds to the determination in the next step S110.

  In step S110, the detection unit 50a acquires the pixel count value of another toner cartridge 19 other than the first toner cartridge 19 that has determined the empty state, and determines whether or not the value exceeds 100% of the reference value. Make a decision. If it is determined that the pixel count values of all other toner cartridges 19 do not exceed 100% of the reference value, the process executed by the detection unit 50a branches to step S122.

  On the other hand, if the detection unit 50a determines in step S110 that the pixel count value of the other toner cartridge 19 exceeds 100% of the reference value, the process executed by the detection unit 50a is performed in step S112. move on.

  In step S112, the detection unit 50a adds the toner cartridge 19 having a pixel count value exceeding 100% of the reference value, and determines the empty state. Then, the process proceeds to the next step S114. For the toner cartridge 19 that has been additionally determined to be empty, the toner discharge controller 50d forcibly removes the toner T remaining in the other toner cartridge 19 in the developing unit 46 in step S118 or step S120 in the subsequent stage. The process to discharge to. In step S124 described later, an exchange request is displayed to the user.

  In the above-described embodiment, the condition that the pixel count value exceeds the reference value (100%) is preferentially used as the condition for determining the empty detection of the other toner cartridges 19. This is because the dispense count value may increase more than necessary due to the toner density control in process control or the like. As a condition for determining whether the other toner cartridge 19 is empty, a dispense count value may be used. The reference value of the pixel count value is not limited to 100%, and values such as 110% and 115% can be used.

  In step S114, the toner concentration acquisition unit 50e acquires the latest toner concentration in the developing device 46 corresponding to the other toner cartridge 19 additionally detected as empty. The toner discharge control unit 50d performs environmental correction and temporal correction for the maximum allowable toner density. Then, the toner discharge control unit 50d can calculate the toner concentration that can be increased in the developing device 46, and can discharge the toner concentration from the other toner cartridge 19 to the developing device 46 from the increaseable toner concentration. A prescribed value N (%) (predetermined value) of the toner T is calculated. Details of the processing in step S114 will be described later with reference to FIG. When the calculation process of the specified value N (%) of the toner T discharged from the other toner cartridges 19 is completed, the process proceeds to the next step S116.

  In step S116, the toner discharge control unit 50d calculates a difference ND (%) between the dispense count value of the other toner cartridge 19 additionally detected as empty and the dispense life reference value (100% value), and the difference. It is determined whether ND (%) is N (%) or less. If it is determined that the difference ND (%) is not equal to or less than the specified value N (%), the process executed by the toner discharge control unit 50d branches to the process of step S118.

  In step S118, when the toner discharge control unit 50d discharges the toner T of the dispense life reference value (100% value) from the other toner cartridge 19 additionally detected as empty to the developing device 46, the specified value N ( %), The toner concentration in the developing device 46 becomes too high, and there is a possibility that the printing may be supported. Therefore, the process of limiting the toner discharge amount to the specified value N (%) is performed. Do. Then, the toner discharge control unit 50d acquires the drive time of the toner discharge means 46e necessary for discharge to the specified value N (%), and drives the toner discharge means 46e. In this way, the amount of toner in a range where there is no support in printing is discharged from the other toner cartridge 19 additionally detected as empty to the developing device 46 and replaced with the user together with the toner cartridge 19 detected as empty first. Requests can be notified.

  On the other hand, if the toner discharge control unit 50d determines in step S116 that the difference ND (%) is equal to or less than the specified value N (%), the process proceeds to step S120.

  In step S120, the toner discharge control unit 50d exceeds the specified value N% even if the toner T of the dispense life reference value (100% value) is discharged from the other toner cartridge 19 additionally detected as empty to the developing device 46. In other words, the toner density in the developing device 46 is within a range where there is no support in printing, and therefore the amount of toner discharged is set to the dispense life reference value (100%). Then, the toner discharge control unit 50d discharges the toner in the other toner cartridge 19 that has detected the empty state, which is necessary for discharging the dispense count value until the dispense life reference value (100%) (predetermined value) is reached. The drive time of the means 46e is acquired, and the drive of the toner discharge means 46e is controlled so as to be discharged from the other toner cartridge 19. In this way, the amount of toner in a range where there is no support in printing is discharged from the other toner cartridge 19 that has been additionally detected to the developing device 46, and a replacement request is made to the user together with the toner cartridge 19 that has been initially detected empty. You can be notified.

When the forced discharge process of the toner T from the other toner cartridge 19 is completed in step S118 or step S120, the process proceeds to step S122. Then, the printing control unit 50 interrupts the printing operation in order to prevent a problem in which the toner T of the first toner cartridge 19 is consumed and the printing is continued when printing is continued. Note that if the developing device 46 continues to have a low toner concentration, there is a high possibility that it takes time to restore the toner concentration in the developing device 46, so the printing operation is stopped in step S122.
Then, the process proceeds to next Step S124.

  The toner cartridge 19 that is first detected as empty is determined to be depleted because the toner T has been consumed, but the toner T has been completely consumed with respect to the additionally detected toner cartridge 19. It has not been determined. However, since the pixel count value has already exceeded 100% by printing, printing of the nominal printable number of sheets has been completed. In addition, printing corresponding to the amount of toner discharged to the developing device 46 is possible. Due to these circumstances, in the process shown in FIG. 5, in order to reduce the frequency of replacement of the toner cartridge 19 by the user, printing is interrupted, and the toner cartridge 19 first detected as empty and another toner cartridge additionally detected as empty An exchange request for 19 is made.

  In step S <b> 124, the print control unit 50 displays on the display unit of the operation panel 52 that the toner cartridge first detected as empty and the toner T in the toner cartridge 19 additionally detected as empty are consumed, and a replacement request is displayed. A warning sound is emitted to notify the user. When the warning toner cartridge 19 is replaced by the user, the replacement request display and the warning sound are stopped. Then, the dispense count and the pixel count of the replaced toner cartridge 19 are reset, and preparation for starting a new count is performed. When the process in step S124 ends, the toner cartridge empty detection process ends.

Next, a specific example of the additional sky determination executed by the detection unit 50a in step S110 illustrated in FIG. 5 will be described with reference to FIG. FIG. 6 is a diagram for explaining a wear determination area and a toner discharge area of the toner cartridge 19.
The horizontal axis shown in FIG. 6 is the dispense count value (%) obtained by accumulating the driving amount of the toner T discharged by the toner discharging unit 46e. This value corresponds to a ratio of a value obtained by estimating the mass of the toner T discharged from the toner cartridge 19 to the mass of the toner T accommodated in the toner cartridge 19.

  The vertical axis shown in FIG. 6 is a pixel count value (%) obtained by accumulating the number of printing pixels using the toner T of the toner cartridge 19. This value corresponds to the ratio of the cumulative value up to the present with respect to the nominal number of printable sheets. The black toner cartridge consumption determination area shown in FIG. 6 is an area determined by the relationship between the dispense count value and the pixel count value, and is an area where the printing operation is interrupted.

  The hatched area shown in FIG. 6 is an area determined by the relationship between the dispense count value and the pixel count value. The shaded area is an area where the operation of forcibly discharging the toner T to the developing device 46 is performed after additionally determining that the other toner cartridge 19 is empty.

  First, a specific example of the determination process that branches from step S110 to step S122 shown in FIG. 5 will be described. For example, the case where the relationship between the current dispense count value and the pixel count value in all other toner cartridges 19 is “Point D” shown in FIG. 6 will be described. In “Point D”, the pixel count value of the toner cartridge 19 is 95%, and has not yet reached 100%. Also, the dispense count value is 100%, which does not reach 105% of the toner cartridge consumption determination area. Accordingly, in the determination in step S110, it is determined that the pixel count values of all other toner cartridges 19 do not exceed 100% of the reference value, and the process branches to step S122 without performing additional determination.

  Next, a specific example of the determination process that proceeds from step S110 to step S112 shown in FIG. 5 will be described. For example, the case where the relationship between the current dispense count value and the pixel count value in another toner cartridge 19 is “Point B” shown in FIG. 6 will be described. In “Point B”, the pixel count value of the toner cartridge 19 is 102.5%, which already exceeds 100%. However, since the dispense count value is 97%, it has not reached 100% of the toner cartridge consumption determination area. Accordingly, in the determination in step S110, it is determined that the pixel count value of the other toner cartridge 19 exceeds 100% of the reference value, and the process proceeds to step S112. And the detection part 50a performs empty determination in addition.

  Assume that the value of the specified value N (%) calculated in the next step S114 is the specified value N = 2%. As shown in FIG. 6, since the dispense count value at “Point B” is 95%, the difference ND between the dispense count value = 95% of the other toner cartridges 19 and the dispense life reference value (100% value) = ND = Calculate 5%. Then, it is determined whether or not the difference ND = 5% is equal to or less than the specified value N = 2%. Here, since the difference ND = 5% is not equal to or less than the specified value N = 2%, the process branches to step S118. Then, the toner discharge control unit 50d performs a process of discharging the toner T corresponding to the specified value N = 2% from the second toner cartridge 19 to the developing device 46. As a result, “Point B” shown in FIG. 2 moves to “Point C”. Then, an exchange request is made to the user via the operation panel 52.

  Next, although not shown in FIG. 6, a specific example in the case where the dispense count value of other toner cartridges 19 is 98.5% and the pixel count value is 102.5% will be described. The specific example is an example when the process proceeds to step S120.

  Also in this case, since the pixel count value of the toner cartridge 19 is 102.5%, it already exceeds 100%. However, since the dispense count value is 98.5%, it has not reached 100% of the toner cartridge consumption determination area. Accordingly, in the determination in step S110, it is determined that the pixel count value of the other toner cartridge 19 exceeds 100% of the reference value, and the process proceeds to step S112. And the detection part 50a performs empty determination in addition.

  Assume that the value of the specified value N (%) calculated in the next step S114 is the specified value N = 2%. Since the dispense count value in the other toner cartridge 19 is 98.5%, the difference ND = 1.0.0 between the dispense count value = 98.5% of the other toner cartridge 19 and the dispense life reference value (100% value). Calculate 5%. Then, it is determined whether or not the difference ND = 1.5% is equal to or less than the specified value N = 2%. Here, the difference ND = 1.5% is equal to or less than the specified value N = 2%. Accordingly, the process proceeds to step S120. Then, the toner discharge controller 50d supplies the toner T corresponding to the specified value N = 1.5% until the dispense count value of the other toner cartridge 19 that has been additionally determined reaches the dispense life reference value (100% value). Then, a process of discharging from the other toner cartridge 19 to the developing device 46 is performed. Thereafter, the user is requested to replace another toner cartridge 19 via the operation panel 52.

  The specified value N (%) calculated in step S114 is a variable determined by the capacity of the developing device 46 and the toner density fluctuation margin. This margin changes depending on conditions such as environment and time. Therefore, in order to effectively use the toner T remaining in the other toner cartridges 19, it is preferable to change the specified value N (%) in accordance with these conditions. The calculation process of the specified value N (%) will be described with reference to FIG.

  When the process to be executed in step S114 in FIG. 5 proceeds, the process branches to a process for calculating the forced dischargeable prescribed value N shown in FIG. FIG. 7 is a diagram for explaining the calculation process of the forcible dischargeable specified value N, and is a flowchart showing details of the process in step S114 of FIG. The processing executed by the toner discharge control unit 50d proceeds to the determination in step S202.

  In step S202, the toner concentration acquisition unit 50e determines whether or not the currently set mode is a mode in which process control is newly performed when it is determined that the other toner cartridge 19 is empty. Do. If the currently set mode is not a new process control mode, the toner density acquisition unit 50e branches to step S204, acquires the latest process control result acquired last time, and Processing for calculating the toner density is performed.

  On the other hand, in step S202, if the currently set mode is a mode in which process control is newly performed, the toner concentration acquisition unit 50e branches to step S206 and newly performs process control. The result is acquired and the toner density is calculated.

  In step S <b> 206, for example, at a predetermined printing interval or every elapse of a predetermined time, the print control unit 50 places one or more types of toner image patches on which the density detection patterns for each color are drawn on the photosensitive drum 20. Form. Then, the toner image is read using the ADC sensor 60 to detect the density of each color toner image formed on the photosensitive drum 20. When the TC sensor 61 is disposed in the developing device 46, the toner concentration acquisition unit 50e reads the output of the TC sensor 61 and performs processing for calculating the toner concentration.

  When the toner density acquisition process ends in step S204 or step S206, the process proceeds to the next step S208.

  In step S208, the toner discharge control unit 50d refers to the outputs of the temperature sensor 62 and the humidity sensor 63, and acquires the current temperature and humidity in the image forming apparatus 10. Then, the maximum allowable TC (%) of the toner T in the developing unit 46 corresponding to the environment is obtained. FIG. 8 is a chart in which environmental correction values according to room temperature and humidity are recorded for the allowable density of toner that can be supplied to the developing device 46. In the example shown in FIG. 8, the maximum allowable TC (%) of the toner T is set to increase as the temperature and humidity become lower. Accordingly, as the current environment in the image forming apparatus 10 is lower in temperature and humidity, a larger amount of toner T can be discharged from the other toner cartridge 19 additionally detected as empty to the developing unit 46. When the environmental correction process in step S208 ends, the process proceeds to the next step S210.

  In step S210, the toner discharge control unit 50d acquires the accumulated rotation speed after replacement of the developing roll 46a in the developing device 46 of the other toner cartridge 19, which is stored in a storage unit such as a nonvolatile memory. Then, a time-dependent correction TC (%) of the toner T in the developing unit 46 corresponding to a change with time is obtained. FIG. 9 is a chart in which correction values with time due to changes with time of the developing roll 46a are recorded for the allowable density of toner that can be supplied to the developing device 46. In the example illustrated in FIG. 9, the time-dependent correction TC (%) of the toner T is set to increase as the developing roll 46 a is used more frequently. Accordingly, as the number of times of use of the developing roller 46a is increased, a larger amount of toner T can be discharged from the other toner cartridges 19 to the developing device 46. When the environmental correction process is completed in step S210, the process proceeds to the next step S212.

  In step S212, the toner discharge control unit 50d subtracts the current toner density (TC (%) of the ProCon result) from the maximum allowable TC (%) allowed in the developing device 46 calculated in step S210. Then, a process of calculating an increaseable TC [U (%)], which is a toner density value that can be increased in the developing device 46, is performed. Then, the process proceeds to the next step S214.

  In step S214, the toner discharge control unit 50d determines whether the ascending TC [U (%)] is a positive number. If it is determined that the value of TC [U (%)] that can be increased is not less than or equal to zero (a positive number), the process proceeds to step S218.

  On the other hand, when the toner discharge control unit 50d determines in step S214 that the value of TC [U (%)] that can be increased is equal to or less than zero (a negative number), step S216 “U ( %) = 0 ”, and since a negative number is inappropriate as U (%), 0 is substituted for the value of U (%). Then, the process proceeds to step S218.

  In step S218, the toner discharge control unit 50d performs a process of converting the value of TC [U (%)] that can be increased obtained in step S212 or S216 into a dispense count value (specified value N (%)). . The dispense count value calculated here is used when performing calculations in step S116, step S118, and step S120 in FIG. Next, in step S218, the toner discharge control unit 50d performs a process of converting the value of TC [U (%)] that can be increased into the drive time for toner discharge in the toner discharge means 46e. When the process in step S218 ends, the process for calculating the forced discharge possible specified value N shown in FIG. 7 is ended, and the process proceeds to the process in step S116 shown in FIG.

  As described above, the toner discharge control unit 50d acquires the toner density in the developing device 46, performs environment correction and time correction, and discharges the toner in the other toner cartridges 19 (predetermined value N (%)). Value) can be calculated and determined. Then, based on the value of the specified value N (%), more toner T can be discharged from the toner cartridge 19 additionally detected as empty to the developing device 46 within a range that does not affect the print density. it can. The user convenience can be improved by requesting replacement of the plurality of toner cartridges 19 at the same time.

  Next, a calculation example in which specific numerical values are substituted for the calculation processing of the forced discharge possible specified value N shown in FIG.

  First, in step S204 or step S206, it is assumed that the latest toner density in the developing device 46 corresponding to the toner cartridge 19 additionally detected as empty is estimated to be 5.5%. Then, in the next step S208, the toner discharge control unit 50d acquires the current temperature and humidity temperature environment. Then, the maximum allowable TC (%) allowed for the developing device 46 is obtained with reference to the chart shown in FIG. Here, if the measured current temperature and humidity are normal temperature and normal humidity, a value of maximum allowable TC = 10.0% is obtained with reference to FIG.

  Next, in step S210, the toner discharge controller 50d acquires the cumulative number of rotations of the developing roller 46a corresponding to the other toner cartridge 19 additionally detected as empty from a storage unit such as a nonvolatile memory. If the cumulative number of rotations of the developing roll 46a is 150,000, the time correction TC = + 0.5% allowed for the developing unit 46 is obtained with reference to the chart shown in FIG. In this embodiment, the maximum permissible TC = 10.0% acquired in step S208 is added to the time-dependent correction TC = + 0.5% acquired in step S210 to obtain the maximum permissible TC = 10.5%. be able to.

  Next, in step S212, the toner discharge control unit 50d subtracts the latest toner density = 5.5% from the maximum allowable TC = 10.5%, so that the increaseable TC U = 5.0%. Get. In step S218, the increaseable TC [U (%)] is converted into a dispense count threshold (%) that defines the life of the toner cartridge, whereby the specified value N (%) can be determined. . Further, the toner discharge control unit 50d converts the specified value N (%) into the motor drive time of the toner discharge means 46e. The toner discharge means 46e is driven using the converted motor driving time. In this way, the toner T can be discharged to the developing device 46 from the other toner cartridge 19 additionally detected as empty.

  According to the embodiment of the present invention, it is possible to improve convenience for the user by additionally requesting replacement of toner cartridges whose cumulative pixel count value exceeds the nominal printable page number. Further, by using the pixel count value, it is not necessary to arrange a toner capacity sensor or the like for each toner cartridge. Therefore, the number of replacement operations of the toner cartridge can be reduced with a simple configuration. In particular, in the case of a small printer, the nominal amount of toner that can be printed is small (for example, 1,000 sheets), so that the number of toner cartridge replacement operations can be reduced for a user who prints in large quantities using a small printer.

  Further, the remaining toner can be effectively used by discharging the toner cartridge additionally detected as empty to the developing device. In addition, the remaining toner can be effectively used by discharging the toner in the toner cartridge additionally detected to be empty up to the allowable density of the toner allowed in the developing unit to the developing unit. In addition, by performing environmental correction and aging correction of the maximum allowable toner density, the toner in the toner cartridge additionally detected as empty can be discharged to the developing device, so that the remaining toner can be used effectively. .

  The present invention can be applied to an electrophotographic image forming apparatus such as a printer or a copying machine. In the above embodiment, the example in which the present invention is applied to the image forming apparatus 10 including the rotary type developing unit has been described. However, the present invention is limited to the image forming apparatus 10 including the rotary type developing unit. Instead, it can be applied to a tandem type or other image forming apparatus.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 13 ... Image forming part, 19, 19Y, 19M, 19C, 19K ... Toner cartridge, 20 ... Photosensitive drum, 24 ... Primary transfer roll, 27 ... Intermediate transfer belt, 28 ... Transfer part, 29 ... Fixing device 31 ... paper container 35 ... feeding unit 36 ... vertical transport unit 37 ... registration unit 41 ... discharge unit 42 ... discharge storage unit 44 ... charger 45 ... exposure device 46 ... development 46a ... developing roll, 46b ... supply port, 46c ... rotation center, 46e ... toner discharging means, 46f ... admix auger, 46g ... supply auger, 46u ... developing unit, 47 ... cleaner, 50 ... printing control unit (toner) Replenishment amount estimation means, consumption determination means, replacement time determination means, discharge drive amount acquisition means, specified value acquisition means, allowable concentration acquisition means 52 ... Operation panel (notification means) 53 ... Image processing unit 54 ... Paper detection sensor 54 ... Feeding motor 56 ... Conveyance motor 60 ... ADC sensor 61 ... TC sensor 62 ... Temperature sensor 63 ... Humidity sensor, 64 ... Toner sensor, T ... Toner, Q ... Carrier, P ... Recording medium, LB ... Laser beam

Claims (6)

An image forming apparatus having a plurality of removable toner cartridges,
An informing unit for informing the replacement of the toner cartridge detected as empty;
A pixel count unit that counts the number of image pixels at the time of image formation for each toner cartridge and stores a pixel count value;
A toner discharge portion for discharging the toner in the toner cartridge;
A dispense count unit that counts the discharge drive amount of the toner discharge unit and stores it as a dispense count value;
A detection unit that detects an empty state of toner in the toner cartridge based on the pixel count value and the dispense count value ;
The detection unit refers to a pixel count value of another toner cartridge stored in the pixel count unit when detecting an empty state of one toner cartridge of the plurality of toner cartridges, and An image forming apparatus , wherein when the pixel count value exceeds the number of image pixels corresponding to the nominal number of images that can be formed by the other toner cartridge, the other toner cartridge is detected as being empty. The apparatus according to claim 1, further comprising a control unit that controls the toner discharge unit to discharge the toner in the other toner cartridge that has detected the empty state from the other toner cartridge based on the dispense count value. the image forming apparatus according to 1. The control unit controls the toner discharge unit to discharge the toner in the other toner cartridge that has detected the empty state from the other toner cartridge until the dispense count value reaches a predetermined value. The image forming apparatus according to claim 2 . The toner discharge unit, the image forming apparatus according to claim 1, characterized in that to discharge the toner in the toner cartridge to the developing device. A developer,
A density acquisition unit that acquires the toner density in the developing unit;
Wherein the control unit according to claim 3, wherein based on the toner density in the said concentration acquiring unit and the allowable concentration of the toner is acceptable to the developing unit has acquired the developing unit, and determines the predetermined value Image forming apparatus. The image forming apparatus according to claim 5 , wherein the control unit determines the predetermined value according to at least one of an environmental correction and a temporal correction.