JP2012255836A - Image forming apparatus, and toner supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stable development process without decreasing productivity of printed materials.SOLUTION: An mage forming apparatus includes: a printing rate calculation unit 211 that calculates a printing rate of image data; a dot number calculation unit 203 that calculates the number of dots of the image data; a remaining amount determination unit 207 that determines whether there is an amount of toner exceeding a first threshold in a developing unit that develops an electrostatic latent image formed on the basis of the image data; a first cumulative toner consumption calculation unit 205 that calculates and accumulates the toner consumption from the number of dots in a duration from the end of toner supply to the time when it is determined that there is not the amount of toner that exceeds the first threshold, and calculates a first cumulative toner consumption; a supply control unit 209 that causes a toner supply unit to supply an amount of toner equivalent to the first accumulated toner consumption to the developing unit; and a second cumulative toner consumption calculation unit 213 that accumulates the printing rate calculated during the toner supply and calculates a cumulative printing rate, and calculates a second cumulative toner consumption when the cumulative printing rate equals to or exceeds a second threshold. The supply control unit causes the toner supply unit to supply an amount of toner equivalent to the second cumulative toner consumption to the developing unit.

Description

  The present invention relates to an image forming apparatus and a toner replenishing method.

  In an electrophotographic image forming apparatus, toner is supplied from a toner container to a developing unit, and the developing unit develops an electrostatic latent image on a photoreceptor using toner in the developing unit to form a toner image. Since the deterioration state is different between the toner replenished from the toner container to the developing unit and the toner remaining in the developing unit, if the ratio is largely lost, the developing process becomes unstable.

  For this reason, in such an image forming apparatus, the toner remaining in the developing unit is detected, and when the toner remaining amount falls below a predetermined amount, the toner is supplied from the toner container to the developing unit. And the ratio of the toner remaining in the developing portion to a certain range.

  By the way, when printing an image having a pattern with a high printing rate, the amount of toner consumed from the developing unit due to the formation of the toner image may be larger than the amount of toner supplied from the toner container to the developing unit. If this state continues, the ratio of the toner replenished to the developing unit and the toner remaining in the developing unit is destroyed, and the toner density continues to decrease.

  For this reason, for example, Patent Document 1 discloses that a toner image is formed even when a pattern image with a high printing rate is printed by increasing a printing interval and securing a toner replenishment time longer than the conventional one. Discloses a technology that enables the replenishment of the same amount of toner as that consumed by the toner and prevents a decrease in toner density.

  However, in the conventional technology as described above, there is a problem that productivity of printed matter decreases because the printing interval is increased.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus and a toner replenishing method capable of stabilizing the development process without reducing the productivity of printed matter.

  In order to solve the above-described problems and achieve the object, an image forming apparatus according to an aspect of the present invention includes a printing rate calculation unit that calculates a printing rate of image data, and a dot that calculates the number of dots of the image data. A remaining amount determination that determines whether or not there is an amount of toner exceeding a first threshold in a number calculation unit and a developing unit that develops the electrostatic latent image formed on the image carrier with toner based on the image data And the amount of toner consumed from the number of dots calculated by the number-of-dots calculation unit during the period from the last toner supply until the remaining amount determination unit determines that there is no toner exceeding the first threshold value. A first cumulative toner consumption calculation unit that calculates the first cumulative toner consumption by calculating and accumulating the calculated toner consumption, and the remaining amount determination unit has no toner exceeding the first threshold. If determined, the first Accumulating the print rate calculated by the replenishment control unit for replenishing the toner consumption amount of toner from the toner replenishment unit to the developing unit, and the print rate calculated by the print rate calculating unit during toner replenishment to the developing unit. And a second cumulative toner consumption amount calculation unit that calculates a second cumulative toner consumption amount from the cumulative printing rate when the calculated cumulative printing rate is equal to or greater than a second threshold, and the replenishment control unit Is characterized in that the second cumulative toner consumption amount of toner is further supplied from the toner supply unit to the developing unit.

  The toner supply method according to another aspect of the present invention includes a printing rate calculation step in which the printing rate calculation unit calculates the printing rate of the image data, and a dot number calculation unit calculates the number of dots in the image data. Whether or not there is an amount of toner exceeding the first threshold in the developing unit that develops the electrostatic latent image formed on the image carrier based on the image data with the dot number calculating step and the remaining amount determining unit. A remaining amount determination step for determining whether or not the first cumulative toner consumption amount calculation unit determines that there is no toner exceeding the first threshold by the remaining amount determination step after the previous toner replenishment A first cumulative toner consumption calculation unit that calculates a toner consumption amount from the dot number calculated in the dot number calculation step and accumulates the calculated toner consumption amount to calculate a first cumulative toner consumption amount; control However, when it is determined in the remaining amount determination step that there is no toner exceeding the first threshold, the first replenishment control step of replenishing the developing unit with toner of the first cumulative toner consumption amount from the toner replenishment unit. And a second cumulative toner consumption calculation unit calculates the cumulative printing rate by accumulating the printing rate calculated by the printing rate calculation step during toner replenishment to the developing unit, and the calculated cumulative printing rate is A second cumulative toner consumption calculating step for calculating a second cumulative toner consumption from the cumulative printing rate when the second threshold is exceeded, and the replenishment control unit And a second replenishment control step for further replenishing the developing unit from the toner replenishing unit.

  According to the present invention, it is possible to stabilize the development process without reducing the productivity of printed matter.

FIG. 1 is a mechanical configuration diagram illustrating an example of a printing apparatus according to the present embodiment. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the printing apparatus according to the present embodiment. FIG. 3 is a block diagram illustrating an example of a functional configuration of the printing apparatus according to the present embodiment. FIG. 4 is a flowchart illustrating an example of toner supply processing of the printing apparatus according to the present exemplary embodiment.

  Hereinafter, embodiments of an image forming apparatus and a toner supply method according to the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the image forming apparatus of the present invention is an electrophotographic color printing apparatus, specifically, four colors of black (K), cyan (C), magenta (M), and yellow (Y). A case where the present invention is applied to a printing apparatus that forms an image will be described as an example, but the present invention is not limited to this. The image forming apparatus of the present invention can be applied to any color and monochrome as long as it is an apparatus that forms an image by an electrophotographic method. For example, an electrophotographic facsimile machine, a copying machine, and a multifunction peripheral (MFP) ) Etc. Note that a multifunction peripheral is a device having at least two functions among a printing function, a copying function, a scanner function, and a facsimile function.

  First, the configuration of the printing apparatus according to the present embodiment will be described.

  FIG. 1 is a mechanical configuration diagram illustrating an example of a printing apparatus 1 according to the present embodiment. As shown in FIG. 1, the printing apparatus 1 includes an image forming unit 10K, 10C, 10M, and 10Y, a replenishing unit 20K, 20C, 20M, and 20Y, an exposure unit 30, a transfer belt 40, and a driving roller 41. , Tension roller 42, paper feed tray 50, paper feed roller 51, registration roller 52, secondary transfer roller 60, waste toner box 61, fixing unit 70, paper discharge roller 80, paper discharge A table 81 and a double-sided roller 82 are provided.

  As shown in FIG. 1, the image forming units 10K, 10C, 10M, and 10Y and the replenishing units 20K, 20C, 20M, and 20Y are arranged from the upstream side in the moving direction (arrow S direction) of the transfer belt 40 with K, They are arranged along the transfer belt 40 in the order of C, M, and Y. As described above, the printing apparatus 1 according to the present embodiment uses a so-called tandem method, but is not limited thereto.

  The image forming unit 10K includes a photoreceptor 11K, a charger 12K, a developing unit 13K, a primary transfer roller 18K, and a cleaner blade 19K. The image forming unit 10K and the exposure unit 30 perform an image forming process (charging process, exposure process, developing process, transfer process, and cleaning process) on the photoconductor 11K, thereby forming a black toner image on the photoconductor 11K. Formed and transferred to the transfer belt 40.

  The image forming units 10C, 10M, and 10Y all have the same components as the image forming unit 10K. The image forming unit 10C forms a cyan toner image by performing an image forming process. The image forming unit 10M forms a magenta toner image by performing an image forming process, and the image forming unit 10Y forms a yellow toner image by performing an image forming process. Therefore, in the following, description will be made mainly on the components of the image forming unit 10K, and the components of the image forming units 10C, 10M, and 10Y will be denoted by K attached to the reference numerals of the components of the image forming unit 10K. Instead, only C, M, and Y are attached, and the description thereof is omitted. In this embodiment, non-magnetic one-component toner is used as the toner, but the present invention is not limited to this.

  The photoconductor 11K is an image carrier and is rotationally driven by a drive motor (not shown).

  First, in the charging step, the charger 12K that is in contact with the photoreceptor 11K uniformly charges the outer peripheral surface of the rotationally driven photoreceptor 11K in the dark.

Subsequently, in the exposure process, the exposure unit 30 exposes the photoconductor 11K to form an electrostatic latent image based on black image data generated by a controller (not shown). Specifically, the exposure unit 30 exposes the charged surface of the photosensitive member 11K with the laser beam L _K corresponding to black, to the surface of the photosensitive member 11K, to form an electrostatic latent image based on image data of black. The exposure unit 30, for the photoreceptor 11C, exposed with laser light L _C corresponding to cyan, the photoreceptor 11M, exposed with the laser beam L _M corresponding to magenta, for the photosensitive member 11Y, the yellow exposed with the laser beam L _Y corresponding to.

  Subsequently, in the developing process, the developing unit 13K develops the electrostatic latent image formed on the photoconductor 11K using the black toner stored in the developing unit 13K, and black toner is formed on the photoconductor 11K. Form an image.

  Here, the replenishing units 20K, 20C, 20M, and 20Y will be described. The replenishing unit 20K is a toner cartridge that can be attached to and detached from the developing unit 13K, and contains black toner for replenishment. The replenishing unit 20K replenishes the developing unit 13K with black toner when the remaining amount of black toner in the developing unit 13K falls below the first threshold. The replenishing unit 20C is detachable from the developing unit 13C and contains cyan toner, the replenishing unit 20M is detachable from the developing unit 13M and contains magenta toner, and the replenishing unit 20Y is removable from the developing unit 13Y. Although yellow toner is contained, all of them have the same components as the replenishing unit 20K and perform the same operation as the replenishing unit 20K.

  Subsequently, in the transfer process, the primary transfer roller 18K transfers the black toner image formed on the photoconductor 11K to the transfer belt 40 at a primary transfer position where the photoconductor 11K and the transfer belt 40 are in contact with each other. As a result, a black toner image is formed on the transfer belt 40. A small amount of untransferred toner remains on the photoreceptor 11K even after the toner image is transferred.

  Subsequently, in the cleaning process, the cleaner blade 19K wipes off the untransferred toner remaining on the photoreceptor 11K.

  The transfer belt 40 is an endless belt wound around a driving roller 41 and a tension roller 42, and moves endlessly in the direction of arrow S when the driving roller 41 is rotationally driven. First, a black toner image is transferred to the transfer belt 40 by the image forming unit 10K, then a cyan toner image is formed by the image forming unit 10C, a magenta toner image is formed by the image forming unit 10M, and yellow is formed by the image forming unit 10Y. The toner images are sequentially superimposed and transferred. As a result, a full-color toner image is formed on the transfer belt 40. The transfer belt 40 conveys the formed full-color toner image to a secondary transfer position where the driving roller 41 and the secondary transfer roller 60 are in contact with each other.

  In the paper feed tray 50, a plurality of recording papers are stacked and stored. The paper feed roller 51 is in contact with the recording paper located at the uppermost portion of the paper supply tray 50, and feeds the recording paper in contact with the recording paper by being rotationally driven. The registration roller 52 sends the recording paper fed by the paper feeding roller 51 to the secondary transfer position at a timing when the full color toner image conveyed by the transfer belt 40 overlaps the secondary transfer position.

  The secondary transfer roller 60 collectively transfers the full-color toner image conveyed by the transfer belt 40 onto the recording paper fed by the registration roller 52 at the secondary transfer position.

  The waste toner box 61 collects the toner remaining on the transfer belt 40 without being transferred to the pattern formed on the transfer belt 40 or the recording paper.

  The fixing unit 70 fixes the full color toner image on the recording paper by heating and pressurizing the recording paper on which the full color toner image is transferred.

  The paper discharge roller 80 discharges the recording paper on which the full-color toner image is fixed by the fixing unit 70 to a paper discharge table 81. In the case of performing duplex printing, the paper discharge roller 80 conveys the recording paper to the double-sided roller 82 by reversely rotating immediately before the recording paper passes through the paper discharge roller 80.

  The double-sided roller 82 conveys the recording sheet conveyed from the paper discharge roller 80 to the registration roller 52 again. The recording paper transported to the registration roller 52 is re-fed from the registration roller 52, the toner image is transferred to the surface opposite to the previous time by the secondary transfer roller 60, fixed by the fixing unit 70, and the paper discharge roller 80. As a result, the paper is discharged onto the paper discharge tray 81.

  FIG. 2 is a block diagram illustrating an example of a hardware configuration of the printing apparatus 1 according to the present embodiment. The printing apparatus 1 includes an operation panel I / F 101, an operation panel 103, NVRAM (Non Volatile Random Access Memory) 105K, 105C, 105M, and 105Y, an external I / F 107, an image processing IC 109, and an I / O 111. ROM (Read Only Memory) 113, RAM 115, and CPU (Central Processing Unit) 117, and these devices are connected to each other via a system bus 119. The printing apparatus 1 also includes electrical components such as remaining amount sensors 121K, 121C, 121M, and 121Y, a toner supply drive motor 123, and toner supply clutches 125K, 125C, 125M, and 125Y.

  In the following description, when it is not necessary to distinguish the developing units 13K, 13C, 13M, and 13Y, they may be simply referred to as the developing unit 13, and the replenishing units 20K, 20C, 20M, and 20Y are distinguished from each other. When there is no need, it may be simply referred to as the replenishment unit 20, and when there is no need to distinguish the remaining amount sensors 121K, 121C, 121M, and 121Y, there may be simply referred to as the remaining amount sensor 121, and the toner replenishing clutch 125K. , 125C, 125M, and 125Y may be simply referred to as a toner replenishing clutch 125.

  The operation panel I / F 101 is an interface between the operation panel 103 and the system bus 119. The operation panel 103 inputs settings for various modes of the printing apparatus 1 to the CPU 117 via the operation panel I / F 101.

  The NVRAMs 105K, 105C, 105M, and 105Y are mounted on the replenishing units 20K, 20C, 20M, and 20Y, respectively, and store the cumulative toner consumption amount of the developing unit 13 corresponding to the mounted replenishing unit 20 and the like.

  The external I / F 107 is a communication I / F with an external device (not shown) such as a host computer.

  The image processing IC 109 transmits black, cyan, magenta, and yellow image data generated by a controller (not shown) to the exposure unit 30. Thereby, the exposure unit 30 performs exposure for forming an electrostatic latent image based on image data of the corresponding color on each of the photoreceptors 11K, 11C, 11M, and 11Y. The image processing IC 109 counts the number of dots (number of pixels) of the acquired black, cyan, magenta, and yellow image data.

  The I / O 111 is an interface between the system bus 119 and electrical components such as the remaining amount sensors 121K, 121C, 121M, and 121Y, the toner supply driving motor 123, and the toner supply clutch 125K, 125C, 125M, and 125Y.

  The remaining amount sensors 121K, 121C, 121M, and 121Y are installed in the developing units 13K, 13C, 13M, and 13Y, respectively, and detect the remaining amount of toner stored in the installed developing unit 13. .

  The toner replenishing drive motor 123 is a driving source for the replenishing units 20K, 20C, 20M, and 20Y. The toner replenishing clutches 125K, 125C, 125M, and 125Y are the driving sources for the replenishing units 20K, 20C, 20M, and 20Y, respectively. It is.

  The ROM 113 stores a control program executed by the CPU 117 and the like. The RAM 115 is used as a main memory and a work area of the CPU 117. Specifically, the RAM 115K, 105C, 105M, and 105Y and the data expansion area stored in the ROM 113 and the remaining amount sensors 121K, 121C, 121M, And 121Y are used for a temporary storage area of the data detected by 121Y. The RAM 115 can be expanded in memory capacity by an optional RAM connected to an expansion port (not shown). The CPU 117 generally controls access to each device connected to the system bus 119 based on a control program stored in the ROM 113 and the like, and electrical components connected via the I / O 111. Controls input / output to and from. The CPU 117 communicates with an external device such as a host computer via the external I / F 107.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the printing apparatus 1 according to the present embodiment. The printing apparatus 1 includes a storage unit 201, a dot number calculation unit 203, a first cumulative toner consumption amount calculation unit 205, a remaining amount determination unit 207, a replenishment control unit 209, a print rate calculation unit 211, and a second A cumulative toner consumption amount calculation unit 213; In this embodiment, the storage unit 201 is realized by the NVRAMs 105K, 105C, 105M, and 105Y, the RAM 115, and the like. The dot number calculation unit 203 is realized by the image processing IC 109, and the first cumulative toner consumption calculation unit 205, the remaining amount is calculated. The amount determination unit 207, the replenishment control unit 209, the printing rate calculation unit 211, and the second cumulative toner consumption amount calculation unit 213 are realized by the CPU 117, but are not limited thereto.

  The storage unit 201 calculates a cumulative toner consumption amount of each color (an example of a first cumulative toner consumption amount) calculated by a first cumulative toner consumption amount calculation unit 205 described later, and a second cumulative toner consumption amount calculation unit 213 described later. The accumulated print rate of each color and various threshold values are stored.

  The dot number calculation unit 203 calculates the number of dots in the image data. Specifically, the dot number calculation unit 203 counts the number of dots of black, cyan, magenta, and yellow image data generated by the controller.

  The first cumulative toner consumption amount calculation unit 205 calculates the toner consumption amount from the number of dots calculated by the dot number calculation unit 203, calculates the cumulative toner consumption amount by accumulating the calculated toner consumption amount, and the storage unit 201. To store. Specifically, the first cumulative toner consumption amount calculation unit 205 calculates the toner consumption amount from the number of dots calculated by the dot number calculation unit 203, and the calculated toner consumption amount is stored in the storage unit 201. The cumulative toner consumption amount stored in the storage unit 201 is updated by adding to the cumulative toner consumption amount of the corresponding color.

  Here, in the present embodiment, the first cumulative toner consumption calculation unit 205 determines that there is an amount of toner exceeding the first threshold value in the developing unit 13 by a remaining amount determination unit 207 described later, and the developing unit 13 While the toner is not replenished, the cumulative toner consumption amount of the color corresponding to the developing unit 13 is updated. If the remaining amount determining unit 207 determines that the developing unit 13 does not have an amount of toner exceeding the first threshold, the developing unit 13 is supplied with toner, and the cumulative toner consumption of the color corresponding to the developing unit 13 is performed. The amount is initialized in the storage unit 201. That is, the first cumulative toner consumption amount calculation unit 205 calculates the cumulative toner consumption amount during the period after the previous toner supply until the remaining amount determination unit 207 determines that there is no amount of toner exceeding the first threshold ( Update.

  The remaining amount determination unit 207 determines whether each of the developing units 13K, 13C, 13M, and 13Y has an amount of toner that exceeds the first threshold. Specifically, when the developing unit 13 is not supplied with toner, the remaining amount determination unit 207 reads the output value of the remaining amount sensor 121 installed in the developing unit 13 and uses the read output value as the developing unit. By comparing with the first threshold value of the color corresponding to the part 13, it is determined whether or not there is an amount of toner exceeding the first threshold value in the developing part 13. The first threshold value for each color is stored in the storage unit 201.

  Further, when the toner supply to the developing unit 13 is completed, the remaining amount determining unit 207 determines whether or not there is an amount of toner exceeding the first threshold in the developing unit 13.

  If the remaining amount determination unit 207 determines that the developing unit 13 does not have an amount of toner exceeding the first threshold, the replenishment control unit 209 handles the accumulated toner consumption amount of the color corresponding to the developing unit 13. The developing unit 13 is replenished from the replenishing unit 20 to be performed. Specifically, when the remaining amount determination unit 207 determines that the developing unit 13 does not have an amount of toner exceeding the first threshold, the replenishment control unit 209 determines the color corresponding to the developing unit 13 from the storage unit 201. Read accumulated toner consumption. Then, the replenishment control unit 209 drives the toner replenishment drive motor 123 and the toner replenishment clutch 125 of the color corresponding to the developing unit 13, and reads the toner of the accumulated toner consumption read from the corresponding replenishing unit 20 to the developing unit 13. To replenish.

  Further, the replenishment control unit 209 transfers the toner of the cumulative toner consumption amount (an example of the second cumulative toner consumption amount) calculated by a second cumulative toner consumption amount calculation unit 213 described later from the corresponding color supply unit 20 to the developing unit. 13 is replenished. In this case, the replenishment control unit 209 continues the replenishment of the toner of the accumulated toner consumption amount (calculated by the first accumulated toner consumption amount calculation unit 205) stored in the storage unit 201, and then the second accumulated toner consumption. The toner of the cumulative toner consumption calculated by the amount calculation unit 213 is supplied from the corresponding color supply unit 20 to the developing unit 13.

  The printing rate calculation unit 211 calculates the printing rate of image data. Specifically, the printing rate calculation unit 211 calculates the printing rate of each of black, cyan, magenta, and yellow image data generated by the controller.

  The second cumulative toner consumption amount calculation unit 213 calculates the cumulative printing rate by accumulating the printing rate calculated by the printing rate calculation unit 211. When the calculated cumulative printing rate is equal to or greater than the second threshold, the cumulative amount is calculated. Accumulated toner consumption is calculated from the printing rate.

  Specifically, the second cumulative toner consumption calculation unit 213 adds the print rate calculated by the print rate calculation unit 211 to the cumulative print rate of the corresponding color stored in the storage unit 201, The cumulative printing rate stored in the storage unit 201 is updated. Here, in the present embodiment, when the remaining amount determination unit 207 determines that the developing unit 13 does not have an amount of toner exceeding the first threshold value, the developing unit 13 is supplied with toner and corresponds to the developing unit 13. The accumulated color printing rate is initialized in the storage unit 201. That is, the second cumulative toner consumption calculation unit 213 calculates (updates) the cumulative printing rate after the start of toner supply.

  Then, the second cumulative toner consumption calculation unit 213 reads the cumulative printing rate stored in the storage unit 201, compares the read cumulative printing rate with the second threshold value of the corresponding color, and becomes equal to or larger than the second threshold value. In this case, the cumulative toner consumption is calculated from the cumulative printing rate. The second threshold value for each color is stored in the storage unit 201.

  Next, the operation of the printing apparatus according to the present embodiment will be described.

  FIG. 4 is a flowchart illustrating an example of toner supply processing of the printing apparatus 1 according to the present embodiment. In the example shown in FIG. 4, the black toner replenishment process will be described, but the same process can be applied to the cyan toner, magenta toner, and yellow toner replenishment.

  When the printing apparatus 1 starts printing, the printing rate calculation unit 211 calculates the printing rate of the black image data of the page to be printed (step S100).

  Subsequently, the second cumulative toner consumption calculation unit 213 adds the printing rate calculated by the printing rate calculation unit 211 to the cumulative printing rate of black (black image data) stored in the storage unit 201. Thus, the cumulative printing rate stored in the storage unit 201 is updated (step S102).

  Subsequently, the exposure unit 30 starts exposure to the photoconductor 11K, and starts forming an electrostatic latent image based on the black image data of the print target page on the photoconductor 11K (step S104).

  Subsequently, the dot number calculation unit 203 calculates the number of dots of black image data of the print target page (step S106).

  Subsequently, the first cumulative toner consumption amount calculation unit 205 calculates the toner consumption amount from the number of dots calculated by the dot number calculation unit 203, and the calculated toner consumption amount is stored in the black (black) The cumulative toner consumption amount stored in the storage unit 201 is updated by adding to the cumulative toner consumption amount of (image data) (step S108).

  Subsequently, when the development of the electrostatic latent image based on the black image data of the page to be printed is completed, the remaining amount determination unit 207 reads the output value of the remaining amount sensor 121K and stores the black ( It is determined whether or not there is an amount of black toner in the developing unit 13K that exceeds the first threshold value (step S110).

  If there is an amount of black toner exceeding the first threshold in the developing unit 13K (Yes in step S110) and there is printing of the next page (Yes in step S112), the process returns to step S100, and the next page is printed. . Further, when there is an amount of black toner exceeding the first threshold in the developing unit 13K (Yes in step S110), and the next page is not printed (No in step S112), the process ends.

  On the other hand, if there is no black toner in the developing unit 13K that exceeds the first threshold (No in step S110), the replenishment control unit 209 reads the accumulated toner consumption amount of black from the storage unit 201 and substitutes it for the toner replenishment amount. (Step S114).

  Subsequently, the replenishment control unit 209 drives the toner replenishment drive motor 123 and the toner replenishment clutch 125K to start the replenishment of the black toner of the toner replenishment amount from the replenishment unit 20K to the developing unit 13K (step S116).

  Subsequently, the replenishment control unit 209 initializes the black cumulative printing rate and the black cumulative toner consumption stored in the storage unit 201 (step S118).

  Subsequently, when there is a print request for the next page (Yes in step S120), the print rate calculation unit 211 calculates the print rate of the black image data of the next page to be printed (step S122). If there is no print request for the next page (No in step S120), the process proceeds to step S132.

  Subsequently, the second cumulative toner consumption amount calculation unit 213 adds the print rate calculated by the print rate calculation unit 211 to the black cumulative print rate stored in the storage unit 201, thereby causing the storage unit 201 to store the print rate. The stored cumulative printing rate is updated (step S124).

  Subsequently, the exposure unit 30 starts exposure to the photoconductor 11K, and starts forming an electrostatic latent image based on the black image data of the next page to be printed on the photoconductor 11K (step S126).

  Subsequently, the second cumulative toner consumption calculation unit 213 reads the black cumulative printing rate stored in the storage unit 201, and sets the second threshold value of black (black image data) stored in the storage unit 201. In comparison, it is determined whether or not the read cumulative printing rate is equal to or greater than the second threshold value of black (step S128). Accordingly, the second cumulative toner consumption amount calculation unit 213 determines whether or not the consumed toner amount is larger than the replenished toner amount.

  When the read cumulative print rate is equal to or greater than the second threshold value of black (Yes in step S128), that is, when the consumed toner amount is larger than the replenished toner amount, the second cumulative toner consumption amount calculation unit In step S130, the cumulative toner consumption is calculated from the read cumulative printing rate. Then, the process returns to step S114. As a result, the cumulative toner consumption calculated by the second cumulative toner consumption calculation unit 213 is substituted into the toner supply amount, and the black toner having the cumulative toner consumption calculated by the first cumulative toner consumption calculation unit 205 is supplied. Subsequently, the black toner having the cumulative toner consumption calculated by the second cumulative toner consumption calculator 213 is supplied.

  On the other hand, if the read cumulative printing rate is not equal to or greater than the second threshold value of black (No in step S128), that is, if the consumed toner amount is not greater than the replenished toner amount, the black toner replenishment is completed. If not (No in Step S132), the process returns to Step S120, and if the black toner supply is completed (Yes in Step S132), the process returns to Step S110. When the process returns to step S110, the remaining amount determination unit 207 determines whether or not there is an amount of black toner exceeding the first threshold in the developing unit 13K.

  As described above, according to the present embodiment, since printing of a page is executed even while toner is being replenished, it is possible to prevent the productivity of the printed matter from being lowered and to improve the productivity of the printed matter. In this embodiment, during toner replenishment, the remaining amount of toner in the developing unit is detected using the printing rate of image data, and if necessary, toner is further replenished, so that the development process can be stabilized. For this reason, for example, even when a pattern image with a high printing rate is continuously printed during toner replenishment, the amount of toner consumed from the developing unit is larger than the amount of toner replenished. The process can be stabilized.

(Modification)
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, the remaining amount determination unit 207 may change the first threshold stored in the storage unit 201. In this case, the remaining amount determination unit 207 may change the first threshold according to the accumulated toner consumption (calculated by the first accumulated toner consumption calculation unit 205) stored in the storage unit 201. Alternatively, the first threshold value may be changed in accordance with an input from the operation panel 103. In this way, it is possible to correct individual differences of the remaining amount sensor 121 and meet customer needs.

1 Printing device 10K, 10C, 10M, 10Y Image forming unit 11K, 11C, 11M, 11Y Photoconductor 12K, 12C, 12M, 12Y Charger 13K, 13C, 13M, 13Y Developing unit 18K, 18C, 18M, 18Y Primary transfer roller 19K, 19C, 19M, 19Y Cleaner blade 20K, 20C, 20M, 20Y Supply unit 30 Exposure unit 40 Transfer belt 41 Drive roller 42 Tension roller 50 Paper feed tray 51 Paper feed roller 52 Registration roller 60 Secondary transfer roller 61 Waste toner box 70 Fixing Unit 80 Paper Discharge Roller 81 Paper Discharge Stand 82 Double-Sided Roller 101 Operation Panel I / F
103 Operation panel 105K, 105C, 105M, 105Y NVRAM
107 External I / F
109 Image processing IC
111 I / O
113 ROM
115 RAM
117 CPU
119 System bus 121K, 121C, 121M, 121Y Remaining amount sensor 123 Toner replenishing drive motor 125K, 125C, 125M, 125Y Toner replenishing clutch 201 Storage unit 203 Dot number calculating unit 205 First cumulative toner consumption calculating unit 207 Remaining amount determining unit 209 Supply control unit 211 Print rate calculation unit 213 Second cumulative toner consumption calculation unit

JP-A-10-123906

Claims (5)

A print rate calculation unit for calculating the print rate of image data;
A dot number calculation unit for calculating the number of dots of the image data;
A remaining amount determining unit that determines whether or not there is an amount of toner that exceeds a first threshold in a developing unit that develops the electrostatic latent image formed on the image carrier with toner based on the image data;
A toner consumption amount is calculated from the number of dots calculated by the dot number calculation unit during a period from the previous toner supply until the remaining amount determination unit determines that there is no toner exceeding the first threshold; A first cumulative toner consumption calculating unit that calculates the first cumulative toner consumption by accumulating the calculated toner consumption;
A replenishment control unit that replenishes the developing unit with toner of the first cumulative toner consumption amount when the remaining amount determination unit determines that there is no toner exceeding the first threshold;
The cumulative printing rate is calculated by accumulating the printing rate calculated by the printing rate calculating unit during toner supply to the developing unit, and the cumulative printing rate is calculated when the calculated cumulative printing rate is equal to or greater than a second threshold value. A second cumulative toner consumption calculating unit that calculates a second cumulative toner consumption from the rate,
The image forming apparatus, wherein the replenishment control unit further replenishes the developing unit with the toner of the second cumulative toner consumption amount from the toner replenishment unit.   If the cumulative printing rate does not exceed the second threshold during toner replenishment to the developing unit, the remaining amount determining unit may cause the developing unit to exceed the first threshold after toner replenishment. The image forming apparatus according to claim 1, wherein it is determined whether or not there is.   The image forming apparatus according to claim 1, wherein the remaining amount determination unit changes the first threshold value.   The replenishment control unit supplies the second cumulative toner consumption amount of toner from the toner replenishment unit to the developing unit following the replenishment of the toner of the first cumulative toner consumption amount. The image forming apparatus according to any one of 1 to 3. A printing rate calculating step in which a printing rate calculating unit calculates a printing rate of the image data;
A dot number calculating unit that calculates the number of dots of the image data; and
The remaining amount determining unit determines whether or not the developing unit that develops the electrostatic latent image formed on the image carrier based on the image data with toner includes an amount of toner exceeding the first threshold. A determination step;
The first cumulative toner consumption calculation unit calculates the dot number calculation step during the period from the previous toner replenishment until the remaining amount determination step determines that there is no toner exceeding the first threshold. A first cumulative toner consumption calculating unit that calculates a toner consumption amount from the number of dots and accumulates the calculated toner consumption amount to calculate a first cumulative toner consumption amount;
When the replenishment control unit determines that there is no toner exceeding the first threshold in the remaining amount determination step, the first cumulative toner consumption amount of toner is replenished from the toner replenishment unit to the developing unit. A replenishment control step;
The second cumulative toner consumption amount calculation unit calculates the cumulative printing rate by accumulating the printing rate calculated by the printing rate calculating step during toner supply to the developing unit, and the calculated cumulative printing rate is the second A second cumulative toner consumption calculating step of calculating a second cumulative toner consumption from the cumulative printing rate when the threshold is equal to or greater than a threshold;
A second supply control step in which the supply control unit further supplies the second cumulative toner consumption amount of toner from the toner supply unit to the developing unit;
And a toner replenishing method.

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