JP2015114572A - Image forming apparatus, method of supplying toner to developing device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, a method of supplying toner to a developing device, and a program enabling the correction of ununiformity in the charge amount occurring due to a toner supply operation to suppress a fogging phenomenon.SOLUTION: A method of supplying toner to a developing device includes the steps of: calculating, when a developer including toner is conveyed to circulate in a developing device 34, the consumption of the developer for each of a plurality of areas on the basis of image data (S4, S5); determining whether the calculated consumption calculated for each of the plurality of areas is in a first area of less than a predetermined first consumption or in a second area of the predetermined consumption or more (S6); when determined that the calculated consumption is in the first area, supplying a toner of a first supply amount corresponding to the calculated consumption in the first area to the first area from a storage part having the toner stored therein (S7, S8); and when determined that the calculated consumption is in the second area, supplying a toner of a second supply amount smaller than the calculated consumption in the second area to the second area from the storage part (S7, S8).

Description

  The present invention relates to an image forming apparatus for supplying toner to a developing device, a toner supplying method for supplying toner to a developing device, and a control program for supplying toner to a developing device.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers that form images on paper by electrophotography are equipped with a developing device that performs development using toner. As an example of the developing device, a developing device that performs development by a two-component developing method using toner and a magnetic carrier is known. An electrostatic latent image formed on an image carrier such as a photoreceptor is supplied with toner by a developing device and developed as a toner image. The toner image is transferred from the photoreceptor to the paper by a transfer device. The sheet on which the toner image is transferred is heated and pressed by a fixing device. As a result, the toner image is fixed on the paper and an image is formed on the paper. This completes a series of image forming operations.

  A developer containing toner used in the above-described image forming operation is accommodated in the developing device. When the image forming operation is repeated, the toner contained in the developing device is consumed and the amount of toner is reduced. Therefore, the image forming apparatus is provided with a detection unit that detects the amount of consumed toner so that the amount of toner in the developing device is always a specified amount based on the detected amount of consumed toner. The toner is automatically supplied from the toner container. In addition, the developing device is provided with an agitating unit that conveys the toner in one direction while agitating the toner. The supplied toner is appropriately stirred by the stirring unit. As a result, the toner necessary for development is charged in the toner.

  By the way, when development is performed based on image data in which a region with a high printing rate on a sheet and a region with a low printing rate are mixed, the developer in the developing device includes a region with a large amount of consumed toner and a consumption amount. Resulting in less area. Then, it is circulated and conveyed while maintaining the state for a while. When the next image forming operation is executed in such a state where regions having different toner amounts are mixed, there is a possibility that the density of the developed toner image is uneven due to the difference in the toner amount. On the other hand, in Patent Document 1, a toner density difference is eliminated by detecting a low toner density area in the toner storage chamber and supplying a toner with a shortage of a specified quantity to the area. A technique for making the amount uniform is disclosed.

JP 2007-304524 A

  In the technique disclosed in Patent Document 1, when a large amount of toner is consumed locally, such as when a solid black image is formed on a sheet, the toner is replenished only in that region. In this case, the newly replenished toner is not sufficiently agitated until it is used for the next development, resulting in poor charging, and the toner adheres in addition to the electrostatic latent image, causing fog development on the formed paper. Let Further, since the charge amount of the newly supplied toner and the charge amount of the toner remaining in the developing device are different, the developability becomes non-uniform. In this state, when a halftone image or the like is formed on a sheet, density unevenness may occur in the image.

  An object of the present invention is to provide an image forming apparatus, a toner replenishing method for a developing device, and a program capable of correcting unevenness in the amount of charge caused by a toner replenishing operation and suppressing a fog phenomenon.

  An image forming apparatus according to one aspect of the present invention includes a developing device, an agitation transport unit, a storage unit, a replenishment unit, a consumption calculation unit, and a replenishment control unit. The developing device supplies toner to an electrostatic latent image based on image data formed on the surface of the image carrier, and develops the electrostatic latent image with toner. The agitating and conveying unit is provided in the developing device and circulates and conveys at least a developer containing toner while stirring. The accommodating portion accommodates toner for replenishing the developing device. The replenishment unit replenishes the developing device with toner accommodated in the accommodation unit. The consumption amount calculation unit calculates a toner consumption amount for each of a plurality of regions in the developer circulated and conveyed in the developing device based on the image data. The replenishment control unit adds a first replenishment amount corresponding to the calculated consumption amount of the first region to a first region in which the calculated consumption amount calculated by the consumption amount calculation unit is less than a predetermined first consumption amount. The toner is replenished from the storage unit by the replenishing unit, and the calculated consumption calculated by the consumption calculating unit is greater than or equal to the first consumption, based on the calculated consumption of the second region. The second replenishment amount of the toner is replenished from the storage unit by the replenishment unit.

  A developing device toner replenishing method according to another aspect of the present invention includes first to fourth steps. In the first step, when the developer containing at least toner is circulated and conveyed in the developing unit, the consumption amount of each of the plurality of regions in the developer is determined by the electrostatic latent image developed by supplying the toner to the developing unit. Calculation is performed based on the image data of the image. In the second step, the calculated consumption amount for each of the plurality of regions calculated in the first step is a first region that is less than a predetermined first consumption amount, or is a second region that is greater than or equal to the first consumption amount. Determine if it is an area. In the third step, when the second region is determined to be the first region, the first supply amount of toner corresponding to the calculated consumption amount of the first region is transferred from the storage unit in which the toner is stored. Replenish the first area. In the fourth step, when the second region is determined to be the second region, the second supply amount of toner smaller than the calculated consumption amount of the second region is transferred from the container to the second region. Replenish.

  A program according to another aspect of the present invention is for causing a computer that controls the image forming apparatus to execute the first step to the fourth step. In the first step, when the developer containing at least toner is circulated and conveyed in the developing unit, the consumption amount of each of the plurality of regions in the developer is determined by the electrostatic latent image developed by supplying the toner to the developing unit. Calculation is performed based on the image data of the image. In the second step, the calculated consumption amount for each of the plurality of regions calculated in the first step is a first region that is less than a predetermined first consumption amount, or is a second region that is greater than or equal to the first consumption amount. Determine if it is an area. In the third step, when the second region is determined to be the first region, the first supply amount of toner corresponding to the calculated consumption amount of the first region is transferred from the storage unit in which the toner is stored. Replenish the first area. In the fourth step, when the second region is determined to be the second region, the second supply amount of toner smaller than the calculated consumption amount of the second region is transferred from the container to the second region. Replenish.

  According to the present invention, it is possible to correct the non-uniform charge amount caused by the toner replenishment operation and to suppress the fog phenomenon.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of a developing device provided in the image forming apparatus of FIG. 1. The figure which shows the cross section of the cut surface III-III in FIG. The figure which shows the structure of an image formation part. The functional block diagram which shows schematic structure of the replenishment control system of this invention. FIG. 4 is a diagram illustrating a relationship between a virtual area of a developing device and a position of an image developed on a sheet. FIG. 5 is a diagram illustrating an example when toner is supplied to a virtual area based on toner density. FIG. 6 is a diagram illustrating an example when toner is supplied to a virtual region based on a toner charge amount. FIG. 6 is a diagram illustrating an example of a comparison between a case where toner is supplied to a virtual area based on toner density and a case where toner is supplied to a virtual area based on a toner charge amount. FIG. 6 is a diagram illustrating a correspondence relationship between a toner replenishment amount, a toner charge amount, and an image density. FIG. 6 is a diagram illustrating an example of a relationship between a toner flying force and a toner adhesion force that change according to a toner charge amount. The flowchart which shows an example of the procedure of the replenishment control process performed by the control part. The flowchart which shows another example of the procedure of the replenishment control process performed by the control part.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

[Schematic Configuration of Image Forming Apparatus 100]
First, a schematic configuration of the image forming apparatus 100 according to the embodiment of the present invention will be described. As shown in FIG. 1, the image forming apparatus 100 includes an image reading unit 1, an ADF (Automatic Document Feeder) 2, an image forming unit 3, a paper feeding unit 4, a control unit 5, an operation display unit 6, and the like. Yes. The operation display unit 6 is a touch panel that displays various types of information in accordance with control instructions from the control unit 5 and inputs various types of information to the control unit 5 in response to user operations. Here, FIG. 1A is a front view of the image forming apparatus 100, and FIG. 1B is a plan view of the image reading unit 1. For convenience of explanation, the vertical direction in a state where the image forming apparatus 100 is installed is defined as the vertical direction 7, and the side where the operation display unit 6 is provided is the front side (front side), and the front-rear direction 8 is defined. The horizontal direction 9 is defined with the operation display unit 6 as the front. The image forming apparatus 100 is only an example of the image forming apparatus of the present invention, and may be, for example, a printer, a FAX apparatus, a copying machine, or the like.

  The image reading unit 1 acquires image data from the paper P. The image reading unit 1 is an image reading unit including a document cover 2A, a contact glass 11, a reading unit 12, a mirror 13, a mirror 14, an optical lens 15, a CCD (Charge Coupled Device) 16, and the like. The contact glass 11 is provided on the upper surface of the image reading unit 1, and is a transparent paper base on which a paper P that is an image reading target of the image forming apparatus 100 is placed.

  The document cover 2A covers the contact glass 11 as necessary. The image reading unit 1 reads an image from the paper P placed on the contact glass 11 under the control of the control unit 5.

  The reading unit 12 includes an LED light source 121 and a mirror 122, and is configured to be movable in the sub-scanning direction (the horizontal direction 9 in FIG. 1) by a moving mechanism (not shown) such as a stepping motor. When the reading unit 12 is moved in the sub-scanning direction by the moving mechanism, the light emitted from the LED light source 121 toward the contact glass 11 is scanned in the sub-scanning direction.

  The LED light source 121 includes a large number of white LEDs arranged along the main scanning direction of the image forming apparatus 100 (front-rear direction 8 in FIG. 1). The LED light source 121 emits white light for one line toward the paper P at the reading position 12 </ b> A on the contact glass 11. Note that the reading position 12A moves in the sub-scanning direction as the reading unit 12 moves in the sub-scanning direction.

  The mirror 122 reflects the reflected light when the light is irradiated from the LED light source 121 to the paper P at the reading position 12 </ b> A toward the mirror 13. The light reflected by the mirror 122 is guided to the optical lens 15 by the mirror 13 and the mirror 14. The optical lens 15 collects incident light and makes it incident on the CCD 16.

  The CCD 16 is a photoelectric conversion element that converts received light into an electrical signal (voltage) corresponding to the amount of light and outputs it to the control unit 5. Specifically, the CCD 16 generates image data based on an electrical signal corresponding to an image on the paper P based on light reflected from the paper P when light is emitted from the LED light source 121.

  The ADF 2 is provided on the document cover 2A. The ADF 2 is an automatic document feeder including a paper tray 21, a feeding mechanism 22, a plurality of transport rollers 23, a paper press 24, a paper discharge unit 25, and the like. The ADF 2 drives each of the feeding mechanism 22 and the transport roller 23 with a stepping motor (not shown), thereby causing the paper P set on the paper tray 21 to pass through the reading position 12A on the contact glass 11 and the paper discharge unit 25. Transport to. At this time, the image reading unit 1 reads the image of the paper P passing through the reading position 12A.

  The sheet presser 24 is provided at a position above the reading position 12 </ b> A on the contact glass 11 with an interval through which the sheet P can pass. The sheet presser 24 is formed in an elongated shape in the main scanning direction, and a white sheet is attached to the lower surface (the surface on the contact glass 11 side). In the image forming apparatus 100, the image data of the white sheet is read as white reference data. The white reference data is used for known shading correction and the like.

  The image forming unit 3 is an electrophotographic system that executes image forming processing (printing processing) based on image data read by the image reading unit 1 or image data input from an information processing apparatus such as an external personal computer. Image forming means. The image forming unit 3 includes a photosensitive member 31 (an example of an image carrier of the present invention), a charging device 32, an LSU (Laser Scanner Unit) 33, a developing device 34 (an example of a developing unit of the present invention), a transfer device 35, a charge eliminating device. A device 36, a fixing roller 37, a pressure roller 38, a toner container 39 (an example of a storage portion of the present invention), and the like are provided.

  In the image forming unit 3, an image is formed on the paper S fed from the paper feeding unit 4 according to the following procedure, and the paper S after the image formation is discharged to the paper discharge tray 40. Specifically, first, the photoreceptor 31 formed in a cylindrical shape by the charging device 32 is uniformly charged to a predetermined potential. Next, the LSU 33 irradiates the surface of the photoreceptor 31 with light based on the image data. As a result, an electrostatic latent image is formed on the surface of the photoreceptor 31. The electrostatic latent image on the photoconductor 31 is supplied with toner from the developing device 34 and is developed (visualized) as a toner image. Subsequently, the toner image formed on the photoreceptor 31 is transferred onto the paper S by the transfer device 35. Thereafter, the toner image transferred to the paper S is heated by the fixing roller 37 and melted and fixed to the paper S when the paper S passes between the fixing roller 37 and the pressure roller 38 and is discharged. The electric potential of the photoconductor 31 is neutralized by the neutralization device 36. Details of the developing device 34 will be described later.

  The paper feeding unit 4 feeds the paper S on which an image is formed in the image forming unit 3. The paper feed unit 4 feeds a plurality of sheets S placed in a paper feed cassette (not shown) mounted in a cassette mounting unit (not shown) one by one to the image forming unit 3.

[Configuration of Developing Device 34]
Next, the developing device 34 will be described in detail with reference to FIGS. The developing device 34 is a developing device that stores a developer containing at least toner and develops the toner using the toner.

  As shown in FIGS. 2 and 3, the developing device 34 is formed in a shape that is long in the front-rear direction 8. The developing device 34 has a casing 60 that is long in the front-rear direction 8. The housing 60 plays a role of a frame that supports the developing roller 61 (see FIG. 4) and a role of a container that accommodates the developer inside. A supply port 70 is formed outside the developing device 34. As shown in FIG. 4, the toner container 39 contains toner to be supplied to the developing device 34. When the toner container 39 is attached to the developing device 34, a shutter that opens and closes the replenishing port 70 is opened, so that the toner can be supplied from the toner container 39 to the developing device 34. Inside the toner container 39, a container screw 69 (an example of a replenishing portion of the present invention) is provided. The container screw 69 is provided with spiral wings around its axis, and is rotated by a drive motor (not shown) to replenish toner contained in the toner container 39 to a supply port 70 provided in the developing device 34. To do.

  Inside the housing 60 of the developing device 34, a developer storage unit 63, a screw feeder 64 (an example of the agitating and conveying unit of the present invention), a developing roller 61, a magnetic roller 62, and the like are provided. As shown in FIGS. 3 and 4, the developer reservoir 63 is formed in the bottom portion of the housing 60, and stores the developer supplied from the toner container 39 and the developer including the magnetic carrier. Container. A magnetic roller 62 that is a developer carrying member is disposed above the developer reservoir 63. The developing roller 61 that is a toner carrier is disposed opposite to the magnetic roller 62 at a position obliquely above the magnetic roller 62.

  Further, as shown in FIG. 5, the developing roller 61, the magnetic roller 62, the screw feeder 64 </ b> A, and the screw feeder 64 </ b> B are connected to a stepping motor 65. The stepping motor 65 supplies rotational force via a gear to rotate the screw feeder 64A, the screw feeder 64B, the developing roller 61, and the magnetic roller 62 in conjunction with each other. The developing roller 61 and the magnetic roller 62 are rotated in the forward rotation direction for supplying toner to the photoconductor 31 during development, and the screw feeder 64A and the screw feeder 64B are also rotated in the forward rotation direction determined by the gear in conjunction with this. To do.

  The developer storage unit 63 includes two adjacent developer storage chambers 63A and 63B extending in the longitudinal direction (front-rear direction 8) of the developing device 34. Each of the developer storage chambers 63A and 63B is formed in a cylindrical shape that is long in the front-rear direction 8. The developer storage chambers 63 </ b> A and 63 </ b> B are partitioned from each other by a partition plate that is integrally formed with the housing 60 and extends in the front-rear direction 8. However, the developer storage chambers 63A and 63B are not completely partitioned, and partition plates are not provided at both ends in the front-rear direction 8. Specifically, both end portions in the front-rear direction 8 of the developer storage chambers 63A and 63B are communicated with each other through a communication path. A replenishing port 70 is provided on the front side in the front-rear direction 8 of the developer storage chamber 63 </ b> A, and is a replenishment position where toner is replenished from the toner container 39.

  Each of the developer storage chambers 63A and 63B accommodates screw feeders 64A and 64B that agitate and convey the developer by rotating around the axis. The screw feeders 64A and 64B are provided with spiral wings around the axis. The screw feeders 64A and 64B are rotated by a stepping motor 65. The rotation directions of the screw feeders 64A and 64B are set in opposite directions. Accordingly, the developer is circulated and conveyed between the developer storage chamber 63A and the developer storage chamber 63B while being stirred. Further, since the screw feeder 64 circulates and conveys the developer via the replenishment position while stirring, the toner replenished from the toner container 39 is stirred together with the developer originally in the developing device 34. By this stirring, the toner of the developer in which the toner and the carrier are mixed has a charge.

  The magnetic roller 62 is formed long in the longitudinal direction (front-rear direction 8) of the developing device 34. The magnetic roller 62 is disposed along the developing device 34 and is rotated during development. A fixed so-called magnet roll (not shown) is arranged inside the magnetic roller 62. The magnet roll has a plurality of magnetic poles, and magnetically pumps the developer from the developer reservoir 63 onto the circumferential surface of the magnetic roller by magnetic force. When the developer layer attached on the circumferential surface of the magnetic roller is conveyed to the regulation gap as the magnetic roller 62 rotates, the layer thickness of the developer layer is regulated in the regulation gap. As a result, a uniform developer layer having a predetermined thickness is formed on the circumferential surface of the magnetic roller.

  The developing roller 61 is formed long in the longitudinal direction (front-rear direction 8) of the developing device 34. The developing roller 61 is disposed to face the magnetic roller 62 and the photoconductor 31 so as to extend in parallel, and is rotated during development. The developing roller 61 has a developing roller peripheral surface that receives toner from the developer layer and carries the toner layer while rotating in contact with the developer layer held on the peripheral surface of the magnetic roller. During the development in which the development operation is performed, the toner in the toner layer is supplied to the peripheral surface of the photoreceptor 31.

[Toner consumption by area]
As shown in FIG. 6, when the toner image formed on the sheet S has light and shade for each elongated region extending along the transport direction 9 </ b> A, the amount of developer consumed in the developing device 34 becomes non-uniform. The toner is a powder having fluidity, but the fluidity is low. For this reason, the state where the toner amount is not uniform is maintained for a while. The developer having a non-uniform toner amount is circulated and conveyed by the screw feeder 64. The time for one revolution until the developer conveyed while being stirred in the developing device 34 by the screw feeder 64 returns to the same position is sufficiently slower than the time for one rotation of the photosensitive member 31. For example, the moving speed of the developer in the developing device 34 is 30 mm / s, and the rotational speed of the photoconductor 31 is 300 to 400 mm / s. Therefore, a plurality of regions in the developer circulated and conveyed in the developing device 34 are within the time required for the photoreceptor 31 to make one rotation with respect to the direction in which the developer is circulated and conveyed in the developing device 34 (arrow 71). Divide evenly longer than the distance the developer moves. In the example shown in FIG. 6, the plurality of regions in the developer are divided into 16 regions corresponding to the developer storage chambers 63A and 63B. The plurality of regions in the developer are divided into 32 regions corresponding to the entire developer storage chamber 63. These regions move in the developing device 34 as the developer is circulated and conveyed. This makes it easy to handle the partial toner consumption of the developer for each of a plurality of areas. In the example shown in FIG. 6, the toner image developed on the paper S has a large amount of toner consumption in the order of the D4 area, the D9 area, and the D14 area. The amount of toner contained in the developer decreases in the order of region 14. When the plurality of areas of the developer circulated and conveyed by the screw feeder 64 reaches the replenishment position where the replenishing port 70 is provided, the toner is replenished from the toner container 39 to the plurality of areas by the container screw 69. be able to. With the container screw 69, it is possible to replenish toner in an amount corresponding to the amount of toner consumption from the toner container 39 to each of the regions 4, 9, and 14 in the developer.

  Here, a case where the toner amount corresponding to the toner consumption amount for each developer region is supplied will be described. Here, as in the example shown in FIG. 6, the description will be made assuming that the toners in the regions 4, 9, and 14 in the developer of the developing device 34 are consumed and the toners in the other regions are not consumed. FIG. 7A is a diagram illustrating a toner density value indicating a toner consumption amount for each region. FIG. 7B is a diagram illustrating the toner replenishment amount for each region. FIG. 7C is a diagram showing the toner density for each region after toner replenishment. FIG. 7D is a diagram illustrating the toner charge amount for each region after toner replenishment. FIG. 7E is a diagram illustrating the density of a toner image developed based on an electrostatic latent image having a uniform image density using the developer after toner replenishment.

  As shown in FIG. 7A, the toner density in the area where no toner is consumed is 8.0 Wt%, the toner density in area 4 is 7.5 Wt%, the toner density in area 9 is 7.0 Wt%, and The toner density in region 14 is 6.5 Wt%. The toner consumption corresponding to the toner density corresponds to 15 mg in the region 4, 30 mg in the region 9, and 45 mg in the region 14. Here, a toner amount corresponding to the toner consumption amount for each developer region is supplied. As shown in FIG. 7B, the amount of toner replenished from the toner container 39 by the container screw 69 is 15 mg in the region 4, 30 mg in the region 9, and 45 mg in the region 14. When replenished in this way, the toner density in the developing device 34 becomes uniform. As shown in FIG. 7C, the toner density in all regions in the developing device 34 is 8.0 Wt%. However, if the amount of toner to be newly replenished is large, the toner is not sufficiently stirred until it is used for the next development, resulting in poor charging. As shown in FIG. 7D, the toner charge amount in a region where toner is not replenished is 20 μC / g, the charge amount in region 4 is 18 μC / g, the charge amount in region 9 is 17 μC / g, and region 14 Is 15 μC / g. In this state, when the halftone image is formed on the paper S, as shown in FIG. 7E, the areas D4, D9, and D14 of the paper S using the toner in the area where the charge amount is insufficient. The image density is different from the image density of other regions.

[Toner replenishment considering toner charge amount for each area]
Next, a description will be given of a case where the toner amount is replenished in consideration of the toner charge amount for each developer region. Here, as in the example shown in FIGS. 6 and 7, it is assumed that the toner in the regions 4, 9, and 14 in the developer of the developing device 34 is consumed, and the toner in other regions is not consumed. explain. Further, 16 regions corresponding to the developer storage chamber 63B in which toner is supplied from the developing device 34 will be described. FIG. 8A is a diagram illustrating a toner density value indicating a toner consumption amount for each region. FIG. 8B is a diagram illustrating the toner supply amount for each region. FIG. 8C is a diagram illustrating the toner density for each region after toner replenishment. FIG. 8D is a diagram illustrating the toner charge amount for each region after toner replenishment. FIG. 8E is a diagram illustrating the density of a toner image developed based on an electrostatic latent image having a uniform image density using the developer after toner replenishment.

  As shown in FIG. 8A, as in FIG. 7A, the toner density in the area where the toner is not consumed is 8.0 Wt%, the toner density in area 4 is 7.5 Wt%, and the area 9 The toner density is 7.0 Wt%, and the toner density in the region 14 is 6.5 Wt%. The toner consumption corresponding to the toner density corresponds to 15 mg in the region 4, 30 mg in the region 9, and 45 mg in the region 14. However, in the example shown in FIG. 8, the control unit 5 replenishes the toner amount in consideration of the toner charge amount with the container screw 69. Even when the toner amount corresponding to the toner consumption amount is replenished, the toner amount corresponding to the toner consumption amount is replenished in the region where the toner charge amount is within the allowable range, and the toner amount corresponding to the toner consumption amount is replenished. In a region where the toner charge amount is outside the allowable range, a toner amount smaller than the toner consumption amount is supplied. In the example shown in FIG. 8B, the first consumption amount indicating whether or not the toner charge amount is within the allowable range even if the toner amount corresponding to the toner consumption amount is replenished (an example of the first consumption amount of the present invention). Is 15 mg. Hereinafter, a region where the toner consumption amount of the region is less than the first consumption amount is referred to as a first region (an example of the first region of the present invention), and a region where the toner consumption amount of the region is equal to or greater than the first consumption amount is referred to as the second region. This is referred to as a region (an example of the second region of the present invention). Note that the toner amount 15.0 mg corresponding to the toner consumption amount is replenished in the second area 4 where the toner consumption amount is 15.0 mg corresponding to the first consumption amount. In the region 9 (an example of the second region of the present invention) where the toner consumption amount is larger than the first consumption amount, the region 14 (an example of the second region of the present invention) has a toner amount smaller than the toner consumption amount. To be replenished.

  The amount of toner supplied to the second region 9 and the second region 14 is the remaining second consumption amount obtained by subtracting the reference consumption amount from the toner consumption amount of each second region (an example of the second consumption amount of the present invention). ) Is multiplied by a coefficient less than 1 to add the third consumption (an example of the third consumption according to the present invention) and the first consumption. In the example shown in FIG. 8B, for the second area 9, the remaining second consumption amount of 15 mg is obtained by subtracting the first consumption amount of 15 mg from the toner consumption amount of 30 mg in the second area 9. The third consumption multiplied by 0.5 is 7.5 mg. The toner replenishment amount in the second area 9 is 22.5 mg obtained by adding 7.5 mg as the third consumption amount and 15 mg as the first consumption amount. Similarly, for the second region 14, the remaining second consumption amount 30 mg, which is obtained by subtracting 15 mg as the first consumption amount from 45 mg as the toner consumption amount in the second region 14, is multiplied by 0.5. 3 Consumption is 15 mg. The amount of toner replenishment in the second region 14 is 30 mg obtained by adding 15 mg as the third consumption amount and 15 mg as the first consumption amount.

  In the first areas 1 to 3, 5 to 8, 10 to 13, 15, and 16 where the toner consumption amount is less than 15.0 mg, which is the first consumption amount, the toner amount corresponding to the toner consumption amount (first Replenishment amount) is replenished. Since the toner replenishment amount replenished to the second area is smaller than the toner consumption amount, the deficient insufficient toner amount is equally divided, and the toner amount equally divided into the first area is replenished. In other words, when there is the second area, a third supply amount corresponding to an amount obtained by subtracting the third consumption amount from the second consumption amount is divided equally, and an equal amount of toner is added to the first region. Is replenished. In the example shown in FIG. 8B, 15 mg is supplied to the second area 4, 22.5 mg is supplied to the second area 9, and 30 mg is supplied to the second area 14. The insufficient toner supply amount in the second area 4 is 0 mg, the insufficient toner supply amount in the second area 9 is 7.75 mg, and the insufficient toner supply amount in the second area 14 is 15 mg, for a total of 22.5 mg. A shortage occurs. Therefore, about 1.7 mg obtained by dividing 22.5 mg by 13 which is the number of the remaining first areas is replenished to the first area.

  As shown in FIG. 8B, when the replenishment is performed based on the toner charge amount, the toner density in the developing device 34 is not uniform. As shown in FIG. 8C, the toner density in the first area is 8.1 Wt%, the toner density in the second area 4 is 8.0 Wt%, the toner density in the second area 9 is 7.7 Wt%, The toner density in the second region 14 is 7.6 Wt%. However, the toner replenishment amount in the region where the toner consumption amount is large is relatively small, and the toner replenishment amount in the region where the toner replenishment amount is small is relatively large and is agitated substantially evenly until it is used for the next development. The charge amount becomes substantially uniform. In the example shown in FIG. 8D, the charge amount of the first region and the second region is 19 μC / g. When a halftone image is formed on the paper S in this state, the density of the image becomes substantially uniform as shown in FIG. The areas D4, D9, and D14 of the paper S that are developed with the toner of the second areas 4, 9, and 14 that consumed a large amount of toner in the previous development are the areas of the paper S that are developed with the toner of the other first areas. The image density is almost the same as that of other areas.

  The difference in developability between toner supply corresponding to the toner consumption and toner supply considering the toner charge amount will be described. FIG. 9A is a table of toner replenishment amounts corresponding to the toner consumption amounts for each region shown in FIG. FIG. 9B is a table showing the toner density, the charge amount, and the image density of the developed paper S in each region by toner replenishment corresponding to the toner consumption amount for each region shown in FIG. FIG. 9C is a table of toner replenishment amounts in consideration of the toner charge amount for each region shown in FIG. FIG. 9D is a table showing the toner density of each region, the charge amount, and the image density of the developed paper S according to the toner replenishment amount in consideration of the toner charge amount for each region shown in FIG. As shown in FIG. 9B, in the case of replenishment corresponding to the toner consumption, the standard deviation of the toner density after replenishment is 0.077, whereas as shown in FIG. 9D. In the case of replenishment in consideration of the toner charge amount, the standard deviation of the toner density after replenishment is 0.151. For this reason, in the replenishment considering the toner concentration, the variation in the toner concentration becomes large. However, in the case of replenishment corresponding to the toner consumption amount, the standard deviation of the toner charge amount after replenishment is 1.672, whereas in the case of replenishment considering the toner charge amount, the standard of the toner charge amount after replenishment The deviation is 0.544. For this reason, in the replenishment considering the toner charge amount, the variation in the toner charge amount is reduced. Therefore, in the case of replenishment corresponding to the toner consumption amount, the standard deviation of the value (Gray ID) indicating the image density after replenishment is 0.021, whereas in the case of replenishment considering the toner charge amount, The standard deviation of the value (Gray ID) indicating the image density after replenishment is 0.008. Therefore, in the replenishment considering the toner charge amount, the standard deviation of the value indicating the image density (Gray ID) is a value that is one digit lower. The image density is made uniform by replenishing in consideration of the toner charge amount.

  Here, the relationship between the toner charge amount and the image density (Gray ID) will be described. FIG. 10A is a graph showing the relationship between the toner replenishment amount for one region and the toner charge amount. FIG. 10B is a graph showing the relationship between the toner replenishment amount for one area and the image density. The toner charge amount tends to gradually decrease when the replenishment amount in one region exceeds 10 mg. On the other hand, the image density tends to deteriorate when the replenishment amount in one area exceeds 30 mg. For this reason, even if the toner charge amount is somewhat reduced, the image density is hardly affected, but when the toner charge amount is greatly reduced, the image density tends to deteriorate. This is because when the toner replenishment amount increases, the contact frequency between one toner and the carrier decreases, and it takes time until the toner charge amount is suitable for development. For this reason, when the second region is transported for use in the next development and used, the toner charge amount is not sufficient, which is considered to be a cause of unevenness in image density.

The relationship between the toner charge amount and the image density will be examined in more detail with reference to FIG. In FIG. 11, the horizontal axis represents the toner charge amount, and the vertical axis represents the strength of the force at each toner charge amount. A solid line F1 represents a flying force of the toner when a development electric field necessary for development is applied, and can be represented by Expression (1) F = qE. Here, q is the toner charge amount, and E is the developing electric field. A broken line F2 represents an adhesion force acting between the toner and the developing roller 61, and can be represented by an equation (2) F = kq ² + D. Here, k is a proportional constant of k = 1 / (4πε), and D represents the adhesion force other than the electromagnetic force. As shown in FIG. 11, the expression (1) representing the flying force and the expression (2) representing the adhesion force are overlapped at two places, and α indicates the smaller charge amount and γ indicates the larger charge amount. . Further, a point where the difference between the flying force and the adhesion force is the largest is defined as β. β is obtained by differentiating the difference between the equations (1) and (2) by the toner charge amount q and obtaining the toner charge amount q when the value obtained by the differentiation becomes zero. The value of the toner charge amount q is q = E / 2K, and the value of β at that time is β = E / 2K. In the range A1 in which the toner charge amount q is smaller than α and the range A4 in which the toner charge amount q is larger than γ, the adhesion force exceeds the flying force, so that the toner cannot fly to the photosensitive member 31 and development. Can not do it. Therefore, the amount of toner supplied from the toner container 39 to the developing device 34 is agitated by the screw feeder 64, so that the toner replenished from the replenishing port 70 is conveyed to the development storage chamber 63B used for development. By the time, the flying force that causes the toner to fly to the photosensitive member 31 is stronger than the adhesion force of the developing roller 61 that causes the toner to adhere when the toner is supplied to the electrostatic latent image. .

  The range in which the toner charge amount q is larger than α and smaller than γ is divided into a range A2 smaller than β and a range A3 larger than β. In the range A3, as the toner charge amount q increases, the adhesion force becomes stronger than the flying force, and the developability decreases. In the range A2, as the toner charge amount q increases, the flying force becomes stronger than the adhesion force, and the developability is improved. However, in the range A2, since the toner charge amount q is low, a toner fog phenomenon may occur. Therefore, when the developing device 34 uses toner for development, the toner charge amount q is preferably in the range of β to γ. In other words, the amount of toner to be replenished is an amount that can be charged within a range in which the difference between the flying force and the adhesion force is reduced as the toner charge amount q to be replenished and stirred increases. The amount of toner replenished from the toner container 39 is an amount capable of maintaining the above relationship between the flying force and the adhesion force of the toner. This toner amount is determined by the bias voltage of the developing roller 61, the charging voltage of the photosensitive member 31, the distance between the photosensitive member 31 and the developing roller 61, the shape and the rotational speed of the screw feeder 64, and the supply port 70 to the developer storage chamber 63B. It is determined by the length.

[Configuration of Control Unit 5]
The control unit 5 performs overall control of the image forming apparatus 100. As shown in FIG. 1, the control unit 5 is configured as a microcomputer including a CPU 5A, ROM 5B, RAM 5C, EEPROM 5D, DRIVER 5E, and the like as main components. The control unit 5 may be configured by an electronic circuit such as an integrated circuit (ASIC, DSP).

  The control unit 5 is connected to the image reading unit 1, the ADF 2, the image forming unit 3, the paper feeding unit 4, the operation display unit 6, and the like inside the image forming apparatus 100, and controls these components. In addition, the control unit 5 includes each element constituting the image forming unit 3, specifically, a charging device 32, an LSU 33, a developing device 34, a transfer device 35, a charge eliminating device 36, a fixing roller 37, a pressure roller 38, and It is connected to a container screw 69 or the like. The ROM 5B stores a program for executing image forming processing. The CPU 5A controls each element connected to the control unit 5 by executing a control program in the ROM 5B, and prints an image on printing paper.

  In this embodiment, the ROM 5B of the control unit 5 stores a program for executing toner replenishment processing described later. The CPU 5A executes the toner supply process by executing this program. In addition, when the CPU 5A executes the program, in the toner supply process, the control unit 5 includes a scanning control unit 51, a consumption calculation unit 52 (an example of the consumption calculation unit of the present invention), a comparison unit 53, and a supply. It functions as a control unit 54 (an example of a replenishment control unit of the present invention) and a drive control unit 55.

  In addition to the program, the ROM 5B stores a voltage value used for the toner supply process, a calculation formula, a threshold value, a toner consumption value, a supply timing, and the like. For example, the consumption calculation unit 52 stores a calculation formula for calculating the toner consumption for each of a plurality of areas based on the image data scanned by the scanning control unit 51 in the ROM 5B. The ROM 5B stores a value of the first consumption amount, which is a comparison target threshold value for the comparison unit 53 to determine whether the toner consumption amount for each region is less than or equal to the first consumption amount. When the replenishment control unit 54 replenishes toner corresponding to the toner consumption amount for each region, a calculation formula for calculating the second replenishment amount, a formula for calculating the replenishment amount to be evenly replenished to the first region, and The ROM 5B stores a calculation formula for calculating the position of the toner replenishment region and the rotational speed for driving the container screw 69 in accordance with the amount of toner to be replenished. Note that the remaining amount of toner in the toner container 39 is stored in the EEPROM 5D. The RAM 5C stores the toner consumption value for each region calculated by the consumption calculation unit 52, the toner supply amount for each region to be supplied by the supply control unit 54, and the like. The DRIVER 5D operates a stepping motor that drives the container screw 69. The DRIVER 5D operates a stepping motor 65 that drives each of the rollers such as the screw feeder 64, the developing roller 61, and the magnetic roller 62 of the developing device 34.

  The scanning control unit 51 controls the LSU 33 based on the image data to form an electrostatic latent image on the photoconductor 31. It is possible to calculate which region of the developer of the developing device 34 is consumed from the region where the scanning control unit 51 irradiates the LSU 33 with light.

  The consumption calculation unit 52 calculates a printing rate indicating the area of the image per predetermined area for each of a plurality of regions that are long in the transport direction 9A based on the number of dots included in the image data that is the source of development. The plurality of elongated regions correspond to a plurality of regions where toner in the developer of the developing device 34 is consumed. The consumption amount calculation unit 52 calculates the toner consumption amount according to the printing rate calculated for each of the plurality of areas. The consumption amount calculation unit 52 calculates how much toner needs to be replenished in which region of the developer of the developing device 34 by calculating the toner consumption amount for each of a plurality of regions based on the image data. Can be calculated. Note that specific consumption calculation by the consumption calculation unit 52 will be described later.

  The comparison unit 53 determines whether the toner consumption amount for each region calculated by the consumption amount calculation unit 52 is less than or equal to the first consumption amount. The comparison unit 53 distinguishes between the first region where no problem occurs in developability even when the first supply amount corresponding to the toner consumption is supplied, and the second region where a problem occurs in developability. According to this division, the replenishment control unit 54 performs toner replenishment processing according to the first area and the second area. A specific comparison by the comparison unit 53 will be described later.

  Based on the comparison result of the comparison unit 53, the replenishment control unit 54 replenishes the first region with toner of the first replenishment amount corresponding to the toner consumption amount from the toner container 39 by the container screw 69. The replenishment control unit 54 replenishes the second area from the toner container 39 with the second replenishment amount of toner smaller than the toner consumption amount by the container screw 69. Thus, it is possible to prevent the toner replenishment amount from increasing in the second region and causing toner charging failure.

  The second replenishment amount is obtained by multiplying the first consumption amount, which is a reference for distinguishing the first region and the second region, and a second consumption amount exceeding the first consumption amount by a coefficient less than 1. It is the amount obtained by adding the obtained third consumption amount. In the example shown in FIGS. 8 and 9, the coefficient less than 1 is 0.5. Further, the remaining toner amount that has not been replenished to the second area is divided equally and replenished to the first area. As a result, it is possible to prevent toner from being insufficiently replenished as a whole of the developing device 34 and to uniformize the toner charge amount as a whole. Note that specific toner supply processing by the supply control unit 54 will be described later.

  The drive control unit 55 rotates or stops the stepping motor 65 that drives the developing roller 61, the magnetic roller 62, the screw feeder 64A, the screw feeder 64B, and the like in the developing device 34.

[Toner supply processing]
Hereinafter, the procedure of the toner replenishment process executed by the control unit 5 will be described with reference to FIG. In the flowchart of FIG. 12, steps S1, S2,... Represent processing procedure (step) numbers. The toner replenishing process by the control unit 5 is performed when the image forming process of the image forming apparatus 100 is executed. Here, the control unit 5 when executing the toner replenishment processing corresponds to a consumption calculation unit and a replenishment control unit according to the present invention.

(Step S1)
In step S <b> 1, the control unit 5 determines whether an image formation instruction of the image forming apparatus 100 is input. Specifically, it is determined whether or not an instruction for copying or printing has been input from the user. The controller 5 waits until an image formation instruction is input (NO side of S1). When the image forming instruction is input, the control unit 5 proceeds to step S2 (YES side of S1).

(Step S2)
In step S <b> 2, the control unit 5 drives a stepping motor 65 that drives each roller in the developing device 34. Thereby, the screw feeder 64A and the screw feeder 64B in the developing device 34 are driven, and the developer is circulated and conveyed while being stirred. The toner of the developer is charged to a charge amount suitable for development by stirring.

(Steps S3 to S5)
In step S <b> 3, the control unit 5 forms an electrostatic latent image on the surface of the photoreceptor 31 by the LSU 33 based on the image data. In step S4, when forming an electrostatic latent image based on the image data, the control unit 5 calculates a time during which the LSU 33 is irradiated or not irradiated with light for each region long in the transport direction 9A. Accordingly, the control unit 5 calculates a printing rate indicating the area of the image per predetermined area based on the number of dots included in the image data for each region long in the transport direction 9A. In step S <b> 5, the control unit 5 calculates consumption for each of a plurality of areas in the developer based on the printing rate. It should be noted that the area long in the transport direction 9A corresponds to each area of the developer of the developing device 34. Moreover, the control part 5 when performing step S4 and step S5 is an example of the consumption calculation part of this invention. Steps S4 and S5 correspond to the first step in the toner replenishing method of the developing device of the present invention.

(Step S6)
In step S <b> 6, the control unit 5 determines whether or not there is an area equal to or greater than the first consumption amount in which the toner consumption amount for each of the plurality of areas in the developer is a threshold value. As a result, the control unit 5 distinguishes between the first area where no problem occurs in developability even if the first supply amount of toner corresponding to the toner consumption amount is supplied and the second area where the problem occurs in developability. To do. If it determines with there being no area | region more than the said 1st consumption, the control part 5 will transfer a process to step S8 (NO side of S6). In this case, the control unit 5 determines that all the plurality of areas are the first area. Therefore, even if the control unit 5 replenishes the toner amount corresponding to the toner consumption amount for each region, there is no problem in toner developability. On the other hand, if it is determined that there is an area greater than or equal to the first consumption, the control unit 5 proceeds to step S7 (YES side of S6). In this case, the control unit 5 determines that there is the second region that is greater than or equal to the first consumption amount. For this reason, when the control unit 5 replenishes the toner amount corresponding to the toner consumption amount for each region by the container screw 69, there is a region where a problem occurs in the toner developability. Step S6 corresponds to the second step in the toner replenishing method for the developing device of the present invention.

(Step S7)
In step S7, the control unit 5 corrects the toner replenishment amount for each region. The control unit 5 sets a toner amount smaller than the toner consumption amount as the toner replenishment amount in the region determined to be the second region. Thereby, the control part 5 can prevent that a problem arises in developability in the said 2nd area | region. Further, the control unit 5 sets the first supply amount corresponding to the toner consumption amount as the toner supply amount in the region determined to be the first region. Further, the control unit 5 divides the amount of toner that has not been replenished into the second region into the first region by dividing the toner amount evenly by the number of the first regions to replenish the first region. to add. As a result, it is possible to prevent toner from being insufficiently replenished as a whole of the developing device 34 and to uniformize the toner charge amount as a whole.

(Step S8)
In step S <b> 8, the control unit 5 replenishes toner from the toner container 39 by the container screw 69 when the developer in the first area or the second area reaches the replenishment position. In addition, the control part 5 when performing step S6 thru | or step S8 is an example of the replenishment control part of this invention. Steps S7 and S8 correspond to the third step and the fourth step in the toner replenishing method of the developing device of the present invention.

(Step S9)
In step S9, the control unit 5 determines whether or not all development has been completed. If it is determined that all development has not been completed, the control unit 5 moves the process to step S3 (NO side of S9). The control unit 5 repeatedly executes the toner supply process while the development is being performed. On the other hand, if it is determined that all development has been completed, the control unit 5 shifts the processing to step S10 (YES side of S9).

(Step S10)
In step S <b> 10, the control unit 5 stops the stepping motor 65 that drives each roller in the developing device 34 and ends the processing.

[Effect of the embodiment]
As described above, according to the image forming apparatus 100 of the present invention, it is possible to correct the non-uniform charge amount caused by the toner replenishment operation. Thereby, it is possible to suppress the occurrence of the toner fog phenomenon during development. Further, the image forming apparatus 100 can make the toner amount of the entire developing device 34 uniform by supplying insufficient toner to the first area different from the second area where the toner supply amount is reduced.

[Modification of Embodiment]
In the toner replenishment process, the controller 5 replenishes the other first area with the toner amount that is insufficient in the second area, but the present invention is not limited to this. When the controller 5 replenishes the second replenishment amount of toner to the second region and then circulates and conveys again through the replenishment position where the replenishment port 70 is provided via the second region, The amount of toner to be replenished may be used. Here, the modified example of the embodiment differs from the above-described embodiment in the toner replenishing process shown in FIG. 13, and other parts are common to the configuration and the process of the above-described embodiment. For this reason, only different parts will be described here, and description of common parts will be omitted.

(Step S16)
In step S5, when the consumption amount for each of the plurality of areas is calculated, the control unit 5 determines whether the second area is equal to or more than the first consumption amount for each area. If it is determined that the second region is not equal to or greater than the first consumption amount, the control unit 5 proceeds to step S8 (NO side of S16). On the other hand, if it is determined that there is the second region that is greater than or equal to the first consumption, the control unit 5 moves the process to step S17 (YES side of S16).

(Step S17)
In step S17, the controller 5 corrects the toner replenishment amount only for the area determined to be the second area, and the process proceeds to step S8. The controller 5 maintains the toner supply amount in the first area. As described above, the toner replenishment amount is changed only in a region where a problem may occur in the toner charge amount.

(Step S21)
In step S8, after the toner is replenished in each region, in step S21, the controller 5 determines that the replenishment position where the second region of the developer circulated and conveyed by the screw feeder 64 is provided with the replenishment port 70 again. It is determined whether or not to pass. The control unit 5 waits until the second region passes through the supply position again (NO side of S21). On the other hand, when the second region passes through the replenishment position again, the control unit 5 moves the process to step S22 (YES side of S21).

(Step S22)
In step S22, the control unit 5 replenishes the second area with the toner amount reduced during the previous replenishment, and the process proceeds to step S9. In other words, the control unit 5 replenishes the second region with the third replenishment amount of toner corresponding to the amount obtained by subtracting the third replenishment amount from the second consumption amount from the toner container 39 by the container screw 69. . Thus, the control unit 5 can replenish the area with the consumption corresponding to the consumption for each area and prevent the toner charge amount from being insufficient.

  The process of replenishing the toner deficient in the second area by the processes of Step S21 and Step S22 may be performed by the control unit 5 in a plurality of times. In other words, the control unit 5 replenishes the second region one or more times with the fourth replenishment amount of toner obtained by dividing the third replenishment amount into one or more. As described above, the toner amount that is insufficient for the replenishment of the second region may be replenished over time.

[Other Modifications of Embodiment]
In the description of the present embodiment, the image forming apparatus 100 that does not include the toner density sensor has been described. However, the present invention is not limited to this. A developing surface of the developing device 34 is provided with a detection surface of the toner density sensor, and the control unit 5 replenishes a combination of calculation of toner consumption based on image data and calculation of toner consumption based on density detection of the toner density sensor. May be. For example, the controller 5 replenishes the second replenishment amount of toner when the second region passes the replenishment position, and then based on the toner density when the second region passes the replenishment position. You may replenish it.

  In the description of the present embodiment, the second supply amount is obtained by multiplying the first consumption amount and the second consumption amount that exceeds the first consumption amount by a coefficient 0.5 (see FIGS. 8 and 9) that is less than 1. However, the present invention is not limited to this example. For example, the second replenishment amount is not a uniform coefficient, but a replenishment factor based on a coefficient determined for each replenishment amount, a coefficient determined by a calculation formula, and a table storing the correspondence between the replenishment amount and the charge amount. What extracts a quantity etc. may be sufficient.

  For example, a case will be described in which a table storing the correspondence between the replenishment amount and the charge amount is stored in the EEPROM 5D. In this case, as shown in FIG. 10, the stored correspondence relationship is that the replenishment amount replenished to the second region by the container screw 69 and the second replenishment before being used for development by the developing device 34. This is the relationship with the amount of charge that the toner supplied to the region is agitated by the screw feeder 64 and charged. Then, the control unit 5 extracts the second supply amount corresponding to the toner consumption amount based on the correspondence stored in the EEPROM 5D, and supplies the second region with the second supply amount of toner. By storing the information on the correspondence relationship in the EEPROM 5D, the control unit 5 can suppress the toner fog phenomenon rather than calculating the second supply amount using a uniform coefficient.

100: Image forming apparatus 3: Image forming unit 5: Control unit 31: Photoconductor 33: LSU
34: developing device 39: toner container 50: toner replenishing unit 51: scanning control unit 52: consumption calculation unit 53: comparison unit 54: replenishment control unit 55: drive control unit 61: developing roller 62: magnetic rollers 63A, 63B: Developer storage chambers 64A and 64B: screw feeder

Claims (10)

A developing unit that supplies toner to an electrostatic latent image based on image data formed on the surface of the image carrier and develops the electrostatic latent image with toner;
An agitating and conveying unit that is provided in the developing unit and circulates and conveys a developer containing at least toner;
An accommodating portion for accommodating toner for replenishing the developing portion;
A replenishment unit that replenishes the developing unit with toner contained in the accommodation unit;
A consumption amount calculating unit that calculates a toner consumption amount for each of a plurality of regions in the developer that is circulated and conveyed in the developing unit, based on the image data;
A first supply amount of toner corresponding to the calculated consumption amount of the first area is supplied to the first area where the calculated consumption amount calculated by the consumption amount calculation unit is less than a predetermined first consumption amount. The second replenishment amount is less than the calculated consumption amount of the second region in the second region where the calculated consumption amount calculated by the consumption amount calculation unit is greater than or equal to the first consumption amount. A replenishment control unit that replenishes the toner from the storage unit by the replenishment unit;
An image forming apparatus comprising:   The replenishment control unit, when there is the second area, a third consumption amount obtained by multiplying a remaining second consumption amount obtained by subtracting the first consumption amount from the calculated consumption amount by a coefficient less than 1. The image forming apparatus according to claim 1, wherein the second replenishment amount of toner added to the first consumption amount is replenished to the second region by the replenishment unit.   The replenishment control unit equally divides a third replenishment amount corresponding to an amount obtained by subtracting the third consumption amount from the second consumption amount when there is the second region, and equalizes the first region. The image forming apparatus according to claim 2, wherein an amount of toner is supplied by the supply unit.   The replenishment control unit, when there is the second area, has a fourth replenishment amount toner obtained by dividing a third replenishment amount corresponding to an amount obtained by subtracting the third consumption amount from the second consumption amount into one or more. The image forming apparatus according to claim 2, wherein the second region is replenished by the replenishment unit one or more times. The second replenishment amount replenished to the second region by the replenishment unit, and the charge that the toner replenished to the second region before being used for development by the developing unit is agitated and charged by the agitation transport unit A storage medium storing the correspondence with the quantity;
5. The supply unit according to claim 1, wherein the supply control unit causes the supply unit to supply the second supply amount of toner to the second region based on the correspondence relationship stored in the storage medium. Image forming apparatus.   The consumption amount calculation unit calculates a printing rate indicating an area of an image per predetermined area for each of the plurality of regions based on the number of dots included in the image data that is a source of development, and the plurality of regions The image forming apparatus according to claim 1, wherein a consumption amount corresponding to the printing rate calculated for each is calculated to obtain the calculated consumption amount. The developing unit is disposed facing the image carrier and is formed long in one direction,
The circulating transport unit circulates and transports the developer along the longitudinal direction of the developing unit,
The plurality of regions are longer and evenly divided with respect to the direction in which the developer is circulated and conveyed in the developing unit, and longer than the distance that the developer moves within the time required for one rotation of the image carrier. The image forming apparatus according to claim 1. The replenishing unit replenishes toner accommodated in the accommodating unit to a replenishing port provided in the developing unit,
The agitating and conveying section circulates and conveys the developer via the replenishment position provided with the replenishing port while agitating,
The replenishment control unit is configured such that when the developer in the first area or the second area circulated and conveyed by the agitation conveyance unit reaches the replenishment position, the replenishment unit moves the storage unit to the replenishment port. The image forming apparatus according to claim 1, wherein toner is supplied. When the developer containing at least toner is circulated and conveyed in the developing unit, the consumption amount of each of the plurality of regions in the developer is based on the image data of the electrostatic latent image developed by supplying the toner to the developing unit. A first step of calculating
It is determined whether the calculated consumption for each of the plurality of areas calculated in the first step is a first area that is less than a predetermined first consumption or a second area that is greater than or equal to the first consumption. The second step;
When the second region is determined to be the first region, a first supply amount of toner corresponding to the calculated consumption amount of the first region is supplied to the first region from the storage unit storing the toner. And a third step
A fourth step of replenishing the second region with a second supply amount of toner that is smaller than the calculated consumption amount of the second region when the second step is determined to be the second region; When,
A toner replenishing method for a developing device. To the computer that controls the image forming device,
When the developer containing at least toner is circulated and conveyed in the developing unit, the consumption amount of each of the plurality of regions in the developer is based on the image data of the electrostatic latent image developed by supplying the toner to the developing unit. A first step of calculating
It is determined whether the calculated consumption for each of the plurality of areas calculated in the first step is a first area that is less than a predetermined first consumption or a second area that is greater than or equal to the first consumption. The second step;
When the second region is determined to be the first region, a first supply amount of toner corresponding to the calculated consumption amount of the first region is supplied to the first region from the storage unit storing the toner. And a third step
A fourth step of replenishing the second region with a second supply amount of toner that is smaller than the calculated consumption amount of the second region when the second step is determined to be the second region; When,
A program for running

Images