JP6897584B2 - Image forming device and toner replenishment method - Google Patents

Description

The present invention relates to an image forming apparatus including a developing apparatus for developing an electrostatic latent image with toner and a toner replenishing method.

The electrophotographic image forming apparatus has a developing apparatus for developing an electrostatic latent image formed on a photoconductor by supplying toner, and a toner container for accommodating toner supplied to the developing apparatus. There is.

In Patent Document 1, the toner (developer) is stirred while being conveyed so as to circulate in the developing apparatus. The timing at which the toner consumption region reaches the toner replenishment position is calculated based on the toner transfer speed, and the toner is replenished to the developing device according to the calculated timing.

Japanese Unexamined Patent Publication No. 2009-205125

The speed at which toner is conveyed in the developing device is not constant because it is affected by environmental factors such as temperature and humidity. Therefore, even if the toner is replenished at the timing based on the calculated transfer speed as in the technique disclosed in Patent Document 1, it cannot always be said that the toner is replenished evenly at the places where the toner is actually consumed. Absent.

To improve the accuracy of toner replenishment, the frequency of calculating the toner transfer rate should be increased. However, in the configuration of Patent Document 1 in which the toner consumption region is actually generated and the transport speed is calculated, the toner consumption amount also increases as the calculation frequency is increased.

In consideration of the above circumstances, it is an object of the present invention to appropriately supply toner to a developing apparatus that develops an electrostatic latent image with toner.

The image forming apparatus according to the present invention stirs the image carrier on which an electrostatic latent image is formed on the surface while transporting the two-component developer so as to circulate along the transport path, and on the image carrier. A developing device that develops the electrostatic latent image formed in the above with toner contained in the two-component developer, and a toner replenishing device that replenishes the toner to the two-component developer at a toner replenishment position on the transport path. A control device for controlling the toner replenishment operation by the toner replenishment device. At the toner consumption position on the transport path of the developing device, the toner is supplied to and consumed by the image carrier, and the control device performs the two in a unit printing period corresponding to a printing operation of one medium. A unit area, which is a virtual area to be conveyed on the transfer path, is set for each distance that the component developer is conveyed on the transfer path, and is consumed when the unit area passes through the toner consumption position. The toner replenishment amount for the unit region is determined based on the determined toner consumption amount, and the toner replenishment device replenishes the toner of the determined toner replenishment amount to the two-component developer in the unit region. ..

Preferably, the control device passes a finite impulse response filter having the order of the number of printed media while the unit area passes through the toner consumption position, and the unit area passes through the toner consumption position. The amount of toner replenished with respect to the unit area is determined by applying to the amount of toner consumed while printing.

Preferably, the image forming apparatus further includes a toner concentration sensor for measuring the toner concentration of the two-component developer on the transport path, and the control device has the toner concentration measured by the toner concentration sensor equal to or higher than a threshold value. If, the toner replenishment amount is determined based on the toner consumption amount, and if the toner concentration measured by the toner concentration sensor is less than the threshold value, the toner consumption amount and the toner concentration are determined. Based on this, the toner replenishment amount is determined.

Preferably, the image forming apparatus further includes a latent image forming apparatus for forming the electrostatic latent image by irradiating the image carrier with a light beam corresponding to the image information, and the control device provides the image information with the latent image forming apparatus. Based on this, the toner consumption corresponding to the unit area is calculated.

Further, in the toner replenishment method according to the present invention, an image carrier on which an electrostatic latent image is formed and a two-component developer are stirred while being transported so as to circulate along a transport path, and the image is supported. A developing device that develops the electrostatic latent image formed on the body with toner contained in the two-component developer, and toner replenishment that replenishes the toner to the two-component developer at a toner replenishment position on the transport path. A toner replenishment method in an image forming apparatus including an apparatus and a control device for controlling the toner replenishment operation by the toner replenishment device, wherein the image is carried at a toner consumption position on the transport path of the development device. The toner is supplied to the body and consumed, and the two-component developer is transported on the transport path at each distance during the unit printing period corresponding to the printing operation of one medium. A unit area, which is a virtual area, is set, and the toner replenishment amount for the unit area is determined based on the toner consumption amount consumed when the unit area passes through the toner consumption position. It includes supplying the toner of the determined toner replenishment amount to the two-component developer in the unit region.

According to the present invention, it is possible to appropriately supply toner to a developing apparatus that develops an electrostatic latent image with toner.

It is sectional drawing which shows the image forming apparatus which concerns on one Embodiment of this invention. It is a top sectional view of the developing apparatus of the image forming apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the image forming apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of the developing apparatus of the image forming apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the toner supply amount determination process based on the toner consumption amount in the image forming apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows an example of the toner supply amount determination process based on the toner consumption amount and the toner density in the image forming apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of the developing apparatus of the image forming apparatus which concerns on one Embodiment of this invention. It is a table which shows the relationship between the toner consumption amount and the toner supply amount in the image forming apparatus which concerns on one Embodiment of this invention.

1. 1. Overall Configuration of Image Forming Device First, the overall configuration of the image forming apparatus 1 according to the embodiment of the present invention will be described with reference to FIG. The image forming apparatus 1 is, for example, a multifunction device having a printing function, a copying function, a fax function, and the like. The image forming apparatus 1 of the present embodiment employs a two-component developing method in which magnetic powder is used as a carrier together with toner.

Hereinafter, for convenience of explanation, the front side of the paper surface of FIG. 1 is referred to as the front side of the image forming apparatus 1. The arrows L, R, U, Lo, Fr, and Rr appropriately attached to each figure indicate the left side, the right side, the upper side, the lower side, the front side, and the rear side of the image forming apparatus 1, respectively. Further, in the following description, the scale of each member may be appropriately changed in order to make each member a recognizable size.

The image forming apparatus 1 includes a substantially box-shaped apparatus main body 2. A paper cassette for storing a medium such as printing paper is provided in the lower part of the apparatus main body 2, and a paper ejection tray is provided in the upper part of the apparatus main body 2. An upper cover 3 can be opened and closed on the upper surface of the apparatus main body 2 on the side of the output tray. The toner container 42 is stored below the upper cover 3. By opening the upper cover 3, the storage space of the toner container 42 in the apparatus main body 2 is exposed, and the toner container 42 can be attached to and detached from the apparatus main body 2.

An exposure device 5 (latent image forming device) composed of a laser scanning unit (LSU) is arranged below the output tray in the upper part of the device main body 2. An image forming unit 6 is provided below the exposure device 5. The image forming unit 6 has a rotatable photoconductor drum 7 (image carrier). A charging unit 8, a developing device 41 connected to the toner container 42, a transfer roller, and a cleaning unit are arranged around the photoconductor drum 7 along the rotation direction of the photoconductor drum 7.

A medium transport path 10 is provided inside the apparatus main body 2. A paper feed unit is provided near the paper feed cassette at the upstream end of the medium transport path 10. A transfer portion having a photoconductor drum 7 and a transfer roller is provided in the middle stream portion of the medium transport path 10. A fixing device is provided downstream of the medium transport path 10. A paper ejection portion is provided near the paper ejection tray at the downstream end of the medium transport path 10.

The apparatus main body 2 includes a control device 15 that controls each part of the image forming apparatus 1 inside. Further, the apparatus main body 2 is provided with a display unit 17 on the upper surface or the side surface for displaying the state of the image forming apparatus 1. The display unit 17 is composed of a touch panel, a display, or the like. The display unit 17 may include operation keys for operating the image forming apparatus 1, such as a start key, a stop / clear key, and a numeric keypad.

2. Outline of Operation of Image Forming Device Next, an image forming operation executed by the image forming apparatus 1 having the above-described configuration will be schematically described. The control device 15 of the image forming apparatus 1 controls each part of the image forming apparatus 1 so as to execute the image forming operation when the image data (image information) is input from an external computer or the like and the printing start is instructed. More specifically, in the image forming operation, first, the charging part 8 of the image forming part 6 charges the surface of the photoconductor drum 7, and then the light beam (laser light) corresponding to the image data is emitted by the exposure device 5. Is applied to the photoconductor drum 7 to form an electrostatic latent image on the surface of the photoconductor drum 7. Then, the developing device 41 of the image forming unit 6 develops the above electrostatic latent image into a toner image with the toner contained in the two-component developer.

On the other hand, the medium stored in the paper feed cassette is taken out by the paper feed unit and conveyed on the medium transfer path 10. The medium on the medium transport path 10 is transported to the transfer unit at a predetermined timing, and the toner image on the photoconductor drum 7 is transferred to the medium by the transfer unit. The medium on which the toner image is transferred is conveyed to the fixing device, and the toner image is fixed to the medium by the fixing device. The medium on which the toner image is fixed is discharged from the paper ejection section to the paper ejection tray.

3. 3. Developing Device Next, the developing device 41 will be described. FIG. 2 is a plan sectional view of the developing device 41. The developing device 41 is formed in a substantially box-shaped shape that is long in the front-rear direction, and houses a two-component developing agent containing toner and a carrier inside.

The developing device 41 includes two spiral rollers 41a and 41b arranged substantially in parallel. Each of the spiral rollers 41a and 41b includes a blade that is wound around a rotation axis that is long in the front-rear direction, and is rotatably provided with respect to the housing of the developing device 41. By rotationally driving each of the two spiral rollers 41a and 41b, the two-component developer in the developing apparatus 41 is conveyed in the direction of each rotation axis. The rotation of the spiral rollers 41a and 41b is controlled by the control device 15.

As shown in FIG. 2, the spiral roller 41a and the spiral roller 41b are configured to convey the two-component developer in the opposite directions. As a result, a transport path P for the two-component developer is formed inside the developing apparatus 41. The two-component developer is agitated while being conveyed in the illustrated transport direction so as to circulate along the transport path P by rotating the spiral roller 41a and the spiral roller 41b.

Further, the developing device 41 includes a developing roller 41c in which a part of the circumference thereof is exposed to the photoconductor drum 7 side at the opening. The developing roller 41c is composed of, for example, a magnetic roller, and is arranged so as to face the photoconductor drum 7 through an opening. The developing roller 41c has a long rotation axis in the front-rear direction, and is rotatably provided with respect to the housing of the developing device 41. The rotation of the developing roller 41c is controlled by the control device 15.

By rotating the developing roller 41c, only the toner of the two-component developer in the developing apparatus 41 is supplied to the photoconductor drum 7. The carrier adhering to the developing roller 41c and the toner not adhering to the photoconductor drum 7 are collected inside the developing apparatus 41 as the developing roller 41c rotates.

The toner container 42 (see FIG. 1) is an element for accommodating the toner to be replenished in the developing device 41, and communicates with the developing device 41 via the toner replenishing device 43. The toner container 42 includes a stirring member (not shown) that stirs the contained toner. The stirring member is configured as, for example, a stirring screw having a rotating shaft long in the front-rear direction and a spiral stirring blade formed on the outer peripheral surface of the rotating shaft. The toner is agitated by the rotation of the agitating blade.

The toner replenishment device 43 is connected to the side of the developing device 41 via a replenishment port. The toner replenishing device 43 replenishes the toner contained in the toner container 42 to the two-component developer at the toner replenishing position S on the transport path P in the developing device 41. The toner replenishment device 43 replenishes the toner in the toner container 42 to the toner replenishment position S of the developing device 41 by driving a transport member provided inside. The toner replenishing device 43 may replenish the toner from the intermediate hopper. As will be described in detail later, the toner replenishment operation by the toner replenishment device 43 described above is controlled by the control device 15.

A toner concentration sensor 44 is provided on the transport path P of the developing device 41. The toner concentration sensor 44 can measure the toner concentration (ratio value (T / C) of toner and carrier) of the two-component developer on the transport path P. A signal indicating the measured toner concentration is output to the control device 15.

4. Control device Next, the control device 15 will be described. FIG. 3 is a block diagram showing an electrical configuration of the control device 15. The control device 15 is composed of a CPU or the like, and is connected to a storage device 16 composed of a ROM, a RAM, or the like. Further, the control device 15 is electrically connected to each part of the image forming device 1 such as two spiral rollers 41a and 41b, a developing roller 41c, a toner container 42, a toner replenishing device 43, and a toner concentration sensor 44. ..

The control device 15 controls each unit connected to the control device 15 based on the control program, control data, sensor output, and the like stored in the storage device 16. For example, the control device 15 controls the exposure device 5 based on the image data received from an external computer or the like, and irradiates the photoconductor drum 7 with a light beam corresponding to the image data. As a result, an electrostatic latent image corresponding to the image data is formed on the photoconductor drum 7.

Based on the above-mentioned image data, the control device 15 can calculate the amount of toner (toner consumption) consumed when executing the printing operation based on the image data. The toner consumption can be calculated based on the area of the electrostatic latent image formed on the photoconductor drum 7. The control device 15 determines the toner replenishment amount based on the calculated toner consumption amount and the like, and controls the toner replenishment device 43 to replenish the toner. Details of the toner replenishment operation will be described later.

Further, the control device 15 can calculate the transport speed (toner transport speed) of the two-component developer. For example, the control device 15 reads out the speed measurement pattern stored in advance in the storage device 16 and controls the exposure device 5 so as to form an electrostatic latent image corresponding to the speed measurement pattern on the photoconductor drum 7. .. Next, the control device 15 supplies toner from the developing device 41 to the photoconductor drum 7 and controls the developing device 41 so that the speed measurement pattern is developed.

A part of the toner in the developing apparatus 41 is consumed with the development of the speed measurement pattern described above, and a toner consumption region is formed on the transport path P. The toner consumption region is conveyed to the detection region of the toner concentration sensor 44 along with the flow of the two-component developer by the spiral rollers 41a and 41b. As a result, after a certain amount of time has passed since the speed measurement pattern was developed, a signal indicating a decrease in toner concentration is supplied from the toner concentration sensor 44 to the control device 15.

Since the speed measurement pattern is a known pattern stored in advance, the control device 15 can know the location where the toner consumption region is formed inside the developing device 41. Therefore, in the control device 15, the distance from the location where the toner consumption region is formed by the development of the speed measurement pattern to the toner concentration sensor 44 and the signal indicating the decrease in the toner concentration from the development of the speed measurement pattern are transmitted from the toner concentration sensor 44. The toner transfer speed can be calculated based on the time until input.

As described above, the control device 15 can estimate the toner consumption area. However, the toner transfer speed is affected by environmental factors such as temperature and humidity, deterioration of the developing agent, the type of medium used, and the like, and is not actually constant. Therefore, even if the toner is replenished only in the portion estimated to be the toner consumption region, it is not always possible to replenish the toner in the portion where the toner is actually consumed. If the toner replenishment points are displaced, uneven toner concentration will occur in the developing device 41. In order to solve the above problems, in the present embodiment, the toner replenishment operation is controlled by the configuration as described below.

5. Toner Replenishment Amount Determination Process and Toner Replenishment Operation With reference to FIGS. 4 to 8, a toner replenishment amount determination process and a toner replenishment operation according to the present embodiment will be described. In summary, in the control device 15 of the image forming apparatus 1, the two-component developer is conveyed on the transport path P during the unit printing period corresponding to the printing operation of one medium (that is, one printing job). A unit area U, which is a virtual area to be transported on the transport path P, is set for each distance D, and is based on the amount of toner consumed when the unit area U passes through the toner consumption position C. Then, the amount of toner replenished with respect to the unit region U is determined. Then, the toner replenishing device 43 replenishes the determined amount of toner to the corresponding two-component developer in the unit region U.

FIG. 4 is a schematic view of the developing apparatus 41, which conceptualizes the configuration of FIG. 2 for the purpose of explaining the toner replenishment control. A unit area U, which is a virtual area serving as a toner replenishment unit, is set by the control device 15 on the transport path P of the developing device 41. The unit region U is set to move with the two-component developer (ie, at the same speed and in the same direction).

The unit region U has relative coordinates based on some parameters (for example, a predetermined position on the transport path P (for example, the toner replenishment position S)) and a length in the transport path P direction (equivalent to the above-mentioned distance D). ) Can be expressed. It is preferable that the control device 15 updates the above parameters (that is, the position of the unit area U) in a timely manner and stores them in the storage device 16.

The toner consumption position C is a position where the toner contained in the two-component developer is supplied to the photoconductor drum 7 via the developing roller 41c and consumed. As shown in FIG. 4, the toner consumption position C exists on the transport path P of the developing device 41. More specifically, the toner consumption position C exists at a position facing the developing roller 41c on the spiral roller 41a on the photoconductor drum 7 side of the developing device 41.

The control device 15 applies an FIR (Finite Impulse Response) filter, which is a kind of digital filter, to the toner consumption amount, and determines the toner supply amount for the unit region U. More specifically, the control device 15 passes an FIR filter whose order is the number of printed media while the unit area U passes through the toner consumption position C, and the unit area U passes through the toner consumption position C. It is applied to the toner consumption amount (a plurality of toner consumption amount values) consumed at the time of printing, and the toner replenishment amount for the unit area U is determined. If the number of media printed while the unit area U passes through the toner consumption position C is not an integer, the decimal part of the number of sheets is rounded down or rounded up, and only the integer part is used as the order of the FIR filter. Suitable.

FIG. 5 is a flowchart showing an example of the toner replenishment amount determination process according to the present embodiment. First, the control device 15 acquires print information for the unit area U that is the target of toner replenishment (step S100). The print information includes, for example, information on the type of medium that is the target of the printing operation corresponding to the unit area U, and information on the amount of toner consumed when the unit area U passes through the toner consumption position C. Is done.

When the medium type is different from that at the time of the previous replenishment amount determination process (step S110: NO), the control device 15 is set to use the FIR filter suitable for the current medium type for the subsequent replenishment amount determination (step S120). ). On the other hand, when the medium type is the same as that at the time of the previous replenishment amount determination process (step S110: YES), the control device 15 is set to use the same FIR filter as the previous time for the subsequent replenishment amount determination (step S130).

Next, the control device 15 acquires the toner consumption amount consumed when the target unit area U passes through the toner consumption position C (step S140), and sets the acquired plurality of toner consumption amounts first. The FIR filter is applied (step S150) to determine the amount of toner replenished for the unit region U (step S160). The details of determining the toner supply amount will be described later with reference to FIGS. 7 and 8 together with specific numerical examples.

When the above-mentioned toner replenishment amount determination process is completed, the control device 15 replenishes the toner replenishment amount of toner for the determined unit region U to the binary developer 43 in the unit region U. To control. That is, the control device 15 controls the toner replenishment device 43 so as to replenish the toner in the determined toner replenishment amount at the timing when the unit region U reaches the toner replenishment position S.

FIG. 6 is a flowchart showing an example of a toner replenishment amount determination process using the toner concentration in addition to the toner consumption amount. In the example of FIG. 6, the toner replenishment amount is determined by feedback control using the toner concentration sensor 44.

First, the control device 15 confirms the toner concentration in the developing device 41 based on the output from the toner concentration sensor 44 (step S200). When the toner concentration is equal to or higher than a predetermined threshold value (step S210: YES), the control device 15 executes a toner replenishment amount determination process based on the toner consumption amount described with reference to FIG. 5 (step S220), and the unit is The amount of toner replenished to the area U is determined (step S230).

On the other hand, when the toner concentration is less than a predetermined threshold value (step S210: NO), the control device 15 will be described with reference to FIG. 5 after executing the toner replenishment amount determination process (step S240) based on the toner concentration. The process of determining the toner replenishment amount based on the toner consumption amount is executed (step S250), and the toner replenishment amount based on the toner concentration and the toner replenishment amount based on the toner consumption amount are totaled and the toner replenishment amount to be replenished to the unit area U. Is confirmed (step S260). In step S240, it is preferable that the toner replenishment amount is determined so as to reduce the deviation from the target toner concentration (preferably set to a value higher than the above-mentioned predetermined threshold value).

When the above-mentioned toner replenishment amount determination process is completed, the control device 15 replenishes the toner replenishment amount of toner for the determined unit region U to the binary developer 43 in the unit region U. To control. That is, the control device 15 controls the toner replenishment device 43 so as to replenish the toner in the determined toner replenishment amount at the timing when the unit region U reaches the toner replenishment position S.

According to the configuration according to the flowchart of FIG. 6, particularly the configuration in which the toner concentration threshold is set to determine the toner replenishment amount, the toner concentration in the developing device 41 is maintained above a suitable value that can be experimentally or theoretically determined. Therefore, it is possible to maintain high print quality. On the contrary, if the toner concentration is lower than the above preferable value, printing defects may occur.

A specific example of the process of determining the toner replenishment amount based on the toner consumption amount will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic view of the developing apparatus 41 in this example, and FIG. 8 is a table showing the relationship between the toner consumption amount and the toner replenishment amount in this example.

In this example, when the transport speed of the two-component developer (moving speed of the unit region U) is 40 mm / sec and the length of the toner consumption position C is 300 mm, the unit region U passes through the toner consumption position C. The time required for this is 300/40 = 7.5 seconds. Assuming that the transport speed of the medium is 120 mm / sec, the length that can be transported in the time required for the unit region U to pass through the toner consumption position C (7.5 seconds) is 120 × 7.5 = 900 mm. ..

In this case, when the A4 horizontal medium (medium length 210 mm) is printed with a distance of 15 mm between the media, the number of media to be printed within the time (7.5 seconds) required for the unit area U to pass through the toner consumption position C. Is 900 / (210 + 15) = 4 sheets. Therefore, the number of unit regions U included in the toner consumption position C in FIG. 7 is 4, and the order of the FIR filter used for calculating the toner supply amount is also 4. The time required to print one sheet of the medium (the unit printing period described above) is 7.5 / 4 = 1.875 seconds. It is naturally understood that the above calculation formula is a general formula that can be applied even if specific numerical values change.

In FIG. 8, one print job corresponds to one medium. For job number 1, the toner consumption calculated by the control device 15 based on the print area of the corresponding image data is 0.5 g. However, since the toner consumption position C includes four unit regions U (U1 to U4), the toner consumption per unit region U in the printing operation by job number 1 is 0.125 g. If 0.5 g is replenished to one unit area U, the amount of toner replenished becomes excessive compared to the amount of toner consumed, and the toner concentration (T / C) becomes locally high. The toner consumption amount according to the job number 1 is apportioned to the four unit areas U (U1 to U4) existing in the consumption position C.

Similarly, for job number 2 following job number 1, the toner consumption of 0.2 g is applied to the four unit areas U (U2 to U5) existing at the toner consumption position C during the printing operation by job number 2, and the job number 1 is applied. Toner consumption is apportioned. Hereinafter, for job numbers 3 to 8, the toner consumption is similarly apportioned while shifting the unit area U by one. As a result, a value obtained by moving and averaging the toner consumption as shown in FIG. 8 is calculated as the toner replenishment amount. The above moving average of toner consumption is realized by the FIR filter of the present embodiment.

6. Technical effects of the present embodiment According to the present embodiment, as described above, the image forming apparatus 1 transmits the photoconductor drum 7 on which the electrostatic latent image is formed on the surface and the two-component developer to the transport path P. A developing device 41 that develops an electrostatic latent image formed on the photoconductor drum 7 with toner contained in a two-component developer while agitating while conveying the mixture so as to circulate along the same, and toner supply on the conveying path P. A toner replenishing device 43 for replenishing the toner to the two-component developer at the position S and a control device 15 for controlling the toner replenishing operation by the toner replenishing device 43 are provided. Further, at the toner consumption position C on the transport path P of the developing device 41, toner is supplied to and consumed by the photoconductor drum 7. The control device 15 is a virtual area in which the two-component developer is transported on the transport path P for each distance D in which the two-component developer is transported on the transport path P during the unit printing period corresponding to the printing operation of one medium. A certain unit area U is set, and the toner replenishment amount for the unit area U is determined based on the toner consumption amount consumed when the unit area U passes through the toner consumption position C. The toner replenishing device 43 replenishes the determined toner replenishing amount of toner to the two-component developer in the unit region U.

According to the above configuration, the toner replenishment amount for the unit area U is determined based on the toner consumption amount consumed when the unit region U passes through the toner consumption position C, so that the conventional toner replenishment amount is determined. The toner replenishment amount is determined more easily than the calculation method of. Further, since the toner is widely replenished in the region where the toner is likely to be actually consumed, the influence of the fluctuation of the transport speed of the two-component developer can be suppressed.

Further, the control device 15 uses an FIR filter (for example, moving average processing) whose order is the number of media printed while the unit area U has passed the toner consumption position C, and the unit area U is the toner consumption position. The amount of toner replenished for the unit region U is determined by applying it to the amount of toner consumed while passing through C. According to the above configuration, since the toner can be widely replenished to the two-component developer in which the toner is consumed, it is possible to suppress the local increase in the toner concentration.

Further, the image forming apparatus 1 further includes a toner concentration sensor 44 for measuring the toner concentration (T / C) of the two-component developer on the transport path P, and the control device 15 further includes the toner measured by the toner concentration sensor 44. When the density is equal to or higher than the threshold value, the toner replenishment amount is determined based on the toner consumption amount, and when the toner concentration measured by the toner concentration sensor 44 is less than the threshold value, the toner consumption amount and the toner concentration are used. To determine the amount of toner to be replenished. According to the above configuration, when the toner concentration is low, the toner replenishment amount based on the toner consumption amount is corrected according to the toner concentration, so that the toner concentration in the developing device 41 can be made more stable (particularly, printing). It is possible to suppress the occurrence of a toner concentration difference of a predetermined value or more, which causes defects).

Further, the image forming apparatus 1 further includes an exposure device 5 that irradiates the photoconductor drum 7 with a light beam corresponding to the image data to form an electrostatic latent image, and the control device 15 further includes a unit region U based on the image data. Calculate the toner consumption corresponding to. According to the above configuration, the toner consumption amount is calculated more appropriately based on the image data, and the toner replenishment amount is determined more accurately.

Further, according to the above-described embodiment, the toner replenishment method in the above-mentioned image forming apparatus 1 is realized.

7. Modification Example In the present embodiment, the case where the configuration of the present invention is applied to the monochrome image forming apparatus 1 is described, but in other different embodiments, other devices such as a color printer, a copying machine, a facsimile, and a multifunction device are described. It is also possible to apply the configuration of the present invention to an image forming apparatus.

1 Image forming device 5 Exposure device (latent image forming device)
7 Photoreceptor drum (image carrier)
9 Developing device 15 Control device 16 Storage device 41 Developing device 43 Toner replenishment device 44 Toner concentration sensor C Toner consumption position P Transport path S Toner replenishment position U Unit area

Claims (4)

An image carrier on which an electrostatic latent image is formed and
A developing device that stirs while transporting the two-component developer so as to circulate along a transport path, and develops the electrostatic latent image formed on the image carrier with the toner contained in the two-component developer. When,
A toner replenishing device that replenishes the toner to the two-component developer at the toner replenishing position on the transport path, and
An image forming apparatus including a control device for controlling the toner replenishment operation by the toner replenishment device.
At the toner consumption position on the transport path of the developing device, the toner is supplied to and consumed by the image carrier.
The control device is a unit that is a virtual area in which the two-component developer is transported on the transport path for each distance during the unit printing period corresponding to the printing operation of one medium. A region is set, and the toner replenishment amount for the unit region is determined based on the toner consumption amount consumed when the unit region passes through the toner consumption position.
The toner replenishment device replenishes the toner in the determined toner replenishment amount to the two-component developer in the unit region .
A toner concentration sensor for measuring the toner concentration of the two-component developer on the transport path is further provided.
When the toner concentration measured by the toner concentration sensor is equal to or higher than a threshold value, the control device determines the toner replenishment amount based on the toner consumption amount, and the toner concentration measured by the toner concentration sensor. When is less than the threshold value, the image forming apparatus is characterized in that the toner replenishment amount is determined by summing the toner replenishment amount based on the toner concentration and the toner replenishment amount based on the toner consumption amount. The control device is a finite impulse response filter whose order is the number of printed media while the unit area is passing through the toner consumption position, and when the unit area is passing through the toner consumption position. The image forming apparatus according to claim 1, wherein the toner replenishment amount with respect to the unit region is determined by applying to the toner consumption amount consumed in the above. A latent image forming device for forming the electrostatic latent image by irradiating the image carrier with a light beam corresponding to the image information is further provided.
The image forming apparatus according to claim 1 or 2 , wherein the control device calculates the toner consumption corresponding to the unit region based on the image information. An image carrier on which an electrostatic latent image is formed and
A developing device that stirs while transporting the two-component developer so as to circulate along a transport path, and develops the electrostatic latent image formed on the image carrier with the toner contained in the two-component developer. When,
A toner replenishing device that replenishes the toner to the two-component developer at the toner replenishing position on the transport path, and
A toner replenishment method in an image forming apparatus including a control device for controlling the toner replenishment operation by the toner replenishment device.
At the toner consumption position on the transport path of the developing device, the toner is supplied to and consumed by the image carrier.
A unit area, which is a virtual area to be transported on the transport path, is set for each distance that the two-component developer is transported on the transport path during the unit printing period corresponding to the printing operation of one medium. To determine the amount of toner replenished for the unit area based on the amount of toner consumed when the unit area passes through the toner consumption position.
And to replenish the toner determined the toner supply amount to the two-component developer in the unit area,
When the toner concentration measured by the toner concentration sensor for measuring the toner concentration of the two-component developer on the transport path is equal to or higher than the threshold value, the toner replenishment amount is determined based on the toner consumption amount, and the toner is replenished. When the toner concentration measured by the density sensor is less than the threshold value, the toner replenishment amount is determined by summing the toner replenishment amount based on the toner concentration and the toner replenishment amount based on the toner consumption amount. comprising the door, toner replenishing wherein the.

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