JP2008164909A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus 1 preventing toner to be used for development from being insufficiently electrified by accurately controlling the replenishment of the toner for a developing device 16. <P>SOLUTION: The image forming apparatus 1 is equipped with: the developing device 16 supplying the toner to an image carrier; a detection part 65 detecting the amount of toner in the developing device 16; a replenishing part 20 replenishing the developing device 16 with the toner when the detection part 65 detects that the amount of the toner in the developing device 16 does not attain predetermined amount; and a control part 80 controlling the detection part 65 to detect the amount of the toner in the developing device 16 at predetermined time intervals. If the time taken from starting replenishment until finishing the replenishment in replenishing operation performed by the replenishing part 20 is shorter or longer than predetermined time, the control part 80 makes control so that the predetermined time interval required until the detection part 65 detects the amount of the toner in the developing device 16 next may be shorter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine. In particular, the present invention relates to an electrophotographic image forming apparatus that develops an electrostatic latent image with toner.

  In general, in an electrophotographic image forming apparatus (such as a copying machine or a printer), an electrostatic latent image is formed on an image carrier, and toner is supplied to the image carrier, and a toner image developed with the toner is displayed. An image is formed by transferring and fixing it onto a sheet or the like. Here, the developing device plays a role of supplying toner to the image carrier. Specifically, the developing device charges the toner to a predetermined potential, the charged toner is supplied toward the electrostatic latent image on the image carrier, and the electrostatic latent image is developed.

  In general, a developing device includes a one-component developing method and a two-component developing method. The one-component development method is a method using a developer mainly composed of toner, and the two-component development method is a method using a developer mainly composed of toner and a carrier (magnetic material). Development devices based on the one-component development system have been conventionally disposable because they are generally lower in cost and smaller than those based on the two-component development method. However, in recent years, development devices have been developed from the viewpoint of increasing environmental awareness and effective use of resources. Regardless of the system, a long-life developing device has been demanded.

  However, if the toner contained in the developing device is exhausted, the developing device cannot be used. Therefore, in order to use the toner for a long time, it is necessary to additionally supply the developing device with toner. 2. Description of the Related Art Conventionally, in order to replenish toner, a toner storage container such as a bottle or a container is provided in an image forming apparatus, and a configuration is adopted in which toner is supplied from the toner storage container to a developing device. The invention described in Patent Document 1 has been proposed as an invention having such a configuration.

Patent Document 1 describes a developing device having a configuration in which toner can be charged at a location where the developing device is installed when toner is insufficient. Specifically, the developing device as a configuration for filling toner includes a toner replenishing portion for replenishing toner to the developing device, and a filling for filling the developing device with toner formed in the toner replenishing portion. The valve portion and the filling portion are provided with a valve structure that maintains a closed state except when the toner is filled (see Patent Document 1: Claim 1, Claim 2, and FIG. 15). With such a configuration, when the toner is insufficient in the developing device, the toner can be replenished.
JP 2003-223045 A

  Here, in supplying toner to the developing device, if a large amount of toner is supplied at a time, there is a problem that the charge amount of the toner in the developing device is lowered and the quality of the formed image is lowered. That is, when the toner, which is not sufficiently charged immediately after being supplied, is supplied onto the image carrier from the developing roller or the like in the developing device and used for development, a streak is formed on the image formed on the surface of the paper or the like. This causes unevenness, or toner is deposited on a white background portion of paper or the like that should not be printed (so-called fogging), so that the quality of the formed image is deteriorated.

  In particular, in a color-compatible image forming apparatus, the developing apparatus is downsized in order to make the apparatus main body larger than a conventional monochrome image forming apparatus or to further reduce the size of the image forming apparatus than the conventional one. Desired. In the downsized developing device, since the amount of toner that can be accommodated in the developing device is originally small, the influence of toner replenishment on toner charging is relatively large.

  Then, in order to prevent unevenness and fogging in the formed image and maintain the quality of the formed image, it is necessary to appropriately control the developing device, the amount of toner to be replenished, the replenishment timing, etc. Miniaturized developing device). Specifically, in order to avoid insufficient charging of the toner, it is preferable that the amount of toner in the developing device is ensured to be a predetermined amount or more, for example, almost full, and the amount of toner to be replenished is small.

  Therefore, looking at the invention described in Patent Document 1, Patent Document 1 does not have a detailed reference to the amount of toner to be replenished at one time. Moreover, the invention described in Patent Document 1 detects that the remaining toner amount in the developing device is low or no longer detected by the remaining amount detection sensor, and supplies toner until the fullness detection sensor detects fullness. (See Patent Document 1: Paragraphs 0045 and 0049). Therefore, in the invention described in Patent Document 1, there is a possibility that toner is replenished from empty to full in the developing device with a single replenishment, and a large amount of toner may be replenished at a time.

  Then, the developing device described in Patent Document 1 has a configuration in which a large amount of toner that has just been newly supplied and has not been sufficiently charged can be used for development. Therefore, the invention described in Patent Document 1 cannot cope with the problem that unevenness and fogging occur when toner immediately after replenishment is used for development.

  Furthermore, in the developing device miniaturized as described above, the amount of toner in the developing device is originally small. However, in the invention described in Patent Document 1, since the remaining toner amount is detected by the remaining amount detection sensor, the toner amount in the developing device is extremely small. Therefore, when the invention described in Patent Document 1 is applied to a miniaturized developing device, toner that is insufficiently charged immediately after replenishment is likely to be used for development. That is, there is a problem that the development apparatus cannot be reduced in size. In the invention described in Patent Document 1, it is necessary to provide two sensors, a remaining amount detection sensor and a fullness detection sensor. In this respect, it is difficult to cope with downsizing of the developing device, and there is a problem in terms of cost.

  In general, a one-component developing type developing device is likely to be unstable in charging of toner compared to a two-component developing type. In addition, when a large amount of toner is replenished, the charging of the toner tends to become unstable in the developing device of the one-component developing system (note that the invention described in Patent Document 1 uses a two-component developer). (Refer paragraph 1 of literature 1). Therefore, the invention described in Patent Document 1 also has a problem that it is difficult to apply to a single-component developing type developing apparatus.

  The present invention has been made in view of the above-described problems of the prior art, and can cope with the additional replenishment of toner to the developing device and the downsizing of the developing device, and accurately controls the toner replenishment to the developing device. An object of the present invention is to provide an image forming apparatus having a high quality and a stable long life so that the toner used for development does not become insufficiently charged. In particular, it is an object of the present invention to provide a high-quality image forming apparatus adapted to a miniaturized one-component developing type developing apparatus.

  According to a first aspect of the present invention, there is provided a developing device that supplies toner to the image carrier to develop an electrostatic latent image formed on the image carrier, and a toner amount in the developing device. When the detection unit, the detection unit detects that the toner amount in the developing device has not reached a predetermined amount, the replenishing unit that replenishes toner in the developing device, and the detection unit is provided in the developing device. And a controller that controls the toner amount to be detected at predetermined time intervals. In the replenishment operation performed by the replenishment unit, the time from the start of replenishment to the end of replenishment is shorter than the predetermined replenishment time. If it is longer or longer, the control unit controls to shorten the predetermined time interval until the detection unit next detects the toner amount in the developing device.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the control unit determines a predetermined time interval until the detection unit next detects the toner amount in the developing device. In addition, a dot count value which is an integrated value of the number of pixels on which toner is to be placed in the image formed on the image carrier is used.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the detection unit detects that the amount of toner in the developing device has not reached a predetermined amount, and the replenishment unit detects the development. When replenishing toner in the apparatus, the control unit controls the detection unit to perform detection until the toner in the developing device reaches a predetermined amount or more, and the replenishing unit Replenishment is performed until the detection unit detects that the toner has been replenished until the toner amount reaches a predetermined amount or more.

  According to the first aspect of the present invention, the detection unit detects that the toner in the developing device has become a predetermined amount or less, and at that time, the toner is replenished. The existing state can be maintained. When the replenishment time is shorter than the predetermined time and only a small amount of toner is replenished, the amount of toner replenishment increases in the next replenishment operation because the toner is returned to the predetermined amount or more. The time until the detection unit detects the toner amount is controlled to be short, and the toner replenishment operation is performed before the toner amount in the developing device decreases, and a large amount of toner is replenished at a time. You can avoid that. Therefore, a state where a predetermined amount or more of toner is always accommodated in the developing device is maintained, a decrease in toner charge amount due to replenishment is relatively small, and a small amount of toner is replenished at one time. It is done. That is, insufficient toner charging is prevented, and streaks and fogging are prevented from being formed.

  On the other hand, if the replenishment time is longer than the predetermined time, the toner may be low in the toner container for replenishing toner to the developing device, and in this case, the toner replenishing speed to the developing device may be reduced. That is, even if the replenishment time is long, the toner may actually be replenished only in a small amount. Also in this case, the time interval until the next detection is shortened, and the toner replenishing operation is performed before the toner amount in the developing device decreases, thereby preventing a large amount of toner from being replenished at a time.

  Furthermore, since the detection unit for detecting the toner amount in the developing device operates at predetermined time intervals and does not always operate, the life of the detection unit is extended. The life of the detection unit is also extended, and a long-life image forming apparatus can be provided.

  In addition, in a developing device that is downsized (particularly, a one-component developing type developing device is advantageous for downsizing), the amount of toner stored in the developing device is reduced. Since the toner amount is secured above a certain level and the toner is replenished in small amounts, the toner charge is unlikely to decrease, and the development device can be made compact regardless of the development method. Further, it is not necessary to provide two sensors for detecting the remaining amount and fullness, which is advantageous in terms of cost, and corresponds to the downsizing of the developing device in that the space for the sensors can be reduced.

  According to the second aspect of the present invention, since the dot count value is used to determine the time interval, the toner consumption can be easily predicted. Accordingly, since the detection unit operates at a timing when it is recognized that a certain amount of toner has been consumed, the amount of toner to be replenished is stabilized, and a large amount of toner is less likely to be replenished at a time. That is, it is possible to always perform toner replenishment in which the charging of the toner in the developing device does not decrease to such an extent that the image quality deteriorates.

  According to the third aspect of the present invention, the toner amount in the developing device can be reliably maintained to be a predetermined amount or more. For example, if the predetermined amount is set to a value close to full, a large amount of toner will not be replenished at once, and even if the toner is replenished, the decrease in the charge amount of the toner in the developing device will be relative. Can be made small.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

  First, the outline of the image forming apparatus 1 in the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view for explaining a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention. In the present embodiment, the image forming apparatus 1 including the rotary developing device 2 will be described.

  The image forming apparatus 1 according to the present embodiment includes an image forming unit 10, a replenishing unit 20, an intermediate transfer unit 24, a paper feeding unit 30, a paper transport unit 35, a secondary transfer unit 45, a fixing device 47, and the like. .

  As shown in FIG. 1, the image forming unit 10 includes a photosensitive drum 11, a charging roller 12, a drum cleaning device 13, a rotary developing device 2, a laser unit 14, and the like.

  The photosensitive drum 11 has an electrostatic latent image formed on its surface as an image carrier, and is driven to rotate approximately at the center of the image forming apparatus 1 (the direction of rotation is indicated by an arrow). The rotation shaft (not shown) is provided so as to extend perpendicular to the paper surface of FIG. The photosensitive drum 11 is formed to have a photosensitive layer such as amorphous silicon or an OPC photosensitive member.

  The charging roller 12 is provided on the photosensitive drum 11. The charging roller 12 is in contact with the photosensitive drum 11 to uniformly charge the surface of the photosensitive drum 11, and is rotatably supported. Note that a cleaner 12 a for cleaning adhering matter adhering to the charging roller 12 is provided above the charging roller 12.

  The drum cleaning device 13 is provided on the right side of the photosensitive drum 11 in FIG. 1 and is for cleaning toner and deposits remaining on the surface of the photosensitive drum 11.

  The rotary developing device 2 is for developing the electrostatic latent image formed on the photosensitive drum 11 with each color toner, and is provided adjacent to the left side of the photosensitive drum 11 in FIG. . The rotary developing device 2 includes a rotating frame 15 and four developing devices 16B, 16Y, 16C, and 16M supported by the rotating frame 15, and is rotated by a driving mechanism including a motor and a gear (not shown). . Accordingly, the rotary developing device 2 has a cylindrical shape that is rotatable about an axis. The rotary shaft 15 a of the rotary developing device 2 passes through the center of the rotary frame 15, and the axial direction thereof is parallel to the axial direction of the rotary shaft of the photosensitive drum 11.

  As shown in FIG. 1, the rotating frame 15 has four sections that are equally divided into four in the circumferential direction by partition frames 15 b that extend radially from the center of the rotating shaft 15 a. In each section, developing devices 16B, 16Y, 16C, and 16M corresponding to four toner colors of magenta, cyan, yellow, and black are arranged, and the developing devices 16B, 16Y, 16C, and 16M have the same configuration. is there. When the rotary developing device 2 rotates, the developing rollers 53 of the developing devices 16B, 16Y, 16C, and 16M face the photosensitive drum 11 with a predetermined gap. The detailed structure of each developing device 16B, 16Y, 16C, 16M will be described later.

  The laser unit 14 scans and exposes the photosensitive drum 11 based on image information from an external computer, and is provided above the rotary developing device 2. Data for causing the laser unit 14 to output the laser light 14L is created by the data processing unit 17 that receives image information. Then, the laser light 14L is emitted from the laser unit 14. A reflection mirror 18 is provided on the optical path of the laser beam 14L, and the laser beam 14L is irradiated onto the surface of the photosensitive drum 11 by the reflection mirror 18 (the laser beam 14L is shown by a two-dot chain line). The laser unit 14 includes a laser light source, a polygon mirror, a polygon mirror driving motor, and the like as an internal configuration (not shown).

  The replenishing unit 20 includes a toner storage container 21 and a toner replenishing device 22. The toner storage containers 21 are provided above the photosensitive drum 11 and the intermediate transfer belt 25, and four toner storage containers 21 are arranged side by side in the direction perpendicular to the paper surface of FIG. Each toner storage container 21 is a portion that stores toner to be replenished to each developing device 16B, 16Y, 16C, 16M of the rotary developing device 2. That is, each toner storage container 21 stores toner of any one of magenta, cyan, yellow, and black. In FIG. 1, the toner container 21 is invisible except for one toner container 21.

  The toner replenishing device 22 is disposed above the photosensitive drum 11 in a space between the laser unit 14 and the toner storage container 21, and is configured to be movable up and down. Four toner replenishing devices are provided corresponding to the respective colors. . Each toner replenishing device 22 is connected to the corresponding toner storage container 21 by a pipe, a hose or the like, and supplies the toner of each color stored in the toner storage container 21 to the corresponding developing device 16B, 16Y, 16C, 16M.

  Specifically, the toner replenishing device 22 has an insertion portion 22a with a thin tip, and when it moves downward, the tip is inserted into the developing devices 16B, 16Y, 16C, and 16M to supply toner. . Further, when the replenishment is completed, it moves upward and the rotary developing device 2 becomes rotatable. In FIG. 1, the parts other than one toner supply device 22 are invisible. Further, the moving direction of the toner replenishing device 22 is shown by a broken line.

  The intermediate transfer unit 24 includes an intermediate transfer belt 25 to which toner images of respective colors formed on the photosensitive drum 11 are sequentially transferred, a driving roller 26 for tensioning and rotating the intermediate transfer belt 25, a tension roller 27, A primary transfer roller 28 adjacent to the photosensitive drum 11 via the intermediate transfer belt 25, a driven roller 28a provided between the drive roller 26 and the primary transfer roller in the vicinity of the primary transfer roller 28, and intermediate transfer A belt cleaning device 29 for cleaning the belt 25 is configured. The intermediate transfer belt 25 stretched around each roller rotates and passes through the nip between the photosensitive drum 11 and the primary transfer roller 28, and the toner images of the respective colors are superimposed and primarily transferred. The image is later transferred onto the paper P by the secondary transfer unit 45.

  The paper feed unit 30 includes a paper feed cassette 31, a manual feed tray 32, and the like. A paper feed cassette 31 having a placement plate 31 a on which the paper P is placed is provided at the bottom of the image forming apparatus 1. In addition, the paper feed unit 30 prevents the double feed to the right side of the pickup roller 33 and the pickup roller 33 to the right of the pickup cassette 31 in order to send out the paper P on the loading plate 31 a one by one to the paper conveyance path. A roller pair 34 is provided. Further, a manual feed tray 32 is provided on the right side surface of the apparatus so that paper can be separately fed. The manual feed tray 32 is also provided with a pickup roller 33 for sending the paper P one by one to the paper transport path.

  The paper transport unit 35 is for transporting the paper P in the image forming apparatus 1. The sheet conveying section 35 is a sheet for discharging the image-formed sheet P from the sheet feeding section 30 to a secondary transfer roller 46 described later, and from the secondary transfer roller 46 through the fixing device 47. A second conveyance path 37 that reaches the discharge port 42 and a reverse conveyance path 38 that is provided so as to connect the middle of the first conveyance path 36 from the middle of the second conveyance path 37 once downstream of the fixing device 47 in the sheet conveyance direction. Consists of Note that the paper transport direction is indicated by arrows.

  A curved portion 39 is provided in the first conveyance path 36 in order to reverse the conveyance direction of the paper P sent out from the paper feed cassette 31. In addition, at the upper part of the curved portion 39, the conveyance path from the manual feed tray 32 joins. In front of the secondary transfer roller 46, a registration roller pair 40 for controlling the conveyance timing of the paper P is disposed. A plurality of pairs of conveyance rollers 41 are provided in the conveyance path in which these elements are provided, and a guide plate (not shown) for guiding the paper P is also provided as appropriate.

The second transport path 37 is provided with a plurality of transport roller pairs 41. A guide plate (not shown) for guiding the paper P is also provided as appropriate. A paper discharge port 42 is provided at the end of the second transport path 37.
And a discharge tray 43 for receiving the discharged paper P is provided.

  The reverse conveyance path 38 is a conveyance path for duplex printing. The reverse conveyance path 38 is provided so as to join the upstream side of the registration roller pair 40 in the sheet conveyance direction from the branching claw 44 located in the middle of the second conveyance path 37 and downstream of the fixing device 47 in the sheet conveyance direction. The reverse conveyance path 38 is provided so as to pass above the paper feed cassette 31. The reverse conveyance path 38 is also provided with a plurality of conveyance roller pairs 41, and a guide plate (not shown) for guiding the paper P is also provided as appropriate.

  The secondary transfer unit 45 includes a secondary transfer roller 46 and a driving roller 26. The secondary transfer roller 46 is for transferring the toner image transferred to the intermediate transfer belt 25 onto the sheet P conveyed so as to be sandwiched between the secondary transfer roller 46 and the intermediate transfer belt 25. Therefore, the secondary transfer roller 46 is supported so as to be rotatable and in contact with and away from the intermediate transfer belt 25 so as to form a nip via the drive roller 26 and the intermediate transfer belt 25. Further, a voltage is applied to the secondary transfer roller 46 so that the toner is transferred onto the paper P at a predetermined timing by a voltage applying means (not shown).

  The fixing device 47 is for melting and fixing the toner transferred onto the paper P, and is provided in the middle of the second conveyance path 37 and below the rotary developing device 2. The fixing device 47 includes a heating roller 48 that incorporates a heater and a pressure roller 49 that presses the heating roller 48. The toner is heated and pressurized and fixed on the paper P.

  Next, an image forming operation will be briefly described. The image forming apparatus 1 executes an image forming operation based on the input image data as follows.

  First, the photosensitive drum 11 is charged by the charging roller 12. The laser unit 14 scans and exposes the surface of the photosensitive drum 11 in accordance with data from the data processing unit 17 to which image data is input, and the electrostatic latent image is formed on the photosensitive drum 11. Is formed. Next, the rotary developing device 2 is rotated so that any of the corresponding color developing devices 16 faces the photosensitive drum 11. In this state, the electrostatic latent image on the photosensitive drum 11 is developed by supplying the corresponding color toner. The developed toner image is transferred to the intermediate transfer belt 25. The above operation is sequentially repeated for each color, and a full-color toner image is formed on the intermediate transfer belt 25 (if full color, the intermediate transfer belt 25 rotates four times). For example, when a black single-color image is formed, the above operation may be performed once. The toner remaining on the photosensitive drum 11 after the transfer is cleaned by the drum cleaning device 13.

  On the other hand, in the paper feed unit 30, one sheet P is taken out from the paper feed cassette 31 or the manual feed tray 32 by the pickup roller 33 and conveyed to the registration roller pair 40. Thereafter, the sheet P is conveyed from the registration roller pair 40 to the toner image on the intermediate transfer belt 25 in time, and is guided to the secondary transfer unit 45. A predetermined voltage is applied to the secondary transfer roller 46 while being in contact with the intermediate transfer belt 25, and the toner image on the intermediate transfer belt 25 is transferred to the paper P. The sheet P is guided to the fixing device 47 through the second conveyance path 37, and the toner image is fixed on the sheet P by the fixing device 47. In the case of single-sided printing, the paper is sequentially discharged from the paper discharge port 42 via the branching claw 44, and the paper P is received by the discharge tray 43.

  On the other hand, in the case of duplex printing, the paper P that has passed through the fixing device 47 is switched back in the second conveyance path 37 downstream of the branching claw 44 in the paper conveyance direction, and the reverse conveyance path 38 is guided by the branching claw 44. To be introduced. Thereafter, the paper P that is turned upside down is returned to the upstream side of the pair of registration rollers 40 in the first transport path 36 again. Then, the toner image is transferred from the secondary transfer roller 46 in time with the back side of the paper P. After that, it is the same as above.

  Next, the developing devices 16B, 16Y, 16C, and 16M according to the embodiment of the present invention supported by the rotary developing device 2 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a schematic configuration of the developing device 16B according to the embodiment of the present invention. Here, since the configurations of the developing devices 16B, 16Y, 16C, and 16M are the same, the symbols B, Y, C, and M are omitted in the following description unless otherwise indicated. Unify and explain. Therefore, the following description applies in common to the developing devices 16B, 16Y, 16C, and 16M unless otherwise specified.

  The developing device 16 mainly includes a frame 51, a partition member 52, a developing roller 53, a supply roller 54, a regulating member 55, a stirring member 56, a toner supply port 57, and the like.

  The frame 51 constitutes the outer shell of the developing device 16B. Then, the toner is accommodated in the inside and other members are provided.

  The partition member 52 is formed of, for example, a metal plate member, and divides the inside of the developing device 16 into a toner supply unit 58 and a toner storage unit 59. The toner supply unit 58 is a part that supplies toner to the photosensitive drum 11, and includes a developing roller 53, a supply roller 54, a regulating member 55, and the like. A stirring member 56 and a toner supply port 57 are disposed in the toner storage portion 59. The partition member 52 extends from the lower side to the upper side in FIG. 2 and extends in the axial direction of the supply roller 54. The partition member 52 has a plurality of openings, a first opening 60 provided at a position between the supply roller 54 and the frame 51 close to the supply roller 54, and a space in the toner storage portion 59 and the toner supply portion 58. The second opening 61 is provided at a position connecting the two.

  A first opening 60 located below in FIG. 2 is for feeding toner from the toner storage portion 59 to the toner supply portion 58 so as to be pushed in by the stirring member 56. One or a plurality of the first openings 60 are provided, and can be provided side by side extending in the axial direction of the supply roller 54 (the direction perpendicular to the paper surface of FIG. 1). The amount of toner fed into the toner supply unit 58 is adjusted according to the number and size of the first openings 60.

  The second opening 61 located at the upper side in FIG. 2 is for returning the toner to the toner containing portion 59 when the toner is excessively entered into the toner supply portion 58. The second opening 61 is provided with a resin valve member 62 such as PET so as to close the second opening 61 from the toner container 59 side. When the amount of toner in the toner supply unit 58 increases and the pressure increases, the valve member 62 opens toward the toner storage unit 59 due to the pressure, and the toner is returned to the toner storage unit 59 side. As a result, toner deterioration due to an increase in toner pressure in the toner supply unit 58 is prevented.

  As shown in FIG. 2, a part of the developing roller 53 protrudes from the frame 51 so as to face the photosensitive drum 11 (a part is shown by a broken line in FIG. 2) with a certain gap. It is rotatably supported. Then, the rotary developing device 2 rotates, and the developing roller 53 on which a thin layer of toner of each color is formed is opposed to the photosensitive drum 11 and supplies toner to the photosensitive drum 11. A seal member 63 is provided between the developing roller 53 and the frame 51 to prevent toner leakage.

  The supply roller 54 is provided between the developing roller 53 and the partition member 52 so as to contact the developing roller 53 in order to convey the toner to the developing roller 53. The supply roller 54 is rotatable and supported so that the axis of the supply roller 54 and the axis of the developing roller 53 are parallel. The supply roller 54 is rotated in the same direction as the developing roller 53 (clockwise in FIG. 2) by a drive mechanism (not shown) including a gear, a motor, and the like. The supply roller 54 supplies toner to the developing roller 53 at the contact portion between the developing roller 53 and the supply roller 54 in the upper contact portion in FIG. 2 (near the regulating member 55), and the lower contact portion in FIG. In the portion (in the vicinity of the seal member 63), the function of scraping off toner that has not been used for development is achieved.

  The regulating member 55 is formed in a film shape or a blade shape with resin, metal or the like. The regulating member 55 is supported so that one plane abuts along the axial direction of the developing roller 53. Thus, the regulating member 55 has a function of charging the toner by forming a thin layer of toner on the developing roller 53 and further having a predetermined voltage applying means (not shown).

  The agitating member 56 is provided with a shaft portion 56a, a stirring blade 56b, and the like, and the supply roller 54 and the developing roller 53 are provided so that their axes are substantially parallel and parallel. The shaft portion 56a is provided so as to span the toner containing portion 59 and is rotatably supported. As shown in FIG. 2, the shaft portion 56a is configured such that two L-shaped shaft members 56c and 56d are overlapped to form a U-shaped cross section. And the stirring member 56 is comprised by pinching | interposing the film-like or sheet-like stirring blade 56b comprised with resin like PET, for example between shaft members 56c and 56d.

  The agitating member 56 is rotated by a rotational driving force transmitted from a motor (not shown) or a driving mechanism (not shown), and agitates the toner in the toner accommodating portion 59. Also, the agitating member 56 and the toner returned from the second opening 61 The toner in the toner storage unit 59 is mixed, and new toner is fed from the first opening 60 toward the toner supply unit 58. In this way, the toner in the developing device 16 circulates, and the deteriorated toner and the new toner are mixed evenly, so that the image quality does not deteriorate.

  The toner replenishing port 57 is for receiving toner replenishment from the replenishing portion 20, and is provided in the toner containing portion 59 at the portion of the frame 51 that faces the portion of the frame 51 close to the stirring member 56. (Upper position in FIG. 2). The front end portion 22 a of the toner supply device 22 is inserted into the toner supply port 57, and toner is supplied to the developing device 16. Therefore, the toner supply port 57 is provided corresponding to the toner supply device 22. The insertion direction of the toner replenishing device 22 and the position of the toner replenishing port 57 are indicated by a one-dot chain line in FIG.

  Next, the detection unit 65 included in the developing devices 16B, 16Y, 16C, and 16M according to the embodiment of the present invention supported by the rotary developing device 2 will be described with reference to FIG. FIG. 3A is a perspective view illustrating a configuration of the detection unit 65 of the developing device 16 according to the embodiment of the present invention. FIG. 3B is an explanatory diagram for explaining a detection mechanism of the detection unit 65.

  As shown in FIG. 3, the detection unit 65 is for detecting the amount of toner in the developing device 16, and is provided in the toner storage unit 59 in the developing device 16 adjacent to the stirring member 56.

  The detecting unit 65 mainly includes a light emitting unit 66 and a light receiving unit 67 as sensors, two light guides 68 and 69, a rotating member 70, and the like. As shown in FIG. 3B, the light emitting unit 66 and the light receiving unit 67 are provided not on the developing device 16 but on the image forming apparatus 1 side, and the developing devices 16B, 16Y, 16C, and 16M are common. Used in. That is, the rotary developing device 2 is rotated as appropriate, and the developing devices 16B, 16Y, 16C, and 16M are fixed at positions for detecting the toner amount, and the toner amount of the developing device 16 is detected.

  As shown in FIGS. 3A and 3B, the detection unit 65 includes a transmission type optical sensor having a light emitting unit 66 and a light receiving unit 67 as sensors for detecting the amount of toner in the developing device 16. Use. Then, the light from the light emitting unit 66 is reflected through the light guide 68 and travels toward the light guide 69 at the opposite position, and the light reaches the light receiving unit 67 through the light guide 69. At this time, the amount of light received by the light receiving unit 67 changes due to the optical axis crossing the toner containing portion 59 and the detection target toner blocking the optical axis, and the amount of toner in the developing device 16 is detected.

  The rotating member 70 mainly includes a base portion 70a, a holding member 70b, and a cleaning member 70c. The base portion 70a is formed in a disk shape or a cylindrical shape, and a rotational driving force is transmitted from a motor (not shown) or the like, and is supported by the frame body 51 of the developing device 16B so as to be rotationally driven. In the present embodiment, two holding members 70b are provided and are erected on the base portion 70a so as to pass near the light guides 68 and 69 when the base portion 70a rotates. The cleaning member 70c is a sheet-like member made of a fiber material, resin, or the like, and is fixed to the holding member 70b. Then, the rotating member 70 rotates, and the light transmitting surfaces of the light guides 68 and 69 are cleaned by the cleaning member 70c to prevent the toner from adhering and blocking the light.

  Next, the control unit 80 included in the image forming apparatus 1 according to the embodiment of the present disclosure will be described with reference to FIG. FIG. 4 is a block diagram for explaining the control unit 80 according to the embodiment of the present invention.

  As shown in FIG. 4, a control unit 80 is provided as a configuration for controlling toner replenishment to the developing device 16. The control unit 80 includes at least the developing device 16, the detection unit 65, the replenishing unit 20, and a data processing unit. 17 is connected by a signal line.

  Here, the control unit 80 may be provided in a part of the central processing control unit 80 that performs many controls related to the image forming apparatus 1 necessary for using the image forming apparatus 1. In addition, a controller 80 for controlling toner supply may be provided separately. Note that FIG. 4 shows only a portion necessary for controlling toner supply.

  The control unit 80 includes a CPU as a central processing unit, a RAM as a ROM read / write storage unit as a read-only storage unit, and a storage device such as a hard disk drive (not shown). The control unit 80 includes an I / F for controlling the developing device 16, the detection unit 65, the replenishment unit 20, and the data processing unit 17, and for inputting and outputting data. Specific control for exchanging data and signals will be described later.

  Next, based on FIG. 5, the operation of the control unit 80 provided in the image forming apparatus 1 according to the embodiment of the present disclosure will be described. FIG. 5 is a flowchart for explaining the control of the detection unit 65 in the control unit 80 according to the embodiment of the present invention.

  For toner replenishment, the detection unit 65 provided in the image forming apparatus 1 or each developing device 16 detects the toner amount in the developing device 16 (16B, 16Y, 16C, 16M). When the sensors (light emitting unit 66 and light receiving unit 67) are operated, the lifetime of the sensor is shortened. For this reason, the control unit 80 controls the sensor of the detection unit 65 to perform detection while leaving a predetermined time interval, thereby extending the life of the sensor.

  Here, a dot count value is used to determine a predetermined time interval. The dot count value is an integrated value of the number of dots (number of pixels) on which toner is to be placed in the image formed by the image forming apparatus 1. According to this dot count value, it is possible to predict the amount of toner consumed by the developing device 16. When the dot count value is reached, the control unit 80 controls the detection unit 65 so that the detection unit 65 detects the amount of toner in the developing device 16. In this manner, a predetermined time interval at which the detection unit 65 performs detection is determined. In other words, when the constant dot count value is reached, the control unit 80 rotates the developing device 16 containing the toner of the color that has reached the constant dot count value to a position where it can be detected by the sensor, and the rotary unit so as to receive the detection. Controls the developing device 2.

  For example, data necessary for integrating the dot count value is transmitted from the data processing unit 17 to the control unit 80 (the data processing unit 17 is configured such that the laser unit 14 is a photosensitive member based on image information from an external computer or the like. Since data for scanning exposure of the drum 11 is created, it has information for calculating the number of dots (number of pixels) on which toner should be placed. As the dot count value, the number of dots (number of pixels) on which toner should be placed may be counted as it is. However, for each paper size, the number of dots (number of pixels) on which toner is placed relative to the total number of dots (number of pixels). ), In other words, the image printing rate (also referred to as image printing rate) may be calculated by the data processing unit 17 and the image printing rate may be transmitted to the control unit 80. The control unit 80 may calculate the image printing rate. Since there are a plurality of paper P sizes and the toner consumptions are different, the image print ratio may be converted into an image print ratio for one paper P size (for example, A4).

  When the dot count value is used, the predetermined time interval varies depending on the image printing rate, the paper size, and the like according to the actual toner consumption state. The predetermined time interval can be determined by providing a separate timer (not shown) in the control unit 80.

  Further, in the image forming apparatus 1 according to the present embodiment, the control unit 80 causes the predetermined time interval at which the detection unit 65 performs detection to be shortened depending on the replenishment time in the replenishment operation performed by the replenishment unit 20 before. To control. That is, the predetermined time interval is shortened when it is shorter or longer than the predetermined replenishment time.

  The predetermined replenishment time has a certain width and is determined in relation to the amount of toner per time sent from the toner replenishing device 22 into the developing device 16, in other words, the toner replenishment speed. Specifically, for example, the time when the toner replenishment amount is considered to be smaller from the viewpoint of the replenishment speed than the toner consumption amount predicted from the dot count value and the image printing rate can be set as a reference. If it is shorter than the predetermined replenishment time, it can be determined that the toner replenishment amount is less than the consumption amount. On the other hand, even when the toner supply time is longer than the predetermined replenishment time, the toner in the toner storage container 21 is absent or decreased, so it is considered that the toner is hardly replenished in the developing device 16 even if the toner is replenished. There is a case. The replenishment time in the replenishment operation can be easily managed by the control unit 80 because the replenishment unit 20 and the control unit 80 are connected.

  And, as a method for shortening the predetermined time interval, after resetting the dot count value to be integrated to zero, (when the dot count value reaches a constant value), a fixed value Should be added. For example, when a half value is first added to a fixed upper limit value for integrating the dot count value, the detection unit 65 performs the detection operation in half time on average. This addition may be performed by the control unit 80.

  Here, according to the flowchart shown in FIG. 5, the operation until the detection unit 65 performs detection and shifts to the replenishment operation will be described. In order to facilitate understanding, the developing device 16 in this embodiment will be described with specific numbers.

  Since the developing device 16 in the present embodiment is miniaturized, it can accommodate a relatively small amount of one-component developer of 47 to 48 g. Although the reason will be described later, the developing device 16 is always kept in a state where 40 to 46 g, more preferably 43 to 44 g of toner is accommodated as a predetermined amount. The replenishment speed of the toner replenishing device 22 is about 10 g / min.

  First, when the previous toner supply operation is completed (ST1), the dot count value of the control unit 80 is reset (ST2). In the present embodiment, as described above, the dot count value is converted into the image printing rate on the A4 size paper P and managed by the control unit 80.

  Here, until the integrated value of the image printing rate reaches a constant value, the detection unit 65 is in a pause state. In this embodiment, for example, the fixed value of the integrated value of the image printing rate integrated by the control unit 80 is 333%. Specifically, the toner consumption is approximately the same as when three to four sheets of A4 size paper P are solidly applied. Normally, the image printing rate is about 6%, so if it is about 6%, when an image is formed on about 50 to 60 sheets of paper P, the integrated value reaches a constant value.

  Next, control unit 80 determines whether the replenishment time in the previous replenishment operation is shorter or longer than the predetermined replenishment time (ST3). Here, the predetermined replenishment time has a width of 6 to 25 seconds. If it is 6 seconds or less, the toner replenishment amount to the developing device 16 is about 1 g in view of the toner replenishment speed. In the image forming apparatus 1 of the present embodiment, when image formation of about 333% of the integrated value of the image printing rate is performed, about 2 g of toner is consumed on average, so the toner amount in the developing device 16 decreases. Therefore, if the toner in the developing device 16 is secured to a predetermined amount or more, a large amount of toner can be supplied in the next supply.

  On the other hand, if the replenishment time is longer than 25 seconds, about 4 to 5 g is normally replenished, but the average toner consumption at 333% of the integrated value of the image printing rate is about 2 g, which is about twice as much. . However, since the developing device 16 of the present embodiment maintains a predetermined amount or more of toner, replenishment for 25 seconds is a material for determining that the toner in the developing device 16 is becoming less than the predetermined amount. That is, the toner in the toner container 21 is reduced, and the toner replenishment speed may be reduced. Also, it is conceivable that the toner is actually hardly replenished, and if the next replenishment is performed, a large amount of toner can be replenished (particularly, when the toner container 21 is replaced with a new one).

  However, in this embodiment, the control unit 80 adds a value to the image print rate to be integrated when it is shorter or longer than the predetermined replenishment time (ST4). Specifically, the image forming apparatus 1 according to the present embodiment adds a value of 150%. In this way, the predetermined time interval until the detection unit 65 operates next is shortened, so that a large amount of toner can be prevented from being supplied in the next supply operation, and the toner in the developing device 16 is charged. The amount will not drop greatly.

  After ST4, the control unit 80 continues to integrate the image printing rate based on the information from the data processing unit 17 (ST5), and determines whether the image printing rate has reached a certain value (for example, 333%). (ST6) When the constant value is reached, the control unit 80 operates the detection unit 65 and shifts to toner supply control (ST7).

  Next, toner replenishment control of the image forming apparatus 1 in this embodiment will be described with reference to FIG. FIG. 6 is a flowchart for explaining toner supply control of the image forming apparatus 1 according to the embodiment.

  When the image printing rate integrated by the control unit 80 exceeds a certain value (eg, 333%), the control unit 80 starts toner replenishment control (ST11). When the toner supply control is started, the control unit 80 operates the detection unit 65. At this time, the detection unit 65 detects whether or not the toner amount in the developing device 16 to be replenished reaches a predetermined amount (ST12).

  Here, the predetermined amount of toner in the developing device 16 to be replenished is determined to be 40 to 46 g, more preferably 43 to 44 g in the developing device 16 in the present embodiment. That is, since the amount of toner that can be accommodated by the developing device 16 is 47 to 48 g, the amount of toner always changes almost full. The amount of toner that can be stored and the numerical value of the predetermined amount vary depending on the shape and size of the developing device. However, in a developing device of a size other than this embodiment, 85% of the total amount of toner that can be stored. It is preferable that the developing device accommodates a toner amount of 90% or more, more preferably about 93% or more.

  If the detection unit 65 detects that a predetermined amount or more of toner is present in the developing device 16, the control unit 80 ends the toner supply control (Y in ST12). This is because there is a case where there is a difference between the toner consumption predicted by the integrated value of the image printing rate and the actual consumption.

  On the other hand, when the detection unit 65 detects that the toner amount in the developing device 16B or the like is equal to or less than the predetermined amount, the control unit 80 moves the developing device 16 to be supplied to the supply position (ST13). Specifically, the toner supply device 22 is moved so that the toner supply port 57 of the developing device 16 to be supplied is positioned at the position where the toner supply device 22 has moved downward (see FIG. 1). Thereafter, the toner replenishing device 22 is inserted into the toner replenishing port 57 of the developing device 16 (ST14), the developing device 16 to be replenished is operated, the toner is agitated by the agitating member 56, and the toner to be replenished is agitated ( ST15).

  Then, the control unit 80 conveys the toner in the toner storage container 21 to the toner replenishing device 22 and issues a signal for starting toner replenishment to the developing device to be replenished (ST16), and toner replenishment is started. The Meanwhile, the control unit 80 continues to operate the detection unit 65, confirms the detection status of the detection unit 65, and determines whether or not the toner amount in the developing device 16 has reached a predetermined amount (ST17). When the toner supply continues and the detection unit 65 detects that the amount of toner in the developing device 16 exceeds a predetermined amount, the control unit 80 issues a signal to the supply unit 20 to stop the toner supply, and supplies the toner. The unit 20 stops the toner supply (ST18).

  Since toner replenishment control is performed in this way, there is always a certain amount or more of toner in the developing device 16 and the state is almost full. Since the toner is kept almost full, it is possible to prevent the insufficiently charged toner immediately after being supplied from being used for development. In particular, even in the developing device 16 in the miniaturized one-component developing system, the amount of toner in the developing device 16 is extremely reduced, and there is no shortage of toner charging due to a large amount of toner replenished. The developing device 16 is sufficiently compatible with downsizing.

  After the toner supply is stopped (ST18), the control unit 80 resets the integrated value of the image printing rate (ST19, ST2), and stops the developing device 16 to be supplied (ST20). Further, the control unit 80 issues a signal for moving the toner supply device 22 upward (see FIG. 1), and moves the toner supply device 22 to the standby position (ST21). Then, the toner replenishment control is completed (ST22), and thereafter, as the image is formed in the image forming apparatus 1, the control unit 80 shifts to a control for integrating the image printing rate, and is alternately performed with the toner replenishment control. It will be.

  Note that the toner replenishment control may be performed when the image forming apparatus 1 is started or when an image forming operation is not performed for a predetermined time or longer.

  Next, based on FIG. 7, the difference in the amount of toner to be replenished when the toner replenishment control is performed and when it is not performed in the image forming apparatus 1 according to the present embodiment will be described. FIG. 7 is a graph comparing the case where the control unit 80 according to the embodiment of the present invention is performed and the case where it is not performed.

  In FIG. 7, the maximum amount of toner that can be accommodated in the developing device 16 is indicated by a solid line in the left-right direction in FIG. 7, and the predetermined amount to be maintained is indicated by an alternate long and short dash line (in FIG. 7, as described above, In the developing device 16 in the embodiment, the maximum accommodation amount is 47 g, and the predetermined amount is 44 g). In FIG. 7, a solid line with a downward arrow indicates a toner consumption amount, and a broken line with an upward arrow indicates a toner supply amount.

  First, a case where the control according to the present invention is not performed will be described. In FIG. 7, the graphs (a) and (b) are for the case where toner replenishment control is not performed. As shown in (a), the toner is consumed and becomes a predetermined amount or less, and thereafter, the detection unit 65 operates to perform toner replenishment control, and the toner is replenished to the developing device 16 until it exceeds the predetermined amount. The

  At the time of toner replenishment, the toner is replenished until the detection unit 65 detects that the toner amount has exceeded a predetermined amount. Here, the detection by the detection unit 65 may vary to some extent, and the toner replenishment speed of the toner replenishing device 22 to the developing device 16 may vary due to various factors such as remaining amount, temperature, and humidity. is there. Accordingly, as shown in (a), the toner supply may be completed immediately after reaching the predetermined amount, or the toner supply may be performed until the toner exceeds the predetermined amount and is almost full.

  Therefore, as shown in (b), when the toner supply is completed at the stage where the predetermined amount has been reached in the previous toner supply, the toner can be supplied until the toner supply is almost full in the next toner supply. . That is, a large amount of toner can be replenished at a time. Such toner replenishment lowers the charge amount of the toner in the developing device 16 so as to affect the development and formation of the image, and it is desirable to avoid such a large amount of toner replenishment. .

  Therefore, toner replenishment control according to the present invention shown in (c) and (d) will be described. (C) shows a case where toner supply is completed immediately after reaching a predetermined amount, as in the case of (a). When the toner supply is completed immediately after reaching the predetermined amount, the time from the start of toner supply to the end may be short. Here, as described above, the control unit 80 manages and monitors the toner replenishment time.

  Therefore, if the toner replenishment time is shorter than the predetermined replenishment time, it can be predicted that a large amount of toner will be replenished to the developing device 16 in the next replenishment. Therefore, the control unit 80 sets the dot count value (image printing rate). A fixed value is added to the integrated value, and the time interval until the next detection unit 65 detects the toner amount in the developing device 16 is shortened. Then, as shown in (d), even if the toner is replenished to a nearly full state, the amount of toner replenishment at one time can be made smaller than in the case shown in (b). Therefore, if the present invention is carried out, a large amount of toner is not replenished at a time.

  In this way, the developing device 16 (16B, 16Y, 16C, 16M) that supplies toner to develop the electrostatic latent image formed on the photosensitive drum 11 and the amount of toner in the developing device 16 are detected. Detection unit 65, and when the detection unit 65 detects that the toner amount in the developing device 16 has not reached the predetermined amount, the replenishing unit 20 that replenishes toner in the developing device 16 and the detection unit 65 develops the toner. And a control unit 80 that controls the toner amount in the apparatus 16 to be detected at predetermined time intervals. In the replenishment operation performed by the replenishment unit 20, the time from the start of replenishment to the end of replenishment is predetermined. If it is shorter or longer than the replenishment time, the control unit 80 may control the detection unit 65 to shorten a predetermined time interval until the detection of the toner amount in the developing device 16 next time. , Detection unit 65 It detects that toner in the developing device 16 is below a predetermined amount, because the toner supply is carried out At this time, can maintain a state where the toner of the predetermined amount or more in the developing device 16 is present. When the replenishment time is shorter than the predetermined time and only a small amount of toner is replenished, the replenishment operation returns to the predetermined amount or more in the next replenishment operation. Next, control is performed to shorten the time interval until the detection unit 65 detects the toner amount, and the toner replenishment operation is performed before the toner amount in the developing device 16 decreases, so that a large amount of toner is replenished at a time. Can be avoided. Accordingly, a state where a predetermined amount or more of toner is always accommodated in the developing device 16 is maintained, a decrease in the toner charge amount due to replenishment is relatively small, and a small amount of toner is replenished at one time. It can be suppressed. That is, insufficient toner charging is prevented, and streaks and fogging are prevented from being formed.

  On the other hand, if the replenishment time is longer than the predetermined time, the toner storage container 21 for replenishing toner to the developing device 16 may be low in toner, and in this case, the toner replenishment speed to the developing device 16 decreases. Can do. That is, even if the replenishment time is long, the toner may actually be replenished only in a small amount. Also in this case, the time interval until the next detection is shortened, and the toner replenishing operation is performed before the toner amount in the developing device 16 decreases, thereby preventing a large amount of toner from being replenished at a time.

  Furthermore, the detection unit 65 for detecting the amount of toner in the developing device 16 operates at predetermined time intervals and does not always operate, so the life of the detection unit 65 is extended. Accordingly, it is possible to provide a long-life image forming apparatus.

  Further, the developing device 16 that is downsized (particularly, the developing device 16 of the one-component developing system is advantageous for downsizing) reduces the amount of toner accommodated in the developing device 16, but the present invention is a developing device. Since the amount of toner in the device 16 is secured to a certain level or more and the toner is replenished little by little, the toner charge is unlikely to decrease, and it is possible to deal with a downsized developing device regardless of the developing method. Further, it is not necessary to provide two sensors for detecting the remaining amount and fullness, which is advantageous in terms of cost, and corresponds to the downsizing of the developing device 16 in that the space for the sensors can be reduced. .

  In addition, the control unit 80 puts toner on the image formed on the image carrier in order to determine a predetermined time interval until the detection unit 65 next detects the toner amount in the developing device 16. If the dot count value, which is the integrated value of the number of pixels to be used, is used to determine the predetermined time interval, the toner consumption amount can be easily predicted. Therefore, since the detection unit 65 operates at a timing when it is recognized that a certain amount of toner has been consumed, the amount of toner to be replenished is stabilized, and a large amount of toner is less likely to be replenished at a time. That is, it is possible to always perform toner replenishment in which the charging of the toner in the developing device does not decrease to such an extent that the image quality deteriorates.

  When the detecting unit 65 detects that the toner amount in the developing device 16 has not reached the predetermined amount, and the replenishing unit 20 replenishes toner in the developing device 16, the control unit 80 The detection unit 65 controls to detect until the toner reaches a predetermined amount or more, and the replenishment unit 20 detects that the toner has been replenished until the toner amount in the developing device 16 reaches a predetermined amount or more. If replenishment is performed until detection, the amount of toner in the developing device 16 can be reliably maintained to be a predetermined amount or more. For example, if the predetermined amount is set to a value close to full, a large amount of toner will not be replenished at once, and even if the toner is replenished, the charge amount of the toner in the developing device 16 will be reduced. Can be relatively small.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in an image forming apparatus.

1 is a schematic cross-sectional view for explaining a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a schematic configuration of a developing device according to an embodiment of the present invention. FIG. 2A is a perspective view illustrating a configuration of a detection unit of a developing device according to an embodiment of the present invention. (B) is explanatory drawing for demonstrating the mechanism of a detection part's detection. It is a block diagram for demonstrating the control part which concerns on embodiment of this invention. It is a flowchart for demonstrating control of the detection part in the control part which concerns on embodiment of this invention. 4 is a flowchart for explaining toner supply control of the image forming apparatus according to the embodiment. It is the graph which compared the case where not performing with the case where control which concerns on embodiment of this invention is performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Rotary developing device 16 Developing device (16B, 16Y, 16C, 16M)
20 Replenisher 21 Toner container 22 Toner replenishing device 65 Detector 66 Light emitter 67 Light receiver 80 Controller

Claims (3)

A developing device for supplying toner to the image carrier in order to develop an electrostatic latent image formed on the image carrier;
A detection unit for detecting the amount of toner in the developing device;
A replenishing unit that replenishes toner in the developing device when the detecting unit detects that the toner amount in the developing device has not reached a predetermined amount;
A controller that controls the detection unit to detect the toner amount in the developing device at predetermined time intervals;
In the replenishment operation performed by the replenishment unit, when the time from the start of replenishment to the end of replenishment is shorter or longer than a predetermined replenishment time, the control unit next detects the detection unit in the developing device. An image forming apparatus that controls to shorten the predetermined time interval until the toner amount is detected.   The control unit should put toner on the image formed on the image carrier in order to determine a predetermined time interval until the detection unit next detects the toner amount in the developing device. 2. The image forming apparatus according to claim 1, wherein a dot count value which is an integrated value of the number of pixels is used. When the detection unit detects that the amount of toner in the developing device has not reached a predetermined amount, and the replenishing unit replenishes toner in the developing device,
The control unit controls the detection unit to perform detection until the toner in the developing device reaches a predetermined amount or more,
3. The image forming according to claim 1, wherein the replenishing unit replenishes until the detection unit detects that the toner has been replenished until the toner amount in the developing device reaches a predetermined amount or more. apparatus.

Images