JP2014048442A - Image forming device, toner supply method, and toner supply program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device for always keeping proper toner concentration, and to provide a toner supply method and a toner supply program.SOLUTION: When necessity to supply toner is determined on the basis of an output of a toner concentration sensor 59 in a developing unit 14, the number of toner supplies is set to FLAG, the number of toner supplies being decided from the cumulative dot count during a period in which toner is not supplied, latency between supplies is set to WAIT_TIME, the latency being calculated by dividing the time required for the developer to move around the developing unit 14 by the number of toner supplies, and "1" is set to IGNORE_SENSOR for invalidating the output of the toner concentration sensor 59. Every time the toner is supplied, FLAG is subtracted by 1, WAIT_TIME is subtracted by 1 in the last part of a main routine, and the processing is repeated. When WAIT_TIME becomes 0, the next toner supply is permitted. When a set number of toner supplies is completed, 0 is set to IGNORE_SENSOR, and invalidation of the output of the toner concentration sensor 59 is canceled.

Description

  The present invention relates to an image forming apparatus, a toner replenishing method, and a toner replenishing program that always maintain a proper toner density.

  2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses include a type using a one-component developer (toner) and a type using a two-component developer. Since the method using a single component developer is relatively easy to handle and control, a single component toner has been dominant as a developer.

  However, as demand for speeding up printing (hereinafter also referred to as printing) increases as in recent years, a method using a two-component developer can better cope with speeding up printing processing. Various improved two-component developers have been proposed.

  The above two-component developer is composed of toner and carrier. The carrier is mixed and agitated with the toner in the developing unit to give the toner a predetermined charge. The charged toner temporarily adheres to the surface of the carrier and coats the surface of the carrier.

  The carrier carries charged toner onto the photosensitive member, transfers the toner to the electrostatic latent image on the photosensitive member, and develops the toner image on the electrostatic latent image. The carrier that has released the toner on the surface remains on the developing roller, returns to the inside of the developing device, is mixed and stirred again with new toner, charges the toner, and transports the toner onto the photoreceptor. Is done.

  A developing device using such a two-component developer is a unit based on the toner density detected by the upstream toner density detector, the toner density detected by the downstream toner density sensor, and the maintenance target value of the toner density. An electrostatic latent image developing device that determines the amount of toner replenished per hour and enables high-precision toner density control even when outputting a large-sized image with a large amount of toner consumption or an image with a high black ratio Has been proposed. (For example, refer to Patent Document 1.)

  In addition, by increasing the force that transports the developer in the vicinity of the toner sensor surface in the axial direction of the agitating / conveying member, the retention of the developer in the vicinity of the toner sensor surface is suppressed, and the toner concentration is reduced. A developing device that can suppress a decrease in detection accuracy has been proposed. (For example, see Patent Document 2.)

JP 2002-014533 A JP 2010-243904 A

  By the way, in a developing device using a two-component developer, a developer containing toner circulates in the developing device. When toner is consumed by development, the determination as to whether or not to replenish the toner is performed. This is determined by the degree of decrease in toner density detected by the sensor.

  In each of the above-mentioned Patent Documents 1 and 2, the emphasis is placed on improving the accuracy of toner density detection by the toner density sensor. However, no matter how accurately the decrease in toner density is detected, there is only one toner supply port of the developing device.

  In other words, when viewed from the entire developer circulating in the developing device, when a decrease in toner density is detected and toner is replenished, the toner is replenished intensively only at a specific location. Since a certain amount of time is required for stirring in the developing device, the entire developer continues to have a density difference for a certain period of time.

  Furthermore, if toner consumption due to printing and toner replenishment continue at a bad timing, there is a considerable difference in toner density between the light and dark areas of the developer circulating in the developer. It becomes prominent.

  In addition, since it takes time for the supplied toner to be uniformly stirred and mixed in the entire developer, the toner concentration sensor output is stable until it is determined that toner supply is unnecessary. When a low-density part circulates to the position of the toner density sensor, a signal “Toner replenishment required” is output, unnecessary toner replenishment is performed, and there is a problem that the toner is excessively replenished.

  If there is uneven density in the developer that the toner density is uneven between the light and dark areas, there is a problem that the density unevenness directly affects the printing result. In addition, if the toner concentration is too high due to excessive supply of toner, scumming or the like may occur, and in an extreme case, the toner may be scattered outside the developing device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus, a toner replenishing method, and a toner replenishing program that always maintain a proper toner density.

  In order to solve the above-described problems, an image forming apparatus according to the present invention is provided in a developer tank that contains a developer containing toner in a circulatory manner, and in the developer circulation path of the developer tank. A toner density sensor that outputs density information of toner in the interior; a comparison unit that compares the output value of the toner density sensor with a comparison reference value; a replenishment port that is disposed in the circulation path and replenishes replenishment toner; Determining whether or not replenishment is necessary based on the comparison result of the comparison unit; and when it is determined that replenishment is necessary, a toner replenishment unit that replenishes the developing tank with replenishment toner from the replenishment port; and the toner replenishment unit Calculating a toner consumption amount based on a printing result from the time when the previous toner supply is completed until the start of the current toner supply, and calculating a toner amount to be supplied according to a calculation result of the calculation unit, Replenishment of the calculated amount A toner replenishment amount control unit that controls the toner replenishment unit so that the toner is replenished a plurality of times from the replenishment port until the developer circulates around the circulation path. Composed.

  In order to solve the above problems, a toner replenishing method of an image forming apparatus according to the present invention is a toner replenishing method in an image forming apparatus provided with a developing tank that circulately accommodates a developer containing toner. The toner density sensor disposed in the developer circulation path of the developer tank outputs the toner density information in the developer, and compares the output value of the toner density sensor with the comparison reference value. Based on the comparison result, it is determined whether or not replenishment is necessary, and when it is determined that replenishment is necessary, the replenishment toner is replenished to the developing tank with a predetermined replenishment amount from the replenishment port provided in the circulation path. Then, in relation to the replenishment, a toner consumption amount is calculated based on the printing results from the completion of the previous toner replenishment to the start of the current toner replenishment, and the toner to be replenished according to the calculation result of the toner consumption Calculate the amount and the calculated The toner to be replenished in an amount such that the developer is replenished at a plurality of times from the supply port until the circulated one round the circulation path configured to control.

  In order to solve the above problems, the toner replenishment program of the image forming apparatus of the present invention is configured to be readable by a computer in an image forming apparatus having a developing tank that circulates and stores a developer containing toner. A toner replenishment program, a toner concentration information output procedure for outputting toner concentration information in the developer by a toner concentration sensor disposed in the developer circulation path of the developer tank, and the toner concentration information The toner density comparison procedure for comparing the output value of the toner density sensor according to the output procedure and the comparison reference value, and the necessity of replenishment are determined based on the comparison result of the toner density comparison procedure. , A toner replenishing procedure for replenishing the developing tank with toner for replenishment from a replenishing port disposed in the circulation path, and a previous toner replenishing procedure according to the toner replenishing procedure. A toner consumption amount calculation procedure for calculating a toner consumption amount based on a printing result from the end point to the start of toner supply this time, and a toner amount to be replenished according to a calculation result of the toner consumption amount calculation procedure, Toner replenishment amount control for controlling the toner replenishment procedure so that the calculated amount of toner to be replenished is replenished a plurality of times from the replenishment port before the developer circulates around the circulation path. And the procedure is configured to be executed by the computer.

  The present invention can provide an image forming apparatus, a toner replenishing method, and a toner replenishing program that always maintain an appropriate toner density. As a result, it is possible to suppress the density unevenness of the printing result due to the density difference of the developer circulating in the developing device and to prevent the toner from scattering due to the excessive toner replenishment.

1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (printer, main body apparatus) according to Embodiment 1 of the present invention. 1 is a circuit block diagram including a printer control device according to Embodiment 1. FIG. (a) is an enlarged cross-sectional view showing the developing device of the printer according to the first embodiment together with the photosensitive drum, and (b) is a drawing of the developing device cut in a direction indicated by an arrow c in (a) to return the internal configuration and developer. It is sectional drawing which shows a path | route. 6 is a flowchart illustrating a processing operation for controlling toner replenishment to a developing device so as to always maintain an appropriate toner density by a CPU of a printer control apparatus according to the first exemplary embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, printing and printing are used synonymously.

  FIG. 1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (hereinafter simply referred to as a printer or a main body apparatus) according to Embodiment 1 of the present invention. In the printer of this example, the primary transfer employs the shift type instead of the direct pressure type.

  A printer 1 shown in FIG. 1 is an electrophotographic secondary transfer tandem color image forming apparatus, and includes an image forming unit 2, a transfer belt unit 3, a toner supply unit 4, a paper feeding unit 5, and a belt type fixing device. It comprises a unit 6 and a transport unit 7 for duplex printing.

  The image forming unit 2 is in contact with the lower running surface 8a of the intermediate transfer belt 8 of the transfer belt unit 3, and four developing devices 9 (9k, 9c, 9m, 9y) from the right to the left in FIG. Constructed side by side. The image forming unit 2 is held by a frame of the printer 1 main body so as to be movable up and down from a printing execution position shown in FIG. 1 to a maintenance position below it.

  Of the four developing devices 9, three developing devices 9c, 9m, and 9y on the upstream side (the left side in the figure) are cyan (C), magenta (M), and yellow (Y), which are subtractive three primary colors, respectively. A mono-color image is formed with the color toner, and the developing device 9k forms a monochrome image mainly with black (K) toner used for characters and dark portions of the image.

  Each of the developing devices 9 has the same configuration except for the color of the toner that develops the image. Therefore, the configuration of the developing device 9y for yellow (Y) toner will be described below as an example.

  The developing device 9 includes a photosensitive drum 10 at the top. The photosensitive drum 10 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 11, a charging roller 12, an optical writing head 13, and a developing roller 15 of the developing device 14 are disposed in contact with or around the periphery of the photosensitive drum 10.

  The developing device 14 includes an outer wall frame 16 that covers the outside, a partition wall 17 provided inside, a developing roller 15, a first spiral rotary transport member 18, and a second spiral rotary transport member 19. As will be described in detail later, the first and second spiral rotary conveying members 18 and 19 include a rotary shaft and spiral blades that are integrally formed with the rotary shaft and rotate.

  The developing unit 14 includes four toner cartridges 28 of the toner supply unit 4 from black (K), cyan (C), magenta (M), yellow (Y) indicated by K, C, M, and Y in FIG. ) Is supplied.

  The transfer belt unit 3 has an endless intermediate transfer belt 8 that extends in the shape of a flat loop in the left-right direction in the figure at approximately the center of the main unit, and the intermediate transfer belt 8 is stretched over the intermediate transfer belt 8. A driving roller 21 and a driven roller 22 are provided to circulate and move the belt 8 in the counterclockwise direction indicated by an arrow a in the figure.

  The transfer belt unit 3 further includes a secondary transfer backup roller 23 over which the intermediate transfer belt 8 is stretched above the drive roller 21. A secondary transfer roller 24 is pressed against the secondary transfer backup roller 23 via the intermediate transfer belt 8 to form a secondary transfer portion.

  The intermediate transfer belt 8 includes a primary transfer roller 25 integrated with the unit. The primary transfer roller 25 is disposed so as to sandwich the intermediate transfer belt 8 at a position slightly shifted to the downstream side in the circulation movement direction of the intermediate transfer belt 8 with respect to the photosensitive drum 10.

  The primary transfer roller 25 directly transfers (primary transfer) the toner image to the belt surface that circulates below. The intermediate transfer belt 8 reaches the secondary transfer portion where the secondary transfer roller 24 is in pressure contact with the secondary transfer backup roller 23 via the intermediate transfer belt 8 in order to further transfer (secondary transfer) the toner image to the sheet. Transport.

  A belt cleaner 26 is disposed on the intermediate transfer belt 8 so as to contact the surface of the driven roller 22. Below the belt cleaner 26, a waste toner collecting container 27 for storing waste toner removed from the intermediate transfer belt 8 by the belt cleaner 26 is detachably disposed.

  The toner supply unit 4 includes four toner cartridges 28 disposed above the upper running surface of the intermediate transfer belt 8. Each of the four toner cartridges 28 contains black (K), cyan (C), magenta (M), and yellow (Y) supply toner.

  These four toner cartridges 28 are connected to the developing device 14 of the developing device 9 corresponding to the color of the toner accommodated by a toner supply path (not shown in FIG. 1 hidden behind the transfer belt unit 3). It is connected.

  On the left side of the toner supply unit 4, two electrical parts 29 are disposed from the left side of the belt cleaner 26 to above the driven roller 22. A circuit board on which a control device composed of a plurality of electronic components is mounted is mounted on the electrical component 29.

  The paper feed unit 5 includes two paper feed cassettes 31 (31a, 31b) arranged in two upper and lower stages. A paper take-out roller 32, a feed roller 33, a separating roller 34, and a standby conveyance roller pair 35 are arranged in the vicinity of the paper feed opening (right side in the drawing) of the two paper feed cassettes 31, respectively.

  The secondary transfer portion described above is formed in the paper conveyance direction (vertical upward direction in the drawing) of the standby conveyance roller pair 35. A belt-type heat fixing unit 6 is disposed downstream (upward in the drawing) of the secondary transfer portion.

  On the further downstream side of the belt-type heat fixing unit 6, a pair of carry-out rollers 36 for carrying out the fixed paper from the belt-type heat fixing unit 6, and a paper discharge tray 37 formed on the upper surface of the apparatus. A paper discharge roller pair 38 for paper discharge is provided.

  The conveyance unit 7 for double-sided printing also serves as an opening / closing member whose outer surface (right outer surface in the drawing) opens or shields the inside of the printer 1 from the side surface to the outside.

  This double-sided printing transport unit 7 has a return start path 39a that branches rightward in the figure from just before the discharge roller pair 38, a return intermediate path 39b that bends downward, and further bends leftward in the end to finally return. A return path 39 having a return terminal path 39c for inverting the paper is provided.

  In the middle of the return path 39, five pairs of return rollers 41 (41a, 41b, 41c, 41d, 41e) are arranged. The exit of the return end path 39 c joins a conveyance path to the pair of standby conveyance rollers 35 corresponding to the sheet feeding cassette 31 b below the sheet feeding unit 5.

  FIG. 2 is a circuit block diagram including the control device of the printer 1 described above. As shown in FIG. 2, the circuit block has a central processing unit (CPU) 42 as a center, and an interface controller (I / F_CONT) 43 and a printer controller (PR_CONT) 44 are connected to the CPU 42 via data buses. ing. A printer printing unit 45 is connected to the PR_CONT 44.

  The CPU 42 is connected to a ROM (read only memory) 46, an EEPROM (electrically erasable programmable ROM) 47, an operation panel 38 of the main body operation unit, and a sensor unit 48 to which outputs from sensors arranged in the respective units are input. ing.

  The ROM 46 stores a system program, and the CPU 42 performs processing by controlling each unit in accordance with the system program.

  That is, in each unit, first, the I / F_CONT 43 converts print data supplied from a host device such as a personal computer into bitmap data and develops it in the frame memory 49. In the frame memory 49, storage areas are set for each of black (K), magenta (M), cyan (C), and yellow (Y), and data of each color is developed in the corresponding area.

  The data developed in the frame memory 49 is output to the PR_CONT 44, and is output from the PR_CONT 44 to the printer printing unit 45.

  The printer printing unit 45 is an engine unit, and under the control of the PR_CONT 44, a rotation drive system (not shown) including the photosensitive drum 10, the primary transfer roller 21 and the like shown in FIG. An image forming unit having a driven unit such as a head 13 and a driving unit (not shown) that drives the transfer belt unit 3 to move up and down and the transfer belt 8 to rotate are provided.

  Further, the printer printing unit 45 includes a belt driving unit 52 that drives the belt of the belt-type fixing unit 6 and a toner supply unit motor driving unit 53 that drives a motor of the developing device 14.

  Further, the printer printing unit 45 is a drive output to a process load such as a conveyance mechanism including rotationally driven parts such as the paper take-out roller 22 to the paper discharge roller pair 31, and a belt-type fixing unit 6 that is driven and heated. To control.

  The print data for each color of black (K), magenta (M), cyan (C), and yellow (Y) output from the PR_CONT 44 is sent from the printer printing unit 45 to the corresponding optical writing head shown in FIG. 13 is supplied.

  3A is an enlarged cross-sectional view showing the developing device 14 together with the photosensitive drum 10, and FIG. 3B is a sectional view of the developing device 14 in the direction indicated by the arrow c in FIG. 3A. FIG. 3 is a cross-sectional view showing an internal configuration and a developer reflux path.

  3A and 3B, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. In FIG. 3B, illustration of the doctor blade and the cleaning blade shown in FIG. 3A is omitted, and the toner density sensor is shown in a simplified manner.

  As shown in FIGS. 3A and 3B, the developing device 14 includes two developing tanks 57 (57 a and 57 b) partitioned by an outer wall frame 16 and an inner partition wall 17.

  In the upper developing tank 57a, the developing roller 15 and the second spiral rotary conveying member 19 are arranged. A doctor blade 58 is in contact with the developing roller 15. A first spiral rotary conveyance member 18 is disposed in the lower developing tank 57b. In the developing tank 57b, a toner density sensor 59 is arranged with its detection surface 61 exposed in the tank.

  The first spiral rotary conveyance member 18 includes a rotation shaft 62 and a helical fin 63 fixed to the rotation shaft 62 in a spiral shape. The second spiral rotary conveying member 19 includes a rotation shaft 64 and a spiral fin 65 fixed to the rotation shaft 64 in a spiral shape.

  If the toner concentration of the developer in the developing tank 57b is less than a specified level, the toner concentration sensor 59 detects a decrease in toner concentration. When a decrease in toner density is detected, toner is supplied from a toner cartridge 28 corresponding to the developing unit 14 of the toner supply unit 4 via a toner supply port described later.

  Since the detection surface 61 of the toner density sensor 59 is disposed so as to be exposed in the developing tank, the developer tends to stay on the detection surface 61. If the developer stays on the detection surface 61, the detection accuracy of the toner density sensor 59 is lowered.

  In order to prevent the detection accuracy of the toner density sensor 59 from deteriorating, the rotation shaft 62 of the first spiral rotary conveyance member 18 in the developing tank 57b rotates to face the detection surface 61 of the toner density sensor 59. A cleaning blade 68 composed of a blade holding portion 66 and an elastic sheet (blade) 67 held by the blade holding portion 66 is fixedly installed.

  The cleaning blade 68 rotates together with the rotation shaft 62 of the first spiral rotary conveyance member 18, and rubs the detection surface 61 of the toner density sensor 59 with the elastic sheet 67 so as to stay on the detection surface 61. The developer is swept away and replaced with the developer conveyed immediately thereafter to prevent erroneous detection of the toner concentration that may be caused by the developer staying on the detection surface 61 of the toner concentration sensor 59.

  As shown in FIG. 3B, both end portions of the developing roller 15 are rotatably supported by the developing roller support portions 16 a and 16 b of the outer wall frame 16 of the developing device 14 via the rotation shaft 69. One end (left side in FIG. 3B) of the rotating shaft 69 is formed to extend further than the developing roller support 16b, and is provided with a gear 71 at the tip.

  The outer wall frame 16 of the developing device 14 extends to the left in the same manner as the rotation shaft 69 of the developing roller 15 extends further than the developing roller support portion 16b, and is extended by the extended outer wall frame 16c. A discharge tank 72 is formed.

  The extending tank 72 formed by the extending outer wall frame 16c has a shape in which the developing tanks 57a and 57b and the partition wall 17 extend as they are. However, a toner return port 73 is formed in the partition wall 17 in the extension tank 72, and a toner supply port 74 is formed in a side surface of the extension tank 72 communicating with the developing tank 57b.

  One end of the rotation shaft 64 of the second spiral rotary conveying member 19 is rotatably supported by the outer wall frame 16 on the same side as the developing roller support 16a, and the other end is extended to the outer wall frame. 16c is rotatably supported.

  A drive relay gear 76 is fixed to the outer end portion 64a of the second spiral rotary conveying member 19 that protrudes outside the extended outer wall frame 16c of the rotating shaft 64. In addition, an external engagement gear 77 and a drive transmission gear 78 are fixed to the external shaft 62a that protrudes outside the extended outer wall frame 16c of the rotation shaft 62 of the first spiral rotary conveyance member 18.

  The external engagement gear 77 rotates by engaging with a drive system (not shown) on the main body side of the printer 1 to rotate the first helical rotation conveyance member 18 and the drive transmission gear 78. The drive transmission gear 78 meshes with the drive relay gear 76 of the rotary shaft 64 of the second spiral rotary conveyance member 19 and transmits the rotational drive to the drive relay gear 76.

  The drive relay gear 76 rotates the second spiral rotary conveyance member 19 and relays the rotational drive from the drive transmission gear 78 to the gear 71. The gear 71 rotates the developing roller 15.

  3A and 3B, the second spiral rotary conveying member 19 rotates counterclockwise in FIG. 3A as indicated by an arrow d in FIG. While agitating the developer in 57a with the spiral fin 65, as shown by the arrow e in FIG. 3 (a), from the near side in the depth direction of the drawing to the other side (in FIG. 3 (b), the arrows e1, e2, e3 To the left).

  The second spiral rotary conveying member 19 supplies the developer to the developing roller 15 while stirring and conveying the developer as described above. The developing roller 15 supplies only the toner of the developer to the photosensitive drum 10 shown in FIGS. 1 and 3A, and converts the electrostatic latent image on the circumferential surface of the photosensitive drum 10 into a toner image (development). .

  The developer carrier on the developing roller 15 from which only the toner has been taken up by the photosensitive drum 10 is mixed with the developer in the developing tank 57a. Thereafter, the developer is fed back from the toner feed-back port 73 to the developing tank 57b as indicated by an arrow e4.

  The first spiral rotary conveying member 18 in the developing tank 57b rotates counterclockwise in FIG. 3A as indicated by an arrow g in FIG. 3A, and the developer in the developing tank 57b. As shown by the arrow f while being stirred by the spiral fin 63, the sheet is conveyed from the far side in the depth direction of FIG. 3A to the near side (the right side shown by the arrows f1, f2, f3, and f4 in FIG. 3B). To do.

  The first spiral rotary conveyance member 18 is indicated by an arrow f5 from the toner delivery port 79 on the near side in the depth direction of the paper surface in FIG. 3A (right side in FIG. 3B) while stirring and conveying the developer. In this manner, the developer is sent to the developing tank 57a.

  When the toner density sensor 59 detects that the toner density has fallen below the specified level, the toner is supplied from the toner supply port 74. In this way, the reflux of the developer and the replenishment of the toner are repeated, and the development with the toner proceeds sequentially.

  By the way, in the developer that is stirred and conveyed by the spiral rotary conveying member and circulated in the developing tank, if the developer concentration is uneven, the uneven density also affects the printing result as it is. As described above, this occurs.

  Therefore, in the image forming apparatus of this example, the CPU 42 of the control device controls the toner supply to the development note 14 so that the toner density is always kept appropriate.

  FIG. 4 is a flowchart for explaining a processing operation for controlling the toner supply to the developing device 14 so as to always keep the toner density appropriately by the CPU 42 of the control device. In the following processing, it is determined that toner replenishment is necessary when the output of the toner density sensor 59 exceeds the toner replenishment start voltage.

  Further, in this process, three variables of FLAG, WAIT_TIME, and IGNORE_SENSOR are used as variables in order to control a process of supplying toner in a plurality of times with a single toner supply command. The cumulative dot counter is set in a predetermined area of the EEPROM 47.

  FLAG_TIME controls the number of toner replenishment, WAIT_TIME controls the waiting time between toner replenishment and the next toner replenishment. This is a variable for controlling to invalidate the output of the toner density sensor 59 in order to prevent detection.

  Further, in order to facilitate understanding of the present invention, specific variables and other numerical values are shown as specific examples. The time required for the developer to make one round of the developing device 14 is 20 seconds, and a single toner replenishment command is required. The number of times of toner replenishment is divided into a plurality of times and the waiting time from replenishment to replenishment is 4 seconds.

  In the processing of FIG. 4, the CPU 42 of the control unit is turned on to the main unit 1 shown in FIG. 1, and the quality of the paper to be used, the number of sheets, the print mode, and other designations are input from a key input or signal from the host device connected Is input, printing is started.

  Prior to starting printing, the CPU 42 first sets the registers set in predetermined areas of the EEPROM 47 corresponding to the three variables FLAG, WAIT_TIME, and IGNORE_SENSOR. "Use") is set to "0" (step S1).

  Subsequently, the CPU 42 determines whether the FLAG value is “0” and toner replenishment is necessary (step S2). In this process, if the FLAG value is “0”, the toner replenishment has been completed. Thereafter, it is determined whether the toner has been consumed and the output of the toner density sensor 59 has exceeded the toner replenishment start voltage. This is a process for determining.

  If the output of the toner density sensor 59 is equal to or lower than the toner replenishment start voltage (NO at S2), the CPU 42 immediately proceeds to the process at step S3, which is the next determination process.

  However, when the output of the toner density sensor 59 exceeds the toner replenishment start voltage and toner replenishment is necessary (Yes in S2), in this case, the CPU 42 proceeds to step S7. Reference is made to the value of the cumulative dot counter, that is, the cumulative dot count during the period when toner supply is not performed.

  Next, the CPU 42 calculates the number of times of toner replenishment (for example, 5) based on the accumulated dot count number referred to, and then the time required for the developer to make one round of the developer 14 (this time is assumed to be known). ) Is divided by the number of toner replenishments to calculate the waiting time (time interval from replenishment to replenishment).

  Further, the CPU 42 sets “5”, which is the number of toner replenishments, to the FLAG. Further, the CPU 42 sets “1” to IGNORE_SENSOR. This is a process of invalidating the output of the toner concentration sensor 59 in order to prevent erroneous detection of the toner concentration of the toner concentration sensor because the toner concentration is thinner than the specified value until the toner supply is completed five times. .

  Finally, the GCPU 42 clears the value of the cumulative dot counter to “0” and proceeds to the process of step S3. In step S3, it is determined whether or not the value of WAIT_TIME is “0” and the value of FLAG is “1” or more.

  Here, if the value of FLAG is not “1” or more, that is, “0” (NO in S3), the replenishment of toner to be replenished in a plurality of times has been completed, so the CPU 42 Immediately shifts to the process of step S4, which is the determination process.

  On the other hand, when the value of WAIT_TIME is “0” and the value of FLAG is “1” or more in the determination in step S3 (Yes in S3), toner supply corresponding to the toner supply command is performed a plurality of times. Since it is not completed and the waiting time is “0”, it is necessary to perform the next toner supply following the previous time.

  In this case, the CPU 42 performs toner replenishment once, subtracts “1” from the FLAG value, sets “4” seconds as the next waiting time to WAIT_TIME (step S8), and then performs step S4. Move on to discrimination. In step S4, the CPU 42 determines whether there is a print request.

  This process is a process of determining whether or not a print command is input from the host device and determining whether or not there is print data developed in the frame memory 49. If there is no print request (No in S4), the CPU 42 immediately proceeds to the process in step S5, which is the next determination process.

  On the other hand, if there is a print request in the determination in step S4 (Yes in determination in S4), the CPU 42 executes printing and adds the number of print dots corresponding to the value to the cumulative dot counter (step S9). ), The process proceeds to the determination process in step S5.

  In step S5, the CPU 42 determines whether or not the value of WAIT_TIME is “1” or more. This process is a process for determining whether or not the number of replenishments remains one or more. If the value of WAIT_TIME is not “1” or more, that is, “0” (No in S5), in this case, the CPU 42 immediately proceeds to the next determination process of step S6.

  On the other hand, if the value of WAIT_TIME is equal to or greater than “1” in the determination of step S5 (Yes in S5), there is still a waiting time. Therefore, to subtract the elapsed time from the waiting time to the present time, the CPU 42 After subtracting “1” from the value (step S10), the process proceeds to step S6.

  In step S6, the CPU 42 determines whether the value of WAIT_TIME is “0” and the value of IGNORE_SENSOR is “1”.

  In this process, if the value of WAIT_TIME is “0”, the toner supply for a plurality of times corresponding to the toner supply command is completed. Therefore, since the output invalidity of the toner density sensor 59 must be canceled, it is checked whether the output invalidity of the toner density sensor 59 has been canceled.

  That is, if the value of WAIT_TIME is “0” and the value of IGNORE_SENSOR is not “1”, that is, “0” (No in S6), the output invalidity of the toner density sensor 59 is canceled. The CPU 42 returns to step S2 and performs the processing from step S2 onward.

  On the other hand, if the value of WAIT_TIME is “0” and the value of IGNORE_SENSOR is “1” (Yes in S6), the output invalidity of the toner density sensor 59 has not been cancelled. After “0” is set to the value (step S11), the process returns to step S2 to perform the processing from step S2.

  As described above, in this example, when it is determined that the toner replenishment voltage exceeds the toner replenishment start voltage and the toner replenishment is necessary, the toner replenishment is not performed first. The number of toner replenishments is determined from the cumulative dot count, and this is set to FLAG.

  Next, the known time for the developer to make one round of the developing device 14 is divided by the number of times of toner replenishment to calculate a waiting time from replenishment to the next replenishment, and this is set to WAIT_TIME. Further, during a plurality of times of toner replenishment, “1” is set in IGNORE_SENSOR as a flag for invalidating the output so that the toner density sensor 59 does not erroneously detect that the toner density is low.

  Each time the toner is replenished, “1” is subtracted from FLAG, and a waiting time is set in WAIT_TIME. WAIT_TIME subtracts “1” at the end of the main routine of the process. When WAIT_TIME becomes “0”, the next toner supply is permitted.

  When the toner supply is completed for the set number of toner supply times, “0” is set in IGNORE_SENSOR to cancel the invalid output of the toner density sensor 59.

Although several embodiments of the present invention have been described, the present invention is included in the invention described in the claims and the equivalents thereof. Hereinafter, the invention described in the scope of claims of the present application will be appended.
[Appendix 1]

A developing tank for containing a developer containing toner in a circulating manner;
A toner concentration sensor disposed in a circulation path of the developer in the developer tank and outputting density information of toner in the developer;
A comparison unit for comparing the output value of the toner density sensor with a comparison reference value;
A replenishing port disposed in the circulation path for replenishing replenishing toner;
A toner replenishing unit that determines whether or not replenishment is necessary based on the comparison result of the comparison unit, and replenishes the developing tank with replenishment toner from the replenishing port when it is determined that replenishment is necessary;
A calculating means for calculating a toner consumption amount based on a printing result from a time point when the previous toner supply by the toner supply unit is completed to a start of the current toner supply;
The amount of toner to be replenished is calculated according to the calculation result of the calculating means, and the calculated amount of toner to be replenished from the replenishing port until the developer circulates around the circulation path once. A toner replenishment amount control unit for controlling the toner replenishment unit so as to be replenished a plurality of times;
An image forming apparatus comprising:
[Appendix 2]

A toner replenishing method in an image forming apparatus including a developing tank that circulates a developer containing toner,
Output toner density information in the developer by a toner density sensor disposed in the developer circulation path of the developer tank,
The output value of the output toner density sensor is compared with a comparison reference value,
Based on the comparison result, it is determined whether or not replenishment is necessary, and when it is determined that replenishment is necessary, replenishment toner is replenished to the developing tank with a predetermined replenishment amount from a replenishment port provided in the circulation path. ,
In relation to the replenishment, a toner consumption amount is calculated based on a printing result from the completion of the previous toner replenishment to the start of the current toner replenishment,
The amount of toner to be replenished is calculated according to the calculation result of the toner consumption amount, and the replenishment port of the calculated amount of toner to be replenished before the developer circulates around the circulation path. A toner replenishing method, wherein the toner is replenished a plurality of times.
[Appendix 3]
A toner replenishment program configured to be readable by a computer in an image forming apparatus including a developing tank that circulates a developer containing toner.
A toner density information output procedure for outputting toner density information in the developer by a toner density sensor disposed in the developer circulation path of the developer tank;
A toner density comparison procedure for comparing the output value of the toner density sensor according to the toner density information output procedure and a comparison reference value;
Based on the comparison result of the toner density comparison procedure, it is determined whether or not replenishment is necessary. When it is determined that replenishment is necessary, replenishment toner is replenished to the developing tank from a replenishment port provided in the circulation path. Toner replenishment procedure,
A toner consumption amount calculating procedure for calculating a toner consumption amount based on a printing result from the time when the previous toner supply is completed by the toner supply procedure until the start of the current toner supply;
The amount of toner to be replenished is calculated according to the calculation result of the toner consumption amount calculating procedure, and the toner to be replenished with the calculated amount until the developer circulates around the circulation path once. A toner replenishment amount control procedure for controlling the toner replenishment procedure so as to be replenished at a plurality of times from a replenishing port;
A toner replenishment program that causes the computer to execute.

  INDUSTRIAL APPLICABILITY The present invention can be used for an image forming apparatus and a toner replenishing method and a toner replenishing program that always maintain a proper toner density.

1 Full-color image forming device (printer, device body)
2 Image forming unit 3 Transfer belt unit 4 Toner supply unit 5 Paper feeding unit 6 Belt fixing unit 7 Double-sided printing transport unit 8 Transfer belt 8a Lower running surface 9 (9m, 9c, 9y, 9k) Developing device 10 (10m, 10c, 10y, 10k) Photosensitive drum 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developing device 15 Developing roller 16 Outer wall frame 16a, 16b Developing roller support 16c Extending outer wall frame 17 Partition 15 Developing roller 18 First spiral Mold rotation conveyance member 19 Second spiral rotation conveyance member 20 Reserve tank 21 Drive roller 22 Driven roller 23 Secondary transfer backup roller 24 Secondary transfer roller 25 Primary transfer roller 26 Belt cleaner 27 Waste toner collection container 28 Toner cartridge 29 Electrical equipment Part 31 (31a, 31 b) Paper feed cassette 32 Paper take-out roller 33 Feed roller 34 Rolling roller 35 Standby conveyance roller pair 36 Unload roller pair 37 Paper discharge tray 38 Paper discharge roller pair 39 Return path 39a Start return path 39b Intermediate return path 39c End return path 41 (41a, 41b, 41c, 41d, 41e) Return roller pair 42 CPU (central processing unit)
43 Interface Controller (I / F_CONT)
44 Printer controller (PR_CONT)
45 Printer printing section 46 ROM (read only memory)
47 EEPROM (electrically erasable programmable ROM)
48 sensor unit 49 frame memory 52 belt drive unit 53 toner supply unit motor drive unit 54 solid print image recognition unit 57a, 57b developing tank 58 doctor blade 59 toner density sensor 61 detection surface 62 rotation shaft 62a external shaft 63 spiral fin 64 rotation Shaft 64a Outer end portion 65 Spiral fin 66 Blade holding portion 67 Elastic sheet (blade)
68 Cleaning Blade 69 Rotating Shaft 71 Gear 72 Extension Tank 73 Toner Return Port 74 Toner Supply Port 76 Drive Relay Gear 77 External Engagement Gear 78 Drive Transmission Gear 79 Toner Outlet

Claims (3)

A developing tank for containing a developer containing toner in a circulating manner;
A toner concentration sensor disposed in a circulation path of the developer in the developer tank and outputting density information of toner in the developer;
A comparison unit for comparing the output value of the toner density sensor with a comparison reference value;
A replenishing port disposed in the circulation path for replenishing replenishing toner;
A toner replenishing unit that determines whether or not replenishment is necessary based on the comparison result of the comparison unit, and replenishes the developing tank with replenishment toner from the replenishing port when it is determined that replenishment is necessary;
A calculating means for calculating a toner consumption amount based on a printing result from a time point when the previous toner supply by the toner supply unit is completed to a start of the current toner supply;
The amount of toner to be replenished is calculated according to the calculation result of the calculating means, and the calculated amount of toner to be replenished from the replenishing port until the developer circulates around the circulation path once. A toner replenishment amount control unit for controlling the toner replenishment unit so as to be replenished a plurality of times;
An image forming apparatus comprising: A toner replenishing method in an image forming apparatus including a developing tank that circulates a developer containing toner,
Output toner density information in the developer by a toner density sensor disposed in the developer circulation path of the developer tank,
The output value of the output toner density sensor is compared with a comparison reference value,
Based on the comparison result, it is determined whether or not replenishment is necessary, and when it is determined that replenishment is necessary, replenishment toner is replenished to the developing tank with a predetermined replenishment amount from a replenishment port provided in the circulation path. ,
In relation to the replenishment, a toner consumption amount is calculated based on a printing result from the completion of the previous toner replenishment to the start of the current toner replenishment,
The amount of toner to be replenished is calculated according to the calculation result of the toner consumption amount, and the replenishment port of the calculated amount of toner to be replenished before the developer circulates around the circulation path. A toner replenishing method, wherein the toner is replenished a plurality of times. A toner replenishment program configured to be readable by a computer in an image forming apparatus including a developing tank that circulates a developer containing toner.
A toner density information output procedure for outputting toner density information in the developer by a toner density sensor disposed in the developer circulation path of the developer tank;
A toner density comparison procedure for comparing the output value of the toner density sensor according to the toner density information output procedure and a comparison reference value;
Based on the comparison result of the toner density comparison procedure, it is determined whether or not replenishment is necessary. When it is determined that replenishment is necessary, replenishment toner is replenished to the developing tank from a replenishment port provided in the circulation path. Toner replenishment procedure,
A toner consumption amount calculating procedure for calculating a toner consumption amount based on a printing result from the time when the previous toner supply is completed by the toner supply procedure until the start of the current toner supply;
The amount of toner to be replenished is calculated according to the calculation result of the toner consumption amount calculating procedure, and the toner to be replenished with the calculated amount until the developer circulates around the circulation path once. A toner replenishment amount control procedure for controlling the toner replenishment procedure so as to be replenished at a plurality of times from a replenishing port;
A toner replenishment program that causes the computer to execute.