JP2015129854A - Printing acceleration method and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing acceleration method which continues printing as long as possible in a processing mode which temporarily interrupts printing for supplying toner, in response to sudden reduction of toner concentration, and an image forming apparatus using the same.SOLUTION: A printing acceleration method includes: a toner consumption calculation procedure for calculating toner consumption corresponding to unprocessed print data of a running job by arithmetically operating the unprocessed print data in a dot counter; a toner amount comparison procedure for comparing the toner consumption calculated by the toner consumption calculation procedure with a small amount of toner; a printing continuing procedure which continues printing of the unprocessed print data of the job when the small amount of toner is larger than the toner consumption as a result of the toner amount comparison procedure; and a printing interruption procedure which causes a device to enter toner-supply temporary print interruption mode when the small amount of toner is less than the toner consumption as a result of the toner amount comparison procedure.

Description

  The present invention relates to a print promotion method for continuing a printing process as much as possible even in a processing mode in which the printing process is temporarily interrupted for toner replenishment in response to a rapid decrease in toner density, and an image forming apparatus using the same About.

  Conventionally, there is an electrophotographic image forming apparatus. This apparatus generally initializes a photosensitive member with uniform charging, forms an electrostatic latent image on the photosensitive member by optical writing, develops the electrostatic latent image into a toner image, and directly or indirectly forms the toner image. Then, it is transferred to a recording medium such as paper and fixed with a fixing device.

  Such electrophotographic image forming apparatuses include those using a one-component developer composed only of toner and those using a two-component developer composed of toner and carrier. On the other hand, in recent years, there is an increasing demand for speeding up printing (hereinafter also referred to as printing).

  In order to cope with the high-speed printing process, a two-component developer formed by mixing a carrier and a toner can be used. The carrier of the two-component developer is mixed and agitated with the toner in the developing device to give the toner a predetermined charge.

  The charged toner temporarily adheres to the surface of the carrier. The carrier adheres to the magnetic developing roller and 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 from which the toner on the surface has been released remains on the developing roller, returns to the inside of the developing device, and is mixed and stirred again with new toner to be replenished to the developing device, charges the toner, and transports the toner onto the photoreceptor. , And so on. Toner is supplied to the developing device from a toner supply device.

  Incidentally, in recent years, there has been a strong demand for downsizing of an image forming apparatus in parallel with an increase in printing processing speed. As a countermeasure against this, downsizing of the image forming unit is underway. When the image forming unit is downsized, the developing unit is also downsized. There is a tendency that the amount of developer that can be accommodated in the developing device is also reduced by downsizing the developing device.

  Therefore, it is necessary to estimate the toner density in the developing device using a toner density sensor and replenish the toner consumed by printing in a timely manner. If the replenishment timing and amount of toner to be replenished to the developer circulating in the developing device are not appropriate, partial toner density unevenness occurs in the developer.

  If the toner concentration in the developer of the developing device is too high, scumming or the like occurs, and if the toner concentration is too low, a high-density image cannot be obtained. Therefore, in order to obtain a high-quality image, it is necessary to control the toner density of the developer in the developing device supplied to the photosensitive member within a certain range.

  Based on the output of the toner density sensor, when it is detected that the toner density is lower than a predetermined value, the developer is supplied with toner. When the toner density exceeds the predetermined value, the toner is supplied to the developer. To stop. In this way, in order to maintain the toner density of the developing device appropriately, the timing for detecting the toner density by the toner density sensor is important.

  For example, toner density detection is not performed by the toner density sensor immediately after the toner is replenished, but the toner density when the replenished toner first passes through the toner density sensor is detected, so that excessive toner density is prevented and stable. There has been proposed an image forming apparatus capable of maintaining the toner density. (For example, refer to Patent Document 1.)

JP 2003-76130 A

  However, this is not limited to preventing excessive toner concentration and maintaining a stable toner concentration. In any case, if it is detected that the toner concentration is lower than a predetermined value, the concentration is extremely lowered to cause image deterioration or developing device. In order to prevent the occurrence of abnormalities, the toner is replenished and the agitation process is performed for a certain period of time by performing a printing suspension process.

  In the case of this temporary stop of printing, a time of about 60 to 180 seconds is usually required in total of the toner replenishment time and the stirring time after completion of the replenishment, and the printing process is stopped during that time. Further, in recent years, in order to prevent the temperature inside the machine from increasing, when continuous printing continues for a certain amount or more, printing may be stopped for the purpose of lowering the inside temperature.

  The drive system of the image forming unit continues to operate in order to operate the stirring mechanism in the developing device even when the printing process is temporarily stopped due to the toner replenishment and the stirring after the completion of the replenishment. The resulting increase in cabin temperature is inevitable.

  For this reason, there is still a case where a temporary suspension for cooling for lowering the in-machine temperature is executed immediately after the replenishment and stirring of the toner. This cooling pause usually requires a time of 180 seconds. That is, when the printing pause and the cooling pause are combined, a printing stop time of about 6 minutes at maximum may occur.

  Although it is very inconvenient for the user, Patent Document 1 simply describes “a method of replenishing toner so as to prevent excessive toner concentration and maintain stable toner concentration by detecting toner concentration”. However, there is no description of a solution for the inconvenience of waiting time during toner replenishment as described above.

  The present invention solves the above-described conventional problems, and continues the printing process as much as possible even in the processing mode in which the printing process is temporarily interrupted for the replenishment of toner in response to a rapid decrease in toner density. It is an object of the present invention to provide a printing promotion method and an image forming apparatus using the same.

  In order to solve the above-described problems, the toner replenishing method according to the present invention provides a toner replenishment method in a toner replenishment temporary print interruption process mode in which a print process is temporarily suspended and toner replenishment is performed in response to a rapid decrease in toner density. A printing promotion method for continuing the printing process as much as possible by using a small amount of toner that can be used for printing remaining in the developing unit for functional preservation, and remaining printing of a job that is currently being processed A used toner amount calculation procedure for calculating a toner consumption amount corresponding to the data, a toner amount comparison procedure for comparing the toner consumption amount calculated by the used toner amount calculation procedure with the slight toner amount, and the toner amount When the comparison result by the comparison procedure is larger than the small amount of toner, the print continuation procedure for continuing the printing process for the remaining print data of the job and the ratio by the toner amount comparison procedure Results configured to include a, a print interruption procedure shifts to the toner at replenishing one print interruption processing mode when less is more for a toner amount of the de minimis.

  The present invention relates to a print promotion method for continuing a printing process as much as possible even in a processing mode in which the printing process is temporarily interrupted for toner replenishment in response to a rapid decrease in toner density, and an image forming apparatus using the same Can be provided.

1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (printer, apparatus main body) having a toner supply method 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 the direction indicated by the arrow c in (a) to return the internal configuration and the developer. FIG. 6C is a cross-sectional view showing a path, and FIG. 5C is a diagram schematically showing the configuration of the toner cartridge and the mode of the toner inside. A diagram for explaining the procedure for realizing more efficient printing by reducing the number of transitions to the sleep mode by branching the processing based on a predetermined condition for the determination to shift to the “sleep mode” that occurs during the printing operation. It is. It is a flowchart explaining the branch conditions of the procedure of FIG.

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.
[Example 1]

  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 an apparatus main body) having a toner supply method according to Embodiment 1 of the present invention.

  A printer 1 shown in FIG. 1 is an electrophotographic intermediate 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 unit. 6 and a transport unit 7 for double-sided printing.

  The image forming unit 2 is in contact with the lower running surface 8a of the transfer belt 8 of the transfer belt unit 3 and has four developing devices 9 (9k, 9c, 9m, 9y) arranged in a multistage manner from right to left in FIG. Configured. 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 a housing 16 that covers the outside, a partition wall 17 provided inside, a developing roller 15, a first stirring and conveying screw 18, and a second stirring and conveying screw 19. As will be described in detail later, the first and second agitating and conveying screws 18 and 19 include a screw shaft and a fin that is integrally formed with the screw shaft and rotates.

  The developing unit 14 includes a toner cartridge 21 of the toner supply unit 4 disposed above the transfer belt unit 3, and black (K), cyan (C), K, C, M, and Y shown in FIG. Either magenta (M) or yellow (Y) toner is supplied.

  The transfer belt unit 3 has an endless 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 transfer belt 8 is stretched over the transfer belt 8. A driving roller 22 and a driven roller 23 are provided to circulate and move counterclockwise as indicated by an arrow a in the figure.

  A secondary transfer roller 24 is brought into pressure contact with the driving roller 22 via the transfer belt 8, and a secondary transfer toner image on the transfer belt 8 is secondarily transferred to a sheet as a transfer medium conveyed here. The next transfer portion is formed.

  The 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 transfer belt 8 with respect to the photosensitive drum 10.

  The primary transfer roller 25 directly transfers (primary transfer) the toner image to the lower running surface 8a of the transfer belt 8 that circulates downward. The transfer belt 8 conveys the toner image to the secondary transfer unit in order to further transfer (secondary transfer) the toner image to a sheet.

  Further, a belt cleaner 26 is disposed on the transfer belt 8 so as to abut on the surface of the driven roller 23. Below the belt cleaner 26, a waste toner collecting container 27 for storing waste toner removed from the transfer belt 8 by the belt cleaner 26 is detachably disposed.

  The toner supply unit 4 includes the above-described four toner cartridges 21 disposed above the upper running surface of the transfer belt 8. Although not particularly shown, the toner supply unit 4 is held on the frame of the printer 1 main body so as to be able to be raised and lowered from the printing execution position shown in FIG. 1 to a maintenance position above it.

  The four toner cartridges 21 of the toner supply unit 4 contain black (K), cyan (C), magenta (M), and yellow (Y) toner, respectively.

  These toner cartridges 21 are detachably attached to and removed from the main body of the printer 1 in the front direction, that is, the front side in the depth direction of the drawing. Although not visible in FIG. 1 because of the cross-sectional view of the toner cartridge 21, a toner supply port for supplying toner to the developing device 9 is formed.

  The toner replenishing port communicates with a toner replenishing path extending upward from the rear of the developing device 9 when the toner cartridge 21 is mounted on the main body of the printer 1, and the toner is supplied to the developing device 9 through the toner replenishing path. Replenish. Although not visible in FIG. 1 because of a cross-sectional view, the toner supply path is arranged around the rear of the transfer belt unit 3.

  On the left side of the toner supply unit 4, an electrical unit 29 is disposed from the left side to the upper side of the belt cleaner 26. 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 one paper feed cassette 31. A paper take-out roller 32, a feed roller 33, a separating roller 34, and a standby conveyance roller pair 35 are disposed in the vicinity of the paper feed opening (right side of the drawing) of the paper feed cassette 31.

  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 39c joins the conveyance path to the standby conveyance roller pair 35 corresponding to the paper feed cassette 31 of the paper feed section 5.

  FIG. 2 is a circuit block diagram including the control device of the printer 1 described above. As shown in FIG. 2, the printer controller 50 is the center of the circuit block. The printer controller 50 is connected to an I / F (interface) 48 and a head controller 49 of a network controller 47 via a plurality of buses 45.

  An operation panel unit 51 is connected to the I / F 48 of the network controller unit 47 via another bus 59. In addition, a signal such as print data is input to the I / F 48 from a host device (not shown) such as a personal computer.

  The network controller unit 47 transmits print data input from the outside via the I / F 48 to the head controller unit 49, and transmits command data included in the print data and instruction data input from the operation panel unit 51 to the printer controller unit. 50.

  An EEPROM (electrically erasable programmable ROM) 52, a ROM (read only memory) 53, and a paper feed motor 54 are further connected to the printer controller unit 50 through a bus 45.

  The printer controller unit 50 reads out a control program stored in the ROM 53 and receives it from a DDS (developer drum set, which indicates the developing device 9 in this example) old and new detection sensor 55 for each YMCK according to the read control program. Each unit is controlled according to the sensor output.

  Also, the printer controller 50 monitors whether the sensor output signal received from the toner density sensor 56 (56y, 56m, 56c, 56k) for each YMCK exceeds a detection threshold value for toner supply, and supplies the toner. When the detection threshold value to be performed is exceeded, the motor 46 (46y, 46m, 46c, 46k) of the corresponding toner cartridge 28 is driven for each YMCK to replenish the replenishment toner to the developing device 14.

  Further, the printer controller 50 consumes more of the consumed amount for printing than the amount of toner replenished, and the toner density of the developer in the developing device 14 is lowered, so that the printing is interrupted and the toner replenishment is specialized. As will be described in detail later, the output of the toner density sensor 56 is monitored and the whole is controlled so that printing can be resumed in as short a time as possible without unnecessary stirring.

  The printer controller 50 also performs optical writing of the optical writing heads 13 (13k, 13c, 13m, 13y) for each YMCK via the head controller 49 based on the print data received from the network controller 47. Control.

  FIG. 3A is an enlarged cross-sectional view showing the developing unit 14 together with the photosensitive drum 10, and FIG. 3B is a cross-sectional view of the developing unit 14 shown by an arrow c in FIG. FIG. 3C is a diagram schematically showing the configuration of the toner cartridge 21 and the mode of the internal toner.

  3A, 3B, and 3C, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. Further, in FIG. 3B, the illustration of the cleaning blade 77 shown in FIG. 3A is omitted, and the toner density sensor 56 is also shown very simply.

  As shown in FIGS. 3A and 3B, the developing device 14 includes two developing tanks 65 (65 a and 65 b) partitioned by an outer wall 63 and an inner partition wall 64. In the upper developing tank 65a, the developing roller 15 and the second stirring and conveying screw 19 described above are arranged.

  A doctor blade 66 is in contact with the developing roller 15. The first stirring and conveying screw 18 described above is disposed in the lower developing tank 65a. A toner density sensor 56 is disposed in the developing tank 65a with its detection surface 67 exposed in the tank.

  The second agitating and conveying screw 19 includes a rotating shaft 68 and a helical fin 69 fixed to the rotating shaft 68 in a spiral shape. The first agitating / conveying screw 18 includes a rotating shaft 71 and a helical fin 72 fixed to the rotating shaft 71 in a spiral shape.

  The second agitating and conveying screw 19 rotates in the counterclockwise direction of FIG. 3A as indicated by an arrow d, and the arrow e (e1, e1, e) while stirring the developer in the developing tank 65a by the spiral fin 69. As shown by e 2 and e 3), the developer is conveyed from the front side in the depth direction of FIG. 3A to the far side, and from right to left in FIG. 3B, and the developer is supplied to the developing roller 15.

  The developing roller 15 supplies only the developer toner to the photosensitive drum 10 to form (develop) the electrostatic latent image on the circumferential surface of the photosensitive drum 10 as a toner image. 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 65a, and the other side in the depth direction of FIG. 3 (a), FIG. 3 (b). Then, it returns to the developing tank 65b at the outlet 73 at the left end.

  The first agitating / conveying screw 18 in the developing tank 65 b rotates counterclockwise in FIG. 3A as indicated by an arrow g, while stirring the developer in the developing tank 65 b with the spiral fin 72. As indicated by arrows f (f1, f2, and f3), the paper is conveyed from the far side in the depth direction of FIG. 3A to the front, and from FIG. 3B to the right from the left.

  If the toner density of the developer is less than the specified level, the toner density sensor 56 detects a decrease in toner density. When a decrease in toner density is detected, toner Tn is replenished from the toner cartridge 21 corresponding to the developing device 14 of the toner supply unit 4 through a toner replenishment path (not shown) as shown in FIG. The

  As shown in FIGS. 3A and 3B, the developing device 14 includes two developing tanks 65 (65 a and 65 b) partitioned by an outer wall 63 and an inner partition wall 64. In the upper developing tank 65a, the developing roller 15 and the second stirring and conveying screw 19 described above are arranged.

  A doctor blade 66 is in contact with the developing roller 15. The first stirring and conveying screw 18 described above is disposed in the lower developing tank 65a. A toner density sensor 56 is disposed in the developing tank 65a with its detection surface 67 exposed in the tank.

  The second agitating and conveying screw 19 includes a rotating shaft 68 and a helical fin 69 fixed to the rotating shaft 68 in a spiral shape. The first agitating / conveying screw 18 includes a rotating shaft 71 and a helical fin 72 fixed to the rotating shaft 71 in a spiral shape.

  The second agitating and conveying screw 19 rotates in the counterclockwise direction of FIG. 3A as indicated by an arrow d, and the arrow e (e1, e1, e) while stirring the developer in the developing tank 65a by the spiral fin 69. As shown by e 2 and e 3), the developer is conveyed from the front side in the depth direction of FIG. 3A to the far side, and from right to left in FIG. 3B, and the developer is supplied to the developing roller 15.

  The developing roller 15 supplies only the developer toner to the photosensitive drum 10 to form (develop) the electrostatic latent image on the circumferential surface of the photosensitive drum 10 as a toner image. 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 65a, and the other side in the depth direction of FIG. 3 (a), FIG. 3 (b). Then, it returns to the developing tank 65b at the outlet 73 at the left end.

  The first agitating / conveying screw 18 in the developing tank 65 b rotates counterclockwise in FIG. 3A as indicated by an arrow g, while stirring the developer in the developing tank 65 b with the spiral fin 72. As indicated by arrows f (f1, f2, and f3), the paper is conveyed from the far side in the depth direction of FIG. 3A to the front, and from FIG. 3B to the right from the left.

  If the toner density of the developer is less than the specified level, the toner density sensor 56 detects a decrease in toner density. When a decrease in toner density is detected, toner Tn is replenished from the toner cartridge 21 corresponding to the developing device 14 of the toner supply unit 4 through a toner replenishment path (not shown) as shown in FIG. The

  In FIG. 3B, the toner supply port is not particularly shown, but the toner supply port is connected to substantially the same position as the outlet 73. That is, the replenishment toner is replenished in the vicinity of the outlet 73 where the developer in the developing tank 65a whose toner density has been reduced by the development is sent back to the developing tank 65b.

  The first agitating / conveying screw 18 feeds the developer to the developing tank 65a through the supply port 74 on the front side in the depth direction of FIG. 3A and the right side of FIG. 3B while agitating and conveying the developer. . In this way, the reflux of the developer and the replenishment of the toner are repeated, and the development with the toner proceeds sequentially.

  Since the detection surface 67 of the toner density sensor 56 is exposed in the tank, the developer tends to stay on the detection surface 67. When the developer stays on the detection surface 67, the detection accuracy of the toner density sensor 56 is lowered.

  In order to prevent the detection accuracy of the toner density sensor 56 from being lowered, the rotation shaft 71 of the first agitating / conveying screw 18 in the developing tank 65b is rotated at a position rotating opposite the detection surface 67 of the toner density sensor 56. Further, a cleaning blade 77 including a blade holding portion 75 and an elastic sheet (blade) 76 held by the blade holding portion 75 is fixed.

  The cleaning blade 77 rotates together with the rotating shaft 71 of the first agitating and conveying screw 18, rubs the detection surface 67 of the toner density sensor 56 with the elastic sheet 74, and removes the developer that tends to stay on the detection surface 67. The developer is removed and replaced with the developer conveyed immediately after.

  This prevents erroneous detection of the toner concentration that may be caused by the developer staying on the detection surface 67 of the toner concentration sensor 56. As described above, the cleaning blade 77 periodically rubs the detection surface 67 of the toner density sensor 56, whereby the amount of the developer on the detection surface 67 increases or decreases periodically.

  Accordingly, the output voltage of the toner density sensor 56 periodically increases and decreases in accordance with the periodic increase and decrease of the developer amount. Since the rotation of the first agitating and conveying screw 18, that is, the rotation of the cleaning blade 77 is relatively fast, the periodic increase / decrease in the output voltage of the toner concentration sensor 56 appears as a relatively fast pulse voltage.

  In this example, the voltage obtained by averaging the pulse voltages is used as the detection output voltage of the toner density sensor 56 with respect to the actual toner density of the developer.

  Further, as shown in FIG. 3C, the toner cartridge 21 is not shown in FIG. 1 on the lower surface of the rear end portion in the mounting direction (left end portion in FIG. 3C) attached to the mounting portion. A supply port 79 communicating with the toner supply path 78 is provided.

  The end of the toner supply path 78 communicates with the vicinity of the outlet 73 where the developer is sent from the upper developing tank 65a to the lower developing tank 65b of the developing device 14 shown in FIG. The toner cartridge 21 contains toner Tn, and a conveying screw 81 for conveying the toner Tn to the replenishing port 79 is provided.

  Although not particularly shown, the conveying screw 81 is connected to one end of the rotating shaft at the rear end, the other end of the rotating shaft protrudes outside from the rear end surface of the toner cartridge 21, and has a gear at the protruding end. The gear engages with the drive gear of the drive system of the apparatus main body 1 and is rotationally driven, and transmits the rotational drive to the conveying screw 81 as indicated by an arrow h.

  The toner Tn of the toner cartridge 21 is fed from the replenishment port 79 to the toner replenishment path 78 by the transport screw 81 and replenished to the developing device 14 as indicated by an arrow j. When replenishment of the toner Tn is started, first, a shutter provided in the toner replenishment path 78 is opened, and the conveying screw 81 rotates for a certain time to convey a certain amount of toner Tn to the replenishing port 79 for a certain time. Stop.

  During this time, the shutter is closed, and the developing device 14 mixes and stirs a certain amount of toner Tn replenished from the replenishment path with the developer, and circulates and conveys the toner in the developing tank 65. The printer controller 50 of the control device receives the toner concentration detection signal from the toner concentration sensor 56, and stops the toner replenishment process when determining that the detected toner concentration is appropriate.

  Normally, during printing, when the output of the toner density sensor 56 indicates that the density lowering detection threshold has been exceeded, the control device does not force the printing regardless of the remaining number of prints or the print pattern included in the next image information. Thus, the printing is temporarily stopped and the above-described toner supply process is started.

  Then, the printing is temporarily stopped and the toner replenishment process is started, and the toner replenishment time of 120 seconds at the maximum and the stirring time of 45 seconds after the completion of the replenishment are required until the toner density is stabilized and the printing can be resumed. I need. That is, printing is suspended for 1 to 3 minutes.

  By the way, in an apparatus such as a printer, there is a case where a cooling pause for lowering the internal temperature may be executed in addition to the above-described toner supply printing pause, and for this cooling pause, As described above, it is usually necessary to elapse 180 seconds.

  If the control device determines that a cooling pause is required immediately after the end of the toner replenishment printing pause, the maximum printing time of about 6 minutes is combined with the toner replenishment printing pause and the cooling pause. As described above, the stop time, that is, the waiting time of the user occurs.

  Therefore, in the present invention, when the toner replenishment printing pause is required, the toner replenishment print pause is continued so that the timing for entering the toner replenishment print pause is postponed as much as possible and the printing is continued. Even when the cooling pause is required after the stop process, the resulting waiting time of the user is made as short as possible.

  FIG. 4 shows a transition to the sleep mode by branching the process based on a predetermined condition for the determination to shift to the toner replenishment printing pause processing (hereinafter referred to as the sleep mode) that occurs during the printing operation. It is a figure explaining the procedure which reduces the frequency | count and implement | achieves more efficient printing.

  In the diagram shown in FIG. 4, the horizontal axis indicates time (sec: second), and the vertical axis indicates toner density (T / D (%)). The toner density (T / D = 9.5%) indicated by the upper broken line indicates the first threshold value of toner density detection, and the toner density (T / D = 8.0%) indicated by the lower broken line indicates the toner density. The density detection second threshold is shown.

  A solid line with a standard toner density of 10.0% is shown 0.5% above the first threshold value of toner density detection (T / D = 9.5%). When the toner density indicated by the output of the toner density sensor is equal to or lower than the first threshold value of toner density detection, the toner is successively replenished to the developing unit little by little so that the toner density is not extremely biased even during printing. .

  As a result, the toner density changes while slightly fluctuating up and down along the toner standard density of 10.0%. For example, the concentration curve is as shown in FIG. 4 during the time 0 to 20 sec and during the time 170 to 230 sec.

  On the other hand, the second threshold value of toner density detection of T / D = 8.0% is a threshold value when, for example, a large amount of toner is consumed during printing, toner replenishment is not in time, and the toner density rapidly decreases. This second threshold value for toner density detection also serves as a threshold value (good night mode threshold value) when “sleep mode” is started in which printing is stopped and toner is supplied and stirred.

  There are two ways in which the toner density decreases rapidly. In the first case, as described above, printing with high image density continues and the amount of toner consumption increases, and toner replenishment cannot keep up. In the second case, the toner cartridge runs out of toner. This is the case.

  In any case, when the toner density is drastically lowered, it is necessary to temporarily stop the printing process in order to adjust the toner density. The transition of the toner density curve between 20 and 170 sec in FIG. 4 shows a case where such toner density is drastically decreased.

  In the above transition, first, when it becomes certain that the toner density indicated by the output of the toner density sensor is equal to or lower than the second threshold value of the toner density detection (time point 35 seconds in FIG. 4), The operation is started, printing is paused, and toner is supplied to the developing tank and agitated.

  Then, toner replenishment and agitation are continued until the toner density indicated by the output of the toner density sensor 56 reaches 10.0% or higher as the standard density during a predetermined time. This fixed time corresponds to a total time of 120 seconds for toner replenishment and stirring and a total time of 45 seconds for density stabilization.

  When the toner density indicated by the output of the toner density sensor 56 is equal to or higher than the standard density, the sleep mode is stopped (time 175 seconds in FIG. 4), and printing is resumed.

  On the other hand, if the toner density indicated by the output of the toner density sensor 56 does not reach the standard density even after the toner replenishment timeout period of 120 seconds has elapsed after the transition to the sleep mode processing, the control device will control the toner cartridge of the toner supply unit 4. It is determined that No. 21 has no remaining amount of toner, and therefore the developing device is out of toner.

  By the way, even if it is determined that the developer is out of toner, the developing device does not always stop the printing immediately, and depending on the contents of the printing process, a small amount of the remaining usable in the developing device is not guaranteed. Printing can be continued using a toner until a toner printing consumption amount converted by dot count reaches a very small amount (for example, 1.0 gram).

  The present invention uses such a function of the developing device to avoid the transition to the sleep mode as much as possible or prevent the transition timing from being delayed as much as possible while preventing the toner density from excessively decreasing. It is an object.

  FIG. 5 is a flowchart for explaining the branching conditions of the above-described processing procedure shown in FIG. In this example, if the toner density is lower than the toner density detection second threshold value even in one color during the printing operation, it is determined whether or not to enter the sleep mode.

  Further, in the following description, Job represents one-line printing processing, [A] is the amount of toner consumed for the remaining print of Job1 (first job), and [B] is the printable remaining in the developer. [Xn] represents a toner consumption amount of Job (n) (n = 1, 2,...).

  In addition, this processing is performed when the output of the toner density sensor 56 exceeds the sleep mode threshold value during execution of the normal printing process for Job1 by the printer controller unit 50 (hereinafter simply referred to as the controller unit 50) of the control device. This process is performed when the toner density is lower than the sleep mode threshold.

  In FIG. 5, the controller unit 50 calculates the remaining consumption [A] of Job 1 by dot count (hereinafter, the consumption of Job (n) is calculated by dot count), and develops when toner out is detected. The printable toner consumption amounts [B] and [A] set in the device are compared (step S1).

  If [A] is less than [B] (Yes in step S1), the toner replenishment amount is maximized and printing is continued (step S2). This process is a printing process performed under the toner out detection that is started at the time point of 160 seconds shown in the lower right of FIG.

  Further, in this process, since the printing is being continued and the toner density is equal to or lower than the first threshold value of toner density detection, the toner is replenished while the printing is continued. To maximize the toner replenishment amount means to perform the maximum toner replenishment within a range where there is no problem.

  When Job1 ends, the controller unit 50 determines whether the output of the toner density sensor is larger than the sleep mode threshold (step S3). This process is a process for determining whether or not the toner density is lower than the sleep mode threshold (the output of the toner density sensor increases when the toner density is low).

  In this determination, if the output of the toner density sensor is larger than the sleep mode threshold value (Yes in step S3), it is determined whether or not there is a next job (step S4), and if there is a next job (step S4). The determination in step S4 is Yes), and N = N + 1 (in this case, N = N + 1 = 2 because this is the first procedure).

  Subsequently, it is determined whether or not the toner consumption amount [X2] of Job2 is smaller than the remaining printable consumption amount ([B]-[A]-[X1]) (step S5). The determination in S5 is Yes), printing is continued (Step S6), Job (Job 2 in this case) is terminated, the process returns to Step S3, and Steps S3 to S6 are repeated.

  If the toner consumption amount [Xn] of Job (n) is larger than the remaining printable consumption amount ([B] − [A] −Σ [Xn−1]) in the determination in step S5 (step S5). Since the determination of S5 is No), Job (n) cannot be printed, and the sleep mode is executed (step S7).

  As described above, even when the output of the toner density sensor 56 exceeds the sleep mode threshold, if the developing device has the remaining amount of toner corresponding to Job, the job is executed and the remaining amount of toner corresponding to Job is small. It becomes the sleep mode only after becoming.

  If it is determined in step S4 that there is no next job (determination in step S4 is No), the current process is a process that has been performed in a state where the sleep mode threshold is exceeded. Shift to night mode processing.

  If the output of the toner density sensor is smaller than the sleep mode threshold value in the determination in step S3 (No in step S3), the toner density is sufficient for normal printing. The process proceeds to normal printing (step S8).

  In addition, if there is more [A] than [B] in the determination in the above step S1 (No determination in step S1), Job1 cannot be printed and the current process exceeds the sleep mode threshold. Therefore, the process immediately shifts to the sleep mode process in step S7.

  As described above, according to the processing of this example, even when the processing for pause printing for toner replenishment that occurs during the printing operation of the sleep mode is to be executed, the determination to execute the sleep mode is performed in various predetermined modes. The processing is branched based on the above condition, and the number of transitions to the sleep mode can be reduced as much as possible to perform more efficient printing.

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]

Can be used for printing remaining in the developing device for the maintenance of the function of the developing device in the temporary printing interruption processing mode for replenishing the toner in which the printing processing is temporarily interrupted in response to a sudden drop in the toner density. A printing promotion method that continues printing processing as much as possible using a small amount of toner,
A used toner amount calculation procedure for calculating a toner consumption amount corresponding to the remaining print data of the job currently being processed;
A toner amount comparison procedure for comparing the toner consumption amount calculated by the used toner amount calculation procedure with the small amount of toner;
A print continuation procedure for continuing the printing process for the remaining print data of the job when the result of comparison by the toner amount comparison procedure is larger than the small amount of toner;
A printing interruption procedure for shifting to the toner replenishment temporary printing interruption processing mode when the comparison result by the toner amount comparison procedure is smaller than the small amount of toner;
A method for promoting printing, comprising:
[Appendix 2]

The used toner amount calculation procedure calculates the toner consumption amount corresponding to the remaining print data by calculating the remaining print data of the job with a dot counter.
The printing promotion method according to supplementary note 1, wherein:
[Appendix 3]

In the toner amount comparison procedure, when the used toner amount calculation procedure, the toner amount comparison procedure, and the print continuation procedure are repeatedly performed, the toner amount consumed immediately before the current repetition is subtracted from the small toner amount. Replacing the toner amount with the small amount of toner and comparing with the toner consumption amount,
The printing promotion method according to supplementary note 1, wherein:
[Appendix 4]

  An image forming apparatus, wherein a printing process is performed using the printing promotion method according to any one of appendices 1 to 3.

  The present invention relates to a print promotion method for continuing a printing process as much as possible even in a processing mode in which the printing process is temporarily interrupted for toner replenishment in response to a rapid decrease in toner density, and an image forming apparatus using the same Can be used.

1 Full-color image forming device (printer)
DESCRIPTION OF SYMBOLS 2 Image formation part 3 Transfer belt unit 4 Toner supply part 5 Paper feed part 6 Belt type fixing unit 7 Conveyance unit for double-sided printing 8 Transfer belt 8a Lower traveling surface 8b Back surface 9 (9y, 9m, 9c, 9k) Developing device 10 Photosensitive Body drum 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developer 15 Developing roller 16 Housing 17 Bulkhead 15 Developing roller 18 First agitating and conveying screw 19 Second agitating and conveying screw 21 Toner cartridge 22 Drive roller 23 Followed roller 24 Secondary transfer roller 25 Primary transfer roller 26 Belt cleaner 27 Waste toner collection container 29 Electrical unit 31 (31a, 31b) Paper feed cassette 32 Paper take-out roller 33 Feed roller 34 Rolling roller 35 Standby transport roller pair 36 Transport roller pair 37 Discharge Paper tray 38 Paper discharge roller pair 39 Return path 39a Return start path 39b Return intermediate path 39c Return end path 41 (41a, 41b, 41c, 41d, 41e) Return roller pair 45 Bus 46 (46y, 46m, 46c, 46k) Toner cartridge motor 47 Network controller section 48 I / F (interface)
49 Head Controller 50 Printer Controller 51 Operation Panel 52 EEPROM (electrically erasable programmable ROM)
53 ROM (read only memory)
54 Feeder motor 55 DDS (developer drum set, developing device 9 in this example) New and old detection sensor 56 Toner density sensor 56y Y toner density sensor 56m M toner density sensor 56c C toner density sensor 56k K toner density sensor 57 Pressure unit 58 ( 58y, 58m, 58c, 58k) Driving device for each YMCK 59 Bus 63 Outer wall 64 Internal partition wall 65 (65a, 65b) Developer tank 66 Doctor blade 67 Detection surface 68 Rotating shaft 69 Spiral fin 71 Rotating shaft 72 Spiral fin 73 Exit 74 Supply port 75 Blade holding part 76 Elastic sheet (blade)
77 Cleaning Blade 78 Toner Supply Path 79 Supply Port 81 Conveying Screw Tn Toner

Claims (4)

Can be used for printing remaining in the developing device for the maintenance of the function of the developing device in the temporary printing interruption processing mode for replenishing the toner in which the printing processing is temporarily interrupted in response to a sudden drop in the toner density. A printing promotion method that continues printing processing as much as possible using a small amount of toner,
A used toner amount calculation procedure for calculating a toner consumption amount corresponding to the remaining print data of the job currently being processed;
A toner amount comparison procedure for comparing the toner consumption amount calculated by the used toner amount calculation procedure with the small amount of toner;
A print continuation procedure for continuing the printing process for the remaining print data of the job when the result of comparison by the toner amount comparison procedure is larger than the small amount of toner;
A printing interruption procedure for shifting to the toner replenishment temporary printing interruption processing mode when the comparison result by the toner amount comparison procedure is smaller than the small amount of toner;
A method for promoting printing, comprising: The used toner amount calculation procedure calculates the toner consumption amount corresponding to the remaining print data by calculating the remaining print data of the job with a dot counter.
The printing promotion method according to claim 1, wherein: In the toner amount comparison procedure, when the used toner amount calculation procedure, the toner amount comparison procedure, and the print continuation procedure are repeatedly performed, the toner amount consumed immediately before the current repetition is subtracted from the small toner amount. Replacing the toner amount with the small amount of toner and comparing with the toner consumption amount,
The printing promotion method according to claim 1, wherein: An image forming apparatus, wherein a printing process is performed using the printing promotion method according to claim 1.