JP2010175965A - Image forming apparatus and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid wasteful degradation of a toner in an image forming apparatus with a plurality of developing units. <P>SOLUTION: A printer in this mode, uses a Y (Yellow) toner, M (Magenta) toner and C (Cyan) toner for print operation of color images in addition to a K (black) toner. In supplying the Y toner, when the residual quantity of the Y toner is less than a threshold C, the Y toner is supplied. At the same time, a toner supply prohibition request flag is set from Y (YES at step S50, and step S60, step S160). By setting the flag, if the residual quantity of the M toner is not less than the threshold C in supplying the M toner, the M toner is not supplied. Also, if the residual quantity of the C toner is not less than the threshold C, the C toner is not supplied. The flag is cleared when the residual quantity of the Y toner becomes not less than the threshold C (NO at step S50, and step S100). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of forming an image with a plurality of types of toner and a control method thereof.

  Conventionally, various techniques have been disclosed for an image forming apparatus that forms an image using toner. In such an image forming apparatus, toner is attached to a photosensitive drum on which an electrostatic latent image is formed by a developing unit, and the electrostatic latent image is visualized. Then, the toner image on the photosensitive drum is transferred to a sheet, thereby forming an image on the sheet.

  The toner used in the developing unit is stored in a toner storing unit such as a toner bottle, and is appropriately supplied from the toner storing unit to the developing unit.

  Various techniques relating to toner replenishment to the developing unit in such an image forming apparatus are disclosed.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 11-24513), when toner is replenished from the toner bottle to the developing unit, the toner is replenished according to the remaining amount of toner in the sub hopper provided in the lower part of the toner containing means. A technique for determining the time of a motor to be driven is disclosed.

  Japanese Patent Laid-Open No. 2005-274738 discloses an image forming apparatus that replenishes toner when the toner consumption estimated based on the number of pixels for each color in image data reaches a threshold value. Discloses a technique for changing the threshold according to image forming conditions such as humidity.

Japanese Patent Laid-Open No. 11-24513 Japanese Patent Laid-Open No. 2005-274738

  In the image forming apparatus, when toner is supplied to the developing unit, a stirring member provided with stirring blades is provided in the developing unit in order to avoid uneven accumulation of fine powder toner in the developing unit, and When the toner is replenished to the developing unit, the stirring member is driven to rotate, thereby avoiding uneven deposition of toner in the developing unit.

  Conventional image forming apparatuses may be configured to drive the stirring means provided in each of the plurality of developing units with one motor in order to reduce manufacturing costs. In such a case, even when toner is replenished only to some of the plurality of developing units, the agitation unit is driven in all the developing units. By driving the agitation means, there arises a disadvantage that the deterioration of the toner in the developing unit proceeds wastefully.

  For example, when Y (yellow) toner, M (magenta) toner, and C (cyan) toner are used in an image forming apparatus to form an image, Y toner is supplied. The agitating means is driven not only in the agitating means of the Y developing section, but also in each of the M developing section and the C developing section. As a result, the deterioration of the toner in the M developing unit and the C developing unit is unnecessarily advanced.

  The present invention has been conceived in view of such circumstances, and an object thereof is to avoid useless deterioration of toner in an image forming apparatus including a plurality of developing units.

  An image forming apparatus according to the present invention includes a first developing unit that performs development using toner, a second developing unit that performs development using toner, a second driving unit that drives the second developing unit, First detection means for detecting the toner amount in one developing device, second detection means for detecting the toner amount in the second developing device, and first supply means for supplying toner to the first developing device A second replenishing unit for replenishing toner to the second developing unit, a driving unit for driving the first and second developing units, a driving unit and a control unit for controlling the first and second replenishing units. And the control means causes the first supply means to supply toner and the drive means to execute driving when the detection amount of the first detection means is less than the first amount, and causes the drive means to execute driving. When the detection amount of one detection means is less than the second amount less than the first amount When the detection amount of the second detection means is less than the second amount, the second supply means supplies toner, and the detection amount of the second detection means is less than the first amount and greater than or equal to the second amount. In this case, the toner is supplied to the second supply means on condition that the detection amount of the first detection means is equal to or greater than the second amount.

  The image forming apparatus of the present invention further includes an image forming unit that performs an image forming operation, the image forming unit includes first and second developing devices, and the control unit performs the image forming operation by the image forming unit. And when it is determined that the detection amount of the first detection means is less than the third amount less than the first amount and the second amount, the image forming operation of the image forming unit is stopped and Preferably, the first supply means supplies toner, and if the amount detected by the second detection means is less than the first amount, the second supply means supplies toner.

  In the image forming apparatus according to the aspect of the invention, the control unit may perform the first detection even if the first supply unit supplies toner for a predetermined time or more when the detection amount of the first detection unit is less than the predetermined amount. When the detected amount of the means does not exceed a specific amount greater than a predetermined amount, it is preferable to execute a control operation for an abnormal state.

  A control method for an image forming apparatus according to the present invention is a control method for an image forming apparatus including a plurality of developing units that perform development using toner, and includes a first developing unit and a second developing unit among the plurality of developing units. Detecting the remaining amount of toner in the developing unit, supplying the toner to the first developing unit when the remaining amount of toner in the first developing unit is less than the first amount, When the remaining amount of toner in the developing device is less than the second amount less than the first amount and the remaining amount of toner in the second developing device is less than the first amount and greater than or equal to the second amount And a step of starting toner replenishment to the second developing unit on condition that the remaining amount of toner in the second developing unit becomes equal to or greater than the second amount.

  According to the present invention, in the image forming apparatus, when the toner is replenished so that the respective toner amounts of the plurality of developing units are set to the first amount, the toner amount in one developing unit is the first amount. If the amount is less than the second amount and the amount of toner in the other developing portion is greater than or equal to the second amount, the toner is first supplied only to the one developing portion, and Then, on the condition that the amount of toner in the one developing unit is equal to or more than the second amount, toner supply to the other developing unit is started. The driving unit drives the agitation unit for the toner in the plurality of developing units if the toner is supplied to at least one of the plurality of developing units.

  Thus, according to the present invention, when the replenishment of toner to the one developing portion whose toner amount is less than the second amount is started, the other development whose toner amount is already equal to or larger than the second amount is started. The toner replenishment timing for one part is started after the toner amount in the one developing part becomes equal to or greater than the second amount. Therefore, in the other developing part, the toner to one developing part is started. The amount of toner used for the agitation by the agitation means in the other developing unit driven for the replenishment of toner can be reduced from the beginning of the replenishment of toner to the one development unit. .

  Therefore, according to the present invention, in an image forming apparatus including a plurality of developing units, even if the remaining amount of toner in each developing unit at the time of starting toner replenishment is different, the image forming apparatus is subjected to deterioration due to useless stirring. The amount of toner that is applied can be reduced.

1 is a schematic cross-sectional view illustrating an outline of a hardware configuration of a printer that is an example of an image forming apparatus of the present invention. FIG. 2 is an enlarged view of the vicinity of a developing unit in FIG. 1. FIG. 2 is a control block diagram of the printer of FIG. 1. 3 is a flowchart of Y toner replenishment control processing executed in the printer of FIG. 1. 5 is a flowchart of a subroutine of Y interruption printing toner supply processing of FIG. 4. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 6 is a flowchart of a first modified example of Y printing interruption toner supply processing of FIG. 5. FIG. FIG. 2 is a diagram for explaining a mode of toner replenishment to Y, M, and C developing units in the printer of FIG. 1. FIG. 6 is a flowchart of a second modification of the print interruption toner supply process of Y in FIG. 5.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same unless otherwise noted.

[First Embodiment]
In the present embodiment, a case where the image forming apparatus according to the present invention is applied to a tandem digital color printer (hereinafter referred to as a printer) will be described.

  In the color tandem type image forming apparatus, four color image forming units each including a developing unit are arranged along an intermediate transfer belt (which is an intermediate transfer member carrying a toner image formed by the image forming unit). It is installed and configured. Then, each color toner image formed in each image forming unit is transferred to the intermediate transfer belt (primary transfer), and a multicolor image is formed by superimposing the respective color toners. Further, the image superimposed on the intermediate transfer belt is transferred onto a sheet as a printing medium (secondary transfer), and output through a fixing process.

  FIG. 1 is a schematic cross-sectional view showing an outline of a hardware configuration of a printer 1 according to the present embodiment to which the image forming apparatus according to the present invention is applied. The printer 1 is a tandem digital color printer, and forms a color image by sequentially superposing four color toners of yellow (Y), magenta (M), cyan (C), and black (K). .

  Referring to FIG. 1, the printer 1 according to the present embodiment includes an image reading unit 10, a paper transport unit 20, an image forming unit 30, and a paper storage unit 40.

  The image reading unit 10 includes a loading table 3 for setting a document, a document table glass 11, a conveyance unit 2 that automatically conveys documents set on the loading table 3 one by one to the document table glass 11, And a discharge table 4 for discharging the read document. Further, the document reading unit 10 includes a scanner (not shown). The scanner moves parallel to the platen glass 11 by a scan motor. The scanner has an exposure lamp that illuminates the document, a reflection mirror that changes the direction of the reflected light from the document, a mirror that changes the optical path from the reflection mirror, a lens that collects the reflected light, and an electrical signal depending on the received reflected light A photoelectric conversion element such as a three-row (R, G, B) CCD (Charge Coupled Device) is included.

  The document transported by the transport unit 2 is set on the document table glass 11 and is exposed and scanned when the scanner moves in parallel with the document table glass 11. The reflected light from the document is converted into an electrical signal by the photoelectric conversion element and input to the image forming unit 30.

  The image forming unit 30 includes an intermediate transfer belt 31, image forming units 21 Y, 21 M, 21 C, and 21 K (representing these as the image forming unit 21), and the image forming units 21 Y, 21 Y, and 21 via the intermediate transfer belt 31. Transfer rollers 25Y, 25M, 25C, and 25K paired with 21M, 21C, and 21K (representatively referred to as transfer rollers 25) and a toner image transferred to the intermediate transfer belt 31 are transferred to a sheet and then fixed. And a control box 1000 that houses circuit members such as a controller 101 including a fixing device 36 and a CPU (Central Processing Unit).

  The intermediate transfer belt 31 is suspended by a plurality of rollers 32, 33, and 34 so as not to be loosened, and these rollers rotate counterclockwise (in the direction of arrow A in FIG. 1) in FIG. It is an endless belt that rotates in the same direction.

  The image forming units 21Y, 21M, 21C, and 21K correspond to yellow (Y), magenta (M), cyan (C), and black (K) toners arranged at predetermined intervals along the intermediate transfer belt 31. Each cartridge is configured so that a cartridge containing toner corresponding to each color can be mounted. The image forming units 21Y, 21M, 21C, and 21K include developing units 24Y, 24M, 24C, and 24K and photoconductors 29Y, 29M, 29C, and 29K, respectively.

  The control box 1000 also accommodates a memory (memory 102 to be described later) that stores a program executed by the controller 101, data used for executing the program, and the like.

  The paper storage unit 40 includes a paper feed cassette 41 that stores the paper S, which is a printing medium, and the paper transport unit 20 includes rollers 42, 43, 35, 37 for transporting the paper S from the paper feed cassette 41, and A paper discharge tray 38 for discharging printed paper is included.

  The controller 101 reads out and executes a program from the memory 102 based on an instruction signal input from an operation panel (an operation panel 103 described later) or the like, and controls the above-described units. Further, the controller 101 may include a timer such as a timer, and execute the program when a predetermined time is measured. The controller 101 and the memory 102 may be provided in the image reading unit 10 other than the image forming unit 30, the paper transport unit 20, or the like.

  The controller 101 executes the above-described program, performs predetermined image processing on the image signal input from the image reading unit 10 or an external device, and performs color conversion to each color of yellow, magenta, cyan, and black. Create a signal. The image color data for cyan, the image color data for magenta, the image color data for yellow, and the image color data for black, which are created by the controller 101 and form the image, 101 is output to the exposure unit of the image forming unit 21.

  The exposure device outputs a laser beam to the photoconductor based on the image data input from the controller 101, so that the surface of the uniformly charged photoconductor is exposed according to the image data, and the electrostatic latent image is generated. It is formed. A developing bias voltage is applied to a developing roller 241 (developing rollers 241K, 241Y, 241M, and 241C described later) of each developing unit 24, and a potential difference is generated between the latent image potential of the photosensitive member. In this state, charged toner is supplied to form a toner image on the surface of the photoreceptor. The toner image formed on the surface of the photosensitive member is transferred to the intermediate transfer belt 31 as an image carrier by a constant voltage or constant current transfer roller 25. This is called primary transfer.

  The toner image primarily transferred to the intermediate transfer belt 31 is transferred onto the paper S conveyed from the paper feed cassette 41 by the roller 34. This is called secondary transfer. The toner image secondarily transferred to the paper is fixed on the paper by the fixing device 36 and is discharged to the paper discharge tray 38 as an electrophotographic image.

FIG. 2 is an enlarged view of the vicinity of the image forming unit 21K in FIG.
Referring to FIG. 2, the image forming unit includes a toner cartridge 40K and a developing unit 24K.

The toner cartridge 40K and the developing unit 24K are connected by a transport pipe 49K.
The toner cartridge 40K contains a toner bottle (not shown) filled with toner. Further, the toner cartridge 40K is provided with a screw 42K that conveys the toner in the toner bottle to the conveyance tube 49K.

The developing unit 24K includes various rollers including a developing roller 241K.
The image forming units 21Y, 21M, and 21C have the same configuration as the developing unit 24K. The developing rollers provided in each of these are referred to as developing rollers 241Y, 241M, and 241C.

FIG. 3 is a control block diagram of the printer 1 of FIG.
Referring to FIG. 3, the image formation control unit 100 controls the operation of the image forming unit 30 described above. The image forming unit 30 includes a motor driving unit 130.

The controller 101 controls the entire system of the printer 1.
When the user performs a copy instruction operation on the operation panel 103, the controller 101 detects the copy instruction. Then, the controller 101 issues an instruction to the scanner control unit 104 to capture an image of the document on the platen glass 11. The captured image is converted from RGB format data to CMYK format data by the CMYK conversion unit 106 and temporarily stored in the memory 102. The image temporarily stored in the memory 102 is transferred to the image formation control unit 100 by the controller 101. The image formation control unit 100 exposes the transferred image data with the exposure units of the image forming units 21Y, 21M, 21C, and 21K.

  The printer 1 can also execute a printing operation based on an input from an external device such as a personal computer (personal computer) via a network.

  When the network control unit 105 receives a print job from an external device such as a personal computer, the image data (CMYK format) of the job is temporarily stored in the memory 102. Thereafter, similarly to the above-described copying operation, the image temporarily stored in the memory 102 is transferred to the image formation control unit 100 by the controller 101. The image formation control unit 100 exposes the transferred image data as an image pattern in the exposure units of the image forming units 21Y, 21M, 21C, and 21K.

  When the controller 101 transfers image data to the image formation control unit 100, the dot count unit 107 counts the total number of dots in the image data. Then, the controller 101 notifies the image formation control unit 100 of the total number of dots of the transferred image data when the transfer of the image data is completed. The controller 101 individually counts the total number of dots and notifies the total number of dots for each color of YMCK.

  The controller 101 controls the operation of the toner supply control unit 110. The toner replenishment control unit 110 controls the rotational operations of the screws 42Y, 42M, 42C, and 42K.

  The motor driving unit 130 rotationally drives the motor 131 that rotates the developing rollers 241Y, 241M, and 241C and the motor 132 that rotates the developing roller 241K. In the printer 1 of the present embodiment, the developing rollers 241Y, 241M, and 241C are rotationally controlled at once, and cannot be individually controlled.

  The toner introduced into each of the developing units 24Y, 24M, and 24C is agitated and deteriorated by the rotation of the developing rollers 241Y, 241M, and 241C during the developing operation or when the toner is supplied.

  Based on this, in the printer 1 of the present embodiment, the timing of supplying toner to the developing units 24Y, 24M, and 24C for each color of YMC is slower in order to avoid toner deterioration in each developing unit as much as possible. We are going to start at the timing. However, when the toner is supplied to each developing unit, it is necessary to rotate the developing rollers 241Y, 241M, and 241C in order to avoid the toner from solidifying and staying in each developing unit. Therefore, it is preferable that the YMC toner supply is performed all at once in order to shorten the driving time of the motor 131 that rotates the developing rollers 241Y, 241M, and 241C.

  Based on the above, in the printer 1 of the present embodiment, the control for replenishing the YMC toners is executed in consideration of the remaining amount of toner in the developing units of other colors.

  Next, a process for controlling the Y toner supply operation (Y toner supply control process) will be described with reference to FIG. 4 which is a flowchart of the process.

  As a premise of the Y toner replenishment control process of the present embodiment, it is assumed that the printer 1 has a three-stage threshold for toner replenishment set for the remaining amount of toner in the developing units 24Y, 24M, and 24C. . Such a threshold will be described with reference to FIG.

  Referring to FIG. 6, the toner contained in each developing unit is schematically shown as regions 2401, 402, and 2403 in developing units 24Y, 24M, and 24C.

  FIG. 6 schematically shows three threshold values A, B, and C for the remaining amounts of toner in the developing units 24Y, 24M, and 24C.

These three threshold values are A, C, and B in order from the largest amount.
The contents of these thresholds are as follows.

A: Threshold value for remaining amount of toner for normal toner replenishment B: Threshold value for remaining amount of toner that needs to be replenished by interrupting image formation C: Remaining amount of toner for prohibiting replenishment of toner of other colors Threshold value In the present embodiment, toner supply to the developing units 24Y, 24M, and 24C is performed mainly during an image forming operation of a color image. When the remaining amount of toner in at least one of the developing units 24Y, 24M, and 24C falls below the threshold B, which is the lowest threshold among the three thresholds described with reference to FIG. In this case, the image forming operation being executed is interrupted, and toner supply is performed.

  Note that when the remaining amount of toner for all colors of YMC is equal to or greater than the threshold value B, the image forming operation being executed is not interrupted, but if there is a developing unit with a remaining amount of toner less than the threshold value C, The toner supply of the color is performed without supplying toner of other colors whose remaining toner amount is equal to or greater than the threshold value C.

  That is, for example, when the remaining amount of toner in the Y developing unit 24Y is greater than or equal to the threshold B and less than the threshold C, and the remaining amount of toner in the M developing unit 24M and the C developing unit 24C is greater than or equal to the threshold C and less than the threshold A. First, the toner supply of M and C is not performed, and only the toner supply of Y is performed. Then, on the condition that the remaining amount of toner in the Y developing unit 24Y is equal to or greater than the threshold value C, the replenishment of M and C toners is started in conjunction with the replenishment of Y toner.

  Returning to FIG. 4, in the Y toner replenishment control process, the controller 101 first determines in step S10 whether or not the Y print interruption toner replenishment request flag is set.

Here, a flag used in the Y toner supply control process will be described.
The print interruption toner replenishment request flag is a flag that is set on condition that the remaining amount of toner in each color developing unit is less than the threshold B, and replenishes the toner by interrupting the image forming operation. This flag is set when required.

  A toner replenishment prohibition request flag, which will be described later, is a flag that is set when the remaining amount of toner in each color developing unit is greater than or equal to the above threshold value B and less than the threshold value C. This flag is set when it is necessary to prohibit replenishment.

  In step S10, the controller 101 proceeds to step S20 when determining that the Y print interruption toner supply request flag is set, and proceeds to step S30 when determining that it is not set.

  In step S20, the controller 101 executes Y printing interruption toner supply processing, and returns the processing to step S10. The contents of the Y print interruption toner supply process will be described later with reference to FIG.

  In step S30, the controller 101 detects the remaining amount of toner in the Y developing unit 24Y, and proceeds to step S40.

  In step S40, the controller 101 determines whether or not the remaining amount of Y toner detected in step S30 is less than the above-described threshold value A. If it is determined that it is less than the threshold value A, the controller 101 proceeds to step S50. If it is determined as above, the process proceeds to step S130.

  In step S50, the controller 101 determines whether or not the remaining amount of Y toner detected in step S30 is less than the above threshold C. If it is determined that it is less than C, the controller 101 proceeds to step S60, and exceeds the threshold C. If it is determined, the process proceeds to step S100.

  In step S60, the controller 101 sets a toner replenishment prohibition request flag from Y, and proceeds to step S70.

  Here, the toner supply prohibition request flag from Y is a flag for prohibiting toner supply to the M developing unit 24M and the C developing unit 24C.

  In step S70, the controller 101 determines whether or not the remaining amount of toner detected in step S30 is less than the threshold value B. If it is determined that it is less than the threshold value B, the process proceeds to step S80. If it is determined that there is, the process proceeds to step S90.

  In step S80, the controller 101 sets a Y print interruption toner replenishment request flag, and proceeds to step S160.

  On the other hand, in step S90, the controller 101 clears the Y print interruption toner replenishment request flag, and proceeds to step S160.

  In step S100, the controller 101 clears the toner supply prohibition request flag from Y set in step S60, and advances the process to step S110.

  In step S110, the controller 101 clears the Y print interruption toner replenishment request flag, and proceeds to step S120.

  In step S120, the controller 101 determines whether the toner supply prohibition request flag from M or the toner supply prohibition request flag from C is set. If it is determined that the controller 101 has set, the process proceeds to step S150. If it is determined that it is not set, the process proceeds to step S160.

  In step 130, the toner supply prohibition request flag from Y set in step S60 is cleared, and the process proceeds to step S140.

  In step S140, the controller 101 clears the Y print interruption toner replenishment request flag set in step S80, and proceeds to step S150.

  In step S150, the supply operation of the Y toner to the developing unit 24Y is terminated, and the process returns to step S10.

  On the other hand, in step S160, the controller 101 starts (continues) toner supply to the Y developing unit 24Y and returns the process to step S10.

  In the printer 1, toner supply from the toner cartridge 40 </ b> Y to the developing unit 24 </ b> Y is executed by rotating the screw 42 </ b> Y, and the Y toner developing unit 24 </ b> Y is stopped by stopping the rotation of the screw 42 </ b> Y. The supply of is finished.

  Referring to FIG. 5, in the Y print interruption toner replenishment process of the present embodiment, controller 101 first detects the remaining amount of toner in Y developing section 24Y in step SA201, and proceeds to step SA202. Proceed.

  In step SA202, it is determined whether or not the remaining amount of toner detected in step SA201 is less than the above threshold value A. If it is determined that it is less than the threshold value A, the process proceeds to step SA203. The process proceeds to SA209.

  In step SA203, the controller 101 determines whether or not the remaining amount of toner detected in step SA201 is less than the threshold value C. If it is determined that it is less than the threshold value C, the controller 101 proceeds to step SA204 and exceeds the threshold value C. If it is determined that there is, the process proceeds to step SA206.

  In step SA204, the controller 101 sets a toner replenishment prohibition request flag from Y, and proceeds to step SA205.

  In step SA205, the controller 101 sets a Y print interruption toner replenishment request flag, and proceeds to step SA208.

  In step SA206, the controller 101 clears the toner supply prohibition request flag from Y, and proceeds to step SA207.

  In step SA207, the controller 101 sets a Y print interruption toner replenishment request flag, and proceeds to step SA208.

  In step SA208, the controller 101 starts (continues) toner supply to the Y developing unit 24Y, and returns the process to FIG.

  In step SA209, the controller 101 clears the toner replenishment prohibition request flag from Y, and proceeds to step SA210.

  In step SA210, the controller 101 clears the Y print interruption toner replenishment request flag, and proceeds to step SA211.

  In step SA211, the controller 101 ends the toner supply to the Y developing unit 24Y, and returns the process to FIG.

  The Y toner replenishment control process described above with reference to FIGS. 4 and 5 is executed with respect to Y toner replenishment when a print job is executed in the printer 1. When a print job is executed in the printer 1, the same processing as that described with reference to FIGS. 4 and 5 is executed in parallel with the M and C toner supply.

  In the Y toner replenishment control process of the present embodiment described above, the screw 42Y is rotated when the remaining amount of Y toner is less than the above-described threshold C (first amount) (YES in step S50). Thus, toner supply to the developing unit 24Y is started (step S160).

  If the remaining amount of Y toner is less than the above-described threshold B (YES in step S70), a Y print interruption toner supply request flag is set, whereby the printing operation is interrupted and Y print interruption toner supply is performed. Processing is executed (YES in step S10, step S20). The color printing operation is interrupted when the remaining amount of toner for any one of Y, M, and C is less than the threshold value B, and the print interruption toner supply request flag for any of these is set, Toner is supplied.

  When the remaining amount of Y toner is less than the threshold C (YES in step S50), a flag (toner from Y) for prohibiting toner supply for the other colors (M and C) of the color toner A replenishment prohibition request flag) is set (step S60). On the other hand, when Y toner is replenished, if the Y toner remaining amount is equal to or greater than the threshold value C (NO in step S50) and the toner replenishment prohibition request flag is set for another color (YES in step S120). , Y toner is not replenished (step S150). Similarly, when the toner replenishment prohibition request flag from Y is set, if the remaining amount of M toner is greater than or equal to the threshold C when M toner is replenished, M toner is not replenished, and C If the remaining amount of C toner is greater than or equal to the threshold C at the time of toner replenishment, C toner is not replenished. Therefore, when the Y toner remaining amount is less than the threshold C (first amount), the Y toner is replenished, but if the M toner remaining amount is equal to or greater than the threshold C, the M toner is replenished. If the remaining amount of C toner is equal to or greater than the threshold value C, the C toner is not replenished.

  When the Y toner is replenished and the remaining amount of the toner exceeds the threshold C (NO in step SA203), the toner replenishment prohibition request flag from Y is cleared (step SA206). As a result, the replenishment of the M and C toners, which has been prohibited by setting the flag, is released. Even when the remaining amount of toner for other colors is less than the threshold value C and the remaining amount of Y toner is greater than or equal to the threshold value C, even if the supply of Y toner is prohibited, If the remaining amount of toner becomes equal to or greater than the threshold value C due to the replenishment of toner, the prohibition of the replenishment of Y toner is canceled.

  A change in the remaining amount of toner of each color of Y, M, and C as a result of the control related to toner replenishment in the present embodiment will be described in more detail with reference to FIGS.

  In each figure, arrows 401, 402, and 403 represent the flow of toner replenished from the toner cartridges 40Y, 40M, and 40C to the developing units 24Y, 24M, and 24C, respectively. Arrows 2411, 2412 and 2413 indicate the flow of toner output for use in image formation from the developing units 24Y, 24M and 24C, respectively.

  FIG. 6 shows a state 1 in which the remaining amounts of toner of all colors Y, M, and C are larger than the threshold C but below the threshold A.

  In this case, although toner is replenished for each color (YES in step S40 for step Y, step S160), the toner replenishment prohibition request flag and the print interruption toner replenishment request for each color are cleared. The toner supply is performed without interrupting the printing operation and without prohibiting the supply of toner of other colors. Then, the replenishment of the toner of each color ends when the remaining amount of toner becomes equal to or greater than the threshold A (NO in step S40, step S150).

  FIG. 7 shows a state 2 in which the remaining amounts of Y and C toners are larger than the threshold C but below the threshold A, and the consumption of M toner is larger than the consumption of other color toners. , M shows a state where the remaining amount of toner is greater than the threshold B but below the threshold B.

  In this case, M toner is first replenished, but when M toner replenishment is controlled, a toner replenishment prohibition request flag from M is set (state 3 in FIG. 8). Thus, the supply of Y and C toners is prohibited until the remaining amount of M toner reaches the threshold value C or more. When the remaining amount of toner exceeds the threshold value C by replenishing only M toner, the toner replenishment prohibition request flag from M is cleared, the prohibition of replenishment of Y and C toners is canceled, and the Y and C toners are replenished. Replenishment will be performed together.

  FIG. 9 shows a state 4 as a state 4 in which the consumption of M toner does not catch up with the supply of the toner from the state 2 and the remaining amount of M toner falls below the threshold value B. In this case, the M printing interruption toner replenishment request flag is set and the toner replenishment prohibition request flag from M is set. For this reason, the printing operation is stopped, and M toner is replenished (state 5 in FIG. 10). In state 4, the remaining amounts of Y and C toners are greater than the threshold value C. Therefore, since toner supply to Y and C is prohibited, in state 5, toner supply of Y and C is not performed. That is, in state 5, only M toner is supplied. Then, when the remaining amount of toner of M becomes equal to or greater than the threshold C as shown in state 6 of FIG. 11, the toner supply prohibition request flag from M is cleared, and as shown in state 7 of FIG. In addition to toner replenishment, Y and C toner replenishment is performed. The stopped printing operation is not resumed until the toner amounts of all the colors Y, M, and C are equal to or greater than the threshold value A. As shown in step SA210, the Y print interruption toner supply request flag is not cleared until the remaining amount of toner for Y exceeds the threshold A (YES in step SA202), and the same applies to M and C. This is because the following process is performed.

  In state 5, since only the remaining amount of M toner is below the threshold value C, Y and C toners were not replenished. For example, if the remaining amount of Y toner is also below the threshold value C, , Even if the toner supply prohibition request flag from M is set, Y toner supply is performed. If it is determined in step S50 in FIG. 4 that the remaining amount of Y toner is less than the threshold value C, it is determined whether or not the toner supply prohibition request flag for other colors is set as in step S120. This corresponds to the Y toner being replenished in step S160.

[Second Embodiment]
FIG. 13 is a flowchart of a first modification of the Y print interruption toner supply process shown in FIG.

  FIG. 13 is a flowchart of a subroutine of the printing interruption toner supply process of Y in step SB20.

  Referring to FIG. 13, in Y printing interruption toner replenishment processing, controller 101 first clears the toner replenishment detection request flag from Y in step SB201 and advances the processing to step SB202.

  In step SB202, the remaining amount of toner in the Y developing unit 24Y is detected, and the process proceeds to step SB203.

  In step SB203, the controller 101 determines whether or not the Y toner remaining amount detected in step SB202 is less than the above threshold A. If it is determined that it is less than the threshold A, the controller 101 advances the processing to step SB204. If it is determined as above, the process proceeds to step SB206.

  In step SB204, the controller 101 sets a Y print interruption toner replenishment request flag, and proceeds to step SB205.

  In step SB205, the controller 101 starts (continues) the supply of Y toner, and returns the process to FIG.

  In step SB206, the controller 101 clears the Y print interruption toner replenishment request flag, and proceeds to step SB207.

  In step SB207, the controller 101 ends the Y toner supply and returns the process to FIG.

  In the Y printing interruption toner replenishment processing of the present embodiment, as shown in steps SA203, SA204, and SA206 in FIG. 5, the replenishment of other toners is prohibited until the remaining amount of Y toner exceeds the threshold C. The toner supply prohibition request from Y is not set or cleared.

  As a result, in this embodiment, once one of Y, M, and C, the remaining amount of toner is less than the threshold value B (second amount) and the printing operation is stopped, the toner supply for other colors is performed. Even if the remaining amount of toner of the other color is equal to or greater than the threshold value C (first amount), it is prohibited until the remaining amount of toner of the other color is equal to or greater than the threshold value A (third amount). Executed without.

  That is, in the first embodiment, when only the remaining amount of M toner is below the threshold value B (FIG. 9), the printing operation is stopped as in state 5 of FIG. In this embodiment, instead of the state 5 in which only the toner is replenished (until the remaining amount of toner becomes equal to or greater than the threshold value C), in this embodiment, if the printing operation is stopped, as shown in the state 5 in FIG. Replenishment of toner of all colors is performed (the remaining amount is less than the threshold value A).

[Third Embodiment]
In the Y print interruption toner replenishment process of the present embodiment, when it is detected that the remaining amount of toner in the Y developing unit 24Y is less than the threshold value B, toner is replenished to the developing unit. However, if the remaining amount of toner does not exceed the above-described threshold value A even if the toner supply is continued for a predetermined time, it is determined that the toner in the toner cartridge 40Y itself is not stored, and the toner empty signal Is output and a notification to that effect is made.

  FIG. 15 is a flowchart of a second modification of the print interruption toner supply process of Y in FIG.

  Referring to FIG. 15, in the print interruption toner replenishment process of the present embodiment, controller 101 first detects the remaining amount of toner in Y developing section 24Y in step SC201, and advances the process to step SC202.

  In step SC202, the controller 101 determines whether or not the remaining amount of toner detected in step SC201 is less than the threshold A described above. If it is determined that it is less than the threshold A, the process proceeds to step SC203. If it is determined that there is, the process proceeds to step SC212.

  In step SC203, the controller 101 increments the Y empty detection time counter and advances the process to step SC204.

  In step SC204, the controller 101 determines whether the elapsed time of the Y empty detection time counter is less than 60 seconds due to the increment in step SC203. If it is determined that it is less than 60 seconds, the controller 101 proceeds to step SC206. If it is determined that it is 60 seconds or longer, the process proceeds to step SC205.

  In step SC205, the controller 101 executes toner empty processing for Y. The toner empty process for Y is a process executed when the toner bottle for Y needs to be replaced. For example, information indicating that the toner bottle for Y is empty and needs to be replaced This is a process for notifying as an abnormal state. In the printer 1, when the toner empty process is executed for any of the colors, the toner empty process is continued until the abnormal state is cleared.

  In step SC206, the controller 101 determines whether or not the remaining amount of toner detected in step SC201 is less than the threshold value C. If it is determined that the remaining toner amount is less than the threshold value C, the process proceeds to step SC207. If it is determined that there is, the process proceeds to step SC209.

  In step SC207, the controller 101 sets a toner replenishment prohibition request flag from Y and advances the process to step SC208.

  In step SC208, the controller 101 sets a Y print interruption toner supply request flag and advances the process to step SC211.

  In step SC209, the controller 101 clears the toner supply prohibition request flag from Y, and advances the process to step SC210.

  In step SC210, the controller 101 sets a Y print interruption toner supply request flag and advances the process to step SC211.

  In step SC211, the controller 101 starts (continues) toner supply to the Y developing unit 24Y and returns the process to FIG.

  When determining in step SC202 that the remaining amount of toner is equal to or greater than the threshold value A, the controller 101 clears the Y empty detection time counter in step SC212, and advances the process to step SC213.

  In step SC213, the controller 101 clears the toner supply prohibition request flag from Y, and proceeds to step SC214.

  In step SC214, the controller 101 clears the Y print interruption toner replenishment request flag and advances the process to step SC215.

  In step SC215, the controller 101 ends the toner supply to the Y developing unit 24Y, and returns the process to FIG.

  In the Y printing interruption toner replenishment processing of the present embodiment described above, the printing operation is stopped and Y toner replenishment is performed when the remaining amount of Y toner is less than the threshold B (predetermined amount). If the toner is replenished for 60 seconds (predetermined time) and the remaining amount of Y does not exceed the threshold A (specific amount), a control operation (toner empty process) corresponding to the abnormal state is executed. The

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Printer, 2 Loading stand, 2 Conveyance part, 4 Discharge stand, 10 Image reading part, 20 Paper conveyance part, 21, 21Y, 21M, 21C, 21K Image formation part, 24, 24Y, 24M, 24C, 24K Image development part, 25, 25Y, 25M, 25C, 25K transfer roller, 30 image forming unit, 31 intermediate transfer belt, 32, 33, 34, 35, 37, 42, 43 roller, 38 paper discharge tray, 40 paper storage unit, 41 paper feed Cassette, 50 display unit, 101 controller, 102 memory, 241Y, 241M, 241C, 241K Developing roller.

Claims (4)

A first developer for developing with toner;
A second developer for developing with toner;
Second driving means for driving the second developing device;
First detecting means for detecting a toner amount in the first developing device;
Second detection means for detecting the amount of toner in the second developer;
First supply means for supplying toner to the first developer;
Second supply means for supplying toner to the second developing device;
Driving means for driving the first and second developing units;
Control means for controlling the drive means and the first and second supply means,
The control means includes
When the detection amount of the first detection unit is less than the first amount, the first supply unit supplies toner, and the drive unit executes driving;
When the detection amount of the first detection means is less than the second amount less than the first amount, and when the detection amount of the second detection means is less than the second amount, the first amount When the amount of detection by the second detection means is less than the first amount and greater than or equal to the second amount, the detection amount of the first detection means is the second detection means. An image forming apparatus that causes the second replenishing means to replenish toner on condition that the amount is 2 or more. An image forming unit that performs an image forming operation;
The image forming unit includes the first and second developing units,
The control means includes
Controlling the image forming operation by the image forming unit,
When it is determined that the detection amount of the first detection means is less than the third amount that is less than the first amount and the second amount, the image forming operation of the image forming unit is stopped, 2. The toner according to claim 1, wherein toner is supplied to the first supply unit, and if the amount detected by the second detection unit is less than the first amount, the second supply unit is supplied with toner. Image forming apparatus.   If the detected amount of the first detecting means is less than a predetermined amount, the control means may detect the detected amount of the first detecting means even if the first supplying means supplies toner for a predetermined time or more. 3. The image forming apparatus according to claim 1, wherein a control operation for an abnormal state is executed when the amount does not exceed a specific amount greater than a predetermined amount. A method for controlling an image forming apparatus including a plurality of developing devices that perform development using toner,
Detecting the remaining amount of toner in the first developer unit and the second developer unit among the plurality of developer units;
Replenishing toner to the first developer when the remaining amount of toner in the first developer is less than a first amount;
The remaining amount of toner in the first developer is less than a second amount less than the first amount, and the remaining amount of toner in the second developer is less than the first amount and the second amount. If the amount is equal to or greater than the amount, the step of starting toner supply to the second developer on the condition that the remaining amount of toner in the second developer is equal to or greater than the second amount. A method for controlling an image forming apparatus.

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