JP4882387B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus that performs image stabilization control and an image forming method thereof.

  For example, in an electrophotographic image forming apparatus, the amount of toner drawn on an image carrier varies due to disturbances such as the environment and history even under the same charging conditions, exposure conditions, and development conditions. Therefore, the image forming apparatus is equipped with a toner adhesion amount sensor for detecting the toner adhesion amount drawn on the image carrier, and an appropriate and stable image is output based on the detection result of the sensor. As described above, an image stabilization control function capable of controlling charging conditions, exposure conditions, and development conditions is installed.

The timing at which this image stabilization control is started is often started every predetermined number of prints.
In addition, although the printing speed of recent image forming apparatuses has been increased, if image stabilization control is activated during printing, a waiting time is given to the user, and the effect of improving the printing speed is not exhibited.
Japanese Patent Laid-Open No. 10-2222023

  In the image forming apparatus in which the image stabilization control is activated at such a specific timing, even if the number of prints is small when the user enters the execution timing of the image stabilization control while printing. In the middle of printing, printing is interrupted and image stabilization control is activated, and the user needs to wait during that time. Such a problem is not limited to the electrophotographic method, but also occurs in the image forming apparatus of the ink jet method and other recording methods.

  The present invention aims to shorten the waiting time by devising the timing at which the image stabilization control is activated.

In order to solve the above-described problems, the present invention provides an image forming apparatus that performs an image stabilization operation, a recording unit that records a print history within a predetermined period, and a use time zone in one day from the recorded print history. A totaling unit that determines and totalizes the usage history for each unit time zone, and a control unit that executes an image stabilization operation in a unit time zone that is less frequently used in the usage time zone determined by the totaling unit, The counting means has a prohibited time zone determining unit that determines a unit time zone having a maximum usage frequency as a prohibited time zone in the aggregated usage time zone, and the control means is arranged before the prohibited time zone. time zone, time zone before the prohibition time zone the number of prints of the stack with aggregated print history in the aggregate means until the after the execution of the previous image stabilization operation the prohibition time zone is completed starts In predicted based on the current number of prints are printed on, if the predicted number of prints equal to or greater than the predetermined number of prints as the execution interval of the image stabilization operation, the time period before the prohibition time zone The image stabilization operation is executed, and the image stabilization operation is not executed during the prohibited time period.

With the configuration as described above, the image stabilization operation is executed in a time zone in which the user is less frequently used, so the probability that the user waits can be reduced. In addition, it is possible to avoid reaching the predetermined number of prints in the prohibited time zone and execute the image stabilization operation in the previous time zone, so that the probability of crossing the user without causing deterioration in image quality Can be reduced.

Also, the number of prints of the accumulation, the current number of prints that have been printed by the time zone of the front of the prohibition time zone begins, the prohibition time zone, which is recorded in the aggregated print history in the aggregate means The total number of prints in the previous time zone and the prohibited time zone is added.

With such a configuration, the number of sheets to be printed during the prohibited time period can be accurately predicted, so that the image stabilization operation is surely executed in the time period before the prohibited time period to prevent deterioration of the image quality. Can do.
In addition, the predetermined period is a period of a plurality of weeks or more, excluding predetermined seven days and public holidays that are less frequently used in consideration of public holiday information, and the use time period is determined every seven days. It is said.

With such a configuration, the reliability of the usage frequency obtained from the print history is improved.
The image forming apparatus further includes a charging unit that charges the surface of the photoconductor, an exposure unit that forms an electrostatic latent image on the surface of the photoconductor, and a developing unit that exposes the electrostatic latent image with toner to form a toner image. The control means adjusts at least one of charging conditions, exposure conditions, and development conditions.

With such a configuration, the image stabilization operation can be reliably executed.
The present invention also relates to an image forming method for an image forming apparatus that performs an image stabilization operation, a recording step for recording a print history within a predetermined period, and a use time zone for one day from the recorded print history. And a totaling step for totalizing the usage frequency for each unit time zone, and a control step for executing an image stabilization operation in a unit time zone with a low usage frequency in the usage time zone determined in the totaling step, The counting step includes a prohibited time zone determining step of determining a unit time zone having a maximum usage frequency as a prohibited time zone in the aggregated usage time zone, and the control step includes a time zone before the prohibited time zone. in the the aggregated print history in the aggregate step the number of prints of the cumulative up when the prohibition time zone is completed after the execution of the previous image stabilization operation If stopped predicted on the basis of the up time period before the beginning of the time zone and the current number of prints have been printed, the predicted number of prints is equal to or more than a predetermined number of printed sheets as the execution interval of the image stabilization operation, The image stabilization operation is executed in a time zone before the prohibited time zone, and the image stabilization operation is not executed in the prohibited time zone.

According to such a method, the image stabilization operation is executed in a time zone in which the user is not frequently used, so that the probability that the user waits can be reduced .

Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings.
(One embodiment)
FIG. 1 is a diagram showing a schematic configuration of a tandem type full-color copying machine which is an example of Embodiment 1 of an image forming apparatus according to the present invention.
The image forming apparatus includes an intermediate transfer belt 106 that is stretched around rollers 101, 102, 103, and 104 and is driven to rotate counterclockwise (in the direction of arrow 105) in the drawing. A cleaner 107 that removes residual toner and the like on the intermediate transfer belt 106 is disposed opposite to the roller 102. A secondary transfer roller 108 is disposed opposite to the roller 101. A fixing device 109 is installed above the secondary transfer roller 108.

  Between the rollers, a yellow image forming unit 110, a magenta image forming unit 120, a cyan image forming unit 130, and a black image forming unit 140 are arranged in this order from the roller 102 toward the roller 101 with respect to the intermediate transfer belt 106. Yes. Each of the image forming units 110, 120, 130, and 140 includes a drum-type photoreceptor 1, and a charging device 2, an exposure device 3, a developing device 4, a primary transfer charger 5, and the like around the photoreceptor 1. Cleaners 6 for removing residual toner and the like on the photoreceptor 1 are arranged in this order. A developing roller 41 is disposed in the developing device 4 so as to face the photoreceptor 1. The primary transfer charger 5 faces the photosensitive member 1 with the intermediate transfer belt 106 interposed therebetween.

  The exposure device 3 receives a drive signal from the control unit 201, emits laser light for image formation, and performs exposure scanning on the photosensitive drum 1 in the main scanning direction. Before the exposure, the photosensitive drum 1 is removed from the toner remaining on the surface by the cleaner 6 and is uniformly charged by the charging device 2. In this state of uniform charging, the exposure by the laser beam is performed. Then, an electrostatic latent image is formed on the surface of the photosensitive drum 1.

Each electrostatic latent image is developed by the developing device 4 of each color, whereby a toner image of each color is formed on the surface of the photosensitive drum 1 and is rotated by an electrostatic force generated by a voltage applied to the primary transfer charger 5. The images are sequentially transferred onto the intermediate transfer belt 106.
At this time, the image forming operation for each color is executed with the timing shifted from the upstream side to the downstream side so that the toner image is primarily transferred to the same position on the intermediate transfer belt 106. As a result, the toner images are sequentially superimposed on the intermediate transfer belt 106.

The toner image transferred onto the intermediate transfer belt 106 is recorded on the recording paper S by the electrostatic force generated between the rollers 101 and the secondary transfer roller 108 and fixed by the fixing device 109.
Further, a toner adhesion amount sensor 151 for reading the toner adhesion amount of the toner patch drawn on the intermediate transfer belt 106 during the image stabilization control is disposed to face the intermediate transfer belt 106.

Of course, the configuration of the image forming apparatus is not limited to the present embodiment.
FIG. 2 is a configuration diagram showing an outline of a control circuit in the image forming apparatus of FIG.
The charging device 2 of each image forming unit receives a predetermined high voltage for charging the photoconductor from the output variable charging power supply YPW2, MPW2, CPW2 or KPW2 for the image forming unit under the instruction of the control unit 201. Are applied at a predetermined timing. The developing roller 41 of the developing device 4 of each image forming unit receives a predetermined developing bias voltage from the developing bias power supply YPW4, MPW4, CPW4 or KPW4 for the image forming unit according to an instruction from the control unit 201. Applied at timing.

The primary transfer charger 5 and the secondary transfer roller 108 of each image forming unit are also supplied from each primary transfer charger power source and each secondary transfer roller power source (not shown) under the instruction of the control unit 201. A predetermined transfer voltage is applied at a predetermined timing.
Further, there are a motor for driving the exposure device 3, the photosensitive member 1 and the developing device 4 in each image forming unit, a motor for driving a roller on which the intermediate transfer belt 106 is stretched, a secondary transfer roller driving motor, and a fixing device It is configured to start at a predetermined timing under the instruction of the control unit 201.

Next, a configuration for executing image stabilization control of the image forming apparatus will be described.
FIG. 3 is a functional configuration diagram for executing image stabilization control of the image forming apparatus.
This image forming apparatus includes a print number history recording unit 301, a built-in clock 302, a total calculation unit 303, a calendar function 304, a control timing determination unit 305, an image stabilization control execution unit 306, and a print number interval holding. A section 307 and a print number counting section 308.

The print number history recording unit 301 records a print history for a predetermined period. For this reason, the counter i is provided, and the number of prints per unit time is recorded on a daily basis with reference to the built-in clock 302.
FIG. 4 is a diagram showing an example of the format of the print number history table prepared in the storage area of the print number history recording unit 301.

The print number history table 401 is provided with an entry for recording the number of prints for 403 per week for each unit time 402. Here, the unit time 402 is 1 hour, but it may be a unit of 30 minutes, a unit of 2 hours, or any other unit time.
Here, it is assumed that the built-in clock 302 is reset every 24 hours.

The counter i is reset at the beginning of each unit time, and i is incremented by 1 every time one print is made. When the unit time elapses, the number of prints is recorded in the corresponding entry. The operation of the print number history recording unit 301 will be described later.
The built-in clock 302 keeps time on a 24-hour basis.
The total calculation unit 303 extracts a history for a predetermined period every seven days from the print number history table 401 recorded in the print number history recording unit 301.

FIG. 5 is a diagram showing the extracted tabulation table.
The totaling table 501 indicates a predetermined period of, for example, four weeks on a specific seven days of the week, for example, Monday. In the right column 502 of the tabulation table 501, the average number of prints in the past four weeks in each unit time zone is calculated. In the bottom column 503, the daily average number of printed sheets for the past four weeks is calculated. Note that this tabulation table 501 is for Monday, and is tabulated similarly for other days of the week. In addition, although it cannot be found in the totaling table 501, a day in which the total number of prints per day is extremely smaller than the average number of prints per day is excluded from the data in this totaling table. For example, data on a day that is 1/10 or less of the average number of prints per day is excluded.

The total calculation unit 303 determines the use time zone based on the average print number history of the day in the total table (the average print number per unit time zone for the past four weeks).
FIG. 6A shows an average print number history on Monday. In the lowermost column of the average print number history 601, an average print number per hour obtained by dividing the total number of prints per day by 24 is calculated. The total calculation unit 303 determines a time zone exceeding the average number of printed sheets as a usage time zone. At this time, a use time zone is defined between the first start time and the last end time exceeding the average number of prints first in the day.

  FIG. 6B shows an average print number history graph 602 of the average print number history 601 shown in FIG. A broken line 603 indicates the average number of printed sheets per hour. As for the time exceeding the average number of printed sheets, the start time is 8:00 and the end time is 19:00. Accordingly, the usage time zone is determined to be between 8 o'clock and 19 o'clock as indicated by an arrow 604. The total calculation unit 303 further determines the priority time zone 605 as the unit time zone in which the number of printed sheets (usage frequency) in the usage time zone is minimized. In addition, the unit time zone in which the number of printed sheets (usage frequency) in the usage time zone is maximized is determined as the prohibited time zone 606.

  The total calculation unit 303 notifies the control timing determination unit 305 of the use time zone, the priority time zone 605, and the prohibited time zone 606. The Monday usage hours shown in FIGS. 6A and 6B start at 8 o'clock and end at 19 o'clock. The priority time zone 605 is from 12:00 to 13:00, and the prohibited time zone 606 is from 13:00 to 14:00. The operation of the total calculation unit 303 will be described later.

The calendar function 304 stores a calendar. Based on this calendar, the tabulation calculation unit 303 may know a holiday such as a holiday or Sunday in advance and exclude this holiday from the print history.
The control timing determination unit 305 executes the image stabilization control based on the use time zone and the priority time zone 605 and the prohibited time zone 606 notified from the total calculation unit 303 and the number of prints after execution of the previous image stabilization control. The unit 306 is activated.

  The control timing determination unit 305 first resets the priority execution flag that it has. It is determined whether or not the time notified from the built-in clock 302 is in the priority time zone notified from the total calculation unit 303. If it is in the priority time zone, nothing is done when the priority execution flag is set. When the priority execution flag is not set, the priority execution flag is set and the image stabilization control execution unit 306 is activated.

  Further, the control timing determination unit 305 determines whether or not the value of the counter j notified from the print number counting unit 308 exceeds the predetermined number J held in the print number interval holding unit 307 when there is a print request. Determine. When it is determined that the time is exceeded, it is determined whether or not the time indicated by the built-in clock 302 belongs to the prohibited time zone notified from the total calculation unit 303. When not belonging to the prohibited time zone, the image stabilization control execution unit 306 is activated. When belonging to the prohibited time period, the image stabilization control execution unit 306 is activated after the prohibited time period ends.

The control timing determination unit 305 instructs the print sheet count unit 308 to reset the counter j to 0 after the image stabilization control execution unit 306 executes the image stabilization operation.
When activated by the control timing determination unit 305, the image stabilization control execution unit 306 controls the image forming unit to execute an image stabilization operation.

Here, the image stabilization operation will be briefly described with reference to FIGS. 1 and 2 again.
A plurality of toner patches having different gradations are drawn on the intermediate transfer belt 106 under a predetermined development condition, charging condition, and exposure condition, and the toner adhesion amount is read by the toner adhesion amount sensor 151, and from the sensor output value. The gradation characteristic of the actual output image is detected. Based on the sensor detection result, the development condition, charging condition, and exposure condition are determined by the control unit 201 so that an image having an appropriate gradation is output after the image stabilization operation is performed. At the time of printing, the developing operation and the like are controlled based on the determined conditions. This image stabilization operation is an example of gradation correction, but other image stabilization operations, for example, known γ correction may be executed, and the interval between toner patches on the intermediate transfer belt 106 is measured. Then, registration correction for controlling exposure conditions and the like may be executed so that the writing timing of each color is appropriate.

The print number interval holding unit 307 holds a predetermined number J of which the image stabilization operation is executed in principle when the number of printed sheets reaches a predetermined number. This number J can be arbitrarily set.
The print number counting unit 308 has a counter j, counts the number of prints of the image forming apparatus, and notifies the control timing determination unit 305 of the value j. When a reset instruction is received from the control timing determination unit 305, the counter j is set to zero.

Next, the operation of the present embodiment will be described using a flowchart.
FIG. 7 is a flowchart for explaining the operation of the print number history recording unit 301.
First, the print number history recording unit 301 resets and starts the timer (S702). It is determined whether or not 24 hours have elapsed (S704). If it has elapsed, the process returns to S702, and if it has not elapsed, the counter i is reset (S706).

  It is determined whether or not printing has been performed on the recording paper S (S708). When printing has been performed, the counter i is incremented by 1 (S710), and when printing has not been performed, it is determined whether or not the unit time has elapsed (S712). . If the unit time has not elapsed, the process returns to S708. If the unit time has elapsed, the number of prints i per unit time is recorded in the corresponding entry of the print number history table 401 (S714), and the process returns to S704.

FIG. 8 is a flowchart for explaining the operation of the total calculation unit 303.
The total calculation unit 303 extracts the number of prints per unit time every seven days for the past four rounds recorded in the print number history recording unit 301 (S802).
Next, the number of prints per day is totaled, and the average number of prints per day is calculated (S804). The historical data for the number of printed sheets that is 1/10 or less of the average number of printed sheets per day is excluded from the tabulation (S806). The average number of printed sheets D every seven days is calculated (S808). The average number of prints Tm = D / 24 per unit time every seven days is calculated (S810).

The average number of printed sheets T per unit time every seven days is calculated (S812). A use time zone is defined between the first start time and the last end time at which T> = Tm for every seven days (S814).
A unit time zone indicating the maximum number of prints T in the usage time zone every seven days is set as a prohibited time zone (S816). A unit time zone indicating the minimum print number T in the usage time zone every seven days is set as a priority time zone (S818).

Next, the operation of the control timing determination unit 305 will be described using the flowchart of FIG.
The control timing determination unit 305 first resets the priority execution flag (S902). With reference to the built-in clock 302, it is determined whether or not it is the priority time zone notified from the total calculation unit 303 (S904). If it is not the priority time zone, the process proceeds to S914. If it is the priority time zone, it is determined whether or not the priority execution flag is set (S906), and if it is set, the process proceeds to S914. If not, a priority execution flag is set (S908) and the image stabilization control execution 306 is activated. The image stabilization control execution unit 306 executes an image stabilization operation (S910).

The control timing determination unit 305 instructs the print sheet count unit 308 to initialize the counter j to zero. The printed sheet count unit 308 sets the counter j = 0 (S912).
Next, the control timing determination unit 305 determines whether or not there is a print request (S914). If not, the control timing determination unit 305 returns to S904. If there is, the control timing determination unit 305 determines whether or not j> = J (S916). If J is less than J, printing is performed and the counter j is incremented by 1 (S920). It is determined whether or not the job has ended (S922). If it has ended, the process returns to S904, and if it has not ended, the process returns to S916.

In S916, if j is greater than or equal to J, it is determined whether or not it is a prohibited time zone (S918). If it is not a prohibited time zone, the process proceeds to S910 as a rule. If it is the prohibited time zone, the process proceeds to S920 and printing is performed.
As described above, in the present embodiment, the image stabilization operation is preferentially executed in the priority time zone, and the time zone after the prohibition time zone is not executed in the prohibited time zone without performing the image stabilization operation. By causing the image stabilization operation to be executed, the probability of waiting for the user who prints is made as small as possible.
(Modification)
In the above embodiment, the image stabilization operation is performed when the predetermined number of prints J is reached. When the image stabilization operation occurs during the prohibition time zone, Although the image stabilization operation is performed, as a modification of the above embodiment, the image stabilization operation is predicted to be performed in the prohibited time zone, and the image is displayed in the time zone before the prohibited time zone. The stabilization operation is performed.

Hereinafter, a description will be given using the flowchart shown in FIG.
After S902 illustrated in FIG. 9, the control timing determination unit 305 determines whether or not the time period is before the prohibited time period notified from the total calculation unit 303 (S1002). If not, the process moves to S1008. If affirmative, the average number of prints of the previous time zone and the prohibited time zone is read from the average print number history 601 and added to the current print number (the value of the counter j), and it is determined whether or not the value is equal to or greater than J. (S1004). If it is less than J, the process moves to S1008.

When the result is affirmative, the image stabilization operation is executed in the previous time zone (S1006).
In S1008, it is determined whether it is a priority time zone. If it is a priority time zone, a priority execution flag is set (S1010), and the process returns to S904 in FIG. If it is not the priority time zone, the process returns to S904 in the same manner.
As described above, in this modification, since the image stabilization operation is completed in the time zone before the prohibition time zone, the probability of executing the image stabilization operation during printing in the prohibition time zone is reduced. Can do.

Although the functional configuration diagram of the image forming apparatus is shown in FIG. 3 in the above embodiment, it is needless to say that the program may be realized by a program that causes a computer to exhibit the function of each unit.
Of course, the image forming apparatus can be applied to any of known monochromatic / color copying machines, printers, fax machines, and complex machines that perform image stabilization control.

  The image forming apparatus according to the present invention can be widely used in the office equipment field as being capable of efficiently performing the timing of the image stabilization operation of the printer or the copying machine in accordance with the use history of the user.

1 is a configuration diagram showing an outline of a tandem type full-color copying machine as an example of an embodiment of an image forming apparatus according to the present invention; FIG. It is a block diagram which shows the control circuit of the image forming apparatus of the said embodiment. FIG. 3 is a functional configuration diagram for performing an image stabilization operation of the image forming apparatus according to the embodiment. It is a figure which shows an example of the printing number log | history table recorded on the storage area of the printing number log | history recording part of the said embodiment. It is a figure which shows an example of the total table extracted by the total calculation part of the said embodiment. (A) is a figure which shows an example of the average number-of-print-sheets history of Monday of the past 4 weeks.

(B) is a graph of the average print number history shown in (a).
It is a flowchart explaining operation | movement of the printing number log | history recording part of the said embodiment. It is a flowchart explaining operation | movement of the total calculation part of the said embodiment. It is a flowchart explaining operation | movement of the control timing determination part of the said embodiment. It is a flowchart explaining operation | movement of the control timing determination part which is a modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging apparatus 3 Exposure apparatus 4 Developing apparatus 5 Primary transfer charger 6 Cleaner S Recording paper 101 Roller 102 Roller 103 Roller 104 Roller 106 Transfer belt 107 Cleaner 108 Primary transfer roller 109 Fixing apparatus 110 Yellow image forming part 120 Magenta image formation Unit 130 cyan image forming unit 140 black image forming unit 201 control unit 301 print number history recording unit 302 built-in clock 303 total calculation unit 304 calendar function 305 control timing determination unit 306 image stabilization control execution unit 307 print number interval holding unit 308 print Number counter

Claims (5)

An image forming apparatus that performs an image stabilization operation,
Recording means for recording a print history within a predetermined period;
A totaling means for determining a usage time zone for one day from the recorded print history and totaling the usage history for each unit time zone;
Control means for executing an image stabilization operation in a unit time zone having a low usage frequency in the usage time zone determined by the counting means,
The counting means includes
In the aggregated use time zone, having a prohibition time zone determination unit that determines a unit time zone having the maximum use frequency as a prohibition time zone,
The control means includes
In the time zone before the prohibited time zone, the cumulative number of prints from the execution of the previous image stabilization operation until the end of the prohibited time zone is counted before the print history and the prohibited time zone. If the predicted number of prints is equal to or greater than a predetermined number of prints as an image stabilization operation execution interval, the estimated time An image forming apparatus, wherein an image stabilization operation is executed in a previous time zone, and an image stabilization operation is not executed in the prohibited time zone.   The cumulative number of prints is the current number of prints printed before the start of the time zone before the prohibited time zone, and the time before the prohibited time zone recorded in the print history tabulated by the counting means. 2. The image forming apparatus according to claim 1, wherein the total number of prints of the belt and the prohibited time zone is added.   The predetermined period is a period of a plurality of weeks or more, and excludes predetermined seven days and public holidays that are less frequently used in consideration of public holidays information from the tabulation, and the usage period is determined every seven days. The image forming apparatus according to claim 1. Charging means for charging the surface of the photoreceptor;
Exposure means for forming an electrostatic latent image on the surface of the photoreceptor;
A developing unit that makes the electrostatic latent image visible with toner and forms a toner image;
The image forming apparatus according to claim 1, wherein the control unit adjusts at least one of a charging condition, an exposure condition, and a developing condition. An image forming method of an image forming apparatus that performs an image stabilization operation,
A recording step for recording a print history within a predetermined period;
A totaling step for determining a usage time zone in one day from the recorded print history and totaling the usage frequency for each unit time zone;
A control step of executing an image stabilization operation in a unit time zone having a low usage frequency in the usage time zone determined in the counting step,
The counting step includes
In the aggregated usage time zone, including a prohibited time zone determination step for determining a unit time zone having the maximum usage frequency as a prohibited time zone,
The control step includes
In the time zone before the prohibited time zone, the cumulative number of prints from the execution of the previous image stabilization operation until the end of the prohibited time zone is counted in the print history and the previous prohibited time zone. If the predicted number of prints is equal to or greater than a predetermined number of prints as an image stabilization operation execution interval, the estimated time An image forming method, wherein an image stabilization operation is executed in a previous time zone, and an image stabilization operation is not executed in the prohibited time zone.

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