JP2012220624A - Image forming apparatus, image forming method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which controls an execution timing for calibration in order not to cause the delay of the execution of print processing as a result of the conflict between the calibration for maintaining the image quality and the print processing.SOLUTION: In order to solve the above problems, the image forming apparatus of the present invention is characterized in having: print means for printing a patch pattern; correction means for correcting the density of an output image using the patch pattern printed by the print means; reception means for receiving an execution request of the correction means; and delay means for delaying the execution of the correction means not responding to the execution request received by the reception means until the image forming apparatus is shifted to a sleep state to reduce power consumption.

Description

  The present invention relates to an image forming apparatus having a calibration function.

  2. Description of the Related Art Conventionally, an image forming apparatus that performs color printing generally incorporates a function for controlling the color reproduction of a printed matter uniformly. This process is generally called a calibration process, and aims to control the gradation characteristics of ink and toner used for printing to a fixed characteristic.

  This calibration is required in an image forming apparatus that applies a so-called electrophotographic process, such as a laser beam printer (hereinafter referred to as LBP). In electrophotography, development is performed by attaching a charged toner (powder ink) to an electrostatic latent image formed by irradiating a photosensitive member with laser light. This image is transferred to a sheet and fixed with heat and pressure. Printing is performed by a print processing method based on the procedure of making the In color LBPs and color copiers, a system is used in which an image drawn with a plurality of colors of toner is once formed on the surface of an intermediate transfer member, which is transferred to a sheet and fixed. Here, for example, yellow toner, magenta toner, cyan toner, and black toner are used as the plurality of color toners. Hereinafter, these toners are expressed as YMCK toners. In the following description, the color LBP is color-printed using YMCK toner, but color printing may be performed with a number of colors different from these four colors.

In such an electrophotographic process, the environmental temperature and the environmental humidity are raised as factors that change the gradation characteristics. The following effects appear in the electrophotographic process due to fluctuations in environmental temperature and humidity.
The state of the electrostatic latent image formed on the photoreceptor changes, and the density of the image produced in the next development process changes.
The charge state of the toner changes and the density of the image produced in the next development process changes.
The transfer rate from the photosensitive drum to the intermediate transfer member changes, and the density of the image formed on the intermediate transfer member changes.
The transfer rate from the intermediate transfer member to the paper changes, and the density of the image formed on the paper changes.
In addition, the fixing temperature changes due to fluctuations in the environmental temperature, and the degree of melting of the toner during fixing changes, so the color development changes.

  As described above, due to variations in environmental temperature and humidity, variations in density characteristics occur in a plurality of steps of the electrophotographic process. Calibration can be positioned as a process for producing a certain color reproduction even when the environmental temperature or humidity varies.

  Next, general calibration will be described in more detail. As described above, LBP includes an intermediate transfer member that forms a color image to be transferred onto a sheet. In the calibration, a plurality of minute regions, called patch patterns, having a predetermined density are formed on the intermediate transfer member.

Then, the density of each patch pattern formed on the intermediate transfer body is read by a density sensor to obtain an actual density characteristic that is a relationship between the read actual density and a specified density, and density conversion for obtaining the density characteristic to be realized Derive properties.
By converting the input density of each color of YMCK according to this density conversion characteristic and using it, the target color can be output.
The patch pattern formed on the intermediate transfer member is erased after being read by the density sensor (see Patent Document 1).

  Further, as described above, the gradation characteristics of electrophotography tend to change as the environmental temperature and humidity change. On the other hand, since calibration is a function for providing stable color reproduction performance against changes in environmental conditions, it is necessary to perform calibration again when changes in environmental temperature and humidity occur. In general, calibration is performed when the temperature inside the apparatus fluctuates when the power is turned on or when continuous printing is performed. In addition, it may be performed when a certain number of sheets have been printed or when a certain period of time has elapsed since the previous calibration.

  On the other hand, if the environmental temperature and humidity fluctuate greatly without performing this calibration for a long time, there is a possibility that the toner will be excessively loaded during printing, and the print medium may be wound around the fixing device. . If this wrapping occurs, the LBP main body may eventually break down. Therefore, it is desirable to perform calibration about once a day to maintain an appropriate concentration.

  Therefore, it can be said that calibration is an indispensable process in order to ensure stable color reproducibility and reduce the risk of failure of the main body. However, when the calibration is executed, a method of forming a patch on the intermediate transfer member and measuring the density with the density sensor is used, and during that time, the printing process which is the original purpose of the image forming apparatus including the LBP cannot be performed. For this reason, if calibration is performed when the user wants to perform printing, printing may not be performed until calibration is completed, and the user may be kept waiting. Therefore, in recent years, when priority is given to the execution of printing over making color reproducibility constant, users who place importance on being able to print without waiting for the end of calibration have desired improvements in the execution timing of calibration. Yes.

  In order to solve this problem, for example, in Patent Document 2, the printing time and date can be managed / recorded, and the frequency of use of the target image forming apparatus during the day is derived from the recorded data. Then, calibration is performed in accordance with a time when the user is unlikely to execute printing. In addition, even if the calibration should be executed during printing, the calibration is delayed within an allowable range if the usage frequency of the image forming apparatus decreases after a while.

JP 63-208369 A JP 2005-119058

As described above, control is performed by predicting the time when the user is unlikely to execute printing based on the frequency of use of the target image forming apparatus derived from the time information when printing is performed. Do. Then, calibration may be executed at a timing that is not intended by the user.
The control of the calibration execution timing using this prediction is performed based on past data. Therefore, if the time period during which the use frequency of the image forming apparatus decreases is not close, calibration occurs even when the user is printing, causing a problem. In addition, since it is not confirmed whether or not jobs are continuously input, there is a possibility that calibration is executed between jobs.
Accordingly, the present invention provides an image forming apparatus that controls the execution of calibration in a time period that is not predicted as described above, and the timing when there is no problem even if the user has not performed printing for a while and the calibration is performed. For the purpose of provision. Specifically, even when the image forming apparatus receives a calibration execution request from the printer unit, the calibration is not executed in response to the request, and the printer unit is postponed at the timing when the printer unit enters sleep or power-off. Perform calibration.

  In order to solve the above problems, an image forming apparatus according to the present invention includes a printing unit that prints a patch pattern, a correction unit that corrects the density of an image output using the patch pattern printed by the printing unit, and the correction. The receiving means for receiving the execution request of the means, and even if the execution request is received by the receiving means, the execution of the correcting means is postponed until the sleep state is entered to reduce power consumption without responding to the execution request. And postponing means.

  Even if there is a calibration execution request, the calibration is postponed without executing calibration. Then, the calibration postponed when part of the image forming apparatus shifts to sleep or power off is executed. This prevents the printing process and calibration from competing. Therefore, it is possible to reduce the possibility that calibration is executed and the user waits for printing when the user wants to print.

2 is a diagram illustrating a hardware configuration example of an image forming apparatus. FIG. 1 is a diagram illustrating a vertical cross section of a schematic configuration of an image forming apparatus. 3 is an example of a flowchart for explaining calibration execution control according to the first embodiment. 12 is an example of a flowchart for explaining calibration execution control according to the second embodiment.

Example 1
FIG. 1 is a diagram illustrating a hardware configuration example of an image forming apparatus that is an LBP. The image forming apparatus 100 includes a controller unit 113 and a printer unit 114. The controller unit 113 controls the entire image forming apparatus 100. That is, the control method of the image forming apparatus 100 and the computer program thereof according to the present embodiment can be realized by the function of the controller unit 113. The controller unit 113 instructs the printer unit 114 to execute image data print processing. In addition, the controller unit 113 acquires information indicating the state of the image forming apparatus 100 from the printer unit 114. The information indicating the state of the image forming apparatus 100 includes, for example, information indicating that the image forming apparatus 100 needs to be calibrated (hereinafter referred to as a calibration execution request).

More specifically, the printer unit 114 includes a sensor that detects environmental fluctuations in temperature and humidity and an integrated amount of the number of sheets used for printing.
When this sensor detects a predetermined environmental change or the accumulated amount of sheets, the information is transmitted to a controller (not shown) of the printer unit 114, and the printer unit 114 needs to execute calibration. Judge. Further, a controller (not shown) included in the printer unit 114 counts time, and the printer unit 114 determines that it is necessary to execute calibration even when a predetermined time has elapsed. Then, the printer unit transmits a calibration execution request to the controller unit 113. The information indicating the state of the image forming apparatus 100 includes, for example, information indicating that the image forming apparatus 100 is in a printing state or a printing completion state, and information indicating that the image forming apparatus 100 is in a sleep state. The controller unit 113 transmits a sleep shift instruction to the printer unit 114 when the printer unit 114 continues to accept printing processing during printing for a preset time, not during printing.

  When the printer unit 114 receives a sleep shift instruction from the controller unit 113, the printer unit 114 shifts to a sleep state. Here, the sleep state is a state in which the power consumption of a part of the circuit constituting the printer unit 114 is not supplied and the power consumption is reduced. If the controller unit 113 executes printing, calibration, or the like when the printer unit 114 is sleeping, the controller unit 113 transmits a sleep return instruction to the printer unit 114 before the execution. In this embodiment, since the controller unit 113 and the printer unit 114 can communicate even in the sleep state, the sleep can be recovered by transmitting a sleep recovery command. In the case of an image forming apparatus that does not supply power to the portion that communicates with the controller unit 113 in the sleep state, for example, a signal for entering / returning to sleep is provided, and the signal is used to instruct the return from sleep. It may be. When the printer unit 114 receives a sleep return instruction from the controller unit 113, the printer unit 114 cancels the sleep state. When the controller unit 113 issues a printing or calibration execution instruction when the printer unit 114 is not in the sleep state, the printer unit 114 executes processing according to the instruction. That is, the controller unit 113 and the printer unit 114 function as printing and calibration execution units in cooperation with each other.

The controller unit 113 includes a CPU 101, a flash ROM (Read Only Memory) 102, and a RAM 103. The controller unit 113 includes an NVMEM (Non-Volatile Memory) 104, a LAN I / F 111, an Image Bus I / F 107, and a USB I / F 106. The controller unit 113 includes a RIP (Raster Image Processor) 108, a printer I / F 110, and an image processing unit 109.
The CPU 101 is a processor that controls the entire controller unit 113. A RAM 103 is a system work memory for the CPU 101 to operate. The RAM 103 is also a program memory for recording a program and an image memory for temporarily recording image data. The NVMEM 104 is a non-volatile memory and records setting information and the like. The Flash ROM 102 is a rewritable nonvolatile memory. Various control programs for controlling the image forming apparatus 100 are recorded in the Flash ROM 102 in advance. The USB I / F 107 enables USB connection with a PC (not shown). The LAN I / F 111 enables LAN connection with a PC (not shown). The Image Bus I / F 107 is a bus bridge that connects the system bus 105 and an image bus 112 that transfers image data at high speed and converts the data structure. The CPU 101 to USB I / F 106 are disposed on the system bus 105.

  The image bus 112 includes a Peripheral Component Interconnect (PCI) bus or IEEE1394. The RIP 108, the printer I / F 110, and the image processing unit 109 are arranged on the image bus 112. The RIP 108 expands vector data such as a PDL (Page Description Language) code into bitmap image data (raster image data). The printer I / F 110 connects the printer unit 114 and the controller unit 113, and performs synchronous / asynchronous conversion of image data and data exchange. An image processing unit 109 corrects, processes, and edits input image data, and performs correction, resolution conversion, and the like on an image forming apparatus for print output image data. The image processing unit 109 performs image data rotation and compression / decompression processing such as JPEG for multi-valued image data and JBIG, MMR, MH, etc. for binary image data.

  The panel unit 115 is a part for a user to input for operating the image forming apparatus 100, and can issue a calibration execution instruction and the like. The panel unit 115 may include a display unit such as an LCD showing the contents input by the user and the state of the image forming apparatus 100. In this embodiment, the panel unit is described as a user interface unit on the image forming apparatus 100. However, an application on a PC (not shown) connected to the image forming apparatus 100 may be used.

  The printer unit 114 converts raster image data developed by the RIP 108 into an image on paper. The printer unit 114 converts raster image data into an image on a sheet of paper, an electrophotographic method using a photosensitive drum or a photosensitive belt, or ejects ink from a micro nozzle array to print an image directly on a sheet. There is an ink jet method. The printer unit 114 may use any of these methods. The printer unit 114 starts the printing operation in response to an instruction from the CPU 101.

  FIG. 2 is an outline of the overall configuration of the image forming apparatus 100 controlled using the hardware calibration shown in FIG. In the following description, the first station is a station for forming a yellow (Y) toner image, and the second station is a station for forming a magenta (M) toner image. Further, the third station is a cyan (C) color toner image forming station, and the fourth station is a black (K) color toner image forming station.

However, the present invention is not limited to these colors, and printing may be performed with a number of colors different from these four colors. Of course, printing may be performed using only a single black (K) toner.
In addition, an example in which toner is used as a recording agent will be described. However, the present invention is not limited to this, and can be used when an image processing apparatus such as an ink or solid ink such as an LBP or a printer that can realize this embodiment performs printing. Anything can be used.

(Image forming part)
In the first station, 1a is an OPC (organic photoconductor) photosensitive drum as an image carrier. The photosensitive drum 1a is formed by laminating a plurality of functional organic materials including a carrier generation layer that generates a charge by exposure on a metal cylinder, a charge transport layer that transports the generated charge, and the outermost layer is an electrical layer. Low conductivity and almost an insulator. The charging roller 2a as a charging unit is in contact with the photosensitive drum 1a and uniformly charges the surface of the photosensitive drum 1a while being driven to rotate as the photosensitive drum 1a rotates (rotated in the direction of the arrow in the figure). The charging roller 2a is connected to a charging bias power source 20a that is a voltage supply unit. Only a DC voltage or a voltage obtained by superimposing an AC voltage on the DC voltage is applied to the charging roller 2a. The surface of the photosensitive drum 1a is uniformly charged to a predetermined potential by generating a discharge in a small air gap on the upstream and downstream side from the contact nip portion between the surface of the charging roller 2a and the photosensitive drum 1a.

  Reference numeral 11a denotes an exposure apparatus as exposure means. The exposure apparatus 11a includes a scanner unit (not shown) or an LED array that scans laser light with a polygon mirror (not shown). Then, the scanning beam 12a modulated based on the image signal is irradiated onto the photosensitive drum 1a (on the image carrier). In this way, by irradiating the scanning beam 12a onto the photosensitive drum 1a, the electrostatic latent image to be output with the yellow toner corresponding to the image information on the surface of the photosensitive drum 1a uniformly charged by the charging roller 2a. Form.

  Next, 8a is a developing unit as developing means. The developing unit 8a stores a nonmagnetic one-component developer 5a (hereinafter simply referred to as toner 5a) that is yellow toner. The developing unit 8a includes a developing roller 4a and a developer application blade 7a. The developing roller 4a is connected to a developing bias power source 21a which is a voltage supply unit, and performs development by applying a developing bias voltage. That is, at the contact nip portion between the developing roller 4a and the photosensitive drum 1a, the photosensitive drum 1a on which the electrostatic latent image is formed is developed by attaching yellow toner, and a toner image as a visible image is formed. The

Reference numeral 3a denotes a cleaning unit for cleaning toner that is not transferred onto the photosensitive drum 1a after primary transfer, which will be described later (also referred to as transfer residual toner). Note that when regularly cleaning, toner is discharged in order to reduce friction between the photosensitive drum 1a and the cleaning blade of the cleaning unit 3a.
The photosensitive drum 1a, the charging roller 2a, the cleaning unit 3a, and the developing unit 8a described above are an integrated process cartridge 9a that is detachable from the image forming apparatus.

Reference numeral 81a denotes a primary transfer roller, which is connected to a primary transfer bias power source 84a that is a voltage supply unit. The primary transfer roller 81a is disposed on the opposite side of the photosensitive drum 1a with an intermediate transfer belt (80) described later interposed therebetween. The toner image formed on the photosensitive drum 1a by the developing unit 8a is nipped and conveyed on a contact nip portion (referred to as a primary transfer portion) between the photosensitive drum 1a and the primary transfer roller 81a on an intermediate transfer belt (80) described later. First, the primary transfer is performed.
Further, a neutralizing member 23a is disposed on the downstream side of the primary transfer roller 81a in the moving direction of the intermediate transfer belt 80.

  The above is the configuration of the first station, and the second, third, and fourth stations have the same configuration, and are denoted by adding the symbols b, c, and d after the same number.

The intermediate transfer belt 80 is supported by three rollers, that is, a secondary transfer counter roller 86, a driving roller 14, and a tension roller 15 as a stretching member, and an appropriate tension is maintained. By driving the drive roller 14, the intermediate transfer belt 80 moves in the forward direction (in the direction of the arrow (clockwise) in the drawing) at substantially the same speed with respect to the photosensitive drums 1a to 1d. In synchronization with the movement of the intermediate transfer belt 80, the primary transfer in the primary transfer portion described above is sequentially performed for each color of yellow, magenta, cyan, and black, and the toner image of each color is superimposed on the intermediate transfer belt 80. A multicolor toner image is obtained. The multicolor toner image primarily transferred onto the intermediate transfer belt 80 is carried and transported to a secondary transfer portion described later.
The driving roller 14, the tension roller 15, the static eliminating member 23a, and the secondary transfer counter roller 86 are electrically grounded.

  A density sensor 90 is provided downstream of the process cartridges 9a to 9d in the intermediate transfer belt moving direction. When calibration is executed, the density of the patch pattern is read by the density sensor 90, and the printer unit 114 reads the actual density described above. Deriving characteristics and density conversion characteristics.

(Feeding department)
When an image is formed from the main cassette 16, the sheet P is separated and fed one by one by the rotation of the cassette pickup roller 17. Then, it is conveyed by the registration roller 18 to a contact portion (referred to as a secondary transfer portion) between the secondary transfer counter roller 86 that is a secondary transfer position and the intermediate transfer belt 80. Here, reference numeral 35 denotes a registration sensor, and the detection result of the registration sensor 35 is used to synchronize the presence or absence of the sheet P and the toner image carried on the intermediate transfer belt 80 in the secondary transfer portion. It is done.

(Sheet conveyance details)
The sheet P fed from the main cassette 16 is conveyed to the secondary transfer unit by the registration roller 18.
The intermediate transfer belt 80 as a toner image carrier constituting the secondary transfer portion is stretched and supported by three rollers, a secondary transfer counter roller 86, a driving roller 14, and a tension roller 15, and all the photosensitive drums 1a. To 1d. The intermediate transfer belt 80 is circulated and moved by the driving roller 14 so that the toner is electrostatically adsorbed on the outer peripheral surface facing the photosensitive drums 1a to 1d. As a result, a multicolor image is formed on the outer periphery of the intermediate transfer belt 80, and the toner image formed on the intermediate transfer belt 80 is conveyed to a contact portion between the secondary transfer roller 82 and the intermediate transfer belt 80, which is the secondary transfer position. Is done.
When the sheet P is conveyed, an electric field is formed on the opposing secondary transfer opposing roller 86 by applying a voltage to the secondary transfer roller 82, and a dielectric is formed between the intermediate transfer belt 80 and the sheet P. Polarization is generated to generate an electrostatic attracting force on both.
The toner image carried on the intermediate transfer belt 80 is collectively transferred onto the sheet P by a secondary transfer roller 82 applied from a secondary transfer bias power source 85 which is a power supply unit. As a result, a multicolor image is formed on the sheet P. Then, the residue (residual toner) that is not transferred onto the sheet P and remains on the intermediate transfer belt 80 is removed from the intermediate transfer belt 80 by the cleaning blade 88.

(Fixing part)
The fixing device 19 as fixing means applies heat and pressure to the image formed on the sheet P to fix the toner image, and has a fixing belt (not shown) and an elastic pressure roller (not shown). The elastic pressure roller sandwiches the fixing belt and forms a fixing nip portion with a predetermined width with a predetermined pressure contact force with a belt guide member (not shown).
In a state where the fixing nip portion rises to a predetermined temperature and is temperature-controlled, the sheet P on which the unfixed toner image conveyed from the image forming portion is formed is between the fixing belt of the fixing nip portion and the elastic pressure roller. The image surface is introduced upward, that is, facing the fixing belt surface. Then, the sheet P is nipped and conveyed along the fixing nip portion together with the fixing belt with the image surface in close contact with the outer surface of the fixing belt at the fixing nip portion.
In the process where the sheet P is nipped and conveyed together with the fixing belt through the fixing nip portion, the sheet P is heated by the fixing belt, and the unfixed toner image on the sheet P is heated and fixed. Then, the sheet P for which the fixing process has been completed is discharged and stacked on the discharge unit 36.

(Toner discharging means)
Further, in the conventional image forming apparatus, when images having a low ratio of the actual print area to the image formable area (hereinafter referred to as print ratio) are continuously formed, the toner stays in the developing unit of the cartridge for a long time and is excessively charged. This is one of the causes of quality degradation of the formed image. Therefore, when it is determined that image formation at a regular or low printing rate has continued, the toner in the developing device is forcibly ejected (hereinafter referred to as toner ejection). The toner discharged on the intermediate transfer belt 80 is scraped off by the cleaning blade 88.

  The calibration execution control in the first embodiment will be described with reference to FIG.

In this calibration, as described in the prior art, a plurality of minute regions having a predetermined density called patch patterns are formed on an intermediate transfer body of an image forming apparatus. Then, the density of each patch pattern formed on the intermediate transfer body is read by a density sensor to obtain an actual density characteristic that is a relationship between the read actual density and a specified density, and density conversion for obtaining the density characteristic to be realized Derive properties.
By converting the input density of each color of YMCK according to this density conversion characteristic and using it, the target color can be output.

  The above processing is performed when calibration is executed.

First, the controller unit 113 confirms whether there is a calibration execution request from the panel unit 115. That is, it is confirmed whether or not there is a calibration execution request from the user. (Step S201). If there is a calibration execution request in step S201, the controller unit checks whether the printer unit 114 is sleeping (step S202). If the user is in sleep at step S202, the controller unit 113 instructs the printer unit 114 to return from sleep because the user desires to perform calibration (step S203). When the printer unit 114 returns from sleep, the controller unit 113 causes the printer unit 114 to execute calibration (steps S204 and S205).

  If there is no calibration execution request in step S201, the controller unit 113 checks whether there is a calibration execution request from the printer unit 114 (step S206). If there is no calibration execution request in step S206, the controller unit 113 ends the calibration execution control process. When there is a calibration execution request in step S206, the controller unit 113 confirms whether the printer unit 114 is sleeping (step S207). If the printer unit 114 is sleeping in step S207, the controller unit 113 does not execute calibration and ends the calibration execution control process.

  On the other hand, if the controller unit 113 is not in the sleep state in step S207, the controller unit 113 receives a calibration execution request from the printer unit 114, but does not respond to the request and performs control so as not to execute (postpone) the calibration (step S208). ). In this calibration postponement process, for example, a condition for the printer unit 114 to notify the controller unit 113 of a calibration execution request during normal times (when not in sleep) (for example, printing a certain number of sheets) is established, and the calibration execution request is received. This is done when This is also performed when the printer unit 114 returns to sleep after a condition that the printer unit 114 notifies the controller unit 113 of a calibration execution request is satisfied, for example, after a certain period of time has elapsed during sleep. That is, control is performed to postpone the execution of the calibration corresponding to the calibration execution request “from the printer unit 114” regardless of when and under what conditions the calibration request is generated.

  As a means for realizing the postponement of the calibration, for example, when the calibration is postponed, information indicating that the calibration is postponed is held in the RAM 103. In this case, when information is held in a volatile memory and the power is turned off, the postponed information is erased. However, since the calibration has not been executed yet, a calibration execution request is notified again from the printer unit 114 after the power is turned on. Therefore, the calibration is not left unexecuted. In the case of an image forming apparatus of a type that does not notify a calibration execution request that has not been executed after the printer unit 114 is turned on, information indicating that the printer unit 114 is postponed may be stored in the NVMEM 104.

While the calibration based on the calibration execution request from the printer unit 114 is postponed in step S208, the controller unit 113 monitors whether the condition for turning the printer unit 114 to sleep or turning off the power is satisfied (step S208). S209). In step S209, when the conditions for putting the printer unit 114 to sleep or turning off the power are satisfied, the controller unit 113 executes the calibration postponed in step S208 (step S210). After executing the calibration in step S210, the controller unit 113 instructs the printer unit 114 to shift to sleep or turn off the power, which is a trigger for the calibration execution, and the printer unit 114 executes it (step S211). If the power SW (not shown) of the image forming apparatus 100 is not a soft switch but a hard switch, calibration cannot be performed before the power is turned off. You may make it do.

  As described above, according to the processing described as the first embodiment, it is possible to execute calibration at a timing when the user clearly does not perform printing, such as at the time of transition to sleep or when the power is turned off. As a result, it is possible to reduce the possibility of a problem that the calibration is being performed when the user is about to perform printing and the user is kept waiting.

  In addition, since the processing described in the first embodiment postpones the execution timing of calibration, the image quality during the postponement of calibration may be slightly deteriorated. Therefore, a mode in which a calibration request from the printer unit is usually executed immediately is set, and a user can be switched to a mode in which the operation of the first embodiment is performed when it is desired to prevent competition between calibration and printing. .

(Example 2)
Next, Example 2 will be described. In the following description of the second embodiment, only differences from the first embodiment will be described.

In the first embodiment, the calibration execution timing is controlled so that the calibration is performed at the timing when the user is not printing as much as possible.
However, in the first embodiment, when the image forming apparatus that has been unused for a long time is used after being turned on, or when the image is returned to sleep after sleeping for a long time, the environmental change or the like significantly occurs. As a result, printing may be performed in a state in which the density characteristic is changed. Further, as described above, if the toner is excessively loaded during printing without performing calibration, it is possible that the fixing device is wound and the image forming apparatus main body is broken. Accordingly, in the second embodiment, a determination is made as to whether or not to perform calibration when the power is turned on or when returning from sleep so that the image quality does not change significantly or the image forming apparatus main body breaks down.

  The calibration execution control in the second embodiment of the present invention will be described with reference to FIG.

  First, the controller unit 113 that has detected that the power SW (not shown) of the image forming apparatus 100 has been turned on checks whether there is a calibration execution request from the printer unit 114 (steps S301 and S302). If there is a calibration execution request in step S302, it is confirmed whether or not a predetermined time (24 hours in the example of FIG. 4) has elapsed since the previous calibration (step S303). For this purpose, the controller unit 113 writes the date and time information of the last execution of calibration into the NVMEM 104. Then, the date and time information stored in the NVMEM 104 is compared with the date and time information when the power is turned on. For the date and time information, a chip (for example, RTC) or a device having a timekeeping function mounted on the image forming apparatus 100 is used. If the image forming apparatus 100 does not have such a function, date information may be acquired from a PC or the like to which the image forming apparatus 100 is connected. Further, the certain time can be set by the user.

  In step S303, when 24 hours or more have elapsed since the previous calibration, calibration is executed and calibration execution date / time information is stored in the NVMEM 104 (steps S304 and S305). If it is determined in step S303 that 24 hours or more have not elapsed since the previous calibration, the calibration execution is postponed (step S306). When the calibration is postponed in step S306, information indicating that the calibration is postponed is held until calibration is executed in any of steps S311, S321, and S325 described later. This information is written in the NVMEM 104 as date / time information.

  If there is no calibration execution request in step S302, nothing is done and the process proceeds to the next process.

  Next, it is confirmed whether or not there is a calibration execution request from the user (step S307). If there is a calibration execution request from the user, if there is a calibration execution request in step S307, it is confirmed whether the printer unit 114 is in sleep (step S308). If the user is in sleep in step S308, the controller unit 113 instructs the printer unit 114 to return from sleep because the user desires to perform calibration (step S309). When the printer unit 114 returns from sleep, the controller unit 113 causes the printer unit 114 to execute calibration (steps S310 and S311). After executing the calibration in step S311, the calibration execution date and time information is stored in the NVMEM 104 (step S312).

  After the calibration execution date / time information is stored in step S312, if the power is not turned off, the process returns to step S307, and if the power is turned off, the calibration execution control is terminated (step S313).

  If there is no calibration execution request in step S307, the controller unit 113 confirms whether there is no scheduled calibration execution request (step S314). The on-time calibration is performed at a specific time set by the user, and the time setting is performed by the panel unit 115. The elapsed time since the previous calibration was performed is calculated using the stored date / time information.

  If there is an on-time calibration execution request in step S314, it is checked whether or not a predetermined time has passed since the previous calibration (step S315). If it is determined in step S315 that a predetermined time or more has elapsed since the previous calibration, it is confirmed whether or not the printer unit 114 is sleeping (step S316). If the printer unit 114 is not in sleep in step S316, calibration is executed and execution date / time information is stored (steps S311 and S312).

  If it is determined in step S315 that the predetermined time or more has not elapsed since the previous calibration, the number of times of calibration is reduced as much as possible, and the calibration is not performed in order not to compete with the user's printing (step S317). Similarly, if the printer unit 114 is in the sleep state in step S316, the calibration is not performed and the process is postponed.

  This is because it is not necessary to perform calibration until returning from sleep unless the user instructs to perform calibration immediately from the panel unit 115. However, since the information indicating that the calibration execution request has been postponed in step S317 is retained, the calibration is performed immediately when the condition that a predetermined time has passed since the last calibration and the device is not in sleep is satisfied. Perform With this process, calibration is performed before the user performs printing, so that printing can be performed without causing a significant deterioration in image quality or failure of the image forming apparatus main body.

  If there is no on-time calibration execution request in step S314, it is confirmed whether there is a calibration execution request from the printer unit 114 (step S318). If there is no calibration execution request in step S318, if the power is not turned off, the process returns to step S307, and if the power is turned off, the calibration execution control is terminated (step S313). If there is a calibration execution request in step S318, the controller unit 113 confirms whether the printer unit 114 is sleeping (step S319).

If the power is not off in step S319, the process returns to step S307, and if the power is off, the calibration execution control is terminated (step S313). Here, since the calibration execution request from the printer unit 114 continues to be notified to the controller unit 113 until the calibration is executed, it is necessary to retain information that the calibration execution has been postponed as in the on-time calibration. There is no. However, in the case of an image forming apparatus of a type in which the printer unit 114 notifies the controller unit 113 of a calibration execution request only once, information that the calibration execution has been postponed may be held.
If the controller unit 113 is not in sleep in step S319, the controller unit 113 ignores the calibration execution request from the printer unit 114, and postpones execution of calibration (step S320). Here, in the example of FIG. 4, the execution of all calibration execution requests from the printer unit 114 is postponed. However, in the case of a calibration execution request caused by component replacement such as CRG or ITB, the image quality may change significantly, so that calibration may be executed.

While the calibration by the calibration execution request from the printer unit 114 is postponed in step S320, the controller unit 113 monitors whether or not the condition for causing the printer unit 114 to sleep is satisfied (step S321). If the condition for causing the printer unit 114 to sleep is satisfied in step S321, the controller unit 113 executes calibration based on the calibration execution request postponed in step S320 (step S322). After execution of calibration in step S322, execution date / time information is stored, the controller unit 113 instructs the printer unit 114 to shift to sleep, and the printer unit 114 executes it (steps S323 and S324).

If the sleep transition condition is not satisfied in step 321, it is confirmed whether the condition for powering off is satisfied (step S 325). If the conditions for turning off the power are not satisfied in step S325, the process returns to step S307 (step S313).

  If the condition for powering off is satisfied in step S325, the controller unit 113 executes calibration based on the calibration execution request postponed in step S320 (step S326). After execution of calibration in step S326, the execution date / time information is stored, the controller unit 113 instructs the printer unit 114 to turn off the power, and the printer unit 114 executes it (steps S327 and S328).

  It should be noted that, as in the first embodiment, the calibration that was postponed only at the time of shifting to the sleep mode may be executed depending on the type of the power supply SW (not shown) of the image forming apparatus 100.

  According to the second embodiment, it is possible not only to prevent the image quality from being greatly deteriorated or to cause the image forming apparatus main body or the engine to fail, but also to maintain the image quality as much as possible. In addition, although the condition that 24 hours or more have passed in S303 and S315 in FIG. 4 is set, calibration is performed by setting conditions such as when a shorter time (for example, 8 hours) has elapsed or after printing a certain number of sheets. Execution frequency can be adjusted.

(Example 3)
Next, Example 3 will be described. In the following description of the third embodiment, only differences from the first and second embodiments will be described. So far, the calibration execution control has been described as normal, in the case of the first embodiment, and in the second embodiment. However, these have independent modes, and the user selects each mode from the panel unit 115. You may be able to do it. By doing so, it is possible to perform calibration execution control in accordance with the intentions of various users.

  Further, the configuration may be such that the user can set the conditions set in S303 and S315 of FIG.

Example 4
So far, in the first, second, and third embodiments, the term “calibration” has been described as meaning density correction. However, in the case of a tandem color image forming apparatus, a process of color misregistration correction is required in addition to the density correction. Similar to the density correction process, the color misregistration correction process also occurs due to a change in the temperature and humidity of the image forming apparatus 100 and a corresponding deflection of the intermediate transfer belt 80. In the case of an image forming apparatus that requires color misregistration correction, the printer unit 114 notifies the controller unit 113 of a color misregistration correction execution request. From the above, if a registration sensor (not shown) is provided alongside the density sensor 90 of FIG. 2, the present embodiment can also be applied to color misregistration correction processing. Therefore, the present embodiment may be configured such that both color misregistration correction and density correction, or each can be applied independently.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

Claims (13)

Printing means for printing the patch pattern;
Correction means for correcting the density of an image output using the patch pattern printed by the printing means;
Receiving means for receiving an execution request of the correcting means;
Even if the execution request is received by the receiving means, the postponement means for postponing the execution of the correction means until shifting to the sleep state in order to reduce power consumption without responding to the execution request;
An image forming apparatus comprising: Printing means for printing the patch pattern;
Correction means for correcting the density of an image output using the patch pattern printed by the printing means;
In order to reduce power consumption, a sleep unit that shifts to a sleep state when a preset condition is satisfied,
Receiving means for receiving an execution request of the correcting means;
A determination means for determining whether a condition for causing the sleep means to enter a sleep state is satisfied;
If the determination means determines that the condition for shifting to the sleep state is not satisfied, even if an execution request is received from the reception means, it is output by the correction means without responding to the execution request. Postpone correction of image density,
When the determination unit determines that the condition for shifting to the sleep state is satisfied, when the execution request is received from the reception unit, the density of the image output by the correction unit in response to the execution request And an image forming apparatus characterized by comprising: When the control means determines that the condition for shifting to the sleep state is satisfied by the determination means and receives an execution request from the reception means, an image output by the correction means in response to the execution request When the correction of the density of the output image is executed,
The image forming apparatus according to claim 2, wherein the sleep unit shifts to a sleep state.   The image forming apparatus according to claim 2, wherein the sleep state is a state for reducing power consumed by the printer unit, and includes a state in which the printer unit is turned off. The conditions for shifting to the sleep state are as follows:
The image forming apparatus according to claim 2, wherein the image forming apparatus is in a state in which a print process can be accepted for a preset time. It further has storage means for storing the execution date and time when the correction means is executed,
Even if it is determined that the condition for shifting to the sleep state is satisfied by the determination means when the execution means is received by the reception means,
The image forming apparatus according to claim 2, wherein the correction by the correction unit is not executed until a predetermined time elapses from the execution date and time stored by the storage unit. A printing step for printing a patch pattern;
A correction step of correcting the density of the image output using the patch pattern printed in the printing step;
A receiving step for receiving an execution request for the correcting step;
Even if the execution request is received by the reception step, the postponement step for postponing the execution of the correction step until shifting to the sleep state in order to reduce power consumption without responding to the execution request;
A method of controlling an image forming apparatus comprising: A printing step for printing a patch pattern;
A correction step of correcting the density of the image output using the patch pattern printed in the printing step;
In order to reduce power consumption, a sleep step that shifts to a sleep state when a preset condition is satisfied,
A receiving step for receiving an execution request for the correcting step;
A determination step of determining whether a condition for causing the sleep step to enter a sleep state is satisfied;
If it is determined in the determination step that the condition for shifting to the sleep state is not satisfied, even if an execution request is received from the reception step, the correction request is output without responding to the execution request. Postpone correction of image density,
When it is determined in the determining step that the condition for shifting to the sleep state is satisfied, when an execution request is received from the receiving step, the density of the image output by the correcting step is received in response to the execution request And a control step for performing correction of the image forming apparatus. In the control step, in the determination step, it is determined that a condition for shifting to the sleep state is satisfied, and when an execution request is received from the reception step, an image output by the correction step according to the execution request When the correction of the density of the output image is executed,
The method for controlling an image forming apparatus according to claim 8, wherein the sleep step is shifted to a sleep state.   The image forming apparatus according to claim 8, wherein the sleep state is a state for reducing power consumed by the printer unit, and includes a state in which the printer unit is turned off. Method. The conditions for shifting to the sleep state are as follows:
9. The method for controlling an image forming apparatus according to claim 8, wherein a state in which the printing process can be accepted continues for a preset time. A storage step of storing the execution date and time when the correction step is executed;
Even if it is determined that the execution request is received by the reception step and the condition for shifting to the sleep state is satisfied by the determination step,
The method for controlling the image forming apparatus according to claim 8, wherein the correction in the correction step is not executed until a predetermined time has elapsed from the execution date and time stored in the storage step.   A program for causing a computer to execute the method for controlling the image forming apparatus according to claim 7.

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