JP4844594B2 - Image forming apparatus and image stabilization method in image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus and an image stabilization method in the image forming apparatus, and more particularly to a configuration including a control unit having a relatively long startup time.

  In the field of image forming apparatuses, a control unit (hereinafter also referred to as a “printer control unit”) that executes a user interface and various applications for the purpose of reducing costs and standardizing operability between a plurality of models. In many cases, a common configuration is adopted. On the other hand, since the configuration of the print engine for performing various image forming processes is usually different for each model, in addition to the printer control unit as described above, a dedicated control unit for controlling the print engine (Hereinafter also referred to as “engine control unit”). These two controllers provide image forming processing in cooperation with each other.

  By the way, with recent advances in digital technology and network technology, processing functions in image forming apparatuses such as MFPs (Multiple Function Peripherals; hereinafter also referred to as “MFPs”) and printers have become more sophisticated and complicated. Yes. For this reason, in a control unit (in particular, the above-described printer control unit) that controls the image forming apparatus, functions are being enhanced so as to cope with an increase in data related to image processing and networks. As a result, from the time the power is turned on until the control unit is activated, for example, initialization of the internal memory, loading of various programs including the OS (Operating System), and initialization of the interface with peripheral devices, etc. It takes a lot of startup time.

For example, Japanese Unexamined Patent Application Publication No. 2007-133168 (Patent Document 1) discloses a method for returning from an energy saving mode in an image forming apparatus including a controller control unit and an engine control unit. More specifically, Japanese Patent Laid-Open No. 2007-133168 (Patent Document 1) determines a return factor when the controller control unit returns from the energy saving mode, and based on the determined return factor, the writing unit and / or A configuration is disclosed in which a signal indicating whether or not the operation of the reading unit is necessary is output, and the engine control unit determines whether or not the writing unit and / or the reading unit needs to be initialized based on the signal.
JP 2007-133168 A

  By the way, in an image forming apparatus, in order to form a higher quality image, an image stabilization process including cleaning and various adjustments is performed when a predetermined event occurs (typically immediately after power-on). Until now, such image stabilization processing has been realized as joint processing by the above-described printer control unit and engine control unit. Therefore, if an image stabilization process is to be executed immediately after the power is turned on, the start of the image stabilization process has to wait until the start of the printer control unit is completed. For this reason, there has been a problem that it takes a longer time from when the power is turned on to when the image forming process can be performed.

  Japanese Patent Laid-Open No. 2007-133168 (Patent Document 1) merely executes the initialization operation of the writing unit and / or the reading unit when returning from the energy saving mode regardless of the state of the controller control unit. It does not solve the problem that the start of the image stabilization process as described above is delayed.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to enable image forming processing from power-on even when the startup time of a specific control unit is long. An image forming apparatus and an image stabilization method in the image forming apparatus capable of shortening the time required until the time is provided.

An image forming apparatus according to an aspect of the present invention performs an image forming process in cooperation with a print engine for performing an image forming process, a first control unit for controlling the print engine, and the first control unit. The second control unit includes a second controller that takes a long time from turning on to starting up as compared with the time required from turning on the power of the first controller. The print engine includes a photosensitive member, an exposure device for exposing the surface of the photosensitive member to form a latent image, a developing device for supplying toner to the latent image to form a toner image, and a contact with the photosensitive member. An image carrier to which a toner image is transferred, a light intensity sensor for detecting the intensity of reflected light from the surface of the image carrier, and a toner image from the image carrier to paper by an attractive force by an electrostatic field. A transfer portion for transferring to a medium. The first control unit and the second control unit can execute a plurality of types of image stabilization processing including a combination of a plurality of sequences for adjusting the components of the print engine. The first control unit is configured to load and start a program stored in advance. The second control unit determines whether or not it is necessary to execute image stabilization processing when a predetermined event occurs, and determines which type of image stabilization processing is required to perform image stabilization. When it is determined that the process needs to be executed, a sequence that can be executed independently by the first control unit is selected and executed from the plurality of sequences of the image stabilization process of the type determined to be required, Subsequently, the second control unit determines whether or not been started, if not the already activated second control unit, and waits for the sequence, the second control unit if already started, is necessary Among the plurality of sequences of the image stabilization processing of the type determined as “”, a sequence that requires joint execution with the second control unit is executed.

Good Mashiku, the first control unit, alone executable sequence, based on the output value of the intensity sensor which detects the surface of the carrier in a state where the toner image is not present, adjust the sensitivity of the intensity sensors .

More preferably , the first control unit operates the exposure device based on the data of the reference density image received from the second control unit, and develops the latent image formed on the surface of the photoconductor by the operation of the exposure device. It was allowed to feed the toner to form a toner image, that after, based on the density of the toner image transferred to the carrier, for adjusting the amount of light from the exposure device.

Preferably , the first control unit adjusts a voltage for generating an attractive force in the transfer unit as a sequence that can be independently executed.

Preferably, the print engine includes a cleaning mechanism for cleaning a transfer unit that transfers the toner image to the paper medium, and the first control unit cleans the transfer unit by the cleaning mechanism as a sequence that can be executed independently.

According to another aspect of the present invention, an image stabilization method in an image forming apparatus is provided. An image forming apparatus performs image forming processing in cooperation with a print engine for performing image forming processing, a first control unit for controlling the print engine, and the first control unit, and is required from power-on to startup. The second control unit includes a second control unit whose time is longer than the time required for the first control unit to be powered on and started. The print engine includes a photosensitive member, an exposure device for exposing the surface of the photosensitive member to form a latent image, a developing device for supplying toner to the latent image to form a toner image, and a contact with the photosensitive member. An image carrier to which a toner image is transferred, a light intensity sensor for detecting the intensity of reflected light from the surface of the image carrier, and a toner image from the image carrier to paper by an attractive force by an electrostatic field. A transfer portion for transferring to a medium. The first control unit and the second control unit can execute a plurality of types of image stabilization processing including a combination of a plurality of sequences for adjusting the components of the print engine. In the image stabilization method, the second control unit loads a program stored in advance to be activated, and whether or not the first control unit needs to execute image stabilization processing when a predetermined event occurs. And a step of determining, by the first control unit, which type of image stabilization processing is to be performed when it is determined that the image stabilization processing needs to be performed. A step of selecting and executing a sequence that can be independently executed by the first control unit from among a plurality of sequences of image stabilization processing of the type determined to be present, and determining whether or not the second control unit has been activated. to the step, the second control unit is not a already started, and waits for the sequence, if already second control unit is started, the type is determined to be necessary image stabilization processing of multiple sequences 2nd control part And performing the joint execution is required sequence.
Preferably, the first control unit adjusts the sensitivity of the light intensity sensor as an independently executable sequence based on the output value of the light intensity sensor that detects the surface of the image carrier in the absence of the toner image. The method further includes the step of:
More preferably, the first control unit operates the exposure apparatus based on the reference density image data received from the second control unit, and the latent image formed on the surface of the photoconductor by the operation of the exposure apparatus. Supplying toner from the developing device to form a toner image, and then adjusting the amount of light from the exposure device based on the density of the toner image transferred to the image carrier.
Preferably, the first control unit further includes a step of adjusting a voltage for generating an attractive force in the transfer unit as a sequence that can be executed independently.
Preferably, the print engine includes a cleaning mechanism for cleaning the transfer unit that transfers the toner image to the paper medium, and the first control unit performs the step of cleaning the transfer unit by the cleaning mechanism as a sequence that can be independently executed. In addition.

  According to the present invention, even when the startup time of a specific control unit is long, the image forming apparatus and the image forming apparatus capable of shortening the time required from when the power is turned on until the image forming process is enabled Stabilization method can be realized.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

<Device configuration>
The image forming apparatus according to the present invention has an electrophotographic image forming function (monochrome and / or color). In this embodiment described below, as a representative example of the image forming apparatus according to the present invention, in addition to a copying function and a printer function using an image forming function, a plurality of functions such as a FAX transmission function and an image reading function are provided. A multi-function peripheral (Multi Function Peripheral: hereinafter also referred to as “MFP”) will be described.

  FIG. 1 is a schematic diagram showing a schematic overall hardware configuration in MFP 1 according to the present embodiment. FIG. 1 also shows control information given to the MFP 1 and sensor information detected by various sensors. FIG. 2 is a schematic diagram showing a hardware configuration for realizing a control function in MFP 1 according to the present embodiment.

Referring to FIG. 1, MFP 1 includes a scanner unit 2 and a print engine 3.
The scanner unit 2 reads image information from a document and generates read data. Specifically, the scanner unit 2 irradiates light from a light source toward a document placed on a platen glass and receives light reflected from the document by an image sensor or the like, thereby reading image information of the document. . Alternatively, the scanner unit 2 may include a document feeding table, a sending roller, a registration roller, a transport drum, and a sheet discharging table so as to enable continuous document reading. Data read by the scanner unit 2 is stored in a RAM (Random Access Memory), an HDD (Hard Disk), or the like, which will be described later.

  The print engine 3 uses the read data read by the scanner unit 2, print data received via a network (not shown), image data such as FAX data received via a telephone line, etc. An image forming process is performed on a paper medium. FIG. 1 typically shows the configuration of a tandem color electrophotographic system, but a monochrome electrophotographic system configuration or a 4-cycle color electrophotographic system configuration can also be employed.

  More specifically, the print engine 3 includes four imaging units (imaging units) 20Y, 20M, and 20M that form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively. 20C, 20K (hereinafter also collectively referred to as “imaging unit 20”). The imaging units 20Y, 20M, 20C, and 20K are arranged in the moving direction of the transfer belt 4 in that order. Each imaging unit 20 sequentially forms toner images of each color on the transfer belt 4 in synchronization with the timing. The transfer belt 4 is an image carrier that holds a toner image on the surface thereof, and when the transfer belt 4 goes around each imaging unit 20, a full-color toner image is formed on the surface.

  Thereafter, the full-color toner image formed on the transfer belt 4 is transferred to the recording sheet S by the transfer roller 5. The transfer roller 5 is biased to a predetermined potential. Due to this bias potential, the charged toner image is attracted by an electrostatic field. That is, the toner image is transferred from the transfer belt 4 to the recording sheet S using the suction force generated in the toner image. The recording sheet S on which the color toner image is transferred is fixed by the fixing device 6 and then output to the discharge tray.

  In addition, a cleaning mechanism 38 is provided for cleaning a toner image that is disposed in the vicinity of the transfer roller 5 and remains on the surface of the transfer roller 5. The cleaning mechanism 38 cleans the surface of the transfer roller 5 as part of an image stabilization process described later.

  Between the imaging unit 20K of the transfer belt 4 and the transfer roller 5, an IDC (Image Density Control) sensor 35 for detecting the amount of toner image formed on the transfer belt 4 is disposed. The That is, the IDC sensor 35 detects the density of the image formed on the recording sheet S. The IDC sensor 35 is a light intensity sensor typically composed of a reflective photosensor, and detects the intensity of reflected light from the surface of the transfer belt 4.

  The imaging units 20Y, 20M, 20C, and 20K are photosensitive drums 21Y, 21M, 21C, and 21K (hereinafter also collectively referred to as “photosensitive drum 21”) for forming toner images of respective colors according to image data. Includes each. The frequently used black photosensitive drum 21K is slightly larger than the other photosensitive drums 21Y, 21M, and 21C so as to have a relatively long life. In each imaging unit 20, a charging device, an exposure device, a developing device, a charge removal device, and the like are arranged along the rotation direction of the photosensitive drum 21. The photosensitive drum 21 is exposed by an exposure device with its surface charged in advance by a charging device. The exposure apparatus includes a laser diode 34 as an exposure source, and scans the surface of the photoconductive drum 21 with laser light according to image data, thereby forming an electrostatic latent image according to the image data on the surface of the photoconductive drum 21. Form. The electrostatic latent image is developed as a toner image by attaching toner supplied by a developing device. Then, the toner image developed on the surface of the photosensitive drum 21 is transferred from each photosensitive drum 21 to the transfer belt 4 by contact between each photosensitive drum 21 and the transfer belt 4. FIG. 1 schematically shows one laser diode 34, but actually, an exposure apparatus including the laser diode 34 is disposed in each of the imaging units 20.

  Control information (control command) 12 used in the image forming process as described above includes secondary transfer output, charging grid output, development bias output, LD (laser diode) light quantity, gamma correction data, color misregistration correction amount, gamma. There is a correction table. Of these pieces of information, the secondary transfer output, charging grid output, development bias output, color misregistration correction amount, and gamma correction table are stored in advance in the backup memory 29 (FIG. 2).

  The secondary transfer output is information that determines the magnitude of the bias potential when transferred from the transfer belt 4 to the recording sheet S by the transfer roller 5. By adjusting the magnitude of the secondary transfer output, the amount of toner that is not transferred to the recording sheet S and remains on the transfer belt 4 is optimized.

  The charging grid output is information for adjusting the charge amount on the surface of each photosensitive drum 21. The development bias output is information for adjusting the toner charge amount in the development device. The LD light quantity is information for adjusting the intensity of the laser light emitted from the laser diode 34 of the exposure apparatus. By adjusting the size of the charging grid output, the developing bias output, and the LD light amount, the density (attachment amount) of the toner image formed on the surface of the photosensitive drum 21 is optimized.

  In order to correct the non-linear relationship between the tone value of the image data and the density of the toner image actually formed, a gamma correction (tone correction) table is acquired in advance. With reference to this gamma correction table, gamma correction (gradation correction) data for correcting the intensity of the laser beam corresponding to each dot of the toner image is calculated.

  The color misregistration correction amount is information for adjusting the timing at which the imaging units 20Y, 20M, 20C, and 20K form each color toner image on the transfer belt 4.

  Each parameter of the control information 12 as described above is adjusted or determined by an image stabilization process described later.

  The sensor information 10 detected by various sensors in the image forming process as described above includes CCD read data, IDC sensor input, temperature / humidity sensor input, PH (Print Head) temperature sensor input, and the like.

  The CCD read data is image data read from a document by the scanner unit 2 described above. The IDC sensor input is density data detected by the IDC sensor 35 described above. The temperature / humidity sensor input is information on temperature and humidity detected by the temperature / humidity sensor 36 disposed in the MFP 1. The PH temperature sensor input is information on the temperature detected by the PH temperature sensor 37 (FIG. 2) disposed in the vicinity of the imaging unit 20.

  Next, a control structure for realizing each control function including an image forming process and an image stabilization process will be described.

  Referring to FIG. 2, MFP 1 includes an engine control unit 30, a printer control unit 40, and an engine activation unit 50. The engine control unit 30 and the printer control unit 40 are connected via an image bus, and image data for image forming processing is transmitted via the image bus. Further, the engine control unit 30 and the printer control unit 40 are also connected via a serial communication line, and various control commands other than the above-described image data are transmitted to each other.

  The engine control unit 30 includes a charging grid high-voltage power supply 31, a development bias high-voltage power supply 32, a secondary transfer high-voltage power supply 33, a laser diode 34, an IDC sensor 35, a temperature / humidity sensor 36, a PH temperature sensor 37, It is connected to the cleaning mechanism 38 and controls the print engine including these.

  The charging grid high-voltage power supply 31 is a power supply that supplies a bias voltage for charging the photosensitive drum 21 by the charging device, and outputs a voltage value according to a command (charging grid output) from the engine control unit 30. The development bias high-voltage power supply 32 is a power supply that supplies a bias voltage for the developing device to charge the toner, and outputs a voltage value according to a command (development bias output) from the engine control unit 30. The secondary transfer high-voltage power supply is a power supply that supplies a voltage for biasing the transfer roller 5 (FIG. 2), and outputs a voltage value according to a command (secondary transfer output) from the engine control unit 30.

  As described above, the laser diode 34 constitutes an exposure apparatus and irradiates laser light having an intensity corresponding to the gradation value of each pixel of image data supplied from the printer control unit 40 to the engine control unit 30.

  The cleaning mechanism 38 cleans the surface of the transfer roller 5 in accordance with a command from the engine control unit 30.

  In addition, the engine control unit 30 receives information detected by the IDC sensor 35, the temperature / humidity sensor 36, and the PH temperature sensor 37 as inputs.

  Further, the engine control unit 30 is connected to a backup memory 29 capable of storing data in a nonvolatile manner, writes an adjustment result obtained after the execution of the image stabilization process to the backup memory 29, and performs the image stabilization process. At the start, the adjustment result of the previous image stabilization process is read from the backup memory 29.

  The engine activation unit 50 is a circuit for enabling (ACTIVE) / invalidating (IN_ACTIVE) the engine control unit 30 according to the power-on state and the activation state of the printer control unit 40. More specifically, the engine activation unit 50 is turned on to the MFP 1 and, as long as the entire system is normal, ACTIVE / Motion_EN is output. Upon receiving this signal, the engine control unit 30 is activated. The

FIG. 3 is a diagram showing a more detailed configuration of engine activation unit 50 according to the present embodiment.
Referring to FIG. 3A, engine activation unit 50 includes an OR circuit 502, a selector 504, and an AND circuit 506. The OR circuit 502 receives / safety SW and / power ON. The / safety SW is a signal that bears a fail-safe function for stopping processing when an abnormality occurs in the entire system including the print engine 3. Specifically, the / safety SW is set to “L” as long as the entire system including the print engine 3 is normal, and is set to “H” when any abnormality occurs. For this reason, the logical sum circuit 502 outputs “L” when / safety SW is “L” and / power ON is “L”.

  The selector 504 receives the output of the OR circuit 502 and the constant “H” as the A input and the B input, respectively. Then, / Boot activation indicating the activation state of the printer control unit 40 is input as the SEL signal. That is, if the printer control unit 40 is not activated, the selector 504 outputs the output value of the OR circuit 502 that is an A input, and if the printer control unit 40 is activated, the B input is always “ H "is output.

  The AND circuit 506 receives the output of the selector 504 and / Boot activation. For this reason, the logical product circuit 506 outputs “L” as an output value when either the output of the selector 504 or / Boot activation is “L”.

  The time waveform of each signal obtained by these circuit configurations is as shown in FIG.

  Referring to FIG. 3B, when the power is turned on, / power ON changes from “H” to “L”. At the same time, when the activation process in the printer control unit 40 is started, the / Boot activation changes from “L” to “H”. At this time, / Motion_EN remains “H” (IN_ACTIVE). Thereafter, when the system check is completed and it is determined that the entire system is normal, the / safety SW transitions from “H” to “L”. Along with this transition, / Motion_EN transitions from “H” to “L” (ACTIVE). Then, / Motion_EN is maintained at “L” (ACTIVE) independently of the completion of activation of the printer control unit 40. While this / Motion_EN is “L”, the printer control unit 40 is enabled.

  Referring again to FIG. 2, the printer control unit 40 is connected to the RAM 44, HDD 45, scanner unit 2, FAXIF (interface) 46, operation panel 47, and network IF (interface) 48. The printer control unit 40 displays a user interface screen on the operation panel 47, executes various processes according to user operations from the operation panel 47, transmits / receives a FAX via the FAX IF 46, and other devices (typically, a network IF 48). Executes various applications such as data communication with a personal computer (PC). Such various applications include a process of transmitting image data to the engine control unit 30.

  The printer control unit 40 includes a CPU (Central Processing Unit) 40a, a work memory 40b, and a boot ROM (Read Only Memory) 40c, which are bus-connected to each other. When the power is turned on or when returning from the sleep mode (power saving mode), the CPU 40a loads the program stored in the boot ROM 40c into the work memory 40b and develops the program in the work memory 40b, so that the printer control unit 40 performs the system operation. to start. The boot ROM 40c stores an OS (Operating System) and programs for the various applications described above in advance. The boot ROM 40c may be a semiconductor memory such as a flash memory or a magnetic disk such as an HDD.

  When the printer control unit 40 starts up the system, in addition to loading the above-described program, the work memory 40b is initialized, and the interfaces between the scanner unit 2, the FAX IF 46, the operation panel 47, and the network IF 48 are initialized. Is executed. Therefore, in MFP 1 according to the present embodiment, the time required for printer control unit 40 to start up the system after power-on or the like is longer than the time required for engine control unit 30 to start up the system.

  The RAM 44 and the HDD 45 are memories capable of temporarily storing image data used for image forming processing, and the printer control unit 40 writes image data and reads image data.

  The FAXIF 46 is a communication unit for transmitting / receiving FAX data via a telephone line (not shown). The network IF 48 is a communication unit for performing data communication with a personal computer PC or the like via a LAN (Local Area Network) or the like.

  The operation panel 47 typically includes a touch panel and push button keys, and accepts user operations and displays various information such as a menu screen to the user.

<Determining the necessity of image stabilization processing>
The image stabilization process is a process executed by the print engine in order to form a higher quality image, and includes cleaning of each part and various adjustments. Such image stabilization processing is performed when the engine control unit 30 generates a predetermined event (for example, immediately after turning on the power, when returning from the sleep mode (power saving mode), or when the print engine cover is opened or closed). This is executed when it is determined that it is necessary. Further, the engine control unit 30 appropriately selects the processing content of the image stabilization processing according to the state of the MFP 1.

  More specifically, which processing content is executed as the image stabilization processing is determined based on a plurality of factors as described below.

  FIG. 4 shows a relationship between each factor and the type of image stabilization processing in MFP 1 according to the present embodiment. FIG. 5 is a diagram schematically showing logic for determining an environmental change among the factors shown in FIG. FIG. 6 is a diagram showing a sequence (processing) of each processing content of the image stabilization processing in MFP 1 according to the present embodiment.

  Referring to FIG. 4, engine control unit 30 determines whether MFP 1 corresponds to states 1 to 9 based on the factors (1) to (7), and if necessary, corresponding image stabilization. Execute the conversion process. The specific contents of the image stabilization determination process by the engine control unit 30 will be described below.

  When a predetermined event occurs, the engine control unit 30 first determines (1) whether the imaging unit 20 and / or the transfer belt 4 are new (immediately after replacement). This is because when the imaging unit 20 and the transfer belt 4 are replaced, the image forming process conditions change accordingly, and this is a factor that is determined most preferentially. Here, when it is determined that the imaging unit 20 or the transfer belt 4 has been replaced, the engine control unit 30 does not determine subsequent factors, and the adjustment obtained in the previous image stabilization process. The result is discarded and the image stabilization process is executed (state 1). In this state 1, stabilization process 1 (new article stabilization) described later is executed. Note that whether or not the imaging unit 20 has been replaced can be determined based on replacement information input by a user or maintenance personnel during replacement work, or an IC chip that stores the identification number of each imaging unit 20 or the like. A determination can also be made based on information from the storage element by adding a storage element.

  On the other hand, if it is determined that neither the imaging unit 20 nor the transfer belt 4 has been replaced, it is determined whether or not (2) the previous image stabilization process was interrupted and ended. This is because it is expected that necessary adjustments are not completely performed when the image stabilization process is terminated halfway. Here, when it is determined that the image stabilization process has been terminated halfway, the engine control unit 30 executes the image stabilization process without determining subsequent factors (state 2). In this state 2, a stabilization process 2 (long + cleaning) described later is executed. Note that whether or not the image stabilization process has been completed is determined based on the previous execution result (flag) of the image stabilization process.

  On the other hand, if it is determined that the image stabilization process has not been completed halfway, (3) a machine activation factor is determined. More specifically, it is determined whether the door of the housing that houses the print engine is started from being opened or closed, or whether the door is started by turning on the power (power ON) or returning from the sleep mode. This is because when the door of the housing that houses the print engine is opened or closed, there is a high possibility that the user has interrupted for a short time, such as JAM processing (for example, paper jam), while the power is turned on or sleeps. This is because, when returning from the mode, there is a long interruption before that and it can be predicted that there is a high possibility that external factors have changed. Therefore, it is preferable to divide the contents of the image stabilization processing according to these factors.

  For this reason, if it is determined that the opening / closing of the door is a machine activation factor, the factor (4) to (6) (external factor) is not determined. From this, it is determined whether the PH temperature has changed by a predetermined threshold value (temperature) Th1 or more.

  On the other hand, when it is determined that the power-on or the return from the sleep mode is a machine activation factor, (4) it is determined whether or not the adjustment result in the previous image stabilization process is abnormal. As an example of the case where the adjustment result in the previous image stabilization process (4) is abnormal, there is a case where printing with a normal density is not possible due to a failure of the imaging unit 20 or the like. (4) If it is determined that the adjustment result in the previous image stabilization process is abnormal, the engine control unit 30 executes the image stabilization process without determining the subsequent factors ( State 5). In this state 5, a stabilization process 4 (long) described later is executed. This is because even if some abnormality has occurred in the previous image stabilization process, there is a possibility that a normal adjustment result can be obtained by performing more precise stabilization process 4 (long). .

  If it is determined that the adjustment result in the previous image stabilization process is normal, (5) the environmental condition has changed by a predetermined threshold (step) Th2 or more from the previous execution of the image stabilization process. It is determined whether or not. This is because the imaging process conditions are greatly affected by the environmental conditions (temperature and humidity) in the machine. This change in the environmental conditions in the machine is determined by the absolute humidity as shown in FIG. That is, as shown in FIG. 5, a plurality of steps are defined in advance based on a two-dimensional relationship between the in-machine temperature and the in-machine humidity. Then, at each timing for determining whether or not the image stabilization process is necessary, it is specified which step is located, and this specified step is changed by a threshold value Th2 (step) or more compared to the previous step. It is determined whether or not.

  If it is determined that the environmental condition has changed greatly by a predetermined threshold value Th2 or more since the previous execution of the image stabilization process, the engine control unit 30 determines the image stability without determining the subsequent factors. The process is executed (state 6). In this state 6, stabilization process 3 (long + ATVC) described later is executed.

  If it is determined that the change in environmental conditions since the previous execution of the image stabilization process is less than the predetermined threshold value Th2, (6) the elapsed time since the last stop of the photosensitive drum 21 is predetermined. It is determined whether or not the threshold value (time) Th3 is greater than or equal to. This is because if the photosensitive drum 21 is in a stopped state and a predetermined threshold time Th3 (for example, 8 hours) or more elapses, a so-called “white spot” is more likely to occur on the photosensitive drum 21. If it is determined that the elapsed time since the most recent stop of the photosensitive drum 21 is equal to or longer than the predetermined threshold time Th3, the engine control unit 30 does not determine the subsequent factors and stabilizes the image. The process is executed (state 7). In this state 7, the stabilization process 4 (long) is executed as in the state 5.

  If it is determined that the elapsed time from the most recent stop of the photosensitive drum 21 is less than the predetermined threshold time Th3, (7) the PH temperature is the predetermined threshold from the previous execution of the image stabilization process. It is determined whether or not the value Th1 or more has changed. This is to determine the possibility of occurrence of minute registration caused by “warping” due to temperature change of the laser diode 34. When it is determined that the PH temperature has changed by a predetermined threshold Th1 or more since the previous execution of the image stabilization process, the engine control unit 30 executes the image stabilization process (state 3 or 8). . In this state 3 or 8, a stabilization process 5 (resist) described later is executed.

  Further, when it is determined that the change in PH temperature since the previous execution of the image stabilization process is less than the predetermined threshold value Th1, the engine control unit 30 does not need to execute the image stabilization process. Therefore, the image stabilization process is not executed (state 4 or 9).

<Each stabilization process>
As described above, in the states 1 to 3 and 5 to 8, it is determined that the image stabilization process is necessary. In these cases, the corresponding process among the stabilization processes 1 to 5 is executed.

  Referring to FIG. 6A, in stabilization processing 1 (stabilization of new products), seven sequences are arranged in the order of IDC sensor correction, Dmax adjustment, LD light amount adjustment, Dmax adjustment, LD light amount adjustment, long resist, and gamma correction. (Processing) is executed.

  Referring to FIG. 6B, in stabilization process 2 (long + cleaning), six sequences (processes) are performed in the order of transfer cleaning, IDC sensor correction, Dmax adjustment, LD light quantity adjustment, long registration, and gamma correction. Executed.

  Referring to FIG. 6C, in stabilization process 3 (long + cleaning), six sequences (processes) are executed in the order of ATVC, IDC sensor correction, Dmax adjustment, LD light quantity adjustment, long registration, and gamma correction. Is done.

  Referring to FIG. 6D, in stabilization process 4 (long), five sequences (processes) are executed in the order of IDC sensor correction, Dmax adjustment, LD light amount adjustment, long registration, and gamma correction.

  Referring to FIG. 6E, in the stabilization process 5 (resist), a simple resist sequence (process) is executed.

  Hereinafter, the contents of each sequence constituting the above-described stabilization process will be described. 6A to 6E, “* (asterisk)” is attached to a sequence (process) that can be independently executed by the engine control unit 30 described later.

(I) IDC Sensor Correction IDC sensor correction is a process for adjusting (calibrating) the initial output of the IDC sensor 35. More specifically, the sensitivity of the IDC sensor 35 is adjusted based on the output value of the IDC sensor 35 that detects the surface of the transfer belt 4 in a state where no toner image exists. That is, the gain and offset of the IDC sensor 35 are adjusted so that the output value from the IDC sensor 35 becomes a predetermined reference value in a state where no toner image is formed on the transfer belt 4. This IDC sensor correction is a sequence that can be executed independently by the engine control unit 30 because it is not necessary to form a toner image.

(Ii) Dmax adjustment Dmax adjustment is based on the relationship between the amount of light irradiated by the laser diode 34 as an exposure source (LD light amount) and the density of the formed toner image, and the maximum value of the amount of light irradiated by the laser diode 34. It is a process to adjust. That is, in the electrophotographic image forming process, the “light quantity” and “dot density” irradiated from the laser diode 34 are changed in order to express multi-level gradation. The Dmax adjustment is a process for adjusting the maximum density (Dmax) for the dots included in the toner image. This Dmax is adjusted based on the formed toner image by forming a toner image according to reference image data (reference density image). Therefore, the engine control unit 30 needs to receive image data serving as a reference from the printer control unit 40. Therefore, the Dmax adjustment is a process that requires joint execution by the engine control unit 30 and the printer control unit 40.

(Iii) LD light quantity adjustment The LD light quantity adjustment is a process of adjusting the correspondence (gradation) between the light quantity of the laser diode 34 and the density of the formed toner image. Specifically, a toner image is formed according to image data having a predetermined dot density, and the amount of light emitted from the laser diode 34 is determined based on the detection result (average density) of the IDC sensor 35 for the formed toner image. Adjusted. As described above, since the LD light amount adjustment needs to receive image data having a predetermined dot density from the printer control unit 40, the LD light amount adjustment needs to be jointly executed by the engine control unit 30 and the printer control unit 40. It is processing.

(Iv) Long resist The long resist is a process (registration correction) for correcting the positional deviation of the toner image formed by each imaging unit 20. Specifically, each imaging unit 20 prints a main scanning detection pattern and a sub-scanning detection pattern on the transfer belt 4, and a toner image printed on the transfer belt 4 is detected by an IDC sensor 35. Based on the result, the registration correction amount is determined. Since this long registration needs to receive the reference image data indicating the main scanning and sub-scanning detection patterns from the printer control unit 40, the long registration is a joint operation between the engine control unit 30 and the printer control unit 40. This is a process that needs to be executed.

(V) Gamma Correction Gamma correction is a process for correcting the nonlinear relationship between the tone value information of the image data given to the engine control unit 30 and the density of the toner image that is actually formed. Specifically, a pattern is printed on the transfer belt 4 based on predetermined gradation (continuously changing gradation value) image data, and the toner image printed on the transfer belt 4 is detected by the IDC sensor 35. Based on the detection result, the gamma (gradation) correction table is updated. This gamma correction table is associated with the gradation value of the image data to be printed (for example, the density value of each pixel expressed by a level of 0 to 255), and the light amount (LD light amount) irradiated by the laser diode 34 and It is a data table which prescribed | regulated the correspondence with dot density (ratio with the dot existence per unit area, and a dot absence). Since the information in the data table needs to be exchanged between the engine control unit 30 and the printer control unit 40, the gamma correction is a process that needs to be jointly executed by the engine control unit 30 and the printer control unit 40.

(Vi) Transfer Cleaning Transfer cleaning is a process in which the cleaning mechanism 38 is operated to clean the surface of the transfer roller 5 (FIG. 1). This transfer cleaning is a sequence that can be executed independently by the engine control unit 30 because it is not necessary to form a toner image.

(Vii) ATVC (Automatic Transfer Voltage Control)
ATVC is a process for adjusting the ability of the transfer roller 5 to transfer a toner image from the transfer belt 4 to the recording sheet S. Specifically, the magnitude of the bias voltage applied to the transfer roller 5, that is, the magnitude of the secondary transfer output given to the secondary transfer high-voltage power supply 33 (FIG. 2) is adjusted. By adjusting the bias voltage, the magnitude of the attractive force caused by the electrostatic field applied to the toner image on the transfer roller 5 is optimized, and the transfer capability is optimized. This ATVC is a sequence that can be executed independently by the engine control unit 30 because it is only necessary to adjust the secondary transfer output supplied to the secondary transfer high-voltage power supply 33.

(Viii) Simple Registration Simple registration is a process for correcting the positional deviation of the toner image formed by each imaging unit 20 with a simpler procedure than the above-described long registration. That is, the simple resist is a process for correcting a minute registration caused mainly by “warping” due to a temperature change of the laser diode 34. Basically, the processing is the same as that of the above-described long resist, but the number of detection patterns and detection locations is reduced, and the processing is completed in a shorter time. This simple registration is a process that needs to be jointly executed by the engine control unit 30 and the printer control unit 40 as in the case of the long registration.

  In each of the image stabilization processes described above, these sequences (i) to (viii) are sequentially executed in the order shown in FIG.

  In the present embodiment, “(i) IDC sensor correction”, “(vi) transfer cleaning”, and “(vii) ATVC” are included as sequences (processes) that can be independently executed by the engine control unit 30.

<Execution Procedure of Prior Image Stabilization Process>
In order to facilitate understanding of the execution procedure of MFP 1 according to the present embodiment, the execution procedure of the image stabilization process in the preceding MFP will be described first. In the present specification, the “preceding MFP” means a preceding MFP having a configuration including the engine control unit 30 and the printer control unit 40 as shown in FIG.

  FIG. 7 is a flowchart showing the execution procedure of the image stabilization process in the preceding MFP. FIG. 7 shows a case where the above-described stabilization process 2 (long + cleaning) is executed as an example of the image stabilization process.

  Referring to FIG. 7, when a predetermined event, for example, power to the MFP is turned on, engine control unit 30 determines whether it is necessary to perform image stabilization (step S100). That is, the engine control unit 30 determines each factor shown in FIG. 4 and specifies which state the current MFP is in. If it is determined that it is not necessary to perform image stabilization (NO in step S100), the image stabilization process ends.

  On the other hand, if it is determined that image stabilization needs to be executed (YES in step S100), engine control unit 30 determines the type of image stabilization process (step S102). That is, it is determined which of the stabilization processes 1 to 5 shown in FIG.

  Subsequently, the engine control unit 30 determines whether or not the printer control unit 40 has been activated (step S104). If the printer control unit 40 has not been activated (NO in step S104), the engine control unit 30 waits for processing until activation of the printer control unit 40 is completed. This is because, as described above, the time required for the printer control unit 40 to start the system after power-on or the like is longer than the time required for the engine control unit 30 to start the system.

  Then, after the printer control unit 40 is activated (YES in step S104), the engine control unit 30 transmits an image stabilization request to the printer control unit 40 (step S106). Information indicating the type of image stabilization processing to be executed by the engine control unit 30 is added to the image stabilization request, and the printer control unit 40 receives an image stabilization process in addition to permitting execution of the image stabilization processing. A pattern image for stabilization is transmitted to the engine control unit 30.

  On the other hand, the engine control unit 30 determines whether or not an image stabilization pattern image has been received from the printer control unit 40 (step S108). If a pattern image for image stabilization has not been received (NO in step S108), the process waits until a pattern image for image stabilization is received.

  When the pattern image for image stabilization is received (YES in step S108), the engine control unit 30 starts execution of image stabilization processing such as steps S110 to S120.

  First, the engine control unit 30 performs transfer cleaning (step S110). Subsequently, the engine control unit 30 executes IDC sensor correction (S112). Next, the engine control unit 30 performs Dmax adjustment (step S114). Next, the engine control unit 30 performs LD light amount adjustment (step S116). Next, the engine control unit 30 executes long registration (step S118). Next, the engine control unit 30 performs gamma correction (step S120).

  When the execution of these image stabilization processes is completed, the engine control unit 30 stores the current MFP state values (in-machine temperature, in-machine humidity, PH unit temperature) in the backup memory 29 (step S122). Further, the engine control unit 30 obtains the adjustment results (IDC sensor correction value, Dmax adjustment value, LD light amount adjustment value, color misregistration correction value, gamma correction table) obtained by executing the image stabilization processing in steps S110 to S120. The data is stored in the backup memory 29 (step S124). In addition, the engine control unit 30 turns on a flag indicating that the execution of the image stabilization process is completed.

  Through the processing as described above, image stabilization processing is executed when a predetermined event occurs. Other image stabilization processing differs only in the processing contents of steps S110 to S120, and the other processing is the same, and therefore detailed description will not be repeated.

<Problems in prior image stabilization processing>
In the processing procedure of the image stabilization process shown in FIG. 7, the process of the engine control unit 30 is waited until the activation of the printer control unit 40 is completed in step S104.

  On the other hand, as shown in FIG. 6 described above, some sequences (processes) constituting the image stabilization process can be executed independently by the engine control unit 30. Therefore, in MFP 1 according to the present embodiment, such a process that can be independently executed by engine control unit 30 is performed in advance before the start of printer control unit 40 is completed, so that when image stabilization processing is performed. The unnecessary waiting time that occurs is reduced.

<Execution Procedure of Image Stabilization Process According to this Embodiment>
FIG. 8 is a flowchart showing an execution procedure of image stabilization processing in MFP 1 according to the present embodiment.

  Referring to FIG. 8, when a predetermined event, for example, power to the MFP is turned on, engine control unit 30 determines whether it is necessary to perform image stabilization (step S200). That is, the engine control unit 30 determines each factor shown in FIG. 4 and specifies which state the current MFP is in. If it is determined that it is not necessary to execute image stabilization (NO in step S200), the image stabilization process ends.

  On the other hand, when it is determined that the image stabilization needs to be executed (YES in step S200), the engine control unit 30 determines the image stabilization processing type (step S202).

  Subsequently, the engine control unit 30 executes processing that can be executed independently by the engine control unit 30 among the types of image stabilization processing determined in step S202 (step S204). If the process that can be independently executed by the engine control unit 30 is not included, no process is performed in step S204.

  When the execution of the process that can be independently executed by the engine control unit 30 is completed, the engine control unit 30 determines whether or not the printer control unit 40 has been activated (step S206). If the printer control unit 40 has not been activated (NO in step S206), the engine control unit 30 waits for processing until the activation of the printer control unit 40 is completed.

  Then, after the printer control unit 40 is activated (YES in step S206), the engine control unit 30 transmits an image stabilization request to the printer control unit 40 (step S208). The image stabilization processing type to be executed by the engine control unit 30 is added to the image stabilization request, and the printer control unit 40 receives an image stabilization process in addition to permission to execute the image stabilization process. The pattern image is transmitted to the engine control unit 30.

  On the other hand, the engine control unit 30 determines whether a pattern image for image stabilization has been received from the printer control unit 40 (step S210). If a pattern image for image stabilization has not been received (NO in step S210), the process waits until a pattern image for image stabilization is received.

  When the pattern image for image stabilization is received (YES in step S210), the engine control unit 30 executes a process that requires joint execution with the printer control unit 40 (step S212).

  When the execution of processing that requires joint execution with the printer control unit 40 is completed, the engine control unit 30 stores the current MFP state values (in-machine temperature, in-machine humidity, PH unit temperature) in the backup memory 29. (Step S214). Further, the engine control unit 30 uses the adjustment results (IDC sensor correction value, Dmax adjustment value, LD light amount adjustment value, color misregistration correction value, gamma correction table) obtained by executing the image stabilization processing in steps S204 and S212. The data is stored in the backup memory 29 (step S216). In addition, the engine control unit 30 turns on a flag indicating that the execution of the image stabilization process is completed.

Through the processing as described above, image stabilization processing is executed when a predetermined event occurs.
As can be seen from a comparison between FIG. 7 and FIG. 8, in the MFP according to the present embodiment, before the activation of the printer control unit 40 is completed, the engine control unit 30 executes a process that can be independently executed in advance. Thus, the unnecessary waiting time is reduced, and the time required from when the power is turned on to when the image forming process (printing) is possible is shortened. Note that the remaining processing of the image stabilization processing, which requires joint execution by the engine control unit 30 and the printer control unit 40, is executed after the printer control unit 40 is activated.

  FIG. 9 is a flowchart showing details of the process in step S204 shown in FIG. FIG. 10 is a flowchart showing details of the process in step S212 shown in FIG. 9 and 10 show an example in which the stabilization process 2 (long + cleaning) described above is executed in correspondence with the processing content shown in FIG. 7 described above.

  Referring to FIG. 9, engine control unit 30 executes transfer cleaning (step S300) and IDC sensor correction (S302) as processing that can be executed independently by engine control unit 30. After executing these processes, the process returns to step S206 in FIG.

  As described above, the processes that can be executed independently by the engine control unit 30 include “IDC sensor correction”, “transfer cleaning”, and “ATVC”. Therefore, the image stabilization determined in step S202 shown in FIG. Depending on the process type, there are combinations of different sequences (processes), or no sequence (process) may be included at all.

  Referring to FIG. 10, the engine control unit 30 performs processing that requires joint execution with the printer control unit 40, and the engine control unit 30 performs Dmax adjustment (step S 400), LD light amount adjustment (step S 402), and long registration. (Step S404), gamma correction (Step S406) is executed. After executing these processes, the process returns to step S214 in FIG.

  Note that the combination of executed sequences (processes) differs depending on the image stabilization process type determined in step S202 shown in FIG.

<Effect in the present embodiment>
FIG. 11 is a time chart relating to the image stabilization processing according to the present embodiment. FIG. 11A shows an image stabilization process in the preceding MFP, and FIG. 11B shows an image stabilization process in MFP 1 according to the present embodiment.

  First, referring to FIG. 11A, when the power is turned on at time t1, the printer control unit 40 executes startup processing such as memory initialization and loading of a program such as an OS. It is assumed that the activation of the printer control unit 40 is completed at time t3. It is assumed that at the time t2 between the time t1 and the time t3, / Motion_EN = ACTIVE is output from the engine starting unit 50, and the engine control unit 30 is in a controllable state.

  Even in such a case, in the preceding MFP, the image stabilization process is not executed unless the activation of the printer control unit 40 is completed. That is, the image stabilization process is started at time t3, which is the completion timing of starting the printer control unit 40. For this reason, it is after time t5 that the preceding MFP is ready for image formation (printing).

  On the other hand, referring to FIG. 11B, in MFP 1 according to the present embodiment, “IDC sensor correction”, which is a sequence (process) that can be independently executed by engine control unit 30 before completion of activation of printer control unit 40. , “Transfer cleaning” and “ATVC” are executed. Then, after time t3 when the activation of the printer control unit 40 is completed, “Dmax adjustment”, “LD light amount adjustment”, “long registration”, and “gamma correction” that require joint execution by the engine control unit 30 and the printer control unit 40. Etc. are executed. As a result, the MFP 1 according to the present embodiment becomes ready for image forming processing (printing) after time t4 earlier than time t5.

  That is, in MFP 1 according to the present embodiment, the waiting time can be shortened by the time difference between time t5 and time t4 as compared to the preceding MFP.

  As described above, according to MFP 1 according to the present embodiment, even when the activation time of a specific control unit (printer control unit 40) is long, the power is turned on until image formation processing is possible. The time required can be shortened.

  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.

FIG. 2 is a schematic diagram showing a schematic overall hardware configuration in an MFP according to the present embodiment. It is a schematic diagram which shows the hardware constitutions for implement | achieving the control function in MFP according to this Embodiment. It is a figure which shows the more detailed structure of the engine starting part according to this Embodiment. It is a figure which shows the relationship between each factor in MFP according to this Embodiment, and the kind of image stabilization process. It is a figure which shows typically the logic for judging an environmental change among the factors shown in FIG. It is a diagram showing a sequence (processing) of each processing content of image stabilization processing in the MFP according to the present embodiment. 6 is a flowchart showing an execution procedure of image stabilization processing in a preceding MFP. It is a flowchart which shows the execution procedure of the image stabilization process in MFP according to this Embodiment. It is a flowchart which shows the detail of a process of step S204 shown in FIG. It is a flowchart which shows the detail of a process of step S212 shown in FIG. It is a time chart which concerns on the image stabilization process according to this Embodiment.

Explanation of symbols

  2 scanner unit, 3 print engine, 4 transfer belt, 5 transfer roller, 6 fixing device, 20, 20Y, 20M, 20C, 20K imaging unit, 21, 21Y, 21M, 21C, 21K photosensitive drum, 29 backup memory, 30 Engine control unit 31 Charging grid high voltage power source 32 Development bias high voltage power source 33 Secondary transfer high voltage power source 34 Laser diode (LD) 35 IDC sensor 36 Temperature / humidity sensor 37 Temperature sensor 38 Cleaning mechanism 40 Printer control Part, 40a CPU, 40b work memory, 40c boot ROM, 47 operation panel, 48 network IF, 50 engine starting part, 502 logical sum circuit, 504 selector, 506 logical product circuit, PC personal computer, S recording sheet G.

Claims (10)

A print engine for performing image forming processing;
A first controller for controlling the print engine;
A second control unit that performs image formation processing in cooperation with the first control unit and takes a long time from power-on to start-up compared to the time required from power-on to start-up of the first control unit; ,
The print engine
A photoreceptor,
An exposure device for exposing the surface of the photoreceptor to form a latent image;
A developing device for supplying toner to the latent image to form a toner image;
An image carrier that is disposed in contact with the photoreceptor and to which the toner image is transferred;
A light intensity sensor for detecting the intensity of reflected light from the surface of the image carrier;
A transfer unit for transferring the toner image from the image carrier to a paper medium by an attractive force by an electrostatic field,
The first control unit and the second control unit can execute a plurality of types of image stabilization processing including a combination of a plurality of sequences for adjusting the components of the print engine.
The second control unit is configured to load and start a prestored program,
The first controller is
Determining whether it is necessary to execute the image stabilization process when a predetermined event occurs, determining which type of image stabilization process is required,
When it is determined that execution of the image stabilization process is necessary, among the plurality of sequences of the type of image stabilization process determined to be necessary, a sequence that can be independently executed by the first control unit Select and execute, and then determine whether the second control unit has been activated,
If the second control unit is not activated, the sequence is set to standby,
If the second control unit is already started, among the plurality of sequences of image stabilization processing it is determined to be necessary the type, to perform a joint run need sequence and the second control unit , Image forming apparatus.   The first control unit, based on an output value of the light intensity sensor that detects the surface of the image carrier in a state where the toner image does not exist, as the independently executable sequence, The image forming apparatus according to claim 1, wherein the sensitivity is adjusted. The first controller is
Operating the exposure apparatus based on the reference density image data received from the second control unit;
A toner image is formed by supplying toner from the developing device to the latent image formed on the surface of the photoconductor by the operation of the exposure device, and then based on the density of the toner image transferred to the image carrier. The image forming apparatus according to claim 1, wherein a light amount from the exposure apparatus is adjusted.   The image forming apparatus according to claim 1, wherein the first control unit adjusts a voltage for generating an attractive force in the transfer unit as the independently executable sequence. The print engine includes a cleaning mechanism for cleaning a transfer portion that transfers a toner image to a paper medium,
The image forming apparatus according to claim 1, wherein the first control unit cleans the transfer unit by the cleaning mechanism as the independently executable sequence. An image stabilization method in an image forming apparatus,
The image forming apparatus includes:
A print engine for performing image forming processing;
A first controller for controlling the print engine;
A second control unit that performs image formation processing in cooperation with the first control unit and takes a long time from power-on to start-up compared to the time required from power-on to start-up of the first control unit; ,
The print engine
A photoreceptor,
An exposure device for exposing the surface of the photoreceptor to form a latent image;
A developing device for supplying toner to the latent image to form a toner image;
An image carrier that is disposed in contact with the photoreceptor and to which the toner image is transferred;
A light intensity sensor for detecting the intensity of reflected light from the surface of the image carrier;
A transfer unit for transferring the toner image from the image carrier to a paper medium by an attractive force by an electrostatic field,
The first control unit and the second control unit can execute a plurality of types of image stabilization processing including a combination of a plurality of sequences for adjusting the components of the print engine.
The image stabilization method includes:
The second controller loading a pre-stored program for activation;
The first control unit determining whether the image stabilization process needs to be executed when a predetermined event occurs;
The first control unit determining which type of image stabilization processing to perform when it is determined that the image stabilization processing needs to be executed;
The first control unit selecting and executing a sequence that can be independently executed by the first control unit from a plurality of sequences of the image stabilization processing of the type determined to be necessary;
Determining whether the first control unit has been activated for the second control unit; and
The first control unit, the if the second controller is not already been started, and waits for the sequence, if the second control unit is already started, image stabilization of the type is determined to be necessary An image stabilization method in an image forming apparatus, comprising: executing a sequence that requires joint execution with the second control unit among a plurality of processing sequences .   Based on an output value of the light intensity sensor that detects the surface of the image carrier in a state where the toner image does not exist as the independently executable sequence, the first control unit The image stabilization method in the image forming apparatus according to claim 6, further comprising a step of adjusting sensitivity. The first control unit operating the exposure apparatus based on reference density image data received from the second control unit;
The first control unit supplies toner from the developing device to the latent image formed on the surface of the photoconductor by the operation of the exposure device to form a toner image, and then transferred to the image carrier. The image stabilizing method in the image forming apparatus according to claim 6, further comprising a step of adjusting a light amount from the exposure device based on a density of a toner image.   The image formation according to any one of claims 6 to 8, further comprising a step of adjusting a voltage for generating an attractive force in the transfer unit as the sequence that can be executed independently by the first control unit. Image stabilization method in apparatus. The print engine includes a cleaning mechanism for cleaning a transfer portion that transfers a toner image to a paper medium,
10. The image stabilization in the image forming apparatus according to claim 6, further comprising a step in which the first control unit cleans the transfer unit by the cleaning mechanism as the independently executable sequence. 10. Method.

Images