JP2009122487A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve user's convenience and to prolong the life of an imaging unit (consumable member). <P>SOLUTION: The image forming apparatus 1 is provided with: an image stabilization processing part 52 which performs image stabilization processing and determines an image forming condition KJ corresponding to an environmental value KT at that time processing detected by a temperature and humidity sensor 23; a memory 29 in which the determined image forming condition KJ is stored in accordance with the environmental value KT; a retrieval part 53 which retrieves, when a factor to be performed YN arises, whether or not the image forming condition KJ corresponding to the environmental value KT at that time is stored in the memory 29; and a stabilization processing control part 54 which controls an image forming part 55 to form an image by using the retrieved image forming condition KJ without performing the image stabilization processing by the image stabilization processing part 52 when the image forming condition KJ is retrieved, and controls the image stabilization processing part 52 to perform the image stabilization processing when the image forming condition KJ is not retrieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an MFP and a control method thereof.

  In an image forming apparatus that forms an image by an electrophotographic method, such as a copier, a printer, a facsimile machine, a multifunction machine, or a multi-function machine called MFP (Multi Function Peripherals), it is formed on a drum-shaped photoreceptor. The electrostatic latent image is developed to form a toner image, the toner image is primarily transferred to an intermediate transfer belt, and then further transferred to a recording paper, and then fixed, thereby forming an image.

  In such an image forming apparatus, there is an apparatus in which a portion for forming a toner image for each color of Y, M, C, and K is unitized as an imaging unit to facilitate replacement and maintenance. In this case, the imaging units of the respective colors are positioned as independent consumable members (consumables), and are exchanged when the service life is reduced by use. The imaging unit includes a photoreceptor and a developing machine corresponding to each color.

  In such an image forming apparatus, the amount of developer of each color, for example, the amount of toner attached varies depending on the use frequency or use environment in each imaging unit. Therefore, in order to obtain high-quality images, image adjustment (hereinafter referred to as “image stabilization processing”) is performed according to the environmental changes in the image forming apparatus and the frequency of use of each imaging unit, and the image forming process is optimized. (For example, refer patent document 1).

  In the method described in Patent Document 1, color material density information determined by image adjustment is recorded as output characteristic information, and the output characteristic information is used as a reference when determining a target for image adjustment to be performed next time.

  Conventionally, image stabilization processing is performed when the image forming apparatus is turned on, when returning from the energy saving mode, or when the temperature change or humidity change in the apparatus after the previous image stabilization process has exceeded each threshold. Or when the cumulative number of printed sheets exceeds a threshold value.

  Further, in recent years, since the FAX function and the network function are standardly installed in the image forming apparatus, there is a method in which the image forming apparatus is left for a long time in a state where the power of the image forming apparatus is always turned on so that various jobs can be always received. It has become common.

  Generally, in an image forming apparatus, when the unused state continues for a predetermined time or more with the power turned on, the operation mode of the image forming apparatus shifts to the power saving mode. Further, when a printing process (image forming process) is executed after receiving a FAX job or a print job, it is necessary to perform a return operation (image stabilization process) from the power saving mode. As a result, when it is necessary to execute a large amount of the various jobs, many return operations must be performed.

  As described above, since the image stabilization process is performed before the printing process, the user must wait for the image stabilization process. In recent years, fixing devices capable of starting up an image forming apparatus in a short time have become widespread, but the processing time (number of processing times) of image stabilization processing has not been reduced. As a result, the user waiting time is not reduced.

  In addition, the image stabilization process performed when the cumulative number of printed sheets exceeds the threshold value may be excessively performed in order to suppress deterioration of the image forming unit and a change in characteristics due to environmental changes. Is not improved.

Therefore, in order to solve such a problem, the image stabilization process is performed based on the current time information, the time information when the previous image stabilization process is performed, and the time information when the previous print process ends. It has been proposed to prevent the image stabilization processing from being performed wastefully by determining whether or not the image stabilization processing is performed (see, for example, Patent Document 2).
JP-A-2005-297408 JP 2003-167394 A

  However, the method described in Patent Document 1 is intended to improve image quality, and does not reduce image stabilization processing. Therefore, user convenience is not improved.

  In the method described in Patent Document 2, the image stabilization process is performed based on the current time information, the time information when the previous image stabilization process is performed, and the time information when the previous print process ends. For example, even when the user has not used the image forming apparatus at all since the end of the previous printing process, the image stabilization process is performed after a predetermined time has elapsed since the end of the printing process. Therefore, the user's standby time is often not reduced, and the user's convenience is not improved.

  As described above, conventionally, since the image stabilization process is often performed unnecessarily, the convenience for the user is not improved, and the above-described imaging unit (photoconductor, etc.) is consumed when the image stabilization process is performed. Will also be faster.

  SUMMARY OF THE INVENTION In view of such problems, the present invention aims to improve user convenience and extend the life of an imaging unit (consumable member).

  An image forming apparatus according to an aspect of the present invention is an image forming apparatus configured to form an image by an electrophotographic process and perform image stabilization processing when a preset activation factor occurs. An image stabilization processing unit that performs the image stabilization process and determines an image formation condition corresponding to the environment value at that time, and the image formation condition determined by the image stabilization process unit corresponds to the environment value The storage means for storing, and when the activation factor occurs, the search means for searching whether the image forming condition corresponding to the environmental value at that time is stored in the storage means, and the search means When an image forming condition corresponding to the environmental value is retrieved, image formation is performed using the retrieved image forming condition without performing image stabilization processing by the image stabilization processing means. And a stabilization processing control means for controlling the image stabilization processing to be performed by the image stabilization processing means when an image forming condition corresponding to the environmental value is not searched by the search means. And having.

  Preferably, the image forming apparatus includes a photosensitive member, a charging unit that charges the photosensitive member, an exposure unit that forms an electrostatic latent image on the photosensitive member, and a toner that adheres to the photosensitive member to form the electrostatic latent image. A developing unit that develops an image, and the image stabilization processing unit includes at least a light amount of the exposure unit, a voltage value applied to the developing unit, and a voltage value applied to the charging unit. Determine as a condition.

  According to the present invention, user convenience can be improved and the life of the imaging unit can be extended.

  FIG. 1 is a diagram illustrating a schematic internal configuration of an image forming apparatus 1 according to an embodiment of the present invention, FIG. 2 is a diagram illustrating an imaging unit U around a development that is a part of the image forming apparatus 1, and FIG. FIG. 4 is a block diagram showing the functional configuration of the image forming apparatus 1.

  First, an outline of functions of the image forming apparatus 1 will be described. As shown in FIG. 4, the image forming apparatus 1 according to the present embodiment is configured to perform image formation by an electrophotographic process and to perform image stabilization processing when a preset activation factor occurs. The image forming apparatus performs an image stabilization process and determines an image forming condition KJ corresponding to an environmental value (temperature and humidity in the apparatus) KT detected by the temperature / humidity sensor (environment sensor) 23 at that time. An image stabilization processing unit 52 to be executed, a memory 29 for storing the image forming condition KJ determined by the image stabilization processing unit 52 in correspondence with the environment value KT, and an activation factor determination for determining whether an activation factor has occurred. When the activation factors YN1 and YN3 occur and the image forming condition KJ corresponding to the environment value KT at that time is stored in the memory 29, it is checked. When the search unit 53 searches for the image forming condition KJ corresponding to the environment value KT, the searched image forming condition is not performed by the image stabilization processing unit 52. When the image forming unit 55 is controlled to perform image formation using KJ, and the image forming condition KJ corresponding to the environment value KT is not searched by the search unit 53, the image stabilization processing unit 52 performs image stabilization. And a stabilization processing control unit 54 that controls to perform the stabilization processing. In addition, the stabilization process control part 54 has the initialization part 54a mentioned later.

  The functions of the image stabilization processing unit 52, the search unit 53, the stabilization processing control unit 54, the initialization unit 54a, the image forming unit 55, and the activation factor determination unit 56 are executed by the CPU of the engine control unit 30 by executing appropriate programs. By doing so, it is realized by software or in combination with an appropriate hardware circuit. Hereinafter, the image forming apparatus 1 will be described in detail.

  As shown in FIGS. 1 and 2, the image forming apparatus 1 according to the present embodiment mainly includes a scanner unit 2 that reads a document and generates image data, and a print unit 3 that performs printing (image formation) on a recording sheet S. Is provided. This image forming apparatus 1 has a tandem image forming unit (image forming unit 55 in FIG. 4), and uses toner of four colors of yellow (Y), magenta (M), cyan (C), and black (K). A color image is formed by sequentially superimposing.

  The image forming apparatus 1 develops an electrostatic latent image formed on a drum-type photoconductor 11 by exposure by a developing device 13, and the obtained toner image is an intermediate transfer as an image carrier by a primary transfer roller 18. The image is transferred to the belt 14 and further transferred to the recording paper S. As shown in FIG. 1, the frequently used black photoconductor 11K is slightly larger in order to adjust the relative life of the photoconductors 11Y, 11M, and 11C for color images.

  In the image forming apparatus 1, four color imaging units UY, UM, UC, and UK of Y, M, C, and K are arranged in a tandem arrangement, and each color toner image formed by these imaging units U. The (toner image) is superimposed on the intermediate transfer belt 14 and transferred and synthesized. The “imaging unit U” indicates all or part of the “imaging units UY, UM, UC, UK”. The same applies to other elements.

  Further, the image forming apparatus 1 is provided with a print head (exposure unit) PH. The print head PH emits a laser beam modulated by image data from the laser diode 16 to irradiate the photoconductor 11 in order to form an electrostatic latent image on the photoconductor 11. A PH temperature sensor 17 for measuring the temperature in the print head PH is provided in the print head PH.

  Here, as shown in FIG. 2, each imaging unit U is configured by a charging device 12, a developing device 13, a cleaner 15, and the like being arranged in the vicinity of the photoreceptor 11. The surface of the photoconductor 11 is charged to a predetermined voltage (charging potential) V0 by the charging device 12, and an electrostatic latent image is formed by exposure by the print head PH. The electrostatic latent image is obtained by supplying toner charged from the developing roller to a potential gap ΔV between the potential of the electrostatic latent image and the developing bias voltage Vdc by the developing roller to which the developing bias voltage Vdc is applied. An image is formed and visualized.

  The toner image visualized on the surface of the photoreceptor 11 is primarily transferred to the intermediate transfer belt 14 by the primary transfer roller 18. The toner remaining on the photoreceptor 11 is scraped off by the cleaner 15. The toner image on the intermediate transfer belt 14 is secondarily transferred onto the recording sheet S by the secondary transfer roller 19. The recording paper S is fixed by the fixing unit 20 and is discharged onto the paper discharge tray 21 as an electrophotographic image.

  Further, the image forming apparatus 1 is provided with an optical IDC sensor (density detection sensor) 22 that detects the density of the toner image on the intermediate transfer belt 14 (image density at the time of transfer to the recording paper S). . That is, the IDC sensor 22 is a reflection type photosensor that irradiates the surface of the intermediate transfer belt 14 with light and detects the amount of light that is reflected and returned.

  When the density of the toner image on the intermediate transfer belt 14 is low, that is, when the amount of toner on the intermediate transfer belt 14 is low, the amount of light reflected by the intermediate transfer belt 14 is returned to increase and the amount of light increases, that is, when the density of the toner image is high. When there is a large amount of light, the light is blocked by the toner and the amount of reflected light decreases.

  In this way, the IDC sensor 22 confirms the state of the surface of the intermediate transfer belt 14. Depending on the density of the toner image detected by the IDC sensor 22, image adjustment is performed by controlling the light amount KR of the laser diode 16, controlling the developing conditions in the developing device 13, and the like. Actually, the density of each pattern (toner patch) of Y, M, C, and K created for image adjustment is detected.

  The image forming apparatus 1 also includes a temperature / humidity sensor 23 that measures the temperature and relative humidity (humidity) in the apparatus, a developing bias voltage Vdc that is applied to the developing roller of the developing device 13, and a charging bias that is applied to the charging device 12. A high voltage generator 24 that generates the voltage Vg is provided.

  As shown in FIG. 3, the image forming apparatus 1 according to the present embodiment includes an engine control unit 30 and a printer control unit 40 as main components of a control system. The engine control unit 30 and the printer control unit 40 communicate with each other (serial communication). The printer control unit 40 provides image data to the engine control unit 30 via the image bus, and communicates with one or a plurality of terminal devices 50 via the communication line TC. Note that a LAN, the Internet, a public line, a dedicated line, or the like can be used as the communication line TC.

  The engine control unit 30 includes a CPU (central processing unit) and peripheral circuit elements, and applies a charging bias to the charging device 12 based on detection results (measurement results) from the IDC sensor 22, the temperature / humidity sensor 23, and the PH temperature sensor 17. A charging grid high voltage power source 24a for applying the voltage Vg, a developing bias high voltage power source 24b for applying the developing bias voltage Vdc to the developing roller, a secondary transfer high voltage power source 24c for applying a voltage to the secondary transfer roller 19, and a laser diode 16 and the like. Control.

  The engine control unit 30 reads / writes various data from / to a memory 29 including a RAM (a readable / writable memory). The memory 29 stores a database composed of tables which will be described in detail later.

  On the other hand, the printer control unit 40 includes a CPU and peripheral circuit elements, and controls a RAM (Random Access Memory) 41, a hard disk 42, a FAX interface 43, an operation panel 44, and components (not shown) of the scanner unit 2. The RAM 41 is superior in terms of transfer speed, and the hard disk 42 is superior in terms of storage capacity, although inferior to the RAM 41 in terms of transfer speed.

  The FAX interface 43 executes facsimile transmission / reception of image data. The operation panel 48 includes a touch panel and push button keys, and performs various displays and accepts an input operation by a user.

  Next, the activation factor of the image stabilization process performed in this embodiment and the processing content of the image stabilization process will be described.

  FIG. 5 is a diagram for explaining the activation factor YN of the image stabilization process and the implementation content NA of the image stabilization process. As shown in FIG. 5A, the temperature and relative humidity in the apparatus have changed beyond a predetermined range in descending order of priority as the activation factor YN for performing the image stabilization process (first factor YN1). For example, the cumulative number of printed sheets or the rotation time of the photosensitive member 11 has exceeded a threshold (second factor YN2), and the temperature in the print head PH has changed beyond a predetermined range (third factor YN3).

  The reason why the temperature or relative humidity in the apparatus changes is the first factor YN1 because the conditions of the image forming process are greatly influenced by the environment such as the temperature or relative humidity in the apparatus. The reason why the second factor YN2 is that the cumulative number of printed sheets exceeds a threshold value (for example, 1000 sheets) is that a gradation change occurs due to a change in sensitivity characteristics of the photoconductor 11 due to a printing process exceeding the threshold value. The reason why the temperature in the print head PH changes is the third factor YN3 because the change in the temperature causes the laser diode 16 in the print head PH to warp and the registration changes. Thus, the priority of the activation factor YN is set in descending order of the degree of influence on the image.

  In this embodiment, when the first factor YN1 occurs, the long stabilization process may be performed as the image stabilization process, and when the second factor YN2 occurs, the short stabilization process as the image stabilization process. When the third factor YN3 occurs, a registration correction process may be performed as an image stabilization process.

  The reason why the image stabilization process may be performed when a predetermined activation factor YN occurs is that image formation is performed using the image formation condition KJ stored in the memory 29 and necessary for image formation. This is because the image stabilization process may not necessarily be performed in the present embodiment. In addition, the type of image stabilization processing performed when the predetermined activation factor YN occurs is not necessarily limited to the above, and will be described later. For example, when the second factor YN2 occurs, long stabilization is performed. Processing may be performed.

  As shown in FIG. 5B, in the long stabilization process, IDC sensor light quantity correction, Dmax correction (maximum density correction), LD light quantity correction, registration correction, and gradation correction are performed in the order of processing.

  The IDC sensor light amount correction is a process of adjusting the reflected light intensity measured by the IDC sensor 22 so that the reflected light intensity in a region where no toner exists on the surface of the intermediate transfer belt 14 (bare surface) becomes a predetermined value.

  Dmax correction refers to the above-mentioned light amount KR, etc., which serves as a reference in order to reproduce multiple levels of gradation by changing the light amount KR and dot density (density per dot) of the laser diode 16 of the print head PH. Is a process for determining the maximum density Dmax of the image based on the above.

  The LD light amount correction is a process for correcting the light amount KR of the laser diode 16 in order to adjust the density detection degree of image data with a certain dot ratio.

  In the resist correction, the main scanning detection pattern and the sub-scanning detection pattern are printed on the intermediate transfer belt 14 and read from the pattern image read by the IDC sensor 22. Is detected and corrected.

  Tone correction is printing a predetermined gradation image (toner patch) on the intermediate transfer belt 14, reading the density of the printed gradation image with the IDC sensor 22, and storing it in the memory 29 based on the read density. This refers to correcting the gradation correction table (γ table). The gradation correction table selects and prints the desired light quantity KR and dot density of the laser diode 16 corresponding to the density of image data to be printed (for example, the density of image data that can be expressed with 256 gradations). The relationship between the input image data and the output light quantity KR and dot density of the laser diode 16 is shown.

  In the short stabilization process, simple registration correction and simple gradation correction are performed in the order of processing. The simple registration correction means correcting a minute registration that changes due to a warp of the laser diode 16 caused by a temperature change in the apparatus.

  The simple gradation correction means that the interruption time during the printing process is suppressed because a gradation change occurs due to a change in sensitivity characteristic of the photoconductor 11 when the cumulative number of printed sheets exceeds a threshold value. Further, in the registration correction process, the above simple registration correction is performed.

  As described above, the control sequence of the image stabilization process performed based on the predetermined activation factor YN is set to include a control sequence performed based on the activation factor YN having a lower priority than the predetermined activation factor YN. ing.

  Subsequently, a flow of image formation by the image forming apparatus 1 according to the present embodiment will be described.

  6 is a flowchart showing the flow of image formation by the image forming apparatus 1, FIG. 7 is a flowchart showing the flow of image stabilization processing, FIG. 8 is a flowchart showing the flow of storage processing, and FIG. 9 is a diagram showing various conversion tables. FIG. 10 is a diagram showing an image forming table storing image forming conditions KJ corresponding to the environment value KT.

  In this embodiment, when an image forming condition (process parameter) KJ corresponding to the current environment (environment value KT) in the apparatus exists in the database, the image forming condition is not performed and the image forming condition is not performed. Image formation is performed using KJ, and if it does not exist, image stabilization processing is performed and image formation is performed using image formation conditions KJ obtained thereby. The obtained image forming condition KJ is stored in a database. As a result, the number of times of image stabilization processing can be reduced.

  As shown in FIG. 6, first, it is determined whether or not the use frequency parameter is equal to or less than a predetermined threshold value Tn (# 1). An example of the usage frequency parameter is the rotation time of the photoconductor 11 or the cumulative number of printed sheets. That is, in the present embodiment, in # 1, it is determined whether or not the second factor YN2 described above is present. In the example, the cumulative number of printed sheets is used as the use frequency parameter here, and the threshold Tn (n is an arbitrary integer) of the cumulative number of printed sheets is set to 1000 sheets, for example.

  When the use frequency parameter is equal to or less than the threshold value Tn (Yes in # 1), the image forming conditions corresponding to the current temperature and relative humidity (environmental value KT) in the apparatus detected by the temperature / humidity sensor 23 and the PH temperature sensor 17 KJ is retrieved from the image forming table GT (# 2).

  Here, the process of # 2 will be described in detail with a specific example. The temperature step conversion table TT, the relative humidity step conversion table ST, and the absolute humidity step conversion table HT shown in FIGS. 9A to 9C are stored in the memory 29. These tables are for converting the temperature and relative humidity, which are the environmental values KT, into different expressions.

  That is, the temperature step conversion table TT is a table for converting the current temperature in the apparatus into a temperature step. For example, if the current temperature is 25 ° C., the temperature step is “8”.

  The relative humidity step conversion table ST is a table for converting the current relative humidity in the apparatus into a relative humidity step. For example, when the current relative humidity is 55%, the relative humidity step is “13”.

  The absolute humidity step conversion table HT is a table for converting a temperature step and a relative humidity step into an absolute humidity step. For example, when the temperature step is “8” and the relative humidity step is “13”, the absolute humidity step is “9”.

  Further, the first image forming table GT1 and the second image forming table GT2 shown in FIGS. 10A and 10B are stored in the memory 29, respectively.

  The first image formation table GT1 and the second image formation table GT2 store the image formation condition KJ corresponding to the absolute humidity step obtained by the absolute humidity step conversion table HT. In the present embodiment, the developing bias voltage Vdc and the charging bias voltage Vg are used as the image forming condition KJ of the first image forming table GT1, and the light amount KR of the laser diode 16 is used as the image forming condition KJ of the second image forming table GT2. Is used.

  In the process of # 2, for example, the image forming condition KJ when the absolute humidity step as the environmental value KT is “9” is the first image forming table GT1 in FIG. 10A and the first image forming table GT1 in FIG. It is determined whether or not it is in the two-image formation table GT2.

In this example, it is determined that the image forming condition KJ when the absolute humidity step is “9” is in the first image forming table GT1 and the second image forming table GT2. That is, as the image forming condition KJ in this case, the developing bias voltage Vdc is −280V, the charging bias voltage Vg is −400V, and the light amount of the laser diode 16 is KR5 mJ / m ² .

  If the image forming condition KJ is found as a result of the search in # 2 (Yes in # 3), the image forming condition KJ (existing forming condition), that is, the developing bias voltage Vdc, the charging bias voltage Vg, and the laser diode 16 are detected. Is read from the memory 29 (# 4), and image formation is performed using the read image forming condition KJ (# 5).

  On the other hand, if the use frequency parameter exceeds the threshold value Tn (No in # 1), a database update request is output (# 6), and image stabilization processing is performed (# 7). If the image forming condition KJ corresponding to the current temperature and relative humidity in the apparatus is not found in the first image forming table GT1 and the second image forming table GT2 as a result of the search in # 2 (No in # 3) Then, image stabilization processing is performed (# 7).

  Here, as image stabilization processing of # 7, first, the engine control unit 30 transmits a request for image stabilization processing to the printer control unit 40, and in response to this, the image stabilization processing is performed. The image data of the necessary patch pattern is received (# 31).

  Next, as the long stabilization process described above, IDC sensor light quantity correction (# 32), Dmax correction (# 33), LD light quantity correction (# 34), registration correction (# 35), and gradation correction (# 36). Are performed in order.

  When the image stabilization process of # 7 ends, it is determined whether or not the image stabilization process has been normally performed (# 8). When the image stabilization process is normally performed (Yes in # 8), a storage process to be described later is performed (# 9). Then, image formation is performed using the image formation condition KJ (new formation condition) obtained by the image stabilization process of # 7 (# 10).

  On the other hand, if the image stabilization process has not been performed normally (No in # 8), image formation is performed using a predetermined value (default value) stored in advance in the memory 29 (# 11). As the default value, the developing bias voltage Vdc, the charging bias voltage Vg, or the average value or median value of the light quantity KR of the laser diode 16 can be used.

  Here, the storage process of # 9 will be described.

  First, when there is no database update request, that is, when the use frequency parameter is equal to or less than the threshold value Tn (No in # 41), the image forming condition KJ obtained in the image stabilization process of # 7 is the first image forming table. They are stored in the corresponding areas of GT1 and second image formation table GT2 (# 44).

  For example, when the temperature in the apparatus is 17 ° C. and the relative humidity is 22%, both the temperature step and the relative humidity step are determined from the temperature step conversion table TT and the relative humidity step conversion table ST. “5”. Thereby, the absolute humidity step becomes “4” from the absolute humidity step conversion table HT.

  As shown in FIG. 10, the first image forming table GT1 and the second image forming table GT2 do not yet store the image forming condition KJ when the absolute humidity step is “4” (“−” in FIG. 10). Is actually stored, however, specific data such as “0” or “0xFFFF” is stored). Therefore, the image forming condition KJ obtained when the absolute humidity step is “4” obtained by the image stabilization process of # 7 is stored in the first image forming table GT1 and the second image forming table GT2.

  As described above, when there is no database update request, that is, when the use frequency parameter is equal to or less than the threshold value Tn (No in # 41), the image forming condition KJ is the first image forming table GT1 and the second image forming table. If not in GT2 (No in # 3), the image forming condition KJ obtained by the image stabilization process is stored in the corresponding area of the first image forming table GT1 and the second image forming table GT2.

  On the other hand, when there is a database update request, that is, when the use frequency parameter exceeds the threshold value Tn (Yes in # 41), the image formation stored in the first image formation table GT1 and the second image formation table GT2 is performed. The condition KJ is initialized by the initialization unit 54a (FIG. 4) (# 42). In this case, the numerical values of the first image formation table GT1 and the second image formation table GT2 are all specific data such as “0” or “0xFFFF”. Note that the image forming conditions KJ of the first image forming table GT1 and the second image forming table GT2 are initialized by the initialization unit 54a when the imaging unit U is replaced.

  Then, the current threshold value Tn is updated to the threshold value Tn + 1 (# 43). As described above, since the current threshold value Tn is set to 1000 sheets, the updated threshold value Tn + 1 is set to 2000 sheets, for example.

  Next, the image forming condition KJ obtained when the absolute humidity step is “4” obtained by the image stabilization process of # 7 is stored in the initialized first image forming table GT1 and second image forming table GT2. (# 44).

  As described above, when the use frequency parameter exceeds the threshold value Tn (No in # 1), the image forming condition KJ (new forming condition) obtained by the image stabilization processing is initialized to the first image forming table. They are stored in the corresponding areas of GT1 and second image formation table GT2.

(Effect in this embodiment)
In this embodiment, the image forming conditions KJ corresponding to the temperature and relative humidity in the apparatus are stored in a database as the first image forming table GT1 and the second image forming table GT2. When image formation is performed at the current temperature and relative humidity (environmental value KT) in the apparatus, the image forming condition KJ corresponding to the environmental value KT is stored in the first image forming table GT1 and the second image forming table GT2. In some cases, image formation is performed using the image formation condition KJ as an existing formation condition without performing image stabilization processing.

  On the other hand, when the image forming condition KJ corresponding to the environment value KT is not in the first image forming table GT1 and the second image forming table GT2, the image stabilizing process is actually performed and obtained by the image stabilizing process. The image formation is performed using the image formation condition KJ as the new formation condition.

  By such a method, it is possible to prevent the image stabilization process from being performed unnecessarily. As a result, the number of times of image stabilization processing can be reduced. Therefore, the life of the imaging unit U can be extended.

  In particular, the number of times that image stabilization processing is performed when the power of the image forming apparatus 1 is restored from the off-state for a long time, or when there is a print request from the user and the image forming apparatus 1 is restored from the long-time power saving mode. Therefore, the waiting time of the user can be reduced. Thereby, a user's convenience can be improved.

  In this embodiment, every time the usage frequency parameter exceeds the threshold value Tn, the image forming conditions KJ of the first image forming table GT1 and the second image forming table GT2 are initialized by the initializing unit 54a. Then, the image forming condition KJ obtained by performing the image stabilization process is stored as a new forming condition in the first image forming table GT1 and the second image forming table GT2. Accordingly, it is possible to update the image forming condition KJ used when performing image formation to an optimum one according to the current use frequency parameter. As a result, it is possible to perform image formation using the optimum image forming condition KJ.

  Furthermore, in this embodiment, the number of times of image stabilization processing is reduced, but the image quality is not substantially inferior. Conventionally, there is an aspect in which the image stabilization process is performed more than necessary. According to the image forming apparatus 1 according to the present embodiment, by reducing the number of times the image stabilization process is performed while maintaining the image quality. The life of the imaging unit U can be extended.

(Other embodiments)
You may perform the preservation | save process demonstrated by the said embodiment as follows. That is, even when the current cumulative print number exceeds the threshold value Tn, the cumulative print at the time when the current cumulative print number and the image forming condition KJ are stored in the first image forming table GT1 and the second image forming table GT2. If the difference from the number of sheets does not exceed the threshold value Tn, the image forming condition KJ may be used for image formation without being initialized. That is, in the first image formation table GT1 and the second image formation table GT2, whether or not the image formation condition KJ is initialized by recording the cumulative number of printed sheets when the image formation condition KJ is stored for each step. This may be determined for each step.

  More specifically, for data of a certain absolute humidity step, for example, when the current cumulative number of printed sheets is 2200, the threshold Tn is 1000, and the accumulated number of printed sheets at the time of storage is 1400, the difference Will be 800. Therefore, since this difference is smaller than the threshold value Tn, it can be used for image formation without initializing the image forming condition KJ.

  In the present embodiment, the cumulative number of printed sheets is used as the use frequency parameter, but instead of this, the cumulative operation time of the developing device 13 may be used. The activation factors YN1 and YN3 of the image stabilization process are as described above, but other factors may be used as the activation factor YN. Note that while the activation factor YN does not occur, image formation may be performed using the same image formation condition KJ.

  In addition, the configuration of the entire image forming apparatus 1 or each part, the processing content, the processing order, and the like can be appropriately changed in accordance with the spirit of the present invention. In this case, the above-described unique and exceptional effects can be obtained. Is done.

1 is a diagram illustrating a schematic internal configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an imaging unit around a development that is a part of the image forming apparatus. FIG. 3 is a block diagram illustrating a main control system of the image forming apparatus. 2 is a block diagram illustrating a functional configuration of the image forming apparatus. FIG. It is a figure for demonstrating the starting factor of an image stabilization process, and the implementation content of an image stabilization process. 3 is a flowchart illustrating a flow of image formation by the image forming apparatus. It is a flowchart which shows the flow of an image stabilization process. It is a flowchart which shows the flow of a preservation | save process. It is a figure which shows various conversion tables. It is a figure which shows the image formation table which stored the image formation conditions corresponding to an environmental value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Photoconductor 12 Charging apparatus (charging means)
13 Developing device (Developing means)
16 Laser diode (exposure means)
17 PH temperature sensor 22 IDC sensor 23 Temperature / humidity sensor 29 Memory (storage means)
30 Engine control unit 40 Printer control unit 52 Image stabilization processing unit (image stabilization processing means)
53 Search part (search means)
54 Stabilization processing control unit (stabilization processing control means)
54a Initialization unit 55 Image formation unit GT1 First image formation table GT2 Second image formation table HT Absolute humidity step conversion table KJ Image formation condition KR Light quantity KT Environmental value NA Description PH Printhead ST Relative humidity step conversion table TT Temperature step Conversion table U Imaging unit YN Activation factor

Claims (6)

An image forming apparatus configured to perform image stabilization processing when a preset activation factor occurs while performing image formation by an electrophotographic process,
Image stabilization processing means for performing the image stabilization processing and determining an image forming condition corresponding to the environmental value at that time;
Storage means for storing the image forming conditions determined by the image stabilization processing means in correspondence with the environmental values;
Search means for searching whether or not an image forming condition corresponding to an environmental value at that time is stored in the storage means when the activation factor occurs;
When the image forming condition corresponding to the environmental value is searched by the searching unit, the image forming process is performed using the searched image forming condition without performing the image stabilizing process by the image stabilizing processing unit. And a stabilization processing control means for controlling the image stabilization processing by the image stabilization processing means when the search means does not search for an image forming condition corresponding to the environmental value. ,
An image forming apparatus comprising: A photoreceptor,
Charging means for charging the photoreceptor;
Exposure means for forming an electrostatic latent image on the photoreceptor;
Developing means for developing the electrostatic latent image by attaching toner to the photoconductor,
The image stabilization processing unit determines at least the light amount of the exposure unit, the voltage value applied to the developing unit, and the voltage value applied to the charging unit as the image forming conditions.
The image forming apparatus according to claim 1. The environmental value includes the temperature and relative humidity in the device.
The image forming apparatus according to claim 1. The stabilization processing control unit initializes the image forming conditions stored in the storage unit when the rotation time of the photoconductor or the cumulative number of printed sheets exceeds a preset threshold value.
The image forming apparatus according to claim 2. The photoconductor and the developing means are integrated as an imaging unit,
The stabilization processing control means initializes the image forming conditions stored in the storage means when the imaging unit is replaced.
The image forming apparatus according to claim 2. A method of controlling an image forming apparatus configured to perform image stabilization by performing image formation by an electrophotographic process and when a preset activation factor occurs,
Performing the image stabilization process and determining an image forming condition corresponding to the environmental value at that time;
Storing the determined image forming conditions corresponding to the environmental value;
Searching for whether or not an image forming condition corresponding to an environmental value at that time is stored when the activation factor occurs;
Performing image formation using the searched image forming condition without performing image stabilization processing when the image forming condition corresponding to the environment value is searched;
Performing an image stabilization process when an image forming condition corresponding to the environment value is not searched; and
A control method for an image forming apparatus, comprising:

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