JP4831206B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming system and an image forming apparatus.

  Conventionally, in the field of image forming apparatuses, calibration is generally performed in order to maintain image quality. For example, Patent Document 1 provides a configuration that can execute calibration at a timing desired by a user. Patent Document 2 discloses a technique for prohibiting execution of calibration even when the apparatus side determines that calibration is necessary when the user restricts execution of calibration.

JP 2004-252573 A JP 2000-190573 A

  By the way, recent printers are connected to a network by a LAN or the like, and are increasingly used by a plurality of users. Therefore, in the configuration in which the calibration can be performed by the user as in the above-mentioned Patent Document 1, there is a possibility that the calibration is performed frequently or silently by many users. Since calibration is generally accompanied by degradation of consumables and noise, it is not desirable to perform more than necessary, and the color that one user prefers may be changed by calibration by another user. There was also the problem of sudden changes.

  On the other hand, Patent Document 2 discloses a technology that regulates the calibration that the apparatus automatically performs according to a user request, but this technology cannot prevent the operation in a state where the image quality is deteriorated, There has been the above problem that the image quality cannot be maintained properly.

  The present invention has been made based on the above-described circumstances, and can prevent operation in a state in which the image quality is lowered while regulating the calibration according to a user request, and can maintain the image quality appropriately. The purpose is to provide a configuration.

As means for achieving the above object, the invention of claim 1 is a calibration for forming a density patch and measuring the density of the density patch, and is an automatic calibration that is automatically performed by the apparatus. The setting means to set whether to limit the execution of the calibration, and when the operation amount from the previously executed calibration exceeds the low threshold, the setting means is set not to limit the execution of the automatic calibration in that case, it is determined to execute the automatic calibration, when it is set to limit the execution of automatic calibration by the setting means, determination means for determining not to perform the automatic calibration, to form a density patch Calibration to measure the density of density patches according to the execution command from the user A command input means for inputting an execution command of the user calibration is the Hare calibration, by the determining means, when if it is determined not to perform an automatic calibration without automatic calibration, it is determined that the run There line automatic calibration in further, and control means for performing user calibration when the execution command is input to the command input means, when it is set to limit the execution of automatic calibration by the setting means And a notifying means for notifying the user to execute the user calibration when the operation amount from the calibration executed last time is equal to or higher than the low threshold, and the determination means further includes the calibration executed last time. The operating amount from is higher than the high threshold, which is the threshold above the low threshold When it becomes, characterized in that it determines to perform an automatic calibration regardless of the setting.

According to a second aspect of the present invention, in the image forming apparatus, calibration is performed to form a density patch and measure the density of the density patch, and the execution of automatic calibration, which is calibration automatically performed by the apparatus, is limited. If the setting means is set not to limit the execution of automatic calibration when the operating amount from the previously executed calibration exceeds the low threshold, the automatic calibration is performed. determines that the execution, measurement if it is set to limit the execution of automatic calibration, a determination unit which determines not to perform an automatic calibration, the density of the density patch to form a density patch by setting means Calibration to be performed in response to an execution command from the user A command input means for inputting an execution command of the user calibration is tio down, by the determining means, without performing automatic calibration if it is determined not to perform an automatic calibration, when it is judged to perform the have line automatic calibration, further comprising control means for performing user calibration when the execution command is input to the command input means, when it is set to limit the execution of automatic calibration by the setting means, A notification means for notifying the user to execute the user calibration when the operation amount from the calibration executed last time is equal to or higher than the low threshold, and the determination means further includes a calibration executed from the calibration executed last time. If the operating amount of the vehicle becomes greater than or equal to the high threshold that is the threshold greater than or equal to the low threshold Characterized in that it determines to perform an automatic calibration regardless of the setting.

<Invention of Claims 1 and 2 >
There is a case where automatic calibration is not performed for a long period of time, and if calibration is not performed for a long period of time as described above, there is a possibility that the image quality may deteriorate without the user's knowledge. On the other hand, in the configuration of claims 1 and 2 , automatic calibration is performed when the operation amount reaches a certain level. Therefore, the operation in a state where the image quality is deteriorated can be prevented, and the image quality is appropriately maintained.

Further, it is configured that can perform a user calibration when the user deems it necessary, that Do enables appropriate image formation in accordance with the needs of the user.

Furthermore, when it is set that the execution of the automatic calibration is restricted by the setting means , the notification is performed when the operation amount becomes the low threshold value or more. Therefore, when the automatic calibration is likely not to be continued for a long period of time, the configuration is such that the user can detect it and cope with it, thereby effectively preventing the operation in a state where the image quality is deteriorated.

1 is a main part schematic cross-sectional view illustrating a color laser printer according to a first embodiment of the invention; 1 is a block diagram illustrating the electrical configuration of the color laser printer of FIG. Flow chart illustrating the flow of steady processing Flowchart illustrating the flow of execution restriction processing Flowchart illustrating the flow of user calibration processing Explanatory drawing illustrating density patch Flowchart illustrating the flow of automatic calibration processing Flowchart illustrating the flow of print processing

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to the drawings.
1. Overall Configuration FIG. 1 is a schematic cross-sectional view of a main part of a color laser printer 1 as an image forming apparatus according to the present embodiment. The color laser printer 1 shown in FIG. 1 is configured as a four-cycle type color laser printer, and is fed into a main body casing 3 for feeding a paper 5 and a predetermined amount of paper 5 fed. The image forming unit 9 for forming the image is provided.

  The paper feed unit 7 is a paper feed tray 11 in which the paper 5 is stacked and accommodated, a paper feed roller 13 that contacts the paper 5 at the top of the paper feed tray 11 and picks up the paper 5 one by one by rotation, A conveyance roller 15 and a registration roller 17 are provided for conveying the paper 5 to the image forming position.

  This image forming position is a transfer position for transferring a toner image on an intermediate transfer belt 51, which will be described later, to the paper 5. In this embodiment, the image forming position is a contact position between the intermediate transfer belt 51 and a transfer roller 27, which will be described later. .

  The image forming unit 9 includes a scanner unit 21, a process unit 23, an intermediate transfer belt mechanism unit 25, a transfer roller 27, a fixing unit 29, and the like.

  The scanner unit 21 includes a laser light emitting unit (not shown), a polygon mirror, a plurality of lenses, and a reflecting mirror at the center in the main body casing 3. In the scanner unit 21, a laser beam based on image data emitted from the laser emitting unit is passed or reflected through a polygon mirror, a reflecting mirror, and a lens, and a belt photosensitive member (belt photosensitive member (described later) of the belt photosensitive member mechanism unit 31). The surface of an OPC (Organic Photo Conductor) 33 is irradiated by high-speed scanning.

  The process unit 23 includes a plurality (four) of developing cartridges 35, a belt photoreceptor mechanism unit 31, and the like. The four developing cartridges 35 include, for each color, a yellow developing cartridge 35Y containing yellow toner, a magenta developing cartridge 35M containing magenta toner, a cyan developing cartridge 35C containing cyan toner, and a black toner. Each of the black developing cartridges 35K in which the toner is stored is sequentially arranged in parallel from the bottom to the top at a predetermined interval in the vertical direction on the front side in the main casing 3.

  Each developing cartridge 35 includes a developing roller 37 (a yellow developing roller 37Y, a magenta developing roller 37M, a cyan developing roller 37C, and a black developing roller 37K), a layer thickness regulating blade (not shown), a supply roller, a toner container, and the like. In order to bring each developing roller 35 into contact with or separate from the surface of the belt photoreceptor 33 to be described later, a separation solenoid 38 (yellow separation solenoid 38Y, magenta separation solenoid 38M, cyan separation solenoid 38C, black separation solenoid The solenoid 38K) is configured to be movable in the horizontal direction.

  In the developing roller 37, a metal roller shaft is covered with a roller made of an elastic member made of a conductive rubber material. More specifically, the roller of the developing roller 37 is composed of an elastic roller portion made of conductive urethane rubber, silicon rubber, EPDM rubber or the like containing fine carbon particles, and urethane coated on the surface of the roller portion. It is formed of a two-layer structure with a coat layer, the main component of which is rubber, urethane resin, polyimide resin or the like. The developing roller 37 is applied with a predetermined developing bias to the belt photosensitive member 33 at the time of development and a predetermined recovery bias at the time of toner recovery. For example, the predetermined development bias is + 300V, and the predetermined recovery bias is −200V.

  The toner storage portions of the developing cartridges 35 store positively chargeable nonmagnetic one-component spherical polymer toners of yellow, magenta, cyan, and black, respectively. At the time of development, the toner is supplied to the developing roller 37 by the rotation of the supply roller, is positively frictionally charged between the supply roller and the developing roller 37, and the toner supplied onto the developing roller 37 is As the developing roller 37 rotates, it enters between the layer thickness regulating blade and the developing roller 37, where it is further sufficiently frictionally charged and carried on the developing roller 37 as a thin layer having a constant thickness. At the time of recovery, a reverse bias is applied to the developing roller 37 to recover the toner from the belt photoreceptor 33 and the toner is stored in the toner storage unit.

  The belt photoreceptor mechanism unit 31 includes a first belt photoreceptor roller 39, a second belt photoreceptor roller 41, a third belt photoreceptor roller 43, the first belt photoreceptor roller 39, the second belt photoreceptor roller 41, and A belt photoreceptor 33 wound around a third belt photoreceptor roller 43, a belt photoreceptor charger 45, a potential adder 47, and a potential gradient controller 49 are provided. The configuration of the belt photoconductor mechanism 31 will be described in detail later.

  The intermediate transfer belt mechanism unit 25 is disposed on the rear side of the belt photosensitive member mechanism unit 31, and a belt photosensitive member 33 and an intermediate transfer belt (ITB: Inter Transfer Belt) 51 described later are attached to the second belt photosensitive roller 41. A first intermediate transfer belt roller 53 disposed substantially opposite thereto, a second intermediate transfer belt roller 55 disposed obliquely below and below the first intermediate transfer belt roller 53, and a rear side of the second intermediate transfer belt roller 55. The third intermediate transfer belt roller 57 and the first intermediate transfer belt roller 53 through the third intermediate transfer belt roller 57 are wound around the outer periphery of a third intermediate transfer belt roller 57 and a first intermediate transfer belt roller 53 or a third intermediate transfer belt roller 57 which are arranged opposite to each other with a transfer roller 27, which will be described later, interposed therebetween. The intermediate transfer belt 51 is provided.

  The intermediate transfer belt 51 is formed from an endless belt made of a resin such as conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed. The first intermediate transfer belt roller 53 to the third intermediate transfer belt roller 57 are arranged in a triangular shape, and the intermediate transfer belt 51 is wound around the triangle. The first intermediate transfer belt roller 53 is driven to rotate by a main motor 96 (FIG. 2: described later) via a drive gear (not shown), and the second intermediate transfer belt roller 55 and the third intermediate transfer belt roller 57 are driven. Is driven, the intermediate transfer belt 51 is rotated between the first intermediate transfer belt roller 53 and the third intermediate transfer belt roller 57 (clockwise movement).

  Further, a density detection sensor 71 for detecting the density of each color on the intermediate transfer belt 51 is provided. The density detection sensor 71 includes a light source that emits light in the infrared region, a lens that irradiates the light source onto the intermediate transfer belt 51, and a phototransistor that receives the reflected light.

  The transfer roller 27 is disposed so as to face the third intermediate transfer belt roller 57 of the intermediate transfer belt mechanism unit 25 with the intermediate transfer belt 51 interposed therebetween, and a metal roller shaft is covered with a roller made of a conductive rubber material. And is rotatably supported. The transfer roller 27 is configured to be movable between a standby position separated from the intermediate transfer belt 51 and a transferable position adjacent to the intermediate transfer belt 51 by a transfer roller contact / separation mechanism (not shown). The transfer roller contact / separation mechanism is disposed opposite to both sides of the paper 5 in the width direction of the paper 5 with the transport path 59 of the paper 5 interposed therebetween. It is configured to press the passing paper 5.

  As will be described later, the transfer roller 27 is positioned at the standby position while the visible images for each color are sequentially transferred to the intermediate transfer belt 51, and all visible images are transferred to the belt photoconductor. When the color image is formed on the intermediate transfer belt 51 by being transferred from 33 to the intermediate transfer belt 51, it is located at a transferable position. At the time of calibration, control is performed so as to be positioned at the standby position.

  The transfer roller 27 is applied with a predetermined transfer bias to the intermediate transfer belt 51 at a transferable position by a transfer bias application circuit (not shown). The fixing unit 29 is disposed behind the intermediate transfer belt mechanism unit 25, and includes a heating roller 61, a pressing roller 63 that presses the heating roller 61, and a pair of downstream units that are provided on the downstream side of the heating roller 61 and the pressing roller 63. A conveyance roller 65. The heating roller 61 includes a halogen lamp for heating, with an outer layer made of silicon rubber and an inner layer made of metal.

  Next, the belt photoreceptor mechanism unit 31 of the image forming unit 9 will be described in more detail.

  The first belt photosensitive roller 39 is disposed opposite to the rear of the four developing cartridges 35, and is disposed below the lowest yellow developing cartridge 35Y. The first belt photoreceptor roller 39 is a roller that is driven to rotate.

  The second belt photosensitive roller 41 is disposed above the first belt photosensitive roller 39 in the vertical direction and above the black developing cartridge 35K positioned at the top. The second belt photosensitive roller 41 is rotationally driven through a driving gear (not shown) by driving a main motor (not shown).

  The third belt photoreceptor roller 43 is disposed obliquely above and rearward of the first belt photoreceptor roller 39. The third belt photoreceptor roller 43 is a roller that is driven to rotate. Therefore, the first belt photosensitive roller 39, the second belt photosensitive roller 41, and the third belt photosensitive roller 43 are arranged in a triangular shape.

  The second belt photoconductor roller 41 is given a potential of +800 volts by the potential adder 47 arranged in the vicinity thereof using the power supply of the belt photoconductor charger 45. The first belt photosensitive roller 39 and the third belt photosensitive roller 43 are made of a conductive member, for example, aluminum, and are in contact with a later-described base material layer of the belt photosensitive member 33 and connected to a GND terminal (not shown). ing. That is, the first belt photoconductor roller 39 and the third belt photoconductor roller 43 keep the potential of the belt photoconductor 33 at the place where they contact each other at GND.

  The belt photoreceptor 33 is wound around a first belt photoreceptor roller 39, a second belt photoreceptor roller 41, and a third belt photoreceptor roller 43. Then, the second belt photosensitive roller 41 is driven to rotate, and the first belt photosensitive roller 39 and the third belt photosensitive roller 43 are driven, so that the belt photosensitive member 33 moves around (in a counterclockwise direction). Move around).

  This belt photoreceptor 33 is an endless belt provided with a base layer (conductive base layer) having a thickness of 0.08 mm and a photosensitive layer having a thickness of 25 μm on one side thereof. The base material layer is made of a nickel conductor formed by a nickel electroforming method, and the photosensitive layer is made of a polycarbonate resin photoconductor.

  The belt photoconductor charger 45 is below the belt photoconductor mechanism 31 and upstream of the exposed portion of the belt photoconductor 33 by the scanner unit 21, in the vicinity of the first belt photoconductor roller 39. In order not to come into contact with the body 33, they are arranged to face each other at a predetermined interval. The belt photoreceptor charger 45 is a positively-charged scorotron charger that generates corona discharge from a charging wire such as tungsten, so that the surface of the belt photoreceptor 33 is uniformly charged positively. It is configured.

  The potential gradient controller 49 is located between the second belt photosensitive roller 41 and the first belt photosensitive roller 39, and is in contact with the base material layer of the belt photosensitive member 33 above the black developing cartridge 35K. This potential gradient controller 49 drops the potential of the base material layer to GND at the place where it contacts.

  Next, the operation during printing of the color laser printer 1 will be described. These operations are realized by the control device 90 described later controlling each unit.

  Of the papers 5 stored in the paper feed tray 11 of the paper feed unit 7, the paper feed roller 13 is pressed to the uppermost one, and the paper feed roller 13 rotates to rotate the paper 5 one by one. It is taken out. The taken paper 5 is fed to the image forming position by the conveying roller 15 and the registration roller 17. A predetermined registration is performed on the fed paper 5 by the registration roller 17.

  The surface of the belt photoreceptor 33 is uniformly positively charged by the belt photoreceptor charger 45 and then exposed by high-speed scanning of a laser beam from the scanner unit 21 based on the image data. Since the charged portion is eliminated in the exposed portion, an electrostatic latent image in which a positively charged portion and an uncharged portion are arranged according to the image data is formed on the surface of the belt photoreceptor 33. Is done.

  At this time, the first belt photoreceptor roller 39 and the third belt photoreceptor roller 43 supply power to the base material layer of the belt photoreceptor 33 with which they abut, and maintain the potential of the abutting portion at GND.

  The yellow developing cartridge 35Y of the developing cartridge 35 is moved rearward in the horizontal direction by the yellow separation solenoid 38Y to the belt photoreceptor 33 on which the electrostatic latent image is formed, and the developing roller 37 of the yellow developing cartridge 35Y is moved. Then, it is brought into contact with the belt photoreceptor 33 on which the electrostatic latent image is formed.

  The yellow toner accommodated in the yellow developing cartridge 35Y is positively charged and adheres only to an uncharged portion on the belt photoconductor 33. As a result, a yellow visible image is formed on the belt photoreceptor 33.

  At this time, the magenta developing cartridge 35M, the cyan developing cartridge 35C, and the black developing cartridge 35K are moved forward in the horizontal direction by the separating solenoids 38M, 38C, and 38K to be separated from the belt photosensitive member 33.

  The yellow visible image formed on the belt photoreceptor 33 is transferred onto the surface of the intermediate transfer belt 51 when the belt photoreceptor 33 moves and faces the intermediate transfer belt 51.

  At this time, a forward bias (+300 V potential) is applied to the second belt photoconductor roller 41 by the power supply of the belt photoconductor charger 45. Then, the photosensitive layer near the second belt photosensitive roller 41 also has a potential of +300 V through the conductive base material layer. Therefore, a repulsive force is generated between the positively charged yellow toner and the photosensitive layer, and is easily transferred to the intermediate transfer belt 51.

  Similarly to the above, for magenta, an electrostatic latent image is formed on the belt photosensitive member 33, and then a magenta visible image is formed. Further, a magenta visible image is formed on the intermediate transfer belt 51. Transcript.

  That is, an electrostatic latent image is formed again on the belt photosensitive member 33, and then the magenta developing cartridge 35M is moved rearward in the horizontal direction by the magenta separation solenoid 38M, and the developing roller 37 of the magenta developing cartridge 35M is moved. The yellow developing cartridge 35Y, the cyan developing cartridge 35C, and the black developing cartridge 35K are moved to the front in the horizontal direction by the separating solenoids 38Y, 38C, and 38K to be separated from the belt photosensitive member 33 while being brought into contact with the belt photosensitive member 33. Thus, when a magenta visible image is formed on the belt photosensitive member 33 only by the magenta toner contained in the magenta developing cartridge 35M, the visible image of the magenta is similar to the above. By moving 33, the magenta When the visible image faces the intermediate transfer belt 51, is already visible image transfer of the yellow, are transferred superimposed onto the intermediate transfer belt 51.

  Such a similar operation is repeated with cyan toner accommodated in the cyan developing cartridge 35C and black toner accommodated in the black developing cartridge 35K, whereby a color image is formed on the intermediate transfer belt 51. .

  The color image formed on the intermediate transfer belt 51 is collectively transferred to the paper 5 by the transfer roller 27 positioned at a transferable position while the paper 5 passes between the intermediate transfer belt 51 and the transfer roller 27. The

  The heating roller 61 of the image forming unit 9 fixes the color image transferred onto the paper 5 while the paper 5 passes between the heating roller 61 and the pressing roller 63.

  Then, the sheet 5 on which the color image is thermally fixed in the fixing unit 29 as described above is conveyed to a pair of paper discharge rollers 67 by the conveyance roller 65. The paper 5 sent to the paper discharge roller 67 is discharged onto a paper discharge tray 69 formed on the upper portion of the main body casing 3 by the paper discharge roller 67.

  In this way, color printing can be performed on the paper.

2. Electrical Configuration Next, the electrical configuration of the laser printer 1 will be described.

  FIG. 2 is a block diagram conceptually showing the electrical configuration of the laser printer 1.

  As shown in FIG. 2, the laser printer 1 includes a control device 90 that controls each component by a control unit 95 including a CPU 91, a ROM 92, a RAM 93, and an application specific integrated circuit (ASIC). Further, in a form electrically connected to the control unit 95, a main motor 96, a scanner motor 97, an operation unit 98 including an input panel, a display unit 99 including various lamps, and a detection unit 100 including various sensors. Etc. are provided, and a control system is constituted by these.

  The ROM 92 and RAM 93 are connected to the CPU 91, and the CPU 91 controls each component via the control unit 95 while storing the processing results in the RAM 93 according to the processing procedure stored in the ROM 92.

  The main motor 96 is a motor that rotates the second belt photosensitive roller 41, the first intermediate transfer belt roller 53, and the like described above in synchronization. The scanner motor 97 is a motor that rotates a polygon mirror or the like in the scanner unit 21.

  The CPU 91 performs drive control of the main motor 96 and the scanner motor 97 based on a program stored in the ROM 92 in advance.

  The control unit 95 controls the image forming unit 5 in accordance with a command from the CPU 91. Specifically, exposure control for exposing the surface of the belt photosensitive member 33 is performed by each unit constituting the scanner unit 21, and a transfer bias is controlled when toner is transferred from the intermediate transfer belt 51 to the paper 5.

  The control device 90 is provided with a network interface (network I / F) 94 for connecting to an external device such as a personal computer. The network interface 94 is connected to the computer 150, and the laser printer 1 and the computer 150 constitute the image forming system 200. The CPU 91 performs processing for forming an image based on image data input from the computer 150 via the network interface 94 on the sheet 3 (recording surface) by performing drive control of each unit as described above.

  The detection unit 100 includes the above-described density detection sensor 71, a paper sensor 82 that detects the density of the paper, and various sensors, and these sensors are electrically connected to the control unit 95.

3. Characteristic Configuration Next, characteristic parts of the present embodiment will be described.

  In the present embodiment, a calibration execution command can be input by the user, and the calibration can be executed in accordance with the input execution command. On the other hand, a restriction setting that restricts calibration is also possible. Based on the restriction setting, it is determined whether or not to restrict calibration according to the execution instruction. The calibration according to the execution command is performed when it is determined that the calibration is not performed and the regulation is not performed. In the present embodiment, the operation unit 98 corresponds to command input means in the claims, and the CPU 91 corresponds to control means, setting means, and determination means in the claims. Hereinafter, a specific control flow for realizing this concept will be described.

  In the color laser printer 1, a display panel is provided as the display unit 99. The display panel can display a plurality of menu items, and a desired menu can be selected from the menu items by operating the operation unit 98. If any menu is selected from the menus displayed on the display panel, the process proceeds to Yes in S10. If the execution restriction setting menu is selected, the process proceeds to Yes in S20, and an effective restriction process is performed (S30).

  As shown in FIG. 4, in the execution restriction process, first, a menu for prompting input of setter confirmation information (for example, combination information of characters and numbers) is displayed (S100). Thereafter, when the setter confirmation information is input within a predetermined period, the process proceeds to Yes in S110, and the setter confirmation information is compared with the registered information registered in advance to determine whether or not it is correct (S120). . On the other hand, if there is no input of the setter confirmation information within the predetermined period, the process proceeds to No in S110 and the process ends. The registration information may be changeable based on an input operation, or may be information that cannot be changed unique to the apparatus. If the setter confirmation information is correct, the process proceeds to Yes in S120, and the execution restriction mode is set (S130). This setting is performed by storing information indicating that the execution restriction mode is set in a storage unit such as the RAM 93 or a nonvolatile memory. On the other hand, if the entered setter confirmation information is not correct, the process proceeds to No in S120, and the process ends without setting the execution restriction mode.

  In this configuration, the restriction setting is made according to an arbitrary input operation of a setter who intends to perform the execution restriction process. In this configuration, the setter can decide whether or not to restrict engine calibration, which will be described later, as necessary. Therefore, the configuration is more convenient. The setter refers to a person who performs an input operation for restriction setting, and is a user who inputs a calibration execution command (that is, selection of user calibration processing in S40 in FIG. 3 and S210 in FIG. 5). It may be a different person (for example, the administrator of the color laser printer 1) from the user who inputs the password, or the same person.

  Returning to FIG. 3, if the execution limit setting menu is not selected, the process proceeds to No in S20. If the user calibration menu is selected, the process proceeds to Yes in S40, and user calibration processing is executed (S50).

  As shown in FIG. 5, in the user calibration process, engine calibration described later is performed in accordance with an authorized user execution command. First, it is determined whether or not the operation amount from the previously performed engine calibration has reached the first threshold value. (S200). Specifically, the operation amount is grasped based on the number of printed sheets, and if the number of printed sheets from the previous engine calibration has not reached the number corresponding to the first threshold value, the process proceeds to Yes in S200. Then, the user calibration process is terminated. That is, in S200, when the operation amount (number of printed sheets) from the previously executed engine calibration is equal to or less than the first threshold value, it is determined that the engine calibration according to the execution command is not performed. As a result, the engine calibration can be omitted at a stage with a small amount of operation that does not pose a problem even if the engine calibration is not performed. Therefore, the frequency of engine calibration can be effectively suppressed without degrading the image quality.

If the number of printed sheets from the engine calibration was last performed reaches the number of printed sheets corresponding to the first threshold value, the process proceeds to No in S200, prompt for password. If a password has been entered within a predetermined time, the process proceeds to Yes in S210, where the entered password is compared with the registered password stored in the storage means, and whether the entered password is correct. Is determined (S220). If no password is input within the predetermined time, the process proceeds to No in S210 and the process is terminated. The registered password may be information that is unique to the apparatus and cannot be changed, or may be information that can be changed by some method (for example, a setting change operation by an authorized person). The “registration password” is information having a different concept from the “registration information” for confirming the setter confirmation information described above. However, the registration information may be the same information or different information. .

  If the input password is correct, the process proceeds to Yes in S220, and engine calibration described later is executed. If it is determined that the input password is incorrect, the process proceeds to No in S220 and the process ends.

  In this flow, a password as authentication information is input by the user, and it is determined whether or not to perform engine calibration according to the execution command based on whether or not the password is authentic. Accordingly, since users who can perform engine calibration can be selected based on the password, engine calibration cannot be performed by an unspecified user.

  In the engine calibration process of S230, a density measurement process is performed in which a density patch is formed and the density of the density patch is measured. In this density measurement process, first, a patch row 100 as shown in FIG. 6 is printed on the intermediate transfer belt 51 (FIG. 1). The patch row 100 is formed on the intermediate transfer belt 51 so as to be linearly connected and to be within one circumference along the circumferential movement direction of the intermediate transfer belt 51. Note that this patch array is configured by combining density patches configured for different colors. Specifically, the K color marks K1, K2,... K5 (middle K3, K4 are omitted) constitute a K color density patch, and the C color marks C1, C2,... C5 (middle C3, C4 are omitted). ) Constitutes a density patch of C color, and density patches of M color and Y color are also constructed, but the density patches of each color are arranged in such a manner that the first is 102 and the second is 103. ing.

  When the patch row 100 is formed, each density of the patch row 100 is measured. This is performed by rotating the intermediate transfer belt 51 and the density detection sensor 71 measuring the patch row 100 on the intermediate transfer belt 51. Note that since the patch row 100 is formed so as to be within one round length along the circumferential movement direction of the intermediate transfer belt 51, the density detection sensor 71 can be moved all around the patch row 100 only by making one turn of the intermediate transfer belt 51. The density of the patch can be measured.

  The measured concentration is stored as a measurement result in a storage means such as the RAM 93 or a non-illustrated non-volatile memory (EEPROM or the like) (S240).

  With such a configuration, the user can arbitrarily perform density measurement processing, and density information can be acquired at a timing desired by the user. On the other hand, if such density measurement processing of the user is allowed unconditionally, there is a concern about problems (for example, developer consumption and noise) caused by increase in the frequency of density measurement processing. Since it is determined whether or not the engine calibration process can be executed based on the input, the density patch formation frequency can be suppressed, and problems caused by increased frequency such as developer consumption and noise can be effectively suppressed.

  Returning to FIG. 3, if there is no menu selection in S10, or if the menu is completed after completion of the menu execution or cancellation after the execution restriction menu or user calibration menu is selected, in S60. An automatic calibration process is performed.

  As shown in FIG. 7, in the automatic calibration process, first, it is determined whether or not at least one of the developing cartridges 35 has been replaced since the previous engine calibration. If it is exchanged, the process proceeds to Yes in S300, and the execution restriction mode is canceled. If not, the process proceeds to No in S300.

  In this configuration, when any of the developing cartridges 35 is replaced, engine calibration is executed regardless of the restriction setting. That is, it is determined that the engine calibration is executed under a predetermined condition regardless of the regulation setting at the timing when the characteristic is easily changed after the development cartridge 35 is replaced. Accordingly, the engine calibration according to the user request is appropriately regulated, and the engine calibration is appropriately performed under a situation to be executed.

  In S320 of FIG. 7, it is determined whether the number of printed sheets (operating amount) from the previous engine calibration has reached the number of printed sheets corresponding to the second threshold (corresponding to the low threshold) (S320). If not, the process proceeds to No in 320 and the process is terminated. If it has reached, the process proceeds to Yes in S320, and it is determined whether or not the execution restriction mode is set (S330). If the execution restriction mode is not set, the process proceeds to No in S330, the above-described engine calibration is executed (S340), and the measurement result is stored in the storage unit in the same manner as described above (S350). As described above, after replacement of the cartridge, the restriction is released in S310, so that No in S330 and engine calibration is performed.

  On the other hand, if the execution restriction mode is set, the process proceeds to Yes in S330, and a warning (notification) that the engine calibration is executed is performed. In other words, in this configuration, when the number of printed sheets (operating amount) from the previously executed engine calibration becomes equal to or greater than the number corresponding to the second threshold value, a notification that prompts execution of engine calibration is performed. Yes. For example, notification is performed by displaying information such as “Please execute calibration” on the display panel constituting the display unit 99. In the present embodiment, the display unit 99 corresponds to notifying means in the claims.

  In the configuration in which the engine calibration is regulated based on the regulation setting as in the present embodiment, there may be a case where the engine calibration is not performed for a long period of time. There is a risk of quality degradation. Therefore, in the present embodiment, notification is performed when the operation amount from the previously executed engine calibration is equal to or greater than the second threshold value. Therefore, when the engine calibration is not performed for a long time, the user can know it and can take measures such as having another user who has a password execute the calibration. As a result, the operation in a state where the image quality is deteriorated is effectively prevented.

  Further, if the engine calibration has not been performed for a long time, the process proceeds to Yes in S370, the execution restriction mode is canceled (S380), and the process ends. If it has not reached the long term, the process proceeds to No in S370 and the process is terminated. In the present embodiment, the number of printed sheets (operating amount) from the previously executed engine calibration is equal to or greater than the number corresponding to the third threshold (corresponding to the high threshold, and the third threshold is equal to or greater than the second threshold). In some cases, it is “not implemented for a long time”. In this process, when the number of printed sheets (operating amount) from the previously executed engine calibration is equal to or greater than the number corresponding to the third threshold, the restriction is released even when the execution restriction mode is set. Engine calibration is executed in the next automatic calibration process (S320: Yes, S330: No).

  In this configuration, the engine calibration according to the user request is moderately regulated based on the regulation setting, and the engine calibration is performed regardless of the regulation setting at a certain operating amount. Therefore, the operation in a state where the image quality is deteriorated can be prevented, and the image quality is appropriately maintained.

  In the present embodiment, the first threshold value, the second threshold value, and the third threshold value are thresholds of different concepts, and any two or three of these threshold values may be the same value. The values may be different (however, the third threshold is equal to or greater than the first threshold and the second threshold).

  Next, the printing process will be described.

  If there is a print request in S70 of FIG. 3, a printing process is performed in S80.

  FIG. 8 is a flowchart illustrating the flow of the printing process. As shown in FIG. 8, when the printing process is started, data acquisition is first performed in S400, and intermediate data is created (S410). Thereafter, it is determined whether or not the execution limit mode is set (S420). If not set, soft calibration is performed in S430.

The soft calibration process is an update process for updating a correction table for correcting image density. That is, as described above, the density of the density patch is measured by the engine calibration process, and the density measurement result is stored in the storage means (such as the RAM 93 and the non-volatile memory). Based on the density measurement results stored in the table, a correction table (γ table) representing the correspondence between the input level given to the printer and the actual output level is created, and the correction table stored up to that point is updated. Do.

  In the soft calibration process, it is estimated from density values (0%, 10%, 15%, 20%, 25%, 30% gradation, etc.) obtained by actually measuring the patches on the intermediate transfer belt 51 in the engine calibration process. The density value on the print medium corresponding to the gradation divided into 256 equal parts from 0% to 100% by a conventionally known interpolation method (for example, linear interpolation or quadratic curve interpolation). Is calculated. Then, correction data is calculated so that each of these density values becomes an ideal density, and the calculated correction data is stored as a correction table in a storage means such as the RAM 93 or a non-volatile memory (not shown), and the soft calibration process is completed. To do.

  As described above, in the present embodiment, when the execution restriction mode is set, the correction table is not updated. Therefore, the correction table is changed to a dark cloud by an unspecified number of users, and the color of the image changes. It is possible to effectively suppress the inconvenience. Further, engine calibration (density measurement processing) is executed independently of soft calibration (correction table creation and update processing), and soft calibration is regulated based on regulation settings. Therefore, the hue is not changed without darkness, and can be updated quickly and accurately according to the accumulated density measurement result, if necessary.

  After the soft calibration process is completed, a γ correction process is performed (S440). The γ correction process is a process in which the correction table created as described above is reflected as correction values in print data at the time of printing. That is, by this processing, correction based on the correction table is performed so that the density included in the print data to be printed from now on matches the density of the printed matter to be printed. After the γ correction process, the dithering process is performed in S450, and then printing on the paper is performed (S460). At the time of printing, adjustment of the pulse width of the laser beam, adjustment of the voltage applied to each developing roller 37 and belt photoreceptor charger 45, and the like are performed based on the correction value reflected in the γ correction processing, and each color is adjusted. The density will be corrected.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) The “operation amount from the calibration executed last time” is not limited to the number of printed sheets, as long as it can quantitatively indicate the operation degree from the calibration executed last time. Other operation amounts such as “operation time from the operation” may be used.

  (2) The restriction setting includes not only a setting made based on a user input (input by a setting person) but also a setting not based on a user input. For example, the color laser printer 1 itself may be configured to automatically set the restriction based on a predetermined condition.

  (3) In this embodiment, the command input means is configured by an input device provided in the color laser printer. However, the command input means may be configured by an input device provided in the computer 150. That is, a configuration in which an execution command can be input from the computer 150 side may be employed.

  (4) In this embodiment, the CPU provided in the color laser printer is configured as control means, setting means, and determination means, but these may be on the computer 150 side. For example, a control unit, a setting unit, and a determination unit may be configured by a CPU provided in the computer 150. For example, the computer 150 may be configured to execute soft calibration, and the software calibration based on the user request may be restricted by processing in the computer 150.

  (5) In the above embodiment, as the replaceable cartridge, the developer cartridge replaceable for each color has been exemplified. However, the configuration may be such that the developer cartridges of all colors are replaced integrally. In this case, when the integrated cartridge is replaced, it is determined Yes in S300. Further, such a developing cartridge may be combined with other parts (for example, a photoconductor in a direct tandem type color laser printer) to be a unitized cartridge.

  (6) In the above embodiment, engine calibration and soft calibration are performed separately as “calibration” in the claims, and both calibrations can be regulated based on the regulation settings. However, the configuration may be such that only one of the calibrations is restricted.

  (7) In the above embodiment, only engine calibration is performed in the user calibration process, but soft calibration may also be performed. For example, the process similar to S430 can be performed after S240 in FIG. If it does in this way, the user will be able to perform the update process which updates density | concentration conversion information arbitrarily, and will be able to regulate the update process with a password.

  (8) In the above embodiment, the calibration is performed immediately after the user inputs the execution command or after performing the predetermined process after the execution command is input, but the “calibration execution command by the user” As long as the user can arbitrarily set the calibration timing, the command is not limited to this. For example, a command for the user to specify calibration execution conditions (for example, execution conditions such as calibration execution every 3 hours and calibration execution every 500 sheets) is also included.

  (9) In the above embodiment, the color laser printer is exemplified by the 4-cycle method, but the color laser printer is not limited to such a 4-cycle method, and may be a color laser printer of another method such as a tandem method.

  (10) In the above embodiment, the density patch is formed on the intermediate transfer belt. However, the density patch may be formed on other objects. For example, it may be on a photoconductor or on a paper transport belt having a paper transport function.

1. Color laser printer (image forming device)
35 ... developer cartridge 91 ... CPU (control means, setting means, determination means)
93 ... RA M
98 ... the operation unit (command input hand stage)
99 ... Display section (notification means)
200: Image forming system

Claims (2)

A calibration unit that forms a density patch and measures the density of the density patch, and a setting unit that sets whether or not to limit execution of automatic calibration, which is calibration automatically performed by the apparatus ;
When the amount of operation from the previously executed calibration exceeds the low threshold, if the setting means is set not to limit the execution of automatic calibration, it is determined that automatic calibration is executed, and the setting means automatically If it is set to limit the execution of calibration, a determination means for determining that automatic calibration is not performed,
A command input means for inputting a user calibration execution command, which is a calibration for forming a density patch and measuring the density of the density patch, in accordance with an execution command from a user;
By the determining means, without performing automatic calibration if it is determined not to perform an automatic calibration, it has line automatic calibration in case it has been decided to perform further execution command to the command input means Control means for performing user calibration when input ,
Informing means for informing the user calibration to be executed when the operation amount from the previously executed calibration is equal to or higher than the low threshold when the setting means is set to restrict the execution of automatic calibration. And <br/>
The determination means further determines that automatic calibration is performed regardless of the setting when the operating amount from the calibration performed last time is equal to or higher than a high threshold which is a threshold equal to or higher than the low threshold. Image forming system. A calibration unit that forms a density patch and measures the density of the density patch, and a setting unit that sets whether or not to limit execution of automatic calibration, which is calibration automatically performed by the apparatus ;
When the amount of operation from the previously executed calibration exceeds the low threshold, if the setting means is set not to limit the execution of automatic calibration, it is determined that automatic calibration is executed, and the setting means automatically If it is set to limit the execution of calibration, a determination means for determining that automatic calibration is not performed,
A command input means for inputting a user calibration execution command, which is a calibration for forming a density patch and measuring the density of the density patch, in accordance with an execution command from a user;
By the determining means, without performing automatic calibration if it is determined not to perform an automatic calibration, it has line automatic calibration in case it has been decided to perform further execution command to the command input means Control means for performing user calibration when input ,
Informing means for informing the user calibration to be executed when the operation amount from the previously executed calibration is equal to or higher than the low threshold when the setting means is set to restrict the execution of automatic calibration. And <br/>
The determination means further determines that automatic calibration is performed regardless of the setting when the operating amount from the calibration performed last time is equal to or higher than a high threshold which is a threshold equal to or higher than the low threshold. Image forming apparatus.