JP2008083151A - Image forming apparatus and method for controlling the apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for performing a condition control process for matching a usage mode selected by a user, in an image forming apparatus that selectively performs a color image forming operation or a monochrome image forming operation and in a control method for the apparatus. <P>SOLUTION: When power source is turned on, the apparatus requests a user to select one among the following operations [A] to perform the condition control processing for all of a plurality of colors, [B] to perform condition control processing for only the color corresponding to a monochrome image, and [C] to stand by for the image forming operation, without performing the condition control processing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that adjusts image forming conditions based on a density detection result of a patch image, and a control method for the apparatus.

  In an electrophotographic image forming apparatus such as a printer, a copying machine, and a facsimile machine, a small test image (patch image) having a predetermined image pattern is formed as necessary. Then, based on the density detection result of the formed patch image, the operating conditions (image forming conditions) of each part of the apparatus when executing the image forming operation are adjusted to the optimum conditions (condition control processing).

  For example, Patent Document 1 describes a technique for executing a condition control process in a color image forming apparatus that forms a color image using a plurality of colors. That is, in this technique, when the apparatus is turned on, a plurality of patch images are formed for each color while changing the charging bias and the developing bias as density control factors that affect the image quality. Then, the optimum values of the charging bias and the developing bias are calculated based on the density detection result of the patch image, and the optimum image forming conditions are obtained by setting the charging bias and the developing bias to the optimum values thus obtained. It is done. An image can be formed with good and stable image quality by executing the image forming operation under the optimized image forming conditions.

JP 2001-75320 A

  Some color image forming apparatuses selectively execute a color image forming operation for forming a color image using a plurality of colors and a monochrome image forming operation for forming a monochrome image using one color. . As described above, in the image forming apparatus that selectively executes the color image forming operation and the monochrome image forming operation, the following problem may occur when the above-described condition control processing is executed.

  For some users, most of the images to be formed are monochrome images, and color images are rarely formed. For such a user, when forming a monochrome image, it is preferable to refrain from the condition control processing for unused colors and suppress the toner consumption associated with the first print time and the patch image formation. In particular, when the monochrome image to be formed is a character or the like and does not require gradation, it is possible to omit the condition control processing for the color used for forming the monochrome image and suppress the first print time and toner consumption. May meet user needs. On the other hand, when forming a color image that requires a high degree of density control, it is preferable to execute a color image forming operation by executing condition control processing for all colors when the power is turned on.

  As described above, there are various execution modes of the required condition control processing depending on the usage mode of the user's image forming apparatus. However, in the above-mentioned Patent Document 1, since the condition control process is executed for each color when the power is turned on, there are cases where it is not possible to appropriately cope with various user usage modes.

  The present invention has been made in view of the above problems, and in an image forming apparatus that selectively executes a color image forming operation and a monochrome image forming operation, and a control method for the apparatus, a condition control process according to a user's usage mode is performed. An object is to provide a technology that enables execution.

In order to achieve the above object, an image forming apparatus according to the present invention performs a color image forming operation for forming a color image using a plurality of colors and a monochrome image for forming a monochrome image using one of the plurality of colors. Image forming means for selectively executing the forming operation, and condition control processing for adjusting the image forming condition when executing the image forming operation to the optimum condition based on the density detection result of the patch image formed by the image forming means. Control means that executes as necessary, and the control means requests the user to select one of the following operations [A] to [C] when the power is turned on, and the user When one of the operations [A] to [C] is selected, the selection operation is executed.
[A] The condition control process is executed for all of a plurality of colors.
[B] The condition control process is executed only for the color corresponding to the monochrome image.
[C] Wait for the image forming operation without executing the condition control process.

The image forming apparatus control method according to the present invention includes a color image forming operation for forming a color image using a plurality of colors, and a monochrome image forming operation for forming a monochrome image using one of the plurality of colors. In the image forming apparatus that selectively executes the image forming apparatus, a condition control process that adjusts the image forming condition to the optimum condition when forming the patch image and executing the image forming operation based on the density detection result of the patch image is necessary. A method for controlling an image forming apparatus to be executed in response to a request to the user to select one of the following operations [A] to [C] when the power is turned on to achieve the above object: In addition, when the user selects one of the following operations [A] to [C], the selection operation is executed.
[A] The condition control process is executed for all of a plurality of colors.
[B] The condition control process is executed only for the color corresponding to the monochrome image.
[C] Wait for the image forming operation without executing the condition control process.

  In the invention configured as described above, when the power is turned on, the user is requested to select one of the operations [A] to [C], and the condition control process is executed based on the user's selection. is doing. Therefore, it is possible to execute an appropriate condition control process in accordance with the usage mode of the user. In other words, in the invention configured as described above, for example, when a monochrome image is formed, the user selects the operation [B], so that the condition control process for colors not used for monochrome image formation is refrained from being performed first. It is possible to suppress print time and toner consumption. In particular, when the monochrome image to be formed is a character and the like and does not require gradation, the user can select the operation [C] to omit the condition control processing for the color used for monochrome image formation, It is possible to suppress the first print time and toner consumption. On the other hand, when forming a color image, when the user selects the operation [A], when the power is turned on, the condition control process is executed for all colors, and a good color image forming operation is executed. It is possible.

  By the way, since only monochrome image formation was scheduled at the time of power-on, there may be a case where a user who selects the operation [B] or [C] at the time of power-on desires color image formation after the selection. Therefore, in order to cope with such user usage mode, the color image forming operation is performed only after the power is turned on when the user selects the operation [B] or [C] when the power is turned on. In the case where the process is executed, the condition control process may be executed for all of a plurality of colors prior to the color image forming operation. If this is the case, even if the user selects the above-mentioned operation [B] or [C] when the power is turned on, if a color image formation is desired, a good color image formation can be achieved. This is because execution is possible.

  In the above-described invention, the condition control process is executed for all the colors regardless of which of the operations [B] and [C] is selected when the power is turned on. However, if the operation [B] is selected when the power is turned on, the condition control process has already been executed for the color corresponding to the monochrome image. Therefore, when the user selects the operation [B] when the power is turned on and the color image forming operation is executed for the first time after the power is turned on, the control means is preceded by the color image forming operation. The condition control process is executed for all colors except for the color corresponding to the monochrome image from a plurality of colors. On the other hand, when the user selects the operation [C] when the power is turned on, When performing a color image forming operation, prior to the color image forming operation, a condition control process may be executed for all of a plurality of colors. Such a configuration is preferable because it is possible to avoid a redundant operation in which color condition control processes corresponding to monochrome images overlap.

  In addition, as described above, depending on the user, when the operation [B] or [C] is selected at the time of power-on and the color image is formed after the selection, the color image actually formed is viewed. In some cases, it is desired to determine whether or not to execute the condition control process for all colors. Therefore, in order to meet such user needs, when the user selects the operation [B] or [C] when the power is turned on, the color image forming operation is executed for the first time after the power is turned on. In this case, after outputting at least one sheet on which a color image is formed to the user, it is selected whether or not to execute condition control processing for all of a plurality of colors based on the color image on the sheet. When the user selects to execute the condition control process for all of the plurality of colors, the condition control process may be executed. If this is the case, it is possible to determine whether or not to execute the condition control processing for all colors by seeing the color image that is actually formed by the user, and more suited to user needs. This is because the condition control process can be executed.

  In the above-described invention, when the user determines that the condition control process is necessary regardless of which of the operations [B] and [C] is selected when the power is turned on, the condition control process is performed for all colors. Is running. However, if the operation [B] is selected when the power is turned on, the condition control process has already been executed for the color corresponding to the monochrome image. Therefore, when the user selects the operation [B] when the power is turned on and the color image forming operation is executed for the first time after the power is turned on, the paper on which the color image is formed is loaded. After outputting to at least one user, the user is requested to select whether or not to execute the condition control process based on the color image of the paper, and the user selects to execute the condition control process In this case, the condition control processing is executed for all colors except for the color corresponding to the monochrome image from a plurality of colors. On the other hand, when the user selects the operation [C] when the power is turned on, the power is turned on. When a color image forming operation is performed for the first time after that, at least one sheet on which a color image is formed is output to the user, and then a condition control process is performed based on the color image on the sheet. With requests the user to select whether may be configured to perform the condition control processing for all the plurality of colors when the user selects to execute the condition controlling process. Such a configuration is preferable because it is possible to avoid a redundant operation in which condition control processing for colors corresponding to a monochrome image is duplicated.

  FIG. 1 is a diagram showing an embodiment of an image forming apparatus to which the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. This apparatus forms a full color image by superposing four color toners (developers) of yellow (Y), cyan (C), magenta (M), and black (K), or only black (K) toner. The image forming apparatus forms a monochrome image using In this image forming apparatus, when an image signal is given to the main controller 11 from an external device such as a host computer, the CPU 101 provided in the engine controller 10 controls each part of the engine unit EG in response to a command from the main controller 11. Then, a predetermined image forming operation is executed, and an image corresponding to the image signal is formed on the sheet S.

  In the engine unit EG, the photosensitive member 22 is provided to be rotatable in the arrow direction D1 in FIG. A charging roller 23, a rotary developing unit 4 and a cleaning unit 25 are arranged around the photosensitive member 22 along the rotation direction D1. The charging roller 23 is applied with a predetermined charging bias, and charges the outer peripheral surface of the photosensitive member 22 to a predetermined surface potential. The cleaning unit 25 removes the toner remaining on the surface of the photosensitive member 22 after the primary transfer, and collects it in a waste toner tank provided inside. The photosensitive member 22, the charging roller 23, and the cleaning unit 25 integrally constitute the photosensitive member cartridge 2, and the photosensitive member cartridge 2 is detachably attached to the apparatus main body as a whole.

  Then, the light beam L is irradiated from the exposure unit 6 toward the outer peripheral surface of the photosensitive member 22 charged by the charging roller 23. The exposure unit 6 exposes the light beam L onto the photosensitive member 22 in accordance with an image signal given from an external device, and forms an electrostatic latent image corresponding to the image signal.

  The electrostatic latent image thus formed is developed with toner by the developing unit 4. That is, in this embodiment, the developing unit 4 is configured as a support frame 40 that is rotatably provided about a rotation axis center orthogonal to the paper surface of FIG. A yellow developing device 4Y, a cyan developing device 4C, a magenta developing device 4M, and a black developing device 4K are provided. The developing unit 4 is rotationally driven by a developing unit drive motor 47 that is a stepping motor controlled by the engine controller 10. Further, the apparatus main body is provided with a rotary lock 45 that comes into contact with and separates from the developing unit 4. If necessary, the rotary lock 45 abuts on the outer peripheral portion of the support frame 40 of the developing unit 4 to act as a brake and lock mechanism that restrains the rotation of the developing unit 4 and stops and positions the developing unit 4 at a predetermined position. .

  Then, based on a control command from the engine controller 10, when the developing unit 4 is driven to rotate, the developing devices 4Y, 4C, 4M, and 4K are selectively positioned at predetermined positions facing the photoconductor 22. A developing roller 44 that is provided in the developing unit and carries toner of a selected color is disposed to face the photosensitive member 22 with a predetermined gap therebetween, and the surface of the photosensitive member 22 from the developing roller 44 at the opposed position. Toner is applied. As a result, the electrostatic latent image on the photosensitive member 22 is visualized with the selected toner color.

  The toner image developed by the developing unit 4 as described above is primarily transferred onto the intermediate transfer belt 71 of the transfer unit 7 in the primary transfer region TR1. The transfer unit 7 includes an intermediate transfer belt 71 stretched between a plurality of rollers 72 to 75, and a drive unit (not shown) that rotates the intermediate transfer belt 71 in a predetermined rotation direction D2 by rotationally driving the roller 73. It has. When a color image is transferred to the sheet S, the color toner images formed on the photosensitive member 22 are superimposed on the intermediate transfer belt 71 to form a color image, and the color image is taken out from the cassette 8 and conveyed. The color image is secondarily transferred onto the sheet S conveyed to the secondary transfer region TR2 along the FF.

  The secondary transfer region TR2 is a nip portion where the surface of the intermediate transfer belt 71 stretched over the roller 73 and the secondary transfer roller 86 that contacts and separates from the belt surface. The sheets S stacked and stored in the cassette 8 are taken out one by one by the rotation of the pickup roller 88 and placed on the transport path FF. Then, the feed rollers 84 and 85 and the gate roller 81 are rotated and conveyed to the secondary transfer region TR2 along the conveyance path FF.

  At this time, in order to correctly transfer the image on the intermediate transfer belt 71 to a predetermined position on the sheet S, the timing of feeding the sheet S to the secondary transfer region TR2 is managed. Specifically, it is as follows. A gate roller 81 is provided on the front side of the secondary transfer region TR2 on the transport path FF, and a pre-gate sheet detection sensor 801 is further provided on the front side thereof. When the pre-gate sheet detection sensor 801 detects that the sheet S conveyed on the conveyance path FF has arrived, the conveyance of the sheet S is temporarily stopped and synchronized with the timing of the circumferential movement of the intermediate transfer belt 71. By restarting the rotation of the gate roller 81, the sheet S is fed into the secondary transfer region TR2 at a predetermined timing. In this way, the toner image formed on the intermediate transfer belt 71 is secondarily transferred onto the surface of the sheet S passing through the secondary transfer region TR2.

  The sheet S on which the color image is thus formed is fixed with the toner image by the fixing unit 9 and is conveyed to the discharge tray portion 89 provided on the upper surface portion of the apparatus main body via the pre-discharge roller 82 and the discharge roller 83. Further, when images are formed on both sides of the sheet S, when the rear end portion of the sheet S on which the image is formed on one side as described above is conveyed to the reversal position PR behind the pre-discharge roller 82. The rotation direction of the discharge roller 83 is reversed, whereby the sheet S is conveyed in the direction of the arrow D3 along the reverse conveyance path FR. Then, it is placed again on the transport path FF before the gate roller 81. At this time, the image is transferred first on the surface of the sheet S that contacts the intermediate transfer belt 71 and transfers the image in the secondary transfer region TR2. It is the opposite surface. In this way, images can be formed on both sides of the sheet S.

  In addition to the above-mentioned pre-gate sheet detection sensor 801, sheet detection sensors 802 to 804 for detecting whether or not a sheet has passed on the path are provided at positions on the sheet conveyance path FF and the reverse conveyance path FR. The sheet conveyance timing is managed based on the outputs of these sensors, and jam detection is performed at each position.

  A cleaner 76 is disposed in the vicinity of the roller 75. The cleaner 76 includes a cleaner blade 761 that can be moved toward and away from the roller 75 by an electromagnetic clutch (not shown), and a waste toner tank 762. Then, the cleaner blade 761 abuts on the surface of the intermediate transfer belt 71 stretched over the roller 75 in a state of moving to the roller 75 side, and the toner remaining on the outer peripheral surface of the intermediate transfer belt 71 after the secondary transfer is removed. Remove by scraping. The toner scraped off is stored in a waste toner tank 762. The waste toner tank 762 is provided with a waste toner sensor 763 for detecting that the tank is full.

  The cleaner blade 761 is controlled to be separated and abutted so as to remove the toner remaining on the intermediate transfer belt 71 in the same rotation when the image is transferred to the sheet S in the secondary transfer region TR2. The Therefore, for example, when the apparatus continuously forms monochrome images, the image transferred to the intermediate transfer belt 71 in the primary transfer region TR1 is immediately transferred to the sheet S in the secondary transfer region TR2, and thus the cleaner blade 761. Is held in contact. On the other hand, when forming a color image, it is necessary to keep the cleaner blade 761 away from the intermediate transfer belt 71 while the toner images of the respective colors are superimposed on each other. Then, the toner images of the respective colors are superimposed on each other to complete a full-color image, and the cleaner blade 761 is brought into contact with the intermediate transfer belt 71 in order to remove residual toner in the same rotation as the secondary transfer onto the sheet S. The Rukoto.

  Further, a density sensor 60 and a vertical synchronization sensor 77 are arranged in the vicinity of the roller 75. The density sensor 60 is provided to face the surface of the intermediate transfer belt 71 and measures the image density of the toner image formed on the outer peripheral surface of the intermediate transfer belt 71 as necessary. Based on the measurement results, this apparatus adjusts the operating conditions of each part of the apparatus that affects the image quality, for example, the developing bias applied to each developing device, the intensity of the light beam L, and the like. The density sensor 60 is configured to output a signal corresponding to the image density of a region of a predetermined area on the intermediate transfer belt 71 using, for example, a reflection type photosensor. The CPU 101 can detect the image density of each part of the toner image on the intermediate transfer belt 71 by periodically sampling the output signal from the density sensor 60 while rotating the intermediate transfer belt 71.

  The vertical synchronization sensor 77 is a sensor for detecting the reference position of the intermediate transfer belt 71 and is used to obtain a synchronization signal output in association with the rotational drive of the intermediate transfer belt 71, that is, a vertical synchronization signal Vsync. Functions as a sensor. In this apparatus, the operation of each part of the apparatus is controlled based on the vertical synchronization signal Vsync in order to align the operation timing of each part and accurately superimpose the toner images formed in the respective colors.

  Further, memory tags 49Y, 49C, 49M, and 49K are respectively attached to the outer peripheral surfaces of the developing devices 4Y, 4C, 4M, and 4K that correspond to the side surfaces of the developing unit 4 that has a substantially cylindrical shape as a whole. For example, a memory tag 49Y attached to the yellow developing device 4Y is electrically connected to the memory 491Y for storing data relating to the manufacturing lot and usage history of the developing device, the remaining amount of built-in toner, and the like. Loop antenna 492Y. In addition, memory chips 491C, 491M, and 491K and loop antennas 492C, 492M, and 492K are also provided in the memory tags 49C, 49M, and 49K provided in the other developing devices, respectively.

  On the other hand, a wireless communication antenna 109 is also provided on the apparatus main body side. The wireless communication antenna 109 is driven by a transceiver 105 connected to the CPU 101, and by performing wireless communication with the wireless communication antenna on the developing device side, the CPU 101 and a memory provided in the developing device Various data such as consumables management related to the developing device are managed by transmitting and receiving data between them.

  Further, as shown in FIG. 2, this apparatus includes a display unit 12 that is controlled by the CPU 111 of the main controller 11. The display unit 12 is constituted by, for example, a liquid crystal display, and in accordance with a control command from the CPU 111, the operation guidance to the user, the progress of the image forming operation, the occurrence of an abnormality in the apparatus, the replacement timing of any unit, etc. A predetermined message for notification is displayed.

  In FIG. 2, reference numeral 113 denotes an image memory provided in the main controller 11 for storing an image given from an external device such as a host computer via the interface 112. Reference numeral 106 is a ROM for storing a calculation program executed by the CPU 101, control data for controlling the engine unit EG, and the like. Reference numeral 107 is a RAM for temporarily storing calculation results in the CPU 101 and other data. is there.

  FIG. 3 is a schematic diagram showing the stop position of the developing unit 4. The developing unit 4 is positioned and fixed at three kinds of positions shown in FIG. 3 by a developing unit drive motor 47 and a rotary lock 45. The three types of positions are: (a) home position; (b) development position; (c) attachment / detachment position. Among these positions, (a) the home position is a position that is positioned when the image forming apparatus is in a standby state in which no image forming operation is performed. As shown in FIG. Each of the provided developing rollers 44 is in a position separated from the photosensitive member 22.

  Further, (b) the development position is a position that is positioned when the electrostatic latent image on the photosensitive member 22 is visualized with a selected toner color. As shown in FIG. 3B, a developing roller provided in one developing device (the developing roller 44 provided in the yellow developing device 4Y in the example shown in FIG. 3) is disposed to face the photosensitive member 22, and has a predetermined value. By applying a developing bias, the electrostatic latent image is visualized with toner.

  Further, (c) the attach / detach position is a position that can be taken only when the attach / detach operation of the developing device is performed. When the developing unit 4 is positioned at this attaching / detaching position, as shown in FIG. 3C, one developing device appears in the opening 124 provided on the side surface of the external housing of the apparatus and is taken out through the opening 124. Will be able to. FIG. 3C shows a state in which the black developing device 4 </ b> K appears in the opening 124. In addition, a developing device can be newly attached to the support frame 40 to which the developing device is not attached. In this attaching / detaching position, the developing roller provided in any developing device is placed at a position separated from the photosensitive member 22. In this way, only one developing device that appears in the opening 124 when the developing unit 4 is positioned at the attachment / detachment position can be taken out. That is, when the developing unit 4 is positioned at the home position shown in FIG. 3A or the developing position shown in FIG. 3B, none of the developing devices can be taken out from the opening 124. Therefore, the user does not inadvertently attach and detach the developing device and damage the apparatus. In this image forming apparatus, the development position and the attachment / detachment position described above are set for each of the four developing devices 4Y, 4M, 4C, and 4K.

  When the developing unit 4 is positioned at the developing position, as shown in FIG. 3B, the wireless communication antenna provided in one developing unit is positioned at a position facing the main body side wireless communication antenna 109. Is done. 3B, the developing roller 44 of the developing device 4Y is adjacent to the downstream side in the rotation direction D3 of the developing unit 4 when viewed from the developing device 4Y. The wireless communication antenna 492K provided in the developing device 4K at the position is positioned at a position facing the main body side wireless communication antenna 109. That is, in this state, wireless communication is performed between the main body side wireless communication antenna 109 and the developing device 4K side wireless communication antenna 492K, and the information stored in the memory 491K provided in the developing device 4K is stored. Read out. Also, new information is written in the memory 491K.

  FIG. 4 is a flowchart showing a startup process when the power is turned on in the present embodiment. In this embodiment, when the power is turned on, the startup process shown in FIG. In such activation processing, first, each part of the apparatus is initialized (step S101). In this initialization operation, the photosensitive member 22 and the intermediate transfer belt 71 are rotated to clean their surfaces, the developing unit 4 is positioned at a predetermined home position, and the temperature of the fixing unit 9 is set to a predetermined fixing temperature. And so on. Since these initialization operations already have many well-known techniques, description thereof will be omitted.

Subsequent to the completion of the initialization operation, display is made on the display unit 12 so as to select any one of the operations [A] to [C] (step S102). Here, each of the operations [A] to [C]
[A] an operation for executing condition control processing for all colors of yellow (Y), cyan (C), magenta (M), and black (K) used for color image formation;
[B] An operation for executing condition control processing only for black (K) used for monochrome image formation;
[C] This is an operation for waiting for the image forming operation without executing the condition control process. Here, it is needless to say that the specific content displayed on the display unit 12 is not necessarily as described in the above [A] to [C]. That is, it is only necessary that the user who has viewed the display unit 12 can display an appropriate operation in accordance with the image forming mode desired by the user among the operations [A] to [C]. For example, if the user desires a color image forming operation, the operation [A] is performed. If the user is planning only a monochrome image forming operation, the operation [B] is performed. If the image quality is not requested, the operation [C] may be displayed on the display unit 12 so as to be executed based on the user's selection. In the following description, the user may be requested to select an operation via the display unit 12, but the same applies to these cases. In the present specification, “condition control processing” refers to processing for adjusting the image forming condition when executing the image forming operation to the optimum condition based on the density detection result of the patch image.

  When the user who has viewed the display on the display unit 12 in step S102 selects the operation [A] (that is, when “YES” is determined in step S103), color patch processing is executed (step S104). .

  FIG. 5 is a flowchart showing color patch processing in the present embodiment. In this specification, “color patch processing” refers to patch processing for all colors of yellow (Y), cyan (C), magenta (M), and black (K) used when forming a color image. Means. “Patch processing” refers to the detection of the image density by forming a patch image while variously changing and setting the image formation conditions in order to keep the formed image at a constant image quality. A process for adjusting the image forming conditions based on the above. In the patch processing according to the present embodiment, the development bias and the exposure power are adjusted as control factors that affect the image quality among the operation parameters that determine the operation conditions of each part of the apparatus. Various other operating parameters that function as control factors are known, and there are many well-known techniques for image quality control principles and control methods using them, so only the processing flow is described here. Briefly described.

  First, for each toner color, the optimum developing bias, that is, the optimum value of the developing bias to be applied to the developing roller 44 such as each developing device 4Y during the image forming operation is calculated. Specifically, one toner color is selected (step S201), and a patch image of a predetermined pattern is formed with each bias value while changing the development bias in multiple stages for the toner color (step S202). Then, the image density of each patch image is detected by the density sensor 60 (step S203). When the image density of each patch image is obtained, the correspondence between the development bias and the image density can be determined from these values. Based on this relationship, the development bias value is set so that the image density matches a predetermined target density. Is calculated. Thereby, the optimum developing bias is obtained (step S204). However, if the optimum value is not within the development bias variable range of the apparatus, the value closest to the optimum value calculated in the variable range is set as the optimum development bias. When the optimum developing bias is obtained for one toner color in this way, the above-described processing S201 to S204 are repeated until the processing for all the toner colors is completed (step S205). By doing so, an optimum developing bias for each toner color is required.

  Subsequently, for each toner color, an optimum exposure power, that is, an optimum value of the intensity of the exposure beam L when an electrostatic latent image corresponding to the toner color is formed on the photosensitive member 22 is calculated (steps S206 to S210). ). The processing here is the same as the optimum development bias calculation processing (steps S201 to S205) described above except that the control factor is exposure power instead of the development bias, but a patch image to be formed as necessary. The image patterns may be different. In this case, it is preferable to use the optimum value obtained previously as the setting value of the developing bias. Thus, the optimum development bias and the optimum exposure power are obtained for all toner colors, and the color patch process is terminated.

  Returning to FIG. 4, when the color patch process (step S104) is completed, the image forming conditions are set to the optimum conditions obtained by the color patch process (step S105), and the start-up process is completed. By executing the subsequent image forming operation under this optimum condition, it is possible to stably form an image with a desired image quality.

  Next, if “NO” is determined in the step S103, it is determined whether or not the user has selected the operation [B] (step S106). If "NO" is determined in the step S106, the user determines that the operation [C] has been selected, ends the activation process, and waits for an image forming operation (that is, waits for an image forming command). On the other hand, if “YES” is determined in step S106, monochrome patch processing is executed (step S107).

  FIG. 6 is a flowchart showing monochrome patch processing in the present embodiment. In this specification, “monochrome patch processing” means that patch processing is performed only for black (K) used when forming a monochrome image. In the monochrome patch processing, after selecting black K as the target of patch processing (step S301), the development bias is changed as a control factor to calculate the optimal development bias (steps S302 to S304) in the same manner as the color patch processing described above. Subsequently, the optimum exposure power is calculated by changing the exposure power as a control factor (steps S305 to S307).

  Returning to FIG. 4, when the monochrome patch processing (step S107) is completed, the image forming conditions are set to the optimum conditions obtained by the monochrome patch processing (step S108), and the start-up processing is completed. By executing the subsequent monochrome image forming operation under this optimum condition, it is possible to stably form a monochrome image with a desired image quality.

  As described above, in this embodiment, when the power is turned on, the user is requested to select one of the operations [A] to [C] via the display unit 12 and the user can select the operation. Based on the condition control processing. Therefore, it is possible to execute an appropriate condition control process in accordance with the usage mode of the user.

  For example, when forming a monochrome image exclusively, the user can select the operation [B] to suppress the first print time and the toner consumption by avoiding the condition control processing for the color that is not used for the monochrome image formation. Is possible. In particular, when the monochrome image to be formed is a character and the like and does not require gradation, the user can select the operation [C] to omit the condition control processing for the color used for monochrome image formation, It is possible to suppress the first print time and toner consumption. On the other hand, when forming a color image, when the user selects the operation [A], when the power is turned on, the condition control process is executed for all colors, and a good color image forming operation is executed. It is possible.

  By the way, the user who selected the operation [B] or [C] during the start-up process (that is, when the power was turned on), because only monochrome image formation was scheduled at the time of power-on, There is a case where image formation is desired. That is, in this case, the color for which the condition control process has been completed in the startup process is only black (K) used for monochrome image formation. On the other hand, since color image formation requires a high degree of density control, it is preferable that the condition control processing is completed for all colors before the color image formation is executed. Accordingly, a technique for enabling good color image formation even when the operation [B] or [C] is selected during the start-up process in order to respond to such user needs will be described below. .

  FIG. 7 is a flowchart illustrating an example of a flow from an image formation command to execution of an image formation operation. In the present embodiment, after the start-up process described with reference to FIG. 4 is completed, the CPU 101 waits for an image formation command from the main controller 11 (step S401). When the CPU 101 receives the image formation command, the CPU 101 determines whether the image formation command is a command for requesting the first color image formation after the power is turned on (step S402). When it is determined that the command is not a command for requesting the first color image formation after the power is turned on (that is, when “NO” is determined in step S402), the monochrome or color image forming operation is executed as it is (step S406). . That is, when “NO” is determined in step S402, the image formation command is a command requesting monochrome image formation or a command requesting color image formation for the second and subsequent times after the power is turned on. If the image formation command is a command for requesting color image formation for the second and subsequent times after the power is turned on, the condition control processing has already been completed for all colors used for color image formation, as will be described later. Therefore, it is possible to form a good color image by executing the color image forming operation as it is.

  On the other hand, when it is determined that the command is for requesting the first color image formation after the power is turned on (that is, when “YES” is determined in step S402), the operation [B] or [C] is selected in the startup process. It is determined whether or not (step S403).

  If it is determined that the operation [B] or [C] is not selected in the activation process (that is, if “NO” is determined in step S403), the color image forming operation is executed as it is (step S406). That is, in this case, the user selects the operation [A] in the startup process. Therefore, since the condition control processing has already been completed for all the colors used for color image formation, a good color image can be formed even if the color image forming operation is executed as it is.

  On the other hand, when it is determined that the operation [B] or [C] is selected in the activation process (that is, when “YES” is determined in step S403), the color for which the condition control process is completed in the activation process is At most, only black (K) used for monochrome image formation is used. Therefore, in such a case, condition control processing is executed for all colors used in the color image prior to the color image forming operation (steps S404 and S405). Then, following the completion of the condition control process, a color image forming operation is executed (step S406).

  As described above, in this embodiment, when the user selects the operation [B] or [C] during the startup process (that is, when the power is turned on), color image formation is performed for the first time after the power is turned on. When the operation is executed, the condition control process is executed for all of a plurality of colors prior to the color image forming operation. Therefore, even when the user selects the above operation [B] or [C] when the power is turned on, if a color image formation is desired, a good color image formation can be performed. In addition, since the condition control process is executed for all colors in the first color image forming operation after the power is turned on, it goes without saying that a good color image is also formed in the second and subsequent color image formation.

  By the way, depending on the user, as described above, when the operation [B] or [C] is selected at the time of power-on and the color image is formed after the selection, the color image actually formed is viewed. In some cases, it is desired to determine whether or not to execute the condition control process for all colors. A technique that can meet such user needs will be described next.

  FIG. 8 is a flowchart illustrating another example of a flow from an image formation command to execution of an image formation operation. The operations of steps S5001 to S5004 in the flow of FIG. 8 are the same as the operations of steps S401 to S403 and S406 of the flow of FIG. 7, and thus description thereof will be omitted. In the following description, the characteristic portions of the flow of FIG. To do.

  In the flow shown in FIG. 8, if it is determined in step S5003 that [B] or [C] has been selected in the activation process (that is, if “YES” is determined in step S5003), the first color image is displayed. The sheet S is formed and output to the user (step S5005). Then, the user is requested to select whether or not to execute the condition control processing for all colors used for color image formation based on the output color image of the sheet S via the display unit 12 (Step S1). S5006). If the user determines that the condition control process is not necessary (that is, if “NO” is determined in step S5007), color image formation is executed from the second color image (step S5008). Here, the reason for executing the image formation from the second color image is that the first color image has already been formed in step S5005.

  On the other hand, if it is determined in step S5007 that the user needs condition control processing for all colors, the condition control processing is executed for all colors (steps S5009 and S5010). Then, based on the image forming conditions optimized by the condition control process, a color image forming operation is executed from the first sheet (S5011).

  As described above, in the flow shown in FIG. 8, when the user selects the operation [B] or [C] when the activation process is performed (that is, when the power is turned on), When the image forming operation is executed, after at least one sheet S (paper) on which a color image is formed is output to the user, the condition control process is performed for all colors based on the color image of the sheet S. Is requested to the user via the display unit 12 to select whether or not to execute. When the user selects to execute the condition control process for all colors, the condition control process is executed. Therefore, it is possible to determine whether or not to execute the condition control process for all colors by looking at the color image actually formed by the user, and it is possible to execute the condition control process more suited to the user needs. Yes.

  As described above, in this embodiment, the engine unit EG that executes the image forming operation functions as the “image forming unit” of the present invention, and the CPU 101 that controls the operation of the engine unit EG of the present invention “control unit”. Is functioning as Further, yellow (Y), cyan (C), magenta (M), and black (K) used for color image formation correspond to the “plural colors” of the present invention, and black (K) represents the “monochrome image” of the present invention. Corresponds to “color corresponding to”.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the flow shown in FIG. 8, the first image of the color image to be actually formed by the image formation command is formed on the sheet S as a criterion for determining whether or not the condition control is executed (step S5005). Output to the user. However, the image that is output as a criterion for determining whether or not to execute the condition control process does not have to be a color image that is actually formed by an image formation command. For example, a predetermined test pattern color image may be output as shown in FIG. Here, FIG. 9 is a flowchart showing still another example of the flow from the image formation command to the execution of the image formation operation. In the flow shown in FIG. 9, when it is determined that the condition control process is not necessary (that is, when “NO” is determined in step S6007), it is necessary to execute the image forming operation from the first sheet. Other points are the same as the flow shown in FIG.

  In the flow shown in FIG. 8, the first image is formed on the sheet S and output as a reference for determining whether or not the condition control process is to be executed. However, the number of color images output as a criterion for determining whether or not to execute the condition control process is not limited to one, and may be two or more.

  In the flow shown in FIG. 7, the condition control process is executed for all colors regardless of which of the operations [B] and [C] is selected in the activation process (steps S404 and S405). However, when the operation [B] is selected in the startup process, the condition control process has already been executed for black (K). Therefore, when the operation [B] is selected in the startup process, the condition control process may be executed only for yellow (Y), cyan (C), and magenta (M) except black (K). Such a configuration is preferable because it is possible to avoid a redundant operation in which the condition control processes for black (K) overlap.

  In the flows shown in FIGS. 8 and 9, when the user determines that the condition control process is necessary regardless of which of the operations [B] and [C] is selected in the startup process, all the colors are displayed. Condition control processing is executed (steps S5009, S5010, S6009, S6010). However, when the operation [B] is selected in the startup process, the condition control process has already been executed for black (K). Therefore, when the operation [B] is selected in the start-up process and the user determines that the condition control process is necessary, yellow (Y) except cyan (K), cyan (C), magenta (M The condition control process may be executed only for). Such a configuration is preferable because it is possible to avoid a redundant operation in which the condition control processes for black (K) overlap.

  In the above embodiment, the monochrome image is formed by black (K). However, the color used for forming the monochrome image is not limited to black (K), and other colors may be used.

1 is a diagram showing an embodiment of an image forming apparatus to which the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus in FIG. 1. FIG. 3 is a schematic diagram showing a stop position of the developing unit 4. The flowchart which shows the starting process at the time of power activation. The flowchart which shows a color patch process. The flowchart which shows a monochrome patch process. 6 is a flowchart illustrating an example from an image formation command to execution of an image formation operation. 9 is a flowchart illustrating another example from an image formation command to execution of an image formation operation. 10 is a flowchart showing still another example from an image formation command to execution of an image formation operation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... CPU (control means) 12 ... Display part 4 ... Development unit 4Y, 4M, 4C, 4K ... Developer 6 ... Exposure unit 60 ... Density sensor 71 ... Intermediate transfer belt EG ... Engine part ( Image forming means), S ... sheet (paper)

Claims (6)

An image forming means for selectively executing a color image forming operation for forming a color image using a plurality of colors and a monochrome image forming operation for forming a monochrome image using one of the plurality of colors;
A control unit that executes, as necessary, a condition control process that adjusts an image forming condition when performing an image forming operation to an optimum condition based on a density detection result of a patch image formed by the image forming unit;
The control means requests the user to select one of the following operations [A] to [C] when the power is turned on, and the user performs one of the following operations [A] to [C]. An image forming apparatus that performs the selection operation when selected.
[A] The condition control process is executed for all of the plurality of colors.
[B] The condition control process is executed only for the color corresponding to the monochrome image.
[C] Wait for the image forming operation without executing the condition control process.   When the user selects the operation [B] or [C] when the power is turned on and the color image forming operation is executed for the first time after the power is turned on, the color image formation is performed. The image forming apparatus according to claim 1, wherein the condition control process is executed for all of the plurality of colors prior to the operation. The control means includes
When the user selects the operation [B] when the power is turned on, and when the color image forming operation is executed for the first time after the power is turned on, the plurality of colors are selected prior to the color image forming operation. Performing the condition control process for all colors except for the color corresponding to the monochrome image,
When the user selects the operation [C] when the power is turned on and when the color image forming operation is executed for the first time after the power is turned on, the plurality of colors are selected prior to the color image forming operation. The image forming apparatus according to claim 1, wherein the condition control process is executed for all.   When the user selects the operation [B] or [C] when the power is turned on and the color image forming operation is executed for the first time after the power is turned on, a color image is formed. After outputting to the user at least one printed sheet, the user is requested to select whether or not to execute the condition control processing for all of the plurality of colors based on the color image of the sheet. The image forming apparatus according to claim 1, wherein when the user selects to execute the condition control process for all of the plurality of colors, the condition control process is executed. The control means includes
When the user selects the operation [B] when the power is turned on and when the color image forming operation is executed for the first time after the power is turned on, at least one sheet on which the color image is formed is given to the user. If the user is requested to select whether or not to execute the condition control process based on the color image of the paper, and the user selects to execute the condition control process, Performing the condition control process for all colors excluding the color corresponding to the monochrome image from the plurality of colors,
When the user selects the operation [C] when the power is turned on, and when the color image forming operation is executed for the first time after the power is turned on, at least one sheet on which the color image is formed is given to the user. If the user selects whether to execute the condition control process based on the color image of the paper after the output, and if the user selects to execute the condition control process, The image forming apparatus according to claim 1, wherein the condition control process is executed for all of a plurality of colors. In an image forming apparatus that selectively executes a color image forming operation for forming a color image using a plurality of colors and a monochrome image forming operation for forming a monochrome image using one of the plurality of colors, a patch image Is a control method for an image forming apparatus that executes a condition control process for adjusting an image forming condition to an optimum condition when an image forming operation is executed based on a density detection result of the patch image. And
When the user requests to select one of the following operations [A] to [C] when the power is turned on, and the user selects one of the following operations [A] to [C] A control method for an image forming apparatus, wherein the selection operation is executed.
[A] The condition control process is executed for all of the plurality of colors.
[B] The condition control process is executed only for the color corresponding to the monochrome image.
[C] Wait for the image forming operation without executing the condition control process.

Images