JP2005121986A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To afford facility to an operator even when an error is caused in the midst of adjusting an image forming condition in an image forming apparatus which adjusts the image forming condition based on a result obtained by detecting the density of a patch image and its control method. <P>SOLUTION: When a power source is turned on by a user, patch processing (step S104) is performed to adjust the image forming condition. If setting for inhibiting the patch processing is inputted when the power source is turned on (steps S101 and S103), the patch processing is not performed and the image forming condition is set to a specified default condition (step S108) and then a status sheet is outputted (steps S109 and S107). <P>COPYRIGHT: (C)2005,JPO&NCIPI

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 thereof.

  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 needed, and the image density is adjusted by a density sensor. A predetermined image quality can be stably obtained by detecting and adjusting the operation condition (image forming condition) of each part of the apparatus based on the detection result.

  For example, in the image forming apparatus described in Patent Document 1, the apparatus warms up immediately after the apparatus is turned on or immediately after the sleep mode is canceled, and when the apparatus is completed, the density adjustment process is subsequently executed. To do. In this density adjustment processing, the optimum values of the charging bias and the developing bias as density control factors that affect the image quality are calculated based on the density detection result of the solid image or halftone image formed as the patch image. Then, by setting the charging bias and the developing bias to the optimum values thus obtained, the optimum image forming conditions can be obtained. An image can be formed with good and stable image quality by executing the image forming operation under the optimized image forming conditions.

  Further, in this type of image forming apparatus, in order to notify the operator such as a user or an operator of the state of the apparatus, a status sheet describing the operation parameters of each part of the apparatus and the result of self-diagnosis processing is output as necessary. There is something that was configured.

Japanese Patent Laying-Open No. 2001-75318 (FIG. 3)

  In the density adjustment process as described above, the image forming condition may not be set to the optimum condition due to the abnormality of the apparatus. For example, if an abnormality occurs in the patch sensor for detecting the density of the patch image, the density of each patch image cannot be detected correctly, and the optimum condition cannot be obtained. In addition, for example, the quality of an image formed due to a change with time of the apparatus may deteriorate, and a predetermined quality may not be maintained. Furthermore, for example, a patch image with sufficient density may not be formed due to insufficient toner remaining. Even if the image forming conditions are adjusted in such a state, the conditions cannot be set appropriately.

  Therefore, when an error occurs during the density adjustment process, an image with poor image quality is formed, the toner or recording paper is prevented from being wasted, and the abnormality is further prevented from being further enlarged. It is desirable to prohibit the forming operation. In addition, it is preferable not only to stop the operation of the apparatus but also to inform the operator of the state of the apparatus because the cause of the error can be identified more easily. For this purpose, it is effective to output the above-described status sheet or other test images.

  However, if an image forming operation is prohibited when an error occurs, it is impossible to output a status sheet or any test image. Therefore, it is inconvenient for the operator because it becomes difficult to identify the cause of the error.

  The present invention has been made in view of the above problems, and in an image forming apparatus and a control method for adjusting an image forming condition based on a density detection result of a patch image, even when an error occurs during the adjustment, an operator's It is an object to provide a technique that can be used for convenience.

  According to the present invention, an image for executing a condition control process for adjusting an image forming condition when executing an image forming operation by the image forming unit to a predetermined optimum condition based on a density detection result of a patch image formed by the image forming unit. In the forming apparatus and the control method thereof, in order to achieve the above object, the condition control process is executed according to a predetermined operation, and the image forming condition cannot be adjusted to the optimum condition in the condition control process. While the execution of the image forming operation by the forming unit is prohibited, when the setting operation for prohibiting the condition control process is performed on the setting unit, the image forming unit by the image forming unit is not performed without performing the condition control process. The image forming operation is permitted to be executed.

  According to another aspect of the present invention, a condition for adjusting an image forming condition when an image forming operation is performed by the image forming unit to a predetermined optimum condition based on a density detection result of a patch image formed by the image forming unit. In the image forming apparatus and the control method for executing the control process, in order to achieve the above object, the setting state of the setting unit is determined according to a predetermined operation, and the condition control process is performed when the condition control process is not prohibited. When the image forming condition cannot be adjusted to the optimum condition in the condition control process, the execution of the image forming operation by the image forming unit is prohibited while the condition control process is prohibited. It is characterized in that execution of the image forming operation by the image forming means is permitted without performing the condition control processing.

  In these inventions, the image forming operation is executed under the image forming conditions adjusted to the optimum conditions by the condition control process. On the other hand, since the execution of the image forming operation is prohibited when the image forming condition cannot be adjusted to the optimum condition, the image forming operation under a poor condition is prohibited. Therefore, the user can stably obtain an image with a constant image quality.

  However, when the user performs a setting operation on the setting unit to prohibit the execution of the condition control process, the image forming operation can be permitted without executing the condition control process. Therefore, even when an abnormality occurs in the apparatus and the image forming conditions cannot be adjusted in the condition control process, the image forming operation can be executed. Thereby, although it is difficult to maintain the image quality, it is possible to output the test image, and it is possible for the operator to search for the cause of the abnormality.

  Here, as the predetermined operation that triggers the start of the condition control process, for example, a power-on operation by a user can be used. By doing so, it is possible to form an image with stable image quality immediately after the power is turned on.

  Further, when the condition control process is prohibited by the setting unit, for example, it is preferable that a status sheet indicating the state of the image forming unit can be output. By using the status sheet output in this way for maintenance work, the convenience for the operator is further improved. In addition, when there is an abnormality in the apparatus, the operator can specify an abnormal part based on the status sheet. For this status sheet, it is sufficient to be able to interpret the print contents, and therefore high image quality is not particularly required unless there is an extremely faint character or uneven density of characters.

  Note that, when an image forming operation is executed without performing the condition control process, how to set the image forming conditions at that time becomes a problem. Since high image quality is not required in the image forming operation here, the default condition that can expect a certain level of image quality may be set. As such a default condition, for example, a predetermined standard condition or an optimum condition in the condition control process performed immediately before can be used. Even if these image forming conditions do not necessarily coincide with the optimum conditions at that time, it is unlikely that the image forming conditions deviate greatly. Therefore, by using these conditions as default conditions, even if it is not the best, it is possible to form an image with a certain level of image quality that does not interfere with the interpretation of the status sheet, for example.

  FIG. 1 is a view showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. This apparatus 1 forms a full color image by superposing four color toners (developers) of yellow (Y), cyan (C), magenta (M), and black (K), or black (K) toner. This is an image forming apparatus that forms a monochrome image using only the image forming apparatus. In the image forming apparatus 1, when an image signal is given to the main controller 11 from an external device such as a host computer, the engine controller 10 controls each part of the engine unit EG in accordance with a command from the main controller 11 to obtain a predetermined image. The 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 unit 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 unit 23 is applied with a predetermined charging bias, and uniformly charges the outer peripheral surface of the photoconductor 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 unit 23, and the cleaning unit 25 integrally constitute the photosensitive member cartridge 2, and this photosensitive member cartridge 2 is detachably attached to the main body of the apparatus 1 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 unit 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. The developing unit 4 is configured as a support frame 40 that is rotatably provided around a rotation axis that is orthogonal to the paper surface of FIG. 1 and a cartridge that is detachable from the support frame 40, and for yellow that contains toner of each color. A developing unit 4Y, a developing unit 4C for cyan, a developing unit 4M for magenta, a developing unit 4K for black, and a rotary driving unit (described later) for rotating them integrally are provided. The developing unit 4 is controlled by the engine controller 10. Based on the control command from the engine controller 10, the developing unit 4 is driven to rotate, and the developing units 4Y, 4C, 4M, and 4K are selectively brought into contact with the photoreceptor 22 or have a predetermined gap. When positioned at a predetermined development position opposed to each other, toner is applied to the surface of the photosensitive member 22 from a developing roller 44 provided in the developing unit and carrying toner of a selected color. 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 that is stretched over a plurality of rollers 72 to 75, and a drive unit that rotates the roller 73 to rotate the intermediate transfer belt 71 in a predetermined rotation direction D2. . When a color image is transferred to the sheet S, each color toner image formed on the photosensitive member 22 is superimposed on the intermediate transfer belt 71 to form a color image and taken out from the cassette 8 one by one. The color image is secondarily transferred onto the sheet S conveyed to the secondary transfer region TR2 along the conveyance path F.

  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, a gate roller 81 is provided on the transport path F on the front side of the secondary transfer region TR2, and the gate roller 81 rotates in accordance with the timing of the circumferential movement of the intermediate transfer belt 71. S is sent to the secondary transfer region TR2 at a predetermined timing.

  Further, the sheet S on which the color image is thus formed is conveyed to the discharge tray portion 89 provided on the upper surface portion of the apparatus main body via the fixing unit 9, 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, the sheet is again placed on the transport path F before the gate roller 81. At this time, the surface of the sheet S to which the image is transferred by contacting the intermediate transfer belt 71 in the secondary transfer region TR2 is first transferred. It is the opposite surface. In this way, images can be formed on both sides of the sheet S.

  A density sensor 60 is disposed 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 uses the operating conditions of each part of the apparatus that affect the image quality, such as the developing bias applied to each developing device, the intensity of the exposure beam L, and the tone correction characteristics of the apparatus. Adjustments are being made.

  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.

  As shown in FIG. 2, each of the developing devices 4Y, 4C, 4M, and 4K is provided with memories 91 to 94 for storing data relating to the manufacturing lot and usage history of the developing devices and the remaining amount of the built-in toner. ing. Further, connectors 49Y, 49C, 49M, and 49K are provided in the developing devices 4Y, 4C, 4M, and 4K, respectively. If necessary, these are selectively connected to a connector 109 provided on the main body side, and data is transmitted / received between the CPU 101 and each of the memories 91 to 94 via the interface 105 to relate to the developing device. It manages various information such as consumables management. In this embodiment, the main body side connector 109 and each developing device side connector 49K and the like are mechanically fitted to each other to exchange data. However, for example, electromagnetic means such as wireless communication is used. Data transmission / reception may be performed without contact.

  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, and reference numeral 117 denotes a calculation result in the CPU 111 and other information. It is a RAM that temporarily stores data. 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.

  As these RAMs 107, 117 and 91 to 94, in order to store information on the usage status of each part of the apparatus, it is preferable to use a non-volatile memory in which information is retained even in a non-energized state. For example, a flash memory or a ferroelectric memory can be used.

  In addition, limit switches 122 and 132 for detecting the opening and closing of a cover provided in the apparatus housing are connected to the CPU 101 of the apparatus 1. These will be described in detail later.

  3 is an external perspective view of the image forming apparatus of FIG. As described above, in the image forming apparatus 1, each developing device 4Y and the like are detachable from the support frame 40, and the photosensitive cartridge 2 is detachable from the apparatus main body. As shown in FIG. 3, an openable / closable external cover 120 is provided on the side surface of the apparatus main body 1. When the user opens the external cover 120, the image is exposed through the photosensitive member opening 125 provided in the apparatus main body. The side part of the body cartridge 2 is exposed. Then, the lock lever 126 for fixing the photoconductor cartridge 2 is rotated in the arrow direction D4 to release the lock, and the photoconductor 2 can be pulled out along the (−y) axis direction of FIG. . Further, by inserting the photoconductor cartridge 2 in the y-axis direction of FIG. 3 through the photoconductor opening 125, a new photoconductor cartridge 2 can be mounted. Then, the photosensitive cartridge 2 is fixed by the lock lever 125. When the photoconductor cartridge 2 is thus mounted, the photoconductor opening 125 is substantially blocked by the side surface of the photoconductor cartridge 2.

  The apparatus main body is provided with a developing device opening 135 for attaching and detaching the developing device cartridge. An openable / closable inner cover 130 is provided so as to cover the developing device opening 135. The inner cover 130 is provided inside the outer cover 120. That is, since the outer cover 120 is formed so as to cover the developer opening 135, the inner cover 130 cannot be opened when the outer cover 120 is closed. Conversely, the outer cover 120 cannot be closed unless the inner cover 130 is closed. When the user opens the inner cover 130, if the developing unit 4 is stopped at a predetermined attachment / detachment position, one of the attached developing devices can be taken out through the developing device opening 135. . In addition, one developing device can be mounted through the developing device opening 135.

  The outer cover 120 is provided with a protrusion 121a, and a hole 121b is provided at a position on the main body side corresponding to the protrusion 121a. Further, a limit switch 122 described later is attached to the bottom of the hole 121b. When the outer cover 120 is closed, the protrusion 121a is inserted into a hole 121b provided on the main body side, and the contact is closed by pressing a limit switch 122 provided at the bottom of the hole 121b. .

  A similar mechanism is also provided in the inner cover 130. That is, the protrusion 131a is provided on the inner cover 130, and the hole 131b is provided at a position corresponding to the main body side. When the inner cover 130 is closed, the protrusion 131a is inserted into the hole 131b, and the contact is closed by pressing a limit switch 132 (described later) provided at the bottom of the hole 131b.

  Further, a limit switch (not shown) is also provided behind the photoconductor opening 125, and the contact is closed when the photoconductor cartridge is mounted on the apparatus main body. This limit switch is preferably installed so that the contact is closed when the photosensitive cartridge 2 is properly mounted on the apparatus main body, while the contact is not closed when the photosensitive cartridge 2 is incompletely mounted. This is because it is necessary to detect that the mounting unit is securely mounted so that the developing unit 4 is not rotated in an incomplete mounting state and the apparatus is not damaged.

  As described above, in the image forming apparatus 1, for each of the external cover 120 and the internal cover 130, the open / close state of the cover can be known from the contact state of each limit switch, and the photosensitive cartridge 2 is mounted. It is possible to know whether or not. The image forming operation described above is executed only when the outer cover 130 and the inner cover 130 are closed and the photosensitive cartridge 2 is mounted.

  FIG. 4 is a diagram showing the connection between the limit switch and the CPU. As shown in FIG. 4, one end of limit switches 122 and 132 for detecting the open / closed states of the outer cover 120 and the inner cover 130 is a 5V power source for driving the control circuit via pull-up resistors 123 and 133, respectively. (Not shown). The terminal voltage is input to the input ports P1 and P2 of the CPU 101, respectively. The other end of each limit switch is grounded. Thereby, CPU101 can grasp | ascertain the open / close state of the external cover 120 and the internal cover 130 separately based on the input voltage of both ports P1 and P2.

  Specifically, when the external cover 120 is open, the limit switch 122 is open, so the input of the port P1 is at the H level. On the other hand, if the outer cover 120 is closed, the limit switch 122 is also closed, so that the port P1 is grounded and becomes L level. The same applies to the inner cover 130, and the input of the port P2 becomes the H or L level according to the opening / closing thereof.

  In the apparatus 1 configured as described above, when the power of the apparatus is turned on by the user, the startup process shown in FIG. 5 is executed prior to image formation. This start-up process is executed to initialize each part of the apparatus so that the image forming operation can be performed and to set the image forming conditions of the apparatus to the optimum conditions.

  FIG. 5 is a flowchart showing the startup process in this apparatus. In this startup process, when the apparatus is powered on, the setting state of each part of the apparatus at that time is read (step S101). The “setting state” here refers to what state the buttons and switches provided in the apparatus and operable by the user are set when the power is turned on. In this embodiment, the processing content of the subsequent startup process changes depending on whether or not a certain switch has been pressed when the power is turned on. Details of the processing contents and the reason for doing so will be described in detail later.

  Next, each part of the apparatus is initialized (step S102). 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.

  Subsequently, it is determined whether or not a predetermined setting input has been made in the setting state reading in step S101 (step S103). Here, the description will be continued assuming that no setting input has been made, that is, the determination result in step S103 is “NO”. That is, in this case, patch processing is subsequently executed (step S103).

  FIG. 6 is a flowchart showing patch processing in this apparatus. In this patch processing, in order to keep the formed image at a constant image quality, a patch image is formed while variously changing the image forming conditions and the image density is detected, and image formation is performed based on the detection result. This is a process for adjusting the conditions. In this patch processing, the development bias and 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 regarding the principle and control method of image quality control using these parameters. Briefly described.

  First, for each toner color, the optimum developing bias, that is, the optimum value of the developing bias 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). At this time, if the output from the density sensor 60 is abnormal, that is, shows a value greatly deviating from the value corresponding to the density assumed from the setting value of the developing bias, the CPU 101 has an abnormality in the apparatus. It is determined as an error, and an internal error flag corresponding to the error is set. Then, the execution of the subsequent patch processing is stopped and the processing returns to the processing in FIG.

  Examples of possible causes of such an error include cases where the patch image itself has an abnormal density, such as when a normal developing bias is not applied to the developing roller 44, or when the toner is insufficient, and the density sensor 60. It can be considered that density detection cannot be performed correctly due to an abnormality of the density sensor 60, such as dirt or a malfunction.

  When the image density of each patch image is obtained, the relationship between the development bias and the image density can be determined from these values. Based on this relationship, the value of the development bias that matches the predetermined target density based on the relationship. Is calculated. Thereby, the optimum developing bias is obtained (step S205). 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). In this way, an optimum developing bias for each toner color is obtained.

  Subsequently, for each toner color, the optimum exposure power, that is, the optimum value of the intensity of the exposure beam L when the 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 above-described optimal development bias calculation processing (steps S201 to S205) except that the control factor is exposure power instead of development bias, but if necessary, a patch image to be formed is formed. These 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. In this way, the optimum development bias and optimum exposure power are obtained for all toner colors, and the patch process is terminated.

  Returning to FIG. 5, when the patch process (step S104) is completed, it is determined whether or not an error has occurred in the patch process (step S105). This determination can be made by checking the internal error flag of the CPU 101. If one of the flags corresponding to each error is set, it is determined that “error has occurred”.

  When no error has occurred and all the optimum values of the respective control factors have been calculated, the optimum value set thus obtained is stored as the apparatus and the optimum image forming condition at that time (step S106).

  Through the processing up to this point, each part of the apparatus is initialized so that an image forming operation can be executed, and the image forming conditions are set to optimum conditions. Therefore, at this time, the execution of the image forming operation by the engine unit EG is permitted (step S107), and the subsequent image forming operation is executed under this optimum condition, so that an image can be stably displayed with a desired image quality. It becomes possible to form.

  On the other hand, if an error has occurred in the patch processing in step S105, the process proceeds to step S110, and the subsequent image forming operation by the engine unit EG is prohibited. By doing so, it is possible to prevent an image with poor image quality from being output when an abnormality occurs in the apparatus.

  In this way, when execution of the image forming operation is prohibited due to the occurrence of an error, an operator such as a user or an operator removes the cause of the error and then turns on the power again to execute the startup process. The image forming condition is adjusted to the optimum condition, and the image forming operation can be executed. However, as described above, various causes of errors can be considered, and it is not easy to identify the cause unless the state of the apparatus is known. In extreme cases, the operator must inspect each part of the device by trial and error and turn on the power again each time, and until the cause of the error is eliminated, the operation is stopped and the power is turned on repeatedly. Become.

  In order to solve such problems, as a method of directly or indirectly knowing the location of the error and the current status of the device when an error occurs and the operation of the device is stopped, It is desirable to enable at least output. Therefore, in this apparatus, when a predetermined special operation is performed, the activation process is executed without performing the patch process, and the execution of the image forming operation is permitted regardless of whether or not the cause of the error is removed. I am doing so.

  Specifically, the “special operation” here means that the operator opens both the outer cover 120 and the inner cover 130 (FIG. 3) and opens the limit switch 122 provided in the back of the hole 121b on the side of the apparatus. It is to turn on the power while pushing with the pen tip. In this state, the limit switch 132 corresponding to the inner cover 130 is open, and the limit switch 122 corresponding to the outer cover 120 is closed. In this device 1, since the inner cover 130 is hidden inside the outer cover 120, the inner cover 130 cannot be opened unless the outer cover 120 is opened. Therefore, the state as described above is a special state that cannot be used normally.

  As to whether the power of the apparatus is turned on under such a special state or in a normal state, the state of these limit switches, that is, the states of the ports P1 and P2 of the CPU 101 are read when the power is turned on. Can be determined. That is, “reading of setting state” in step S101 in FIG. 5 is a processing step for determining this. Specifically, immediately after the power is turned on, the CPU 101 reads the “setting state” of the apparatus, that is, the states of the input ports P1 and P2, and these are at the L and H levels, respectively (the above “special state”). )), An internal flag indicating that is set. On the other hand, any other combination is a normal power-on operation, so the internal flag is reset. In step S103, the internal flag is checked. If it is set, it is determined that there is a setting input, and if it is reset, it is determined that there is no setting input. Since it is determined that there is no setting input at the time of normal power-on, the startup process as described above is executed.

  On the other hand, when there is a setting input, the operation differs from the above. That is, the patch processing is not executed, the image forming condition is set to a predetermined default condition (step S108), the engine unit EG is requested to output a status sheet (step S109), and the image forming operation is executed. Allow (step S107). As a result, the engine unit EG sets the image forming condition as the default condition and executes the formation of the status sheet regardless of whether the cause of the error remains. The operator can know the current state of the apparatus from the contents of the status sheet output on the sheet S, and can help to identify the cause of the error.

  For example, the following items are preferably described in the status sheet, but some of these items may be described, or other items may be described: such as the photosensitive member 22 and each developing device 4Y. Total usage time; remaining amount of toner in each developer; optimum development bias and optimum exposure power for each toner color; internal error flag state; and control software version in CPU 101 and 111.

  Among these, the wear state of each part of the apparatus can be known from the usage time of the photosensitive member 22 and each developing device. Further, from the remaining amount of toner in each developing device, it is possible to know whether the replacement time of the developing device and whether the remaining amount of toner can cause an error. Further, from the setting values of the optimum developing bias and optimum exposure power for each toner color, it is possible to know what state each parameter is set to, that is, what state the apparatus is used. . The setting value to be displayed is not limited to the current setting value, and may be a value set immediately before an error occurs. Also, from the state of the internal error flag, it can be known at which point an error has occurred. Furthermore, the contents of the control process executed in the device can be known from the version of the control software. All of these pieces of information are information that helps to identify the cause of the error.

  In addition, the quality of the image formed in this case is sufficient as long as the above information can be easily read. Therefore, the default condition of the image forming condition in this case may be any as long as it can form a character image with a certain quality. For example, an image forming condition in which each operation parameter is determined by any one of the following methods (1) to (4) can be set as a default condition.

  (1) Set all operating parameters to preset standard values. Although not the best, a standard image forming condition that can expect a certain level of image quality is obtained in advance according to the characteristics of the apparatus, and this is set as a default condition.

  (2) All operating parameters are set to the optimum values immediately before. Although the operation state of the apparatus gradually changes with time, the state does not change greatly in a short period of time. Therefore, the image forming conditions set before executing the patch processing that led to the error, that is, the optimum conditions appropriately obtained in the previous patch processing are set as the default conditions, so that the previous patch processing execution time is reached. A relatively close image quality is obtained.

  (3) The parameter for which the optimum value has been calculated before an error is set to the optimum value, and the parameter whose optimum value cannot be calculated due to the occurrence of an error is set to a preset standard value. If an error occurs during patch processing, there is a possibility that optimum values of some operation parameters have already been obtained so far. Therefore, while setting the operation parameters to the newly determined optimum values, the parameters for which the optimum values have not been obtained due to the interruption of the patch processing due to the occurrence of an error are set to the predetermined standard values at that time. Thus, image formation can be performed under image formation conditions that are close to the optimum conditions in FIG.

  In this embodiment, first, the optimum developing bias for each toner color is obtained in order, and then the optimum exposure power for each toner color is obtained in order. Therefore, even if an error occurs in the process, the calculation of the optimum development bias and the optimum exposure power may be completed at that time depending on at which time the error has occurred. Yes, neither has been calculated yet. In the former case, the newly calculated optimum value may be used for both parameters, and in the latter case, a predetermined standard value may be used. Further, there may be a case where the optimum development bias is calculated but the optimum exposure power is not calculated. In this case, the calculation of the optimum value for the color is not completed, and both parameters may be standard values. For the developing bias for which the optimum value is obtained, the optimum value is used, while the optimum value is A standard value may be used for the exposure power that has not been obtained.

  (4) The parameter for which the optimum value has been calculated before an error is set to the optimum value, and the parameter for which the optimum value cannot be calculated due to the occurrence of an error is set to the immediately preceding optimum value. A part of the above (3) is changed. That is, with respect to a parameter for which the optimum value cannot be obtained due to the interruption of patch processing due to an error occurrence, the optimum value obtained in the previous patch processing is used instead of the predetermined standard value. The same effect is obtained.

  As described above, in this embodiment, when the apparatus is turned on, patch processing is performed in which a patch image is formed and image forming conditions are adjusted based on the density detection result. By executing the image forming operation under the image forming conditions adjusted to the optimum conditions in this way, an image can be stably formed with a predetermined image quality immediately after the power is turned on. Further, when an optimum image forming condition cannot be obtained due to an abnormality of the apparatus, the execution of the image forming operation is prohibited. Therefore, an image with inferior image quality is not formed under inappropriate image forming conditions, and waste of toner and sheet S can be avoided.

  However, in order to enable the output of the status sheet even if an error occurs during patch processing, patch processing is performed when power is turned on while pressing a specific switch, specifically a specific switch. The image forming operation can be performed without any problem. Since the operator of the apparatus can grasp the state of the apparatus from the status sheet output in this way, it is easy to identify the cause of the error and take measures against it. Thus, in the image forming apparatus of this embodiment, the convenience of the operator who tries to find out the cause when an error occurs is achieved.

  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 serves as the “control unit” of the present invention. It is functioning. Further, the patch processing executed to adjust the image forming conditions corresponds to the “condition control processing” of the present invention, and the limit switch 122 for setting so as not to execute this after the power is turned on is “ Functions as a setting means.

  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, the activation process of the above embodiment is configured so that an image forming operation can be performed without performing a patch process whenever the user turns on the power while pressing the limit switch 122. However, such an operation is performed as an exceptional measure to prevent the device from shutting down many times without knowing the cause of the error. Such an operation may be performed.

  Further, for example, in the above embodiment, the image forming operation may be prohibited again after outputting the status sheet. This is because if the status sheet can be output, it is not necessary to be able to form another image. Further, a test image such as a test pattern that easily reflects the state of the apparatus may be output instead of or in addition to the status sheet listing the state of the apparatus.

  In the above embodiment, the status sheet is continuously output when the activation process is performed without the patch process. However, the present invention is not limited to this. For example, the user can specify the status sheet after the activation process. When the above operation is performed, a status sheet may be output according to the operation.

  In the above-described embodiment, when the activation process is performed without the patch process, the image forming operation is executed after setting the image forming conditions for each color as default conditions. However, since the status sheet may be a monochrome image in general, in such a case, for example, only the formation of a monochrome image (practically a black color) is permitted, and image formation with other toner colors is performed. The operation may not be performed.

  Further, in the above-described embodiment, the activation process without the patch process is executed by a special user operation of turning on the power while pressing the limit switch 122 for detecting the open / closed state of the external cover 120. . However, the present invention is not limited to this, and such an operation may be performed by other operations. However, since such an operation should not be performed on a daily basis, it is preferable to perform a special operation that is not normally performed. In this operation, it is not always necessary to go through the steps of turning on the power again and initializing the apparatus. For example, when an operation such as pressing a plurality of buttons in a specific combination at the same time or pressing in a specific order is performed, an image forming operation can be performed without executing patch processing again according to the operation. Good.

  In the above-described embodiment, patch processing is executed in response to a power-on operation. However, the present invention is not limited to this. For example, when a user performs a predetermined key operation while power is being supplied. The patch processing may be executed according to other operations.

  Further, the present invention is not limited to the configuration of the above-described embodiment. For example, a device that includes a developing device that supports black toner and forms a monochrome image, a device that includes a transfer medium (transfer drum, transfer sheet, etc.) other than the intermediate transfer belt, Furthermore, the present invention can also be applied to other image forming apparatuses such as copying machines and facsimile machines.

1 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus in FIG. 1. FIG. 2 is an external perspective view of the image forming apparatus in FIG. 1. It is a figure which shows the connection of a limit switch and CPU. It is a flowchart which shows the starting process in this apparatus. It is a flowchart which shows the patch process in this apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Photosensitive unit (image forming means), 4 ... Developing unit (image forming means), 6 ... Exposure unit (image forming means), 101 ... CPU (control means), 120 ... External cover, 122 ... Limit switch (setting) Means), 130 ... inner cover, EG ... engine part (image forming means)

Claims (9)

An image forming means for performing an image forming operation;
Based on the density detection result of the patch image formed by the image forming means, a condition control process for adjusting the image forming condition when executing the image forming operation to a predetermined optimum condition is executed according to a predetermined operation, Control means for prohibiting execution of the image forming operation by the image forming means when the image forming conditions cannot be adjusted to the optimum conditions in the condition control processing;
Setting means for accepting a setting operation for prohibiting the condition control processing by the control means, the control means,
An image forming apparatus according to claim 1, wherein when the condition control process is prohibited by the setting unit, the execution of the image forming operation by the image forming unit is permitted without performing the condition control process. An image forming means for performing an image forming operation;
Control means for executing a condition control process for adjusting an image forming condition when executing an image forming operation to a predetermined optimum condition based on a density detection result of a patch image formed by the image forming means;
Setting means for accepting a setting operation for prohibiting the condition control processing by the control means, the control means determines a setting state of the setting means according to a predetermined operation,
When the condition control process is not prohibited, the condition control process is executed, and when the image forming condition cannot be adjusted to the optimum condition in the condition control process, the image forming unit is prohibited from executing the image forming operation. While
An image forming apparatus, wherein when the condition control process is prohibited, execution of the image forming operation by the image forming unit is permitted without performing the condition control process.   The image forming apparatus according to claim 1, wherein the predetermined operation is a power-on operation by a user.   4. The image forming apparatus according to claim 1, wherein the control unit forms an image as a status sheet indicating a state of the image forming unit when the condition control process is prohibited by the setting unit.   The control unit sets the image forming condition to a predetermined default condition and permits the image forming unit to execute the image forming operation when the condition control process is prohibited by the setting unit. 5. The image forming apparatus according to any one of 4 to 4.   The image forming apparatus according to claim 5, wherein the control unit adjusts the image forming condition to a predetermined standard condition as the default condition.   The image forming apparatus according to claim 5, wherein the control unit adjusts the image forming condition to the optimum condition in the condition control process performed immediately before as the default condition. Control of an image forming apparatus for executing a condition control process for adjusting an image forming condition when executing an image forming operation by the image forming unit to a predetermined optimum condition based on a density detection result of a patch image formed by the image forming unit In the method
The condition control process is executed in accordance with a predetermined operation, and when the image formation condition cannot be adjusted to the optimum condition in the condition control process, the execution of the image forming operation by the image forming unit is prohibited.
An image characterized by permitting execution of the image forming operation by the image forming means without performing the condition control process when a setting operation for prohibiting the condition control process is performed on the setting means. Control method of forming apparatus. Control of an image forming apparatus for executing a condition control process for adjusting an image forming condition when executing an image forming operation by the image forming unit to a predetermined optimum condition based on a density detection result of a patch image formed by the image forming unit In the method
Determining the setting state of the setting means according to a predetermined operation;
When the condition control process is not prohibited, the condition control process is executed, and when the image forming condition cannot be adjusted to the optimum condition in the condition control process, the image forming unit is prohibited from executing the image forming operation. While
When the condition control processing is prohibited, the image forming apparatus is allowed to execute the image forming operation without performing the condition control processing.

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