JP2005352377A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus with the technology of efficiently printing in a specific color, the image forming apparatus being capable of a printing operation using toner in a cartridge put in a developing position while selective switching between a plurality of cartridges having toners of the specific color takes place. <P>SOLUTION: When at least one of the developing cartridges 4Ka to 4Kd attached to a developing unit has become printable and the temperature rise of the fixing unit is finished so that a toner image is fixable to a sheet, an engine controller outputs a printing preparation completion signal and permits the apparatus to perform the printing operation. Such operation makes it possible to efficiently print in the specific color. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and an image forming method in which one of cartridges mounted in a developing unit is positioned at a developing position and a printing operation of a specific color is performed using toner in the cartridge. Is.

  Conventionally, an image forming apparatus that forms an image using a plurality of developing cartridges is widely known. For example, Patent Document 1 describes a color image forming apparatus including a rotary developing unit in which four developing cartridges are arranged radially around a rotation axis. In this apparatus, one of the four developing cartridges is selectively positioned to face a latent image carrier such as a photosensitive member by rotationally driving the rotating shaft thereof, thereby latent images on the latent image carrier. Is developed and transferred onto an intermediate transfer medium. Then, while switching the developing cartridge, the development and transfer processes are repeated in the same manner as described above, thereby superimposing a plurality of color toner images to form a color image.

  In the color image forming apparatus described above, toners of different colors (yellow, cyan, magenta, and black) are accommodated in the four developing cartridges in order to execute a color image printing operation. For this reason, when a monochrome image is printed using the image forming apparatus, there is a problem that the timing of shortage of black toner is earlier than when a monochrome image is printed by a monochrome-only image forming apparatus. Therefore, in order to solve such a problem, the black developing cartridge is mounted at the position where the developing cartridge for yellow, cyan and / or magenta is installed, and the black toner in the one black developing cartridge is removed. An apparatus that switches to another black developing cartridge when it runs out and executes a monochrome printing operation has been proposed (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2003-215862 (5th page, FIG. 1) JP 2002-351190 A (5th and 6th pages, FIG. 4)

  Incidentally, in order to print an image satisfactorily using the toner in the developing cartridge, it is necessary to execute a print preparation operation on the cartridge in advance. A typical example of the print preparation operation is patch processing. For example, in the apparatus described in Patent Document 1, patch processing is executed after warming up of the apparatus or in parallel with the appropriate timing before the printing operation, for example, immediately after the apparatus is turned on. In this patch processing, the optimum values of development bias and exposure power as density control factors that affect image quality are calculated based on the density detection result of a solid image or a halftone image formed as a patch image. Then, when executing the printing operation, the developing bias and the exposure power are set to the optimum values thus obtained. As a result, optimum printing operation conditions can be obtained. Then, by executing the printing operation under the printing operation conditions optimized in this way, an image can be formed with good and stable image quality. Thus, in view of the importance of the print preparation operation, various proposals have been made for the print preparation operation in the color image forming apparatus.

  On the other hand, in the apparatus described in Patent Document 2, that is, an apparatus in which a plurality of developing cartridges that contain black toner are mounted, a printing preparation operation that is important for executing a good printing operation is not sufficiently considered. For example, in an apparatus equipped with a plurality of black developing cartridges, a large amount of monochrome printing is continuously performed by performing monochrome printing using toner in the cartridge positioned at the developing position while selectively switching the developing cartridge to the developing position. Can be done automatically. However, at the time of switching the developing cartridge, if the patch processing is not performed on the cartridge to be positioned at the developing position, the patch processing must be executed prior to the printing operation using the cartridge. Printing is temporarily interrupted. As a result, there may be a problem that mass printing cannot be performed efficiently.

  Therefore, for example, as a print preparation operation, it is conceivable to apply the patch processing described in Patent Document 1 to the cartridge mounted on the developing unit as it is. That is, patch processing is performed on the cartridge positioned at the developing position while sequentially switching the cartridges mounted on the developing unit to the developing position. For this reason, for example, when all black developing cartridges are mounted instead of yellow, cyan and magenta developing cartridges, the patch processing is repeated four times before the printing operation.

  However, since the printing operation cannot be executed until after the patch processing for all the developing cartridges is completed in this way, the user may have waited more than necessary before starting printing. For example, consider the case where patch processing is performed in parallel with the warm-up operation immediately after power-on or when returning from the sleep mode (print standby state) as described above. Thus, time can be used efficiently by executing the patch processing in parallel with the warm-up operation. However, the following problem occurs when the patch processing for some developing cartridges is incomplete despite the completion of the warm-up operation. That is, although printing can be started using a development cartridge that has already undergone patch processing, printing cannot be started until the remaining patch processing is completed. As described above, in the prior art, since the relationship between the operation state of the warm-up operation and the execution state of the print preparation operation for the developing cartridge is not known, the warm-up operation and the print preparation operation are individually executed as described above. Therefore, if both operations are not completed, the printing operation cannot be executed, and it cannot be said that the efficiency is necessarily high.

  The present invention has been made in view of the above problems, and can perform printing operation using toner in a cartridge positioned at the development position while selectively switching a plurality of cartridges having toner of a specific color to the development position. An object of the present invention is to provide a technology capable of efficiently printing the specific color in such an image forming apparatus.

  In order to achieve the above object, the present invention is provided with a latent image carrier capable of carrying an electrostatic latent image and a plurality of cartridges having toner of a specific color, and the toner in the mounted cartridge is used. A developing unit for executing a printing operation for developing the electrostatic latent image on the latent image carrier to form a toner image, a transfer unit for transferring the toner image on the latent image carrier to a recording material, and a predetermined unit A fixing unit that fixes the toner image on the recording material to the recording material at a fixing temperature of the recording material, and a print preparation operation that is performed on the cartridge that is used for the printing operation before the execution of the printing operation. Control means for executing the printing operation in a state where a warm-up operation for raising the temperature to the fixing temperature is completed, and the control means includes temperature information of the fixing unit, and the current information. Based on the execution state of the print preparation operation for cartridge mounted on the unit, it is characterized in that permits execution of the printing operation.

  The image forming method according to the present invention includes a latent image carrier capable of carrying an electrostatic latent image and a plurality of cartridges having toner of a specific color, which are detachably provided, and uses toner in the attached cartridge. A developing unit for executing a printing operation for developing the electrostatic latent image on the latent image carrier to form a toner image, a transfer unit for transferring the toner image on the latent image carrier to a recording material, and a predetermined unit An image forming apparatus including a fixing unit that fixes a toner image on the recording material to the recording material at a fixing temperature of the printing material, and a print preparation operation performed on the cartridge used for the printing operation before the execution of the printing operation. An image forming method for executing the printing operation in a state in which the warming-up operation for raising the temperature of the fixing unit to the fixing temperature is completed. And degree information, based on the execution state of the print preparation operation for cartridge mounted to the developing unit is characterized in allowing execution of the printing operation.

  In order to develop an electrostatic latent image using toner contained in the cartridge, that is, to execute a printing operation, prior to the printing operation, the cartridge is allowed to perform a printing operation with respect to the cartridge. In addition to executing the print preparation operation, it is necessary to perform a warm-up operation of the fixing unit. However, if the relationship between the operation state of the fixing unit warm-up operation and the execution state of the print preparation operation for the cartridge mounted on the developing unit is unknown, for example, when the warm-up operation of the fixing unit is completed Even if the preparatory operation has been performed and a part of the cartridge mounted on the developing unit is already in a printable state, the print preparatory operation for all the cartridges must be executed to the end as described above. As a result, it is not always efficient because the print preparation operation may be waited more than necessary before the print operation is executed. Therefore, according to the present invention, the execution of the printing operation is permitted based on the temperature information of the fixing unit and the execution state of the printing preparation operation for the cartridge mounted on the developing unit. That is, by confirming the temperature information of the fixing unit, information such as whether the warming-up operation of the fixing unit has been completed or how much time is required until the warming-up operation is completed is known. be able to. Also, by confirming the execution state of the print preparation operation for the cartridge attached to the development unit, among the cartridges attached to the development unit, which cartridge has already been subjected to the print preparation operation and is ready for printing. It is possible to know information such as how many cartridges can be printed or how much time is required to complete the printing preparation operation. Therefore, based on these pieces of information, it becomes clear whether or not the apparatus can already execute the printing operation. When the printing operation can be executed, the printing operation is permitted by allowing the printing operation to be executed. Can start. Therefore, it is possible to efficiently print the specific color.

  In addition, when the control unit confirms that the following two conditions (1) and (2) are satisfied based on the temperature information and the execution state of the print preparation operation, the control unit executes the print operation. It is good also as a structure to permit. Condition (1) is that the fixing unit has reached the fixing temperature, and Condition (2) is that the print preparation operation is performed on at least one of the cartridges mounted on the developing unit. And the cartridge is ready for printing. In the invention configured as described above, when the temperature increase of the fixing unit is completed, a print preparation operation is performed, so that at least one of the cartridges mounted on the developing unit can be printed. If there is another cartridge that cannot be printed, the printing operation can be executed.

  The control unit may be configured to determine an execution state of the print preparation operation for the cartridge mounted on the developing unit when the fixing unit reaches the fixing temperature. In the invention thus configured, when the fixing unit reaches the fixing temperature, the execution state of the print preparation operation for the cartridge mounted on the developing unit is determined. Therefore, if at least one of the cartridges mounted on the developing unit is in a printable state at the time of the determination, the printing operation is immediately performed by permitting the execution of the printing operation using the printable cartridge. Can start.

  The control means is configured to cause the fixing unit to reach the fixing temperature when the print preparation operation is performed on at least one of the cartridges mounted on the developing unit and the cartridge is ready for printing. If the fixing unit has not reached the fixing temperature, the print preparation operation may be executed for another cartridge. In the invention thus configured, when one or more of the cartridges mounted on the developing unit can be printed, it is determined whether or not the fixing unit has reached the fixing temperature, and the fixing unit If the unit has reached the fixing temperature, the printing operation can be started immediately by permitting the execution of the printing operation using the printable cartridge. On the other hand, if the fixing unit has not reached the fixing temperature, the print preparation operation can be executed for other cartridges, so that the printing on the cartridge can be performed without wasting time until the temperature increase of the fixing unit is completed. A preparatory action can be performed.

  When the print request is input during execution of the print preparation operation and the execution of the print operation is permitted, the control unit interrupts the print preparation operation and performs printing based on the print request. It is good also as a structure which performs operation | movement. In the invention configured as described above, if the execution of the printing operation is permitted when there is a print request, even if the print preparation operation is being executed for the cartridge mounted on the developing unit, The print preparation operation is interrupted. Then, the printing operation is executed using a cartridge that has been subjected to the printing preparation operation and can be printed out of the cartridges attached to the developing unit. Therefore, it is possible to reduce the waiting time until the start of printing after a print request is input.

  The control unit may be configured to restart the print preparation operation after the printing operation is completed. In the invention configured as described above, after the printing operation is completed, the printing preparation operation is performed for the cartridge that has not been subjected to the printing preparation operation. Accordingly, when this print preparation operation is completed, all the cartridges are ready for printing, and therefore the specific color can be printed in a large amount and efficiently.

  The control unit may select a cartridge to be subjected to the print preparation operation based on temperature information of the fixing unit and an execution state of the print preparation operation with respect to the cartridge mounted on the developing unit. For example, consider a case where some of the cartridges mounted on the developing unit have already been subjected to the print preparation operation and can be printed, but the fixing unit has not yet completed the warm-up operation. In such a case, since it is possible to execute the printing operation when the warming-up operation of the fixing unit is completed, it is not necessary to perform the print preparation operation for the non-printable cartridge among the cartridges attached to the developing unit. Absent. However, it must be said that it is inefficient to perform no print preparation operation for the cartridge until the warm-up operation of the fixing unit is completed. Therefore, according to the present invention, the number of cartridges that can be subjected to the print preparation operation before the warm-up operation is completed is predicted by checking the temperature information of the fixing unit during the warm-up operation. Based on the prediction result, a cartridge to be subjected to the print preparation operation is selected from the cartridges that are not printable among the cartridges mounted on the developing unit, and the print preparation operation is executed on the selected cartridge. doing. Therefore, it is possible to efficiently execute the print preparation operation without wasting time until the warm-up operation is completed.

  The developing unit may have a configuration in which M (M ≧ 2) cartridges are mounted. Further, it is desirable that M (M ≧ 2) cartridges are mounted on the developing unit. In the invention configured as described above, even if the remaining amount of toner in one cartridge decreases and the printing operation cannot be performed, the printing operation can be continued by switching to the next cartridge.

  Hereinafter, various embodiments of the image forming apparatus according to the present invention will be described. However, since the apparatus configuration and basic operation of these embodiments are the same and the operation is only partially different, all the embodiments are first described. First, the configuration and operation of the apparatus common to the first embodiment will be described, and then the operation unique to each embodiment will be described.

<Device configuration and basic operation>
Here, an embodiment in which the present invention is embodied in an image forming apparatus (color printer) described in Patent Document 1 will be described with reference to the drawings. In other words, in this embodiment, a description will be given by specifically embodying printing with monochrome toner using black toner accommodated in four developing cartridges, that is, monochrome printing.

  FIG. 1 is a diagram showing the configuration 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. The apparatus 1 is an image forming apparatus that forms a monochrome image using only black (K) toner. 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. A forming operation is executed, and a monochrome 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. Further, 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 toner remaining on the surface of the photosensitive member 22 after primary transfer, which will be described later, 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 the 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. Thus, in this embodiment, the photoconductor 22 corresponds to the “latent image carrier” of the present invention.

  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. To 4 Kd, and a rotary drive (not shown) for rotating them integrally. The developing unit 4 is controlled by the engine controller 10. Then, based on a control command given from the main controller 11 to the engine controller 10, the developing unit 4 is driven to rotate, and the developing cartridges 4Ka to 4Kd are selectively brought into contact with the photosensitive member 22 or a predetermined gap. When the toner is positioned at a predetermined developing position facing each other with a gap, toner is applied to the surface of the photosensitive member 22 from the developing roller 44 provided in the developing cartridge. As a result, the electrostatic latent image on the photosensitive member 22 is developed with the toner in the selected developing cartridge. The visualization of the electrostatic latent image by the developing cartridge positioned at the developing position in this way corresponds to the “printing operation” of the present invention.

  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. Yes. The transfer unit 7 transfers the black toner image formed on the photosensitive member 22 onto the intermediate transfer belt 71 to form a monochrome image, and is taken out from the cassette 8 one by one along the conveyance path F. The monochrome image is secondarily transferred onto the sheet S conveyed to the secondary transfer region TR2. Thus, the sheet S corresponds to the “recording material” of the present invention.

  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 in front 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 monochrome toner image is thus formed is sent to the fixing unit 9. The fixing unit 9 is provided with a temperature sensor 91, and a heater (not shown) is controlled based on the detection result of the sensor 91 to be adjusted to a predetermined fixing temperature. The fixing unit 9 fixes the toner image formed on the sheet S on the sheet S at a predetermined fixing temperature. Thereafter, the sheet S is conveyed to a 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-ejection 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 image is transferred first on the surface of the sheet S on which the image is transferred in contact with the intermediate transfer belt 71 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.

  A density sensor 60 is disposed in the vicinity of the roller 75. The density sensor 60 is provided so as 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 result, 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 cartridge, 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.

  As shown in FIG. 2, each of the developing cartridges 4Ka to 4Kd is provided with memories 91 to 94 for storing data relating to the manufacturing lot and usage history of the developing cartridge, the remaining amount of the built-in toner, and the like. Further, each of the developing cartridges 4Ka to 4Kd is provided with wireless communication devices 49Ka, 49Kb, 49Kc, and 49Kd. Then, if necessary, these selectively communicate with the wireless communication device 109 provided on the main body side in a non-contact manner, and data is transmitted between the CPU 101 and each of the memories 91 to 94 via the interface 105. Various information such as consumable management for the developing cartridge is managed by sending and receiving. In this embodiment, non-contact data transmission / reception is performed using electromagnetic means such as wireless communication. However, a connector is provided on the main body side and each developing cartridge side, and the connector is mechanically fitted. By doing so, you may make it mutually transmit / receive data.

  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.

  By the way, in the apparatus configured as described above, before the printing operation is performed by each of the developing cartridges 4Ka to 4Kd, a printing preparation operation is previously performed on the developing cartridges 4Ka to 4Kd, and the fixing unit 9 is used. It is necessary to execute a warm-up operation for raising the temperature to a predetermined fixing temperature. By executing this “print preparation operation” for the developing cartridges 4Ka to 4Kd, printing operations by the developing cartridges 4Ka to 4Kd become possible. Further, by executing the “warming up operation”, the fixing unit 9 can fix the toner image formed on the sheet S on the sheet S at a predetermined fixing temperature. In the image forming apparatus according to the present invention, the execution of the printing operation is permitted based on the temperature information of the fixing unit 9 and the execution state of the print preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4. .

  That is, by confirming the temperature information of the fixing unit 9 based on the detection result of the temperature sensor 91, the warm-up operation of the fixing unit 9 is completed, and the toner image formed on the sheet S is displayed on the sheet S. It is possible to know information such as how much time is required until the fixing unit 9 reaches a predetermined fixing temperature after the warm-up operation is completed. Further, by confirming the execution state of the print preparation operation for the development cartridges 4Ka to 4Kd attached to the development unit 4, the print preparation operation has already been performed among the development cartridges 4Ka to 4Kd attached to the development unit 4. How many developing cartridges can be printed, how many developing cartridges can be printed, or how much time is required to complete the print preparation operation for the developing cartridges 4Ka to 4Kd You can know information such as. Therefore, based on these pieces of information, it becomes clear whether the above-described image forming apparatus can already execute the printing operation. If the printing operation can be executed, the execution of the printing operation is permitted. Thus, the printing operation can be started.

  As described above, various configurations for permitting the execution of the printing operation based on the temperature information of the fixing unit 9 and the execution state of the printing preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4 are various. Although the configuration can be considered, this image forming apparatus employs the configuration described in detail below as an example.

  That is, in this image forming apparatus, printable information for each of the developing cartridges 4Ka to 4Kd is stored in the RAM 107 of the engine controller 10, and is read by the CPU 101 or updated to new information as necessary. . For example, print at an appropriate timing immediately after the device is turned on, when the sleep mode is released, when the device cover that has been opened is closed, or when the replacement operation of the developing cartridge is completed The possible information is read from the RAM 107 by the CPU 101. As a result of confirming this printable information, (1) all the developing cartridges mounted on the developing unit 4 cannot be printed (2) some developing cartridges can be printed (3) all developing cartridges can be printed, etc. It is possible to know the states of the developing cartridges 4Ka to 4Kd. Each of the developing cartridges 4Ka to 4Kd becomes a developing cartridge capable of executing a printing operation by performing a printing preparation operation, and at the same time as the developing cartridge capable of executing the printing operation as described above, or thereafter The printable information stored in the RAM 107 is updated with new information after the print preparation process at an appropriate timing. In addition, information about the developing cartridge that is executing the print preparation operation can be obtained by confirming what operation the CPU 101 executing the print preparation operation is executing.

  On the other hand, the fixing unit 9 is driven and controlled by the CPU 101 of the engine controller 10. If necessary, the temperature information of the fixing unit 9 can be confirmed by the CPU 101 confirming the detection result of the temperature sensor 91 provided in the fixing unit 9. As described above, the CPU 101 confirms the temperature information of the fixing unit 9 and the execution state of the print preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4 as described above. It is determined whether or not the printing operation can be performed. If the printing operation can be executed, the printing operation can be started by permitting the execution of the printing operation. Thus, the engine controller 10 including the CPU 101 functions as the “control unit” of the present invention. In this image forming apparatus, the following operations and processes are executed as a “print preparation operation”.

(1) Checking operation:
This attachment confirmation operation is an operation for confirming that the developing cartridge is securely attached to the support frame 40 of the developing unit 4. Specifically, the data is transmitted and received between the CPU 101 and each of the memories 91 to 94 by wireless communication performed between the main body side and each developing cartridge side. In this regard, the same applies to the (2) conformity confirmation operation described below. Of course, in addition to the non-contact method such as wireless communication, the attachment confirmation may be performed by a contact method using a limit switch or the like.

(2) Conformity check operation:
This conformity confirmation operation is an operation for confirming that the developing cartridge mounted on the support frame 40 of the developing unit 4 is a developing cartridge that contains black toner. In particular, in this embodiment, a monochrome image forming apparatus is configured by mounting a developing cartridge for black at a position where a developing cartridge for yellow, cyan, and / or magenta used as a color image forming apparatus is installed. Therefore, there is a possibility that a user, an operator, or the like erroneously attaches the developing cartridge. Therefore, the conformity confirmation operation is executed to prevent the development cartridge for yellow, cyan or magenta from being used accidentally.

(3) Life check operation:
This life confirmation operation is an operation for confirming that the toner amount necessary for executing the printing operation remains sufficiently in the developing cartridge mounted on the support frame 40 of the developing unit 4. By executing this life checking operation, problems such as density unevenness and fading of an image formed by the printing operation are prevented in advance.

(4) Stir processing:
This stirring process is a process of rotating the developing roller 44 corresponding to the “toner carrier” of the present invention at least once. The reason for executing this stirring process is as follows. In this type of image forming apparatus, if the printing operation is performed for a long time after the power is off or the operation is stopped without performing the printing operation (image forming operation) even when the power is on, It has been conventionally known that periodic density unevenness may appear. In the present specification, this phenomenon is referred to as “abandoned banding phenomenon”.

  This neglected banding phenomenon is difficult because the toner is left on the developing roller 44 of each developing cartridge for a long time and is not easily separated from the developing roller 44, and the degree is not uniform on the surface of the developing roller 44. It is considered that the toner layer on the developing roller 44 is gradually non-uniform. Therefore, in the image forming apparatus according to this embodiment, when the neglected banding generation requirement such that the period in which the operation is stopped exceeds a predetermined period is satisfied, a signal “stirring is required” is generated to empty the developing roller 44. We are turning. That is, the developing roller 44 is rotated at least once by a rotation drive unit (not shown) on the main body side. As a result, the toner layer on the surface of the developing roller 44 is refreshed and the toner layer in a more uniform state is subjected to the developing process, and therefore, density unevenness due to the neglected banding phenomenon is less likely to occur.

(5) Patch processing (condition control processing):
This patch process is a process for adjusting the printing operation condition when executing the printing operation by the developing cartridge to a predetermined optimum condition. This is a process similar to that conventionally used for stabilizing image quality. In this embodiment, a “patch control required” signal is generated at an appropriate timing immediately after the apparatus is turned on, and patch processing is executed in parallel with warming up of the apparatus. Patch processing is also generated when a “patch control required” signal is generated at the timing when the sleep mode is released, when the device cover that was in the open state is closed, or when the replacement of the developing cartridge is completed. Execution request occurs.

  Subsequently, the case where the execution of the printing operation is permitted based on the temperature information of the fixing unit 9 and the execution state of the printing preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4 will be described with reference to FIGS. 6 will be described in detail. Note that when the execution of the printing operation is permitted, there are cases other than the four examples given here, and the conditions for permitting the execution of the printing operation may be changed as appropriate according to the operation status of the apparatus. 3 to 6 are almost the same in format, and in the explanation of FIG. 4 to FIG. 6 after explanation of FIG. 3, only the parts different from FIG. The description of the part is omitted.

1. When the fixing unit warm-up operation and the print preparation operation for the developing cartridge are executed in parallel when the power is turned on, FIG. 3 shows the temperature change of the fixing unit 9 due to the warm-up operation of the fixing unit 9 when the power is turned on, and the development unit 4 It is a figure which shows the relationship with the execution state of the printing preparation operation | movement about mounted developing cartridge 4Ka-4Kd. In FIG. 3, the upper graph in the drawing is a graph showing the temperature change of the fixing unit 9 during the warm-up operation, the vertical axis represents the temperature of the fixing unit 9, and the horizontal axis represents the elapsed time (Time). The chart in the middle of the drawing is stored in the RAM 107 by performing a print preparation operation on the developing cartridges 4Ka to 4Kd mounted on the developing unit 4 in parallel with the warming-up operation of the fixing unit 9. The timing at which the printable information of the developing cartridges 4Ka to 4Kd is updated is shown. In the figure, ON represents a printable state and OFF represents a non-printable state. The chart on the lower side of the drawing shows the timing when the printer is ready for printing by completing both the warm-up operation of the fixing unit 9 and the print preparation operation for the developing cartridge.

  When the power is turned on first in the morning, the temperature of the fixing unit 9 is the room temperature T0 where the apparatus is installed. Therefore, the engine controller 10 starts the warming-up operation of the fixing unit 9 in response to the start command output at the power-on timing, and executes the warming-up operation until the temperature of the fixing unit reaches a predetermined fixing temperature Tr. The engine controller 10 also executes a print preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4 in parallel with the warming-up operation of the fixing unit 9 in response to the activation command.

  When the print preparation operation for each of the developing cartridges 4Ka to 4Kd is completed and the developing cartridge can be printed, the engine controller 10 updates the printable information stored in the RAM 107 for the developing cartridge (see FIG. 3). ). Here, when one of the developing cartridges 4Ka to 4Kd becomes capable of printing for the first time, the engine controller 10 outputs a developing cartridge printing preparation completion signal (in FIG. Timing when printing is possible). When the temperature of the fixing unit 9 reaches the predetermined fixing temperature Tr, a fixing unit temperature increase completion signal is output and the warming-up operation of the fixing unit 9 is ended. At the end timing (tr) of the warm-up operation, as shown in FIG. 3, the developing cartridge 4Kd is not printable, but the other three developing cartridges 4Ka to 4Kc are already printable. By determining the printable information in this way, it is possible to grasp the execution state of the print preparation operation that changes every moment. Therefore, in this image forming apparatus, at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 can be printed at the timing t1, and the temperature rise of the fixing unit 9 is completed. It is possible to confirm that it is possible to fix. The engine controller 10 then outputs a print preparation completion signal and permits execution of the printing operation of the apparatus.

2. When the warming-up operation of the fixing unit and the print preparation operation for the developing cartridge are executed in parallel at the time of returning from the sleep mode (print standby state) FIG. 4 shows the fixing accompanying the warming-up operation of the fixing unit 9 at the time of returning from the sleep mode. FIG. 10 is a diagram illustrating a relationship between a temperature change of the unit 9 and an execution state of a print preparation operation for the developing cartridge. The difference from the above-mentioned “1. When the warm-up operation of the fixing unit and the print preparation operation for the developing cartridge are executed in parallel when the power is turned on” is largely different from the temperature of the fixing unit 9 when the start command is output. (> T0).

  When returning from the sleep mode, the temperature of the fixing unit 9 is the standby temperature T1. In response to the start command output at the timing of returning from the sleep mode, the engine controller 10 starts the warming-up operation of the fixing unit 9 and executes the warming-up operation until the temperature of the fixing unit 9 reaches a predetermined fixing temperature Tr. The engine controller 10 also executes a print preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4 in parallel with the warming-up operation of the fixing unit 9 in response to the activation command.

  When the temperature of the fixing unit 9 reaches a predetermined fixing temperature Tr, the engine controller 10 outputs a fixing unit temperature increase completion signal and ends the warming-up operation of the fixing unit 9 (timing t21). Here, since the temperature T1 of the fixing unit 9 at the start command time is close to the fixing temperature Tr, the time required for the warm-up operation is short, and printing is performed for any of the developing cartridges 4Ka to 4Kd at the end of the warm-up operation (timing t21). The preparation operation has not been completed. Therefore, the engine controller 10 continues the print preparation operation based on the printable information, and when the print preparation operation for each of the development cartridges 4Ka to 4Kd is completed and the development cartridge can be printed, it is stored in the RAM 107 for the development cartridge. The stored printable information is updated (see FIG. 4). When one of the developing cartridges 4Ka to 4Kd is ready to print (timing t22), the engine controller 10 outputs a developing cartridge printing preparation completion signal (in FIG. 4). Timing when the developing cartridge 4Ka can be printed). At the output timing t22 of the print preparation completion signal, as shown in FIG. 4, the fixing unit 9 has already reached the fixing temperature Tr, while the developing cartridges 4Kb to 4Kd are not printable, but the developing cartridge 4Ka. Can be printed, the engine controller 10 outputs a print preparation completion signal and permits execution of the printing operation of the apparatus.

3. When one or more developing cartridges can be printed when returning from the sleep mode (printing standby state) FIG. 5 shows a change in temperature of the fixing unit 9 due to the warm-up operation of the fixing unit 9 when returning from the sleep mode, and the developing cartridge. FIG. 6 is a diagram showing a relationship with an execution state of a print preparation operation for. Unlike the above two cases, when the start command is output (timing t31), when the print preparation operation for the developing cartridges 4Ka to 4Kd mounted on the developing unit 4 is confirmed, at least one of the developing cartridges 4Ka to 4Kd is confirmed. The above is in a printable state. Therefore, the engine controller 10 does not execute the print preparation operation for other developing cartridges.

  On the other hand, at the time of returning from the sleep mode, the temperature of the fixing unit 9 is the standby temperature T1, which is lower than the fixing temperature Tr. Therefore, the engine controller 10 starts a warming-up operation of the fixing unit 9 in response to a start command output at the timing of returning from the sleep mode, and executes the warming-up operation until the temperature of the fixing unit reaches a predetermined fixing temperature Tr. .

  When the temperature of the fixing unit 9 reaches the predetermined fixing temperature Tr, the engine controller 10 outputs a fixing unit temperature increase completion signal and ends the warming-up operation of the fixing unit 9 (timing t32). Thus, the condition (1) that the fixing unit 9 has reached the fixing temperature Tr and the condition (2) that at least one of the developing cartridges can be printed are satisfied. Therefore, the engine controller 10 outputs a print preparation completion signal and permits execution of the printing operation of the apparatus.

4). FIG. 6 is a diagram showing the relationship between the temperature of the fixing unit 9 at the time of replacement of the developing cartridge and the execution state of the print preparation operation for the developing cartridge when the developing cartridge is replaced. It is. Unlike the case of “when one or more developing cartridges can be printed when returning from the sleep mode (printing standby state)” described above, since all the developing cartridges attached to the developing unit 4 are immediately replaced, When the start command is output, all of the developing cartridges 4Ka to 4Kd are in a non-printable state. However, when all of the developing cartridges 4Ka to 4Kd have been replaced, the developing cartridge replacement operation is not so time-consuming and time-consuming. Therefore, the temperature of the fixing unit 9 is confirmed. It was kept at the fixing temperature Tr. In such a case, the engine controller 10 executes the print preparation operation for the developing cartridges 4Ka to 4Kd in response to the start command output at the timing t41 when the developing cartridge replacement operation is completed, but the fixing unit 9 fixes the fixing unit 9. Since the temperature Tr is maintained, the fixing unit 9 is not warmed up.

  When one of the developing cartridges 4Ka to 4Kd is ready for printing (timing t42), the engine controller 10 outputs a developing cartridge print preparation completion signal (in FIG. 6). Timing when the developing cartridge 4Ka becomes printable). At this timing t42, the temperature of the fixing unit 9 is already the predetermined fixing temperature Tr, and at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 is ready for printing, and this is grasped. The engine controller 10 is outputting a print preparation completion signal to permit execution of the printing operation of the apparatus.

  As described above, in the image forming apparatus according to the present invention, the execution of the print preparation operation is permitted based on the temperature information of the fixing unit 9 and the execution state of the print preparation operation. Play. As described above, the print preparation operation is performed in parallel with the warm-up operation immediately after the power is turned on or when returning from the sleep mode (print standby state). Here, the time spent for the warm-up operation differs depending on whether the warm-up operation is performed immediately after the power is turned on or the warm-up operation is performed when returning from the sleep mode. For this reason, although the warm-up operation is completed, the print preparation operation for some developing cartridges may be incomplete. That is, in the warm-up operation immediately after the power is turned on, the warm-up operation must be performed until the temperature of the fixing unit 9 reaches the fixing temperature Tr from the room temperature T0 where the apparatus is installed. In operation, since the temperature of the fixing unit 9 is normally kept at a certain high temperature (standby temperature), only the warming-up operation is performed until the temperature of the fixing unit 9 reaches the fixing temperature Tr from the temperature maintaining temperature in the sleep mode. It's okay. For this reason, normally, the warm-up operation when returning from the sleep mode requires less time for the warm-up operation than the warm-up operation immediately after power-on. As a result, for example, when there is not much difference between the time required for the warm-up operation immediately after power-on and the total time required for the print preparation operation for all the developing cartridges 4Ka to 4Kd, Since the time required for the warm-up operation is short, the print preparation operation for some developing cartridges is not completed even though the warm-up operation is completed. In such a case, printing can be started using a developing cartridge that has already completed the print preparation operation, but printing cannot be started until the remaining print preparation operations are completed. However, in this image forming apparatus, as described above, the execution of the printing operation is permitted based on the temperature information of the fixing unit 9 and the execution state of the printing preparation operation for the cartridge attached to the developing unit 4. Therefore, even if the print preparation operation for all the cartridges is not completed, the print operation can be executed using a cartridge that has already been subjected to the print preparation operation and can be printed. Therefore, it is possible to efficiently print the specific color. Further, when the temperature increase of the fixing unit 9 is completed, a printing preparation operation is performed, so that at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 9 can be printed. For example, even if there is another developing cartridge that cannot be printed, the printing operation can be executed.

  Next, a specific operation of the apparatus including the engine controller 10 that executes the basic operation of the image forming apparatus according to the present invention will be described. In the embodiments described below, the execution modes that permit the execution of the printing operation based on the temperature information of the fixing unit 9 and the execution state of the printing preparation operation for the developing cartridges 4Ka to 4Kd are features based on the present invention, respectively. Accordingly, the execution mode thereof is slightly different. Accordingly, these differences will be mainly described below. In order to facilitate understanding of the content of the invention, a case where four developing cartridges 4Ka to 4Kd are mounted on the developing unit 4 as shown in FIG.

<First Embodiment>
FIG. 7 is a diagram showing an operation in the first embodiment of the image forming apparatus according to the present invention, FIG. 8 is a diagram showing a warm-up operation of the fixing unit, FIG. 9 is a diagram showing a print preparation process, and FIG. It is a figure which shows a process. In the first embodiment, for example, at the timing when the apparatus is turned on, the warm-up operation of the fixing unit 9 and the print preparation process for performing the print preparation operation on all the developing cartridges 4Ka to 4Kd attached to the developing unit 4 are performed. Run in parallel. Further, the first pre-printing process is executed during the warm-up operation of the fixing unit 9 and the print preparation process for the developing cartridge. First, the warm-up operation of the fixing unit 9 and the print preparation process for the developing cartridge will be described with reference to FIGS. 8 and 9, and then the first pre-print process will be described in detail with reference to FIG.

  In the first embodiment, at the timing when the power of the apparatus is turned on, the CPU 101 of the engine controller 10 performs the warm-up operation of the fixing unit 9 and the print preparation for all the developing cartridges 4Ka to 4Kd according to the program stored in the ROM 106. Execute the process. First, the warm-up operation of the fixing unit 9 will be described with reference to FIG. After starting the warming up of the fixing unit 9, the CPU 101 of the engine controller 10 waits until the temperature of the fixing unit 9 reaches a predetermined fixing temperature Tr (step S1). When it is determined that the temperature of the fixing unit 9 has reached the predetermined fixing temperature Tr, the process proceeds to step S2, a fixing unit temperature increase completion signal is output, and the fixing unit warm-up operation is completed. Thereafter, the CPU 101 monitors the temperature of the fixing unit 9 based on the output from the temperature sensor 91, and performs control to maintain a predetermined fixing temperature Tr. In parallel with the warm-up operation, the CPU 101 executes print preparation processing shown in FIG. 9 according to a program stored in the ROM 106. Hereinafter, the print preparation process will be described in detail with reference to FIGS.

  First, data is transmitted and received between the CPU 101 and each of the memories 91 to 94 by wireless communication, and various types of information such as consumables management for the developing cartridges 4Ka to 4Kd are temporarily stored in the RAM 107. In this embodiment, based on the information stored in the memory 107, first, among the mounted cartridges 4Ka to 4Kd, for the developing cartridge 4Ka closest to the developing position, the mounting confirmation operation (step S20) and the conformity confirmation operation (step S21). ) And a life confirmation operation (step S22).

  In step S23, it is determined whether or not a “stirring required” signal is generated. This is a process for preventing the neglected banding phenomenon. Therefore, if the “stirring required” signal is not generated, the process proceeds to step S25 as it is. If the signal is generated, the stirring process (step S24) shown in FIG. 10 is performed for the developing cartridge 4Ka. Executed.

  FIG. 10 is a flowchart showing the stirring process in the print preparation process of FIG. In this stirring process, among the four developing cartridges, the cartridge 4Ka is moved to the developing position (step S241). As a result, the developing roller 44 of the developing cartridge 4Ka is mechanically connected to the rotation drive unit on the main body side. Then, the developing roller 44 is rotated at least once by the rotation driving unit to refresh the toner layer on the surface of the developing roller 44, and the developing cartridge 4Ka is stirred (step S242).

  When the agitation process (step S24) is completed in this way, the process proceeds to step S25, where it is determined whether or not a “patch control required” signal is generated. This is a process for adjusting the printing operation condition to a predetermined optimum condition. Therefore, when the “patch control required” signal is not generated, a printable signal indicating that the developing cartridge 4Ka is printable is output, whereas when the signal is generated, the development is performed. The patch process (step S26) shown in FIG. 11 is executed for the cartridge 4Ka.

  FIG. 11 is a flowchart showing patch processing in the print preparation processing of FIG. In this patch processing, in order to maintain an image formed by executing a printing operation with a constant image quality, a patch image is formed while changing various printing operation conditions, and the image density is detected. Is a process of adjusting the printing operation condition based on the above. 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 for the principle and control method of image quality control using them. Briefly described.

  First, for the developing cartridge 4Ka, the optimum developing bias, that is, the optimum value of the developing bias applied to the developing roller 44 during the printing operation is calculated. Specifically, the developing cartridge 4Ka is selectively moved to the developing position (step S260), and a patch image having a predetermined pattern is formed with each bias value while changing the developing bias in multiple stages for the developing cartridge 4Ka. (Step S261). The image density of each patch image is detected by the density sensor 60 (step S262).

  When the image density of each patch image is obtained, the relationship between the development bias and the image density can be found from these values. Based on this relationship, the development bias value that matches the predetermined target density Is calculated. Thereby, the optimum developing bias is obtained (step S263). However, if the optimum value is not within the development bias variable range in 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 the developing cartridge 4Ka in this way, the optimum exposure power for the developing cartridge 4Ka, that is, the intensity of the light beam L when forming an electrostatic latent image corresponding to the cartridge on the photosensitive member 22 is subsequently obtained. Is calculated (steps S263 to S266). The processing here is the same as the above-described optimal development bias calculation processing (steps S260 to S263) except that the control factor is exposure power instead of the 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 developing bias and optimum exposure power are respectively obtained for the developing cartridge 4Ka, and the patch processing is ended.

  By executing such a print preparation operation (mounting confirmation operation, conformity confirmation operation, life confirmation operation, agitation processing, patch processing), the developing cartridge 4Ka is in a printable state in which the printing operation can be performed satisfactorily. Then, returning to FIG. 9, a printable signal indicating that the developing cartridge 4Ka can execute the printing operation is output, and the printable information on the developing cartridge 4Ka stored in the RAM 107 is updated (step). S27). Thereafter, the same operation is repeated for all of the developing cartridges 4Kb to 4Kd, whereby the processing is advanced until each developing cartridge can execute the printing operation (step S28). Then, after the printing preparation operation is completed for all the developing cartridges 4Ka to 4Kd and all the developing cartridges 4Ka to 4Kd are ready for printing, the developing unit 4 is moved to the home position (HP) and waits (step S29). ). Next, the progress of the print preparation process will be described in detail with reference to FIG.

  FIG. 12 is a diagram showing the progress of the print preparation operation in the print preparation process shown in FIG. First, the progress of processing when the print preparation operation is being executed for the developing cartridge 4Ka will be described. First, mounting confirmation is performed at timing t1, conformity confirmation at timing t2, and lifetime confirmation at timing t3 (see steps S20 to S22 in FIG. 9). Thereafter, when a signal indicating that stirring is necessary is generated in step S23 of FIG. 9, the stirring process is executed at timing t4 (see step S24 of FIG. 9). Subsequently, when a signal requiring patch control is generated in step S25 in FIG. 9, patch processing is executed at timing t5 (see step S26 in FIG. 9). At the timing t5 when the patch processing is completed, the developing cartridge 4Ka can execute the printing operation, a printable signal for the developing cartridge 4Ka is output, and the printable information for the developing cartridge 4Ka stored in the RAM 107 is updated. (See step S27 in FIG. 9). Thereafter, the same operation is repeated with respect to the developing cartridges 4Kb to 4Kd, but the printing operation by each developing cartridge is executed at timings t10, t15, and t20 when the print preparation operation for each developing cartridge is completed and printing becomes possible. A printable signal indicating that printing is possible is output, and printable information corresponding to each developing cartridge stored in the RAM 107 is updated. Next, the first pre-printing process that is simultaneously executed during the warm-up operation and the print preparation process of the fixing unit 9 in the engine controller 10 will be described in detail with reference to FIG.

  FIG. 13 is a diagram illustrating a first pre-printing process that is simultaneously performed during the warm-up of the fixing unit 9 and the print preparation process for the developing cartridge in the engine controller 10. In the first pre-printing process, first, it is confirmed whether or not a temperature raising completion signal indicating that the fixing unit 9 has reached a predetermined fixing temperature Tr is output. Wait (step S30). Then, after confirming that the temperature raising completion signal has been output, the process proceeds to step S31, and among the developing cartridges 4Ka to 4Kd attached to the developing unit 4, a printable signal has already been output for at least one developing cartridge. Check if it is. If the print enable signal is not output, the printer waits until the print preparation operation for at least one developer cartridge is completed and the print enable signal for the developer cartridge is output. Then, after confirming that a printable signal for the developing cartridge has been output, the process proceeds to step S32, where a print preparation completion signal is transmitted to the main controller 11 to permit execution of the printing operation.

  Here, consider a case where a print request is input to the main controller 11 (see FIG. 7). When a print request is input from the external device to the main controller 11 via the interface 112, if the print preparation completion signal is not transmitted from the engine controller 10, the main controller 11 gives the print start signal to the engine controller 10 as it is. Wait. Then, as described above, in the engine controller 10, the warm-up operation and the print preparation process are executed, and after the print preparation completion signal is transmitted from the engine controller 10 to the main controller 11, the main controller 11 is based on the print request. A control command for starting the printing operation is given to the engine controller 10. Here, when the print start signal is input from the main controller 11, the engine controller 10 interrupts the print preparation process even if the print preparation process for all the developing cartridges 4Ka to 4Kd is not completed, and performs the printing operation. To start.

  As described above, in the first embodiment, when the warming-up operation of the fixing unit 9 is completed and the fixing unit 9 reaches the predetermined temperature Tr, preparation for printing on the developing cartridges 4Ka to 4Kd attached to the developing unit 4 is performed. If the execution state of the operation is confirmed and if at least one of the developing and developing cartridges 4Ka to 4Kd attached to the developing unit 4 is in a printable state, the printing operation using the printable developing cartridge is performed. Execution is permitted. Further, when a print request is issued, if the execution of the print operation is permitted, the print preparation is performed even if the print preparation operation is being performed on the development cartridges 4Ka to 4Kd attached to the development unit 4. The operation is interrupted, and among the developing cartridges 4Ka to 4Kd attached to the developing unit 4, the printing operation is performed using the developing cartridge that has been subjected to the printing preparation operation and can be printed. Therefore, after the print request is input, the waiting time until the start of printing can be shortened, and the printing operation can be started immediately without causing the user to wait more than necessary.

Second Embodiment
FIG. 14 is a diagram showing a second pre-printing process in the second embodiment of the image forming apparatus according to the present invention. The second embodiment is greatly different from the first embodiment in that the second pre-printing process is executed instead of the first pre-printing process. Hereinafter, the differences from the first embodiment will be mainly described.

  In the second pre-printing process executed in the second embodiment, first, printing can be performed by performing a print preparation operation on at least one of the developing cartridges 4Ka to 4Kd mounted on the developing unit 4. It is confirmed whether it is in a proper state (step S40). If the determination is NO, at least one developing cartridge is ready for printing and waits until a printable signal is output for the developing cartridge. On the other hand, if YES is determined, the process proceeds to step S41 to check whether or not the temperature of the fixing unit 9 has reached a predetermined fixing temperature Tr. If NO is determined here, the process waits until a temperature increase completion signal indicating that the temperature of the fixing unit 9 has reached the predetermined fixing temperature Tr is output, while the developing cartridge mounted on the developing unit 4 Among these, the print preparation operation for the developing cartridge incapable of executing the print operation is continued. If it is confirmed that the warming-up operation of the fixing unit 9 has been completed and the temperature raising completion signal has been output, the process proceeds to step S42, where a print preparation completion signal is transmitted from the engine controller 10 to the main controller 11, 2 The pre-printing process is terminated.

  At this time, as in the first embodiment, if a print request has already been input to the main controller 11, the main controller 11 instructs the engine controller 10 to start a printing operation based on the print request as a control command. A print start signal is given. When the print start signal is input, the engine controller 10 interrupts the print preparation process and starts the printing operation even if the print preparation process for all the developing cartridges 4Ka to 4Kd is not completed.

  Thus, in the second embodiment, whether or not the fixing unit 9 has reached the fixing temperature Tr when one or more of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 can be printed. Judgment. At this time, if the fixing unit 9 has not reached the fixing temperature Tr, the print preparation operation is executed for the other developing cartridge. Therefore, it is possible to execute the print preparation operation for the developing cartridge without wasting time until the temperature increase (warming up operation) of the fixing unit 9 is completed.

<Third Embodiment>
FIG. 15 is a diagram showing operations in the third embodiment according to the present invention. The third embodiment differs greatly from the first and second embodiments in that the determination function 110 is provided in the engine controller 10 instead of executing the first and second pre-printing processes. . As a method of providing the determination function 110 in the engine controller 10, there are a method of adding hardware for realizing the determination function 110 and a method of realizing the determination function 110 as a program executed in the CPU 101. It goes without saying that the determination function 110 may be implemented in either case. In the third embodiment, the engine controller 10 includes this determination function 110 as a program executed by the CPU 101. Hereinafter, the differences from the first and second embodiments will be mainly described.

  This determination function 110 has the following two functions. That is, an OR function 1101 that outputs a value of “true” when at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 is ready for printing. Further, when the warm-up operation of the fixing unit 9 is completed and the OR function 1101 outputs a “true” value, a “true” value is output (determined that the printing operation can be performed) AND function 1102. It has. As described above, the determination function 110 is used when the temperature of the fixing unit 9 is completed when at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 is in a printable state. Determines that the printing operation can be executed.

  As described above, in the third embodiment, when the engine controller 10 includes the determination function 110, at least one of the developing cartridges 4Ka to 4Kd attached to the developing unit 4 is in a printable state, and Since it can be determined that the printing operation can be performed at the same time as the temperature increase of the fixing unit 9 is completed, the execution of the printing operation can be permitted simultaneously with the determination. Therefore, the execution of the printing operation can be permitted in the shortest time.

<Fourth embodiment>
FIG. 16 is a diagram showing an operation in the fourth embodiment of the image forming apparatus according to the present invention. In the fourth embodiment, after the printing operation is completed, the engine controller 10 reads out printable information about the developing cartridges 4Ka to 4Kd stored in the RAM 107, so that the printing preparation operation for the developing cartridges 4Ka to 4Kd is performed. Is executed, and the print preparation operation is executed for the remaining developing cartridges that have not been subjected to the print preparation operation. Other configurations and operations are the same as those in the first embodiment, and a description of the configurations and operations will be omitted.

  In the fourth embodiment, the engine controller 10 interrupts the second print preparation process in accordance with a control command (print start signal) from the main controller 11. Thereafter, the printing operation is started. After the printing operation is completed, the engine controller 10 reads the printable information for each developing cartridge stored in the RAM 107 and confirms the execution status of the printing preparation operation for each developing cartridge 4Ka to 4Kd. Then, the print preparation process is executed for the remaining developing cartridges that have not been subjected to the print preparation operation. Then, after the print preparation operation for all the developing cartridges is completed, the developing unit 4 is moved to the home position (HP) and waits. By executing the subsequent printing operation under this optimum condition, it is possible to form an image with a desired image quality and stably.

  As described above, in the fourth embodiment, after the printing operation is completed, the engine controller 10 reads the printable information about each of the developing cartridges 4Ka to 4Kd stored in the RAM 107, and is attached to the developing unit 4. The execution state of the print preparation operation for the developing cartridge 4 is known. Then, a print preparation operation is executed for the developing cartridge that has not been subjected to the print preparation operation. Therefore, when this print preparation process is completed, all the cartridges are ready for printing, so that a large amount of monochrome printing can be performed efficiently. Further, even if the print preparation process for all the developing cartridges 4Ka to 4Kd is interrupted in the middle, it is interrupted only by re-executing a part of the process afterwards instead of all the processes during the print preparation process. Since all the print preparation processes can be completed, there is no need to perform a wasteful process and the efficiency is high.

<Fifth Embodiment>
FIG. 17 is a diagram showing an operation in the fifth embodiment of the image forming apparatus according to the present invention. The fifth embodiment is significantly different from the first to fourth embodiments in the temperature information of the fixing unit 9 and the execution state of the print preparation operation for the developing cartridges 4Ka to 4Kd attached to the developing unit 4. On the basis of this, the developing cartridge to be subjected to the printing preparation operation is selected, and the printing preparation operation is executed only for the selected developing cartridge. Hereinafter, the differences from the first to fourth embodiments will be mainly described.

  FIG. 17 shows, for example, temperature information of the fixing unit 9 and printing on the developing cartridges 4Ka to 4Kd attached to the developing unit 4 when an activation command is output at the timing when the apparatus cover that has been opened is closed. When the execution state of the preparatory operation is confirmed, the developing cartridge 4Kd can be printed, and the temperature of the fixing unit 9 has not reached the fixing temperature Tr. In the fifth embodiment, based on the confirmed temperature information of the fixing unit 9, the number of developing cartridges that can be subjected to the print preparation operation until the warm-up operation is completed is predicted to be two, and the developing unit 4 is mounted. Among the developing cartridges 4Ka to 4Kd, the developing cartridges 4Ka and 4Kc are selected as developing cartridges to be subjected to the print preparation operation from the unprintable developing cartridges 4Ka to 4Kc. Note that, as a reference for selecting a developing cartridge to be subjected to the print preparation operation, a part of various information such as consumable management related to the developing cartridge temporarily stored in the RAM 107 is used. After the development cartridge to be subjected to the print preparation operation is selected in this way, the print preparation operation is executed for the selected development cartridges 4Ka and 4Kc. Therefore, it is possible to efficiently execute the print preparation operation without wasting time until the warm-up operation is completed.

<Others>
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 above embodiment, a maximum of four developing cartridges can be mounted on the support frame 40 of the developing unit 4, and the developing cartridges 4Ka to 4Kd are mounted at all mounting positions. The present invention can be applied to an apparatus in which a developing cartridge is mounted only at a position. That is, even in an apparatus in which a developing cartridge 4 having a smaller number M (M ≧ 2) of developing cartridges than the number of developing cartridges that can be mounted is mounted on the developing unit 4, printable information on the developing cartridge mounted in the developing unit 4 is determined. By performing the print preparation operation for these developing cartridges, it is possible to obtain the same effects as those described above. In the above embodiment, the number that can be mounted is four, but this number is arbitrary, and the number M is arbitrary as long as it is 2 or more and not more than the number that can be mounted. Therefore, for example, the developing unit 4 is configured so that the number of support frames 40 that can be mounted is 5 or more, and further, yellow, cyan, and magenta developing cartridges are mounted at three mounting positions, respectively, and the remaining The present invention can also be applied to an image forming apparatus in which a black developing cartridge is mounted at the mounting position.

  Further, in the second embodiment, after the developing cartridge mounted on the developing unit 4 is the first developing cartridge that has undergone the print preparation operation becomes a printable developing cartridge, the fixing unit Although the print preparation operation for the other developing cartridge is continued until the warming-up operation of No. 9 is completed and the temperature raising completion signal is output, the progress of the print preparation operation for the other developing cartridge is not considered. It was. This may be configured to check whether or not the warming-up operation of the fixing unit 9 is completed each time one developing cartridge mounted on the developing unit 4 is ready to perform printing.

  In the fourth embodiment, the first pre-printing process is executed. However, the second pre-printing process may be executed instead of the first pre-printing process. Furthermore, it is a matter of course that the determination function 110 may be provided instead of executing the first and second pre-printing processes.

  In the above embodiment, the toner image on the photoconductor 22 is transferred to the recording paper via the intermediate transfer belt 71. However, the image is directly transferred from the photoconductor 22 to the sheet S without using the intermediate transfer belt 71. The toner image may be transferred.

  In the above embodiment, the present invention is applied to an image forming apparatus in which the specific color is black, but the specific color is not limited to this.

  In the above-described embodiment, a rotary developing method in which a plurality of developing cartridges are mounted on the developing unit 4 is employed. Therefore, the toner stored in each developing cartridge as the developing unit 4 rotates is stirred in the cartridge. Thus, the toner can be made uniform. Therefore, the toner agitation may be executed by the rotation operation of the developing unit 4 as the print preparation operation. Further, conventionally, there is a case where a member such as an agitator or an auger bar is disposed in the developing cartridge to stir the toner in the developing cartridge or actively supply the toner to the developing roller side. Therefore, in an apparatus equipped with members such as an agitator and an auger bar, operations such as toner agitation and toner supply by the members may be executed as print preparation operations.

  In the above-described embodiment, the configuration in which the toner contained in the developing cartridge is used up is employed. However, in the apparatus employing the replenishing type developing cartridge that replenishes toner as necessary, the toner replenishing operation is performed as the print preparation operation. May be further executed.

  In the above embodiment, the four developing cartridges 4Ka to 4Kd having the same shape are used. However, developing cartridges having different shapes may be used. In the above embodiment, the present invention is applied to a so-called rotary type image forming apparatus in which the rotary developing unit 4 is arranged for one photoconductor 22. The present invention can also be applied to an elevator type image forming apparatus in which a developing cartridge moves up and down and develops with each developing cartridge, and also to a so-called tandem type image forming apparatus.

  As the print preparation operation to be executed for the developing cartridge, an appropriate one of the above-described various print preparation operations can be used according to the configuration of the apparatus and the operation status.

  Further, the present invention is not limited to the configuration of the above-described embodiment. For example, an apparatus for forming an image of a specific color by installing a development unit equipped with a plurality of development cartridges having toner of a specific color, or a transfer other than an intermediate transfer belt The present invention can also be applied to an apparatus provided with a medium (transfer drum, transfer sheet, etc.), and also to other image forming apparatuses such as a copying machine and a facsimile machine.

1 is a diagram showing a configuration 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 in FIG. 1. FIG. 10 is a diagram illustrating a relationship between temperature information of the fixing unit when power is turned on and an execution state of a print preparation operation for the developing cartridge. FIG. 10 is a diagram illustrating a relationship between the temperature information of the fixing unit when returning from a sleep mode and the execution state of the print preparation operation for the developing cartridge. FIG. 9 is a diagram illustrating a relationship between temperature information of the fixing unit at the time of return from a sleep mode and an execution state of a print preparation operation for a developing cartridge. FIG. 10 is a diagram illustrating a relationship between the temperature information of the fixing unit when the developing cartridge is replaced and the execution state of the print preparation operation for the developing cartridge. FIG. 3 is a diagram illustrating an operation in the first embodiment of the image forming apparatus according to the present invention. FIG. 10 is a diagram illustrating a warming-up operation of the fixing unit. The figure which shows a print preparation process. 10 is a flowchart illustrating a stirring process in the print preparation process of FIG. 9. 10 is a flowchart showing patch processing in the print preparation processing of FIG. FIG. 11 is a diagram illustrating a progress state of a print preparation operation in the print preparation process of FIG. 10. The figure which shows the 1st printing pre-process in 1st Embodiment. The figure which shows the 2nd printing pre-process in 2nd Embodiment of this invention. FIG. 10 is a diagram illustrating an operation in the third embodiment of the image forming apparatus according to the present invention. FIG. 10 is a diagram showing an operation in the fourth embodiment of the image forming apparatus according to the present invention. FIG. 10 is a diagram illustrating an operation in the fifth embodiment of the image forming apparatus according to the present invention.

Explanation of symbols

  4 ... developing unit, 4Ka to 4Kd ... developing cartridge, 7 ... transfer unit, 10 ... engine controller (control means), 22 ... photosensitive body (latent image carrier), S ... sheet (recording material), Tr ... fixing temperature

Claims (9)

A latent image carrier capable of carrying an electrostatic latent image;
A plurality of cartridges having toner of a specific color are detachably provided, and a toner image is formed by executing a printing operation for developing the electrostatic latent image on the latent image carrier using the toner in the mounted cartridge. A developing unit,
A transfer unit for transferring a toner image on the latent image carrier to a recording material;
A fixing unit for fixing the toner image on the recording material to the recording material at a predetermined fixing temperature;
The print operation is executed in a state where the print preparation operation for the cartridge used for the print operation is completed before the print operation is performed and the warm-up operation for raising the temperature of the fixing unit to the fixing temperature is completed. Control means,
The image forming apparatus, wherein the control unit permits execution of the printing operation based on temperature information of the fixing unit and an execution state of the printing preparation operation for a cartridge mounted on the developing unit. The control means permits execution of the printing operation when it is confirmed that the following two conditions (1) and (2) are satisfied based on the temperature information and the execution state of the printing preparation operation. The image forming apparatus according to claim 1.
Condition (1) is that the fixing unit has reached the fixing temperature,
Condition (2) is that the print preparation operation is performed on at least one of the cartridges mounted on the developing unit so that the cartridge can be printed.   The image forming apparatus according to claim 1, wherein when the fixing unit reaches the fixing temperature, the control unit determines an execution state of the print preparation operation for a cartridge mounted on the developing unit.   The control means is configured to cause the fixing unit to reach the fixing temperature when the print preparation operation is performed on at least one of the cartridges mounted on the developing unit and the cartridge is ready for printing. 3. The image forming apparatus according to claim 1, wherein if the fixing unit has not reached the fixing temperature, the print preparation operation is executed for another cartridge.   When the print request is input during execution of the print preparation operation and the execution of the print operation is permitted, the control unit interrupts the print preparation operation and performs printing based on the print request. The image forming apparatus according to claim 1, wherein the image forming apparatus operates.   The image forming apparatus according to claim 5, wherein the control unit restarts the print preparation operation after the printing operation is completed.   3. The control unit selects a cartridge to be subjected to the print preparation operation based on temperature information of the fixing unit and an execution state of the print preparation operation for the cartridge mounted on the developing unit. Image forming apparatus.   The image forming apparatus according to claim 1, wherein M (M ≧ 2) cartridges are attached to the developing unit. A latent image carrier capable of carrying an electrostatic latent image and a plurality of cartridges having toner of a specific color are detachably provided, and the electrostatic latent image on the latent image carrier using the toner in the attached cartridge is provided. A developing unit that executes a printing operation for developing the image to form a toner image, a transfer unit that transfers the toner image on the latent image carrier to the recording material, and a toner image on the recording material at a predetermined fixing temperature. In the image forming apparatus including the fixing unit for fixing the recording material to the recording material, the print preparation operation performed on the cartridge used for the printing operation before the execution of the printing operation is completed, and the fixing unit is moved to the fixing temperature. An image forming method for executing the printing operation in a state in which the warming up operation for raising the temperature is completed,
An image forming method, wherein execution of the printing operation is permitted based on temperature information of the fixing unit and an execution state of the printing preparation operation for a cartridge mounted on the developing unit.

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