JP6112771B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium.

  As a fixing unit in an image forming apparatus using an electrophotographic process, a film heating type fixing device (fixing unit) has been put into practical use in response to a recent demand for energy saving. The film heating type fixing device is formed by sandwiching a thin film having heat resistance between a ceramic heater as a heat generating means and a pressure roller as a pressure member, thereby forming a fixing nip. By rotating the film and the pressure roller together, the unfixed toner image is fixed by applying heat and pressure while conveying the recording material.

  In this film heating type fixing device, the heat capacity of the film as a heating member is very small compared to the conventional heat roller type fixing device, so that the heat energy from the heating means can be used efficiently in the fixing process. . Therefore, it is possible to perform a quick start that can shorten the waiting time from the power-on of the image forming apparatus to the printable state. Furthermore, since the heat capacity of the heating member is small and it is not necessary to preheat the heating member during standby for printing, the power consumption of the image forming apparatus can be kept low and energy saving can be achieved. Such a fixing device is called a quick start fixing device.

  In order to shorten the time (first printout time: FPOT) from the start of printing to the end of discharging of the printed recording medium by taking advantage of the characteristics of the quick start fixing device as described above, the following steps are performed. Is required. That is, it is necessary to predict the temperature rise of the fixing device and to perform image formation in parallel with the temperature rise of the fixing device so that the recording medium reaches the fixing device when the temperature raising of the fixing device is completed.

  Here, when the image forming apparatus is placed in a low temperature environment, or when the voltage of the power source supplied to the image forming apparatus is lowered to the lower limit value, the fixing device is completely increased in the estimated time. It may not be able to keep warm. For this reason, if timing is set with sufficient time from the start of printing to the start of fixing in consideration of the above-mentioned worst conditions, the FPOT will be delayed even under normal conditions. At the same time, there is a problem in terms of the lifetime of consumable parts of the process cartridge described below.

  Process cartridges are widely used as those that can be attached to and detached from image forming apparatuses, mainly for the purpose of reusing resources. This type of process cartridge integrally includes a photosensitive drum, a charging unit, an exposure unit, a developing unit, a cleaner, and a toner container, which are necessary for forming an image by an electrophotographic process method. Among the components of the process cartridge, for example, the photosensitive drum and the developing roller of the developing unit have a lifetime. Therefore, the control unit of the image forming apparatus counts the rotation time of the photosensitive drum and the developing roller. When the counted cumulative value reaches a predetermined threshold, it is determined that the process cartridge has reached the end of life, and the user replaces the process cartridge. Life is managed by encouraging it.

  Here, when there is an allowance for the time from the start of printing to the start of fixing as described above, the process cartridge components, such as the photosensitive drum and the developing roller, are on standby, so that they wait for the components. A life loss will occur.

  As a technique for minimizing the FPOT while suppressing unnecessary wear of the component parts of the process cartridge, there has been a proposal as disclosed in Patent Document 1, for example. In Patent Document 1, an image formation preparation operation and a fixing device temperature increase are started in parallel, and after the fixing device reaches a predetermined temperature, it is used as a consumable item such as a rotation of a developing roller or a rotation of a photosensitive drum. The control sequence is configured to start the image forming preparation operation that is affected. With such a configuration, even when the image forming apparatus is placed in a low temperature environment or when the voltage of the supplied power supply is lowered, the temperature of the fixing unit can be appropriately waited for. I have to. In other words, in the case of a normal sequence, even when the temperature of the fixing device is not in time for image formation, the fixing device can be appropriately operated without affecting the life of the components of the image forming device such as the developing roller and the photosensitive drum. A method has been proposed that allows waiting for the temperature to rise.

JP 2003-57993 A

  Here, consider a case where printing is started from a state in which the pressure roller of the fixing unit and the fixing roller are separated, such as during sleep of the image forming apparatus. In this case, after the contact operation between the pressure roller and the fixing roller of the fixing unit is performed, the image forming preparation operation and the temperature increase of the fixing unit are started to determine whether the fixing unit has reached a predetermined temperature. Do. When the fixing unit is sufficiently warm, such as when the elapsed time from the previous print is short, if the image forming preparation operation is performed in advance while performing the roller contact operation of the fixing unit, FPOT can be shortened. On the other hand, if the image forming preparation operation is performed in advance when the fixing unit is not warmed, the fixing unit eventually reaches a predetermined temperature with the photosensitive drum and the developing roller rotating. Therefore, the life of the consumables is lost.

  In general, a temperature thermistor for detecting the temperature of the fixing unit is disposed on the fixing roller side of the fixing unit. On the other hand, since it is mainly the heat capacity on the pressure roller side that affects the temperature rise rate of the fixing unit, the fixing unit after the roller abuts in a state where the roller of the fixing unit is separated. It is difficult to predict the heating rate.

  Therefore, it is very difficult to simultaneously solve the problems of increasing the speed of FPOT and suppressing the influence on the life of the components of the image forming apparatus from the state where the rollers are separated as described above. It was.

  An object of the present invention is to suppress the FPOT from being extended by appropriately controlling the timing at which the image forming preparation operation is started, and further to suppress the consumption of the process cartridge components more than necessary. An image forming apparatus is provided.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention
An image carrier;
A developer accommodating portion for accommodating the developer;
Developing means for forming an image on the image carrier by carrying the developer contained in the developer container on a developer carrier;
Transfer means for transferring the image to a recording medium;
Fixing means for fixing the image transferred to the recording medium;
Detecting means for detecting the temperature of the fixing means;
In an image forming apparatus having
Of the image formation preparation operations for starting image formation, a first preparation operation mode in which the start timing of the preparation operation relating to the developing unit is determined by the temperature of the fixing unit;
Among the image formation preparation operations, the start timing of the preparation operation related to the developing unit is determined regardless of the temperature of the fixing unit, and the second preparation is started earlier than the first preparation operation mode. The operation mode is executable,
The value proportional to the remaining amount of the developer accommodated in the developer accommodating portion is compared with the value proportional to the lifetime of the developer carrier, and the value proportional to the lifetime of the developer carrier is When the value is smaller than a value proportional to the remaining amount of developer accommodated in the developer accommodating portion, the image forming preparation operation is performed in the first preparation operation mode, and a value proportional to the life of the developer carrier is In the image forming apparatus, the image forming preparation operation is performed in the second preparation operation mode when the value is larger than a value proportional to the remaining amount of the developer stored in the agent storage portion.

  According to the present invention, when the image formation preparation operation is started, it is possible to suppress the FPOT from being extended by appropriately controlling the timing at which the image formation preparation operation is started. In addition, it is possible to suppress the consumption of the process cartridge components more than necessary.

1 is an overall configuration diagram of an embodiment of an image forming apparatus according to the present invention. 1 is a block diagram showing an embodiment of a system configuration of an image forming apparatus according to the present invention. 3 is a timing chart showing a normal image formation preparation operation in Embodiment 1 of the present invention. 6 is a timing chart showing an image formation preparation operation for shortening the FPOT in Embodiment 1 of the present invention. 6 is a flowchart showing an image formation preparation operation for shortening the FPOT in Embodiment 1 of the present invention. It is a flowchart which shows the control flow in Example 1 of this invention. 10 is a flowchart illustrating an image formation preparation operation for shortening FPOT in Embodiment 2 of the present invention. 10 is a flowchart illustrating an image formation preparation operation for shortening FPOT in Embodiment 3 of the present invention.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

[Example 1]
The image forming apparatus according to this embodiment will be described below with reference to FIGS.

  First, referring to FIG. 1, an outline of the overall configuration of the image forming apparatus 100 will be described.

  The image forming apparatus 100 forms an electrostatic latent image with image light formed based on an image signal transmitted from a controller unit (not shown). The electrostatic latent image is developed and a visible image as a toner image is superimposed and transferred to form a color visible image. This color visible image is transferred to the sheet 2 and the color visible image on the sheet 2 is fixed. It is.

  In this embodiment, the image forming apparatus 100 includes a plurality of, for example, four stations ST, that is, a yellow (Y) station STY, a magenta (M) station STM, a cyan (C) station (STC), and a black (K). It has a station STK. Each station (image forming unit) ST has a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 5 (5Y, 5M, 5C, 5K) as an image carrier for each station ST arranged in parallel for the development color. ). Further, around the photosensitive drum 5, there are a primary charging means 7 (7Y, 7M, 7C, 7K), a developing means 8 (8Y, 8M, 8C, 8K), and a developer container 11 (11Y, 11M) which is a developer accommodating portion. , 11C, 11K) and cleaning means 3 (3Y, 3M, 3C, 3K). Further, an intermediate transfer belt 12, which is a belt-like intermediate transfer body, is disposed facing the photosensitive drum 5. The intermediate transfer belt 12 is stretched around rollers 12a, 12b, 12c, and 18, and is rotatable in the direction of the arrow.

  The photosensitive drum 5, the primary charging unit 7, the developing unit 8, and the cleaning unit 3 are integrated to form a process cartridge 2 (22Y, 22M, 22C, 22K) that can be attached to and detached from the main body of the image forming apparatus 100.

  The photosensitive drum 5 is configured by applying an organic optical conductive layer to the outer periphery of an aluminum cylinder, and rotates by receiving a driving force of a driving motor (not shown). The driving motor drives the photosensitive drum 5 in accordance with an image forming operation. Rotate clockwise in FIG. A primary charging unit 7 is provided on the outer periphery of the photosensitive drum 5 to uniformly charge the surface of the photosensitive drum 5. Each primary charging means 7 is provided with a sleeve 7S (7SY, 7SM, 7SC, 7SK). Then, the exposure light to the photosensitive drum 5 (5Y, 5M, 5C, 5K) is sent from the scanner unit 10 (10Y, 10M, 10C, 10K) and is applied to the surface of the photosensitive drum 5 (5Y, 5M, 5C, 5K). An electrostatic latent image is formed by selective exposure.

  As a developing means, in order to visualize the electrostatic latent image on the photosensitive drum 5 (on the image carrier), yellow (Y), magenta (M), cyan (C), and black (K) are developed for each station ST. 4 developing means 8 (8Y, 8M, 8C, 8K) are provided. Each developing means includes a developing container 11 containing toner and a developing roller 8S (8SY, 8SM, 8SC, 8SK) which is a developer carrying member that carries and conveys the toner to develop the electrostatic latent image on the photosensitive drum 5. Is provided. The intermediate transfer member 12 is in contact with the photosensitive drum 5 (5Y, 5M, 5C, 5K), and rotates counterclockwise in FIG. 1 when forming a color image, so that the photosensitive drum 5 (5Y, 5M, 5C, 5K) is rotated. ) Rotates with the rotation. Then, the visible image, which is a toner image, is transferred by the primary transfer bias applied to the primary transfer roller 4 (4Y, 4M, 4C, 4K). The toner image transferred onto the intermediate transfer body 12 is superimposed and transferred onto the sheet 2 as a recording medium at the position of the secondary transfer roller 9. The sheet 2 is nipped and conveyed by the secondary transfer roller and the intermediate transfer body 12 to simultaneously transfer the color visible image onto the sheet 2.

  The fixing unit 13 heat-fixes the transferred color visible image onto the sheet 2 while transporting the sheet 2. The fixing unit 13 heats the sheet 2 and presses the sheet 2 against the fixing roller 14. And a pressure roller 15. The fixing roller 14 and the pressure roller 15 are formed in a hollow shape, and a heater is built in the fixing roller 14. That is, the sheet 2 holding the color visible image is nipped and conveyed by the fixing roller 14 and the pressure roller 15, and the toner is fixed on the surface by applying heat and pressure by both rollers. The sheet 2 after fixing the visible image is discharged to the paper discharge unit and the image forming operation is completed.

  In addition, when the fixing roller 14 and the pressure roller 15 are left in a pressurized state for a long time, a pressure set mark may be generated. Therefore, in this embodiment, a pressure separation mechanism 16 (pressure separation means) for the fixing roller 14 and the pressure roller 15 is provided. The pressure separation unit 16 keeps the fixing roller 14 and the pressure roller 15 in a separated state when the image forming apparatus 100 is in a power-off state or in a sleep state, thereby preventing the occurrence of a pressure set mark. The pressure separation unit 16 adds the fixing roller 14 and the pressure roller 15 when the image forming apparatus 100 is turned on or when an image forming operation instruction is input when the image forming apparatus 100 is in the sleep state. Convert to pressure and hold.

  Further, a registration sensor 19, a fixing paper discharge sensor 20, and a double-sided conveyance sensor 28 that can detect the leading edge and the trailing edge of the conveyed sheet 2 are disposed in the conveyance path of the sheet 2.

  The information display unit 41 displays the status of the printer system and necessary operation operations to the user. Usually, the controller unit 201 described later generates display data based on status data transmitted from the engine.

[System configuration of image forming apparatus]
Next, the system configuration and interface of the image forming apparatus 100 will be described.

  FIG. 2 is a block diagram showing a system configuration of the image forming apparatus 100 shown in FIG. The image forming apparatus 100 receives print information and image information from the host computer 200 as a print signal by the video controller 201 (controller unit). The video controller 201 analyzes the print information and transmits to the system controller (control means) 211 which is an engine control means which print conditions are used for image formation. Further, the video controller 201 expands the image information into bitmap data and transmits it to the system controller 211 as a video signal. Further, the video controller 201 transmits a print reservation command and a print start command to the system controller 211 for each page of the recording medium 2 (for each recording medium 2).

  The system controller 211 is a control unit that comprehensively controls the printing operation of the image forming apparatus 100 based on the video signal, the print reservation command, and the print start command transmitted by the video controller 201.

  When receiving a print command (print signal input) from the host computer 200, the video controller 201 first transmits a print reservation command to the system controller 211. Thereafter, a print start command is transmitted to the system controller 211 at a timing when printing is possible.

  The system controller 211 prepares for execution of printing in the order of print reservation commands from the video controller 201 and waits for a print start command from the video controller 201. When the system controller 211 receives the print start command, the system controller 211 outputs a / TOP signal as a reference timing for starting the output of the video signal to the video controller 201, and starts a print operation according to the information of the print reservation command.

  The system controller 211 mainly plays a role of driving each load in the image forming apparatus 100, collecting and analyzing information of sensors, and exchanging data with the information display unit 41, that is, a user interface. The internal configuration of the system controller 211 is equipped with a CPU 205 in order to assume the above-described role. Similarly, the CPU 205 executes various sequences related to predetermined image formation using the timer 214 by a program stored in the ROM 212 mounted on the system controller 211. In addition, a RAM 213 is also mounted in order to store data necessary for this. The RAM 213 stores, for example, a high voltage set value for a high voltage control unit 220 described later, various data described later, image formation command information from the information display unit 41 and the video controller 201, and the like.

  The system controller 211 obtains information on printing conditions (for example, the size of the recording medium 2, the image forming speed, and the image density setting value) set by the user from the information display unit 41 or the video controller 201. On the other hand, from the system controller 211 to the information display unit 41 and the video controller 201, the state of the image forming apparatus 100, for example, information on the number of prints, whether or not printing is in progress, occurrence of jams (paper jams) and their locations, etc. The data for sending is shown.

  In this image forming apparatus 100, a plurality of motors, DC loads such as a clutch / solenoid, and sensors such as a photo interrupter are arranged at various locations inside the apparatus. In other words, various sensors are used to transport the recording medium 2 and drive each unit by appropriately driving the motor and each DC load, and monitoring the operation. Therefore, the system controller 211 detects signals from various sensors with the sensor input unit 217, and controls the stopping and driving of each motor by the motor control unit 218 based on the signals. At the same time, the DC load control unit 219 operates the clutch / solenoid to smoothly advance the image forming operation. In addition, by sending various high-voltage control signals to the high-pressure control unit 220, an appropriate bias is applied to each of the next rollers constituting the high-pressure unit 222. That is, charging means 7 (7Y, 7M, 7C, 7K), developing means 8 (8Y, 8M, 8C, 8K), primary transfer means 4 (4Y, 4M, 4C, 4K), secondary transfer means shown in FIG. An appropriate bias is applied to 9 and the like. Further, a fixing heater 223 is incorporated in the fixing roller 14 as a heating body of the fixing unit 13, and each heater is ON / OFF controlled by an AC driver 215. At this time, the fixing roller 14 is provided with a thermistor 224 as a temperature detector for measuring the temperature. The A / D converter 225 converts the resistance value change of the thermistor 224 according to the temperature change of the fixing roller 14 into a voltage value, and then inputs the voltage value to the system controller 211 as a digital value. The aforementioned AC driver 215 is controlled based on this temperature data. In addition, the nonvolatile memory control unit 216 is configured from a nonvolatile memory 221 (221Y, 221M, 221C, 221K) (not shown in FIG. 1) mounted on the process cartridge 22 (22Y, 22M, 22C, 22K). The data is read and written.

[Process cartridge life management]
Each component of the process cartridge 22 includes components having limited life and capacity such as the life of the photosensitive drum 5, the life of the developing roller 8S of the developing unit, and the toner capacity (remaining toner amount). .

  For example, since the life of the developing unit 8 greatly affects the rotation time of the developing roller 8S, the system controller 211 integrates the rotation time of the developing roller 8S as needed. As for the remaining amount of toner, the system controller 211 detects the remaining amount of toner in the developing container 11 as needed by monitoring the output of a sensor for measuring the remaining amount of toner. The toner remaining amount detection method includes a pixel count method, an antenna method, a light detection method, a patch detection method, and a combination thereof, but the method will not be described here.

  The system controller 211 stores values related to the lifetime of the components of each process cartridge 22 as described above in the nonvolatile memory 221 (221Y, 221M, 221C, 221K) mounted on the process cartridge 22 (22Y, 22M, 22C, 22K), respectively. ) Is recorded. For this reason, even when the power of the image forming apparatus 100 is once turned off, the integrated value relating to the life of each process cartridge 22 can be read.

[Normal image formation preparation operation (normal image formation preparation sequence)]
Next, the image forming preparation operation will be described with reference to FIG. FIG. 3 is a timing chart showing an image forming preparation operation sequence after the print signal is input by the image forming apparatus 100 from a state where the pressure roller 15 and the fixing roller 14 of the fixing unit 13 are separated from each other.

  When the system controller 211 receives the print start command from the video controller 201, the system controller 211 starts the pressing operation of the fixing roller 14 and the pressure roller 15 of the fixing unit 13 (A in FIG. 3). When the pressing of the fixing roller 14 is completed, the system controller 211 first adjusts the fixing temperature to control the fixing unit 13 to a predetermined temperature, rotates the photosensitive drum 5 (5Y, 5M, 5C, 5K), and the scanner unit 10 ( 10Y, 10M, 10C, 10K) is started (B in FIG. 3).

  Next, application of a charging bias is started after a predetermined time from the rotation of the photosensitive drum 5 (5Y, 5M, 5C, 5K) (C in FIG. 3). This is because if a photosensitive drum 5 is rotated and a charging bias is applied at the same time, a charging memory may be formed on the photosensitive drum 5. Here, the above four processes (fixing temperature control, scanner, photosensitive drum, and charging bias) are combined to form the first sequence group. At this time, the developing roller 8S (8SY, 8SM, 8SC, 8SK) remains stopped.

  Next, the system controller 211 determines whether the temperature T of the fixing unit 13 has reached a predetermined temperature T1 after a predetermined time T_dev from the start of charging bias application (C in FIG. 3). If the predetermined temperature T1 is adjusted as it is, the fixing unit 13 is sufficient even when the image forming apparatus 100 is in a low temperature environment or when the supplied power supply voltage is at the lower limit. This is the temperature that is expected to reach the temperature. That is, if the temperature of the fixing unit 13 can reach a temperature sufficient for fixing the toner on the recording medium 2 from the timing when the rotation contact of the developing roller 8S starts until the recording medium 2 reaches the fixing unit 13. Expected temperature. The predetermined time T_dev is a time from when charging of the photosensitive drum 5 is started until the surface potential of the photosensitive drum 5 becomes a normal potential. This is the minimum time required to apply the developing bias after applying the charging bias so that the toner does not fly from the developing roller 8S to the photosensitive drum 5.

  If the temperature T of the fixing unit 13 has reached T1, the rotation and contact operation of the developing roller 8S (8SY, 8SM, 8SC, 8SK) and the application of the developing bias are started (D in FIG. 3). At this time, if the temperature T of the fixing unit 13 has not reached T1, the temperature of the fixing unit 13 is continuously monitored, and after waiting for the temperature to reach T1, the developing roller 8S (8SY, 8SM, 8SC, 8SK) is rotated. Starts contact operation and development bias application. Here, the control of the application of the developing bias and the rotation / contact of the developing roller 8S of the developing unit 8 correspond to the second sequence group, and the detected temperature of the fixing unit 13 is set to the predetermined temperature T1 as described above. The operation timing of the second sequence group is determined depending on whether or not it has been reached. After the contact operation of the developing roller 8S is started, the developing roller 8S comes into full contact with the photosensitive drum 5 after a predetermined time T_D_R-on, and image formation on the photosensitive drum 5 is started at that timing (FIG. 3). E).

  As described above, in the conventional normal image formation preparation operation, after the pressurizing operation of the fixing roller 14 of the fixing unit 13 is finished, the image formation and the temperature increase of the fixing unit 13 are started simultaneously with the start timing. When the temperature of the fixing unit 13 is not in time for image formation, the image forming operation such as rotation of the developing roller 8S as the second sequence group is performed after the fixing unit 13 reaches a predetermined temperature. (Hereinafter referred to as “first preparation operation mode”). As a result, even when the image forming apparatus 100 is in a low temperature environment or when the supplied power supply voltage is lowered to the lower limit value, the FPOT does not extend and unnecessary consumption of the developing roller 8S is consumed. It is possible to prevent.

[Sequence for Starting Image Formation Preparation Operation Before Completion of Fixing Pressing (FPOT Shortening Sequence)]
4 and 5, in this embodiment, a sequence for shortening the FPOT by starting the image forming preparation operation in parallel with the pressing operation of the fixing roller 14 of the fixing unit 13 (hereinafter, referred to as “FPOT”). "FPOT shortening sequence") will be described.

  FIG. 4 is a timing chart of the FPOT shortening sequence, and FIG. 5 is a flowchart of the FPOT shortening sequence.

  When the system controller 211 receives the print start command from the video controller 201, the system controller 211 starts the pressurizing operation and temperature control of the fixing roller 14 of the fixing unit 13. At the same time, rotation of the photosensitive drum 5 (5Y, 5M, 5C, 5K) and rotation of the scanner unit 10 (10Y, 10M, 10C, 10K) are started (A in FIG. 4, step S501 in FIG. 5). At this time, since the pressurizing operation of the fixing unit 13 is not completed, the fixing temperature adjustment is not started. The system controller 211 starts the temperature control of the fixing unit 13 as soon as the pressurizing operation of the fixing unit 13 is completed (B in FIG. 4).

  Next, application of a charging bias is started after a predetermined time from the rotation of the photosensitive drum 5 (5Y, 5M, 5C, 5K) (C in FIG. 4, step S502 in FIG. 5). At this time, the developing roller 8S (8SY, 8SM, 8SC, 8SK) remains stopped. Next, the system controller 211 rotates and contacts the developing roller 8S (8SY, 8SM, 8SC, 8SK) regardless of the temperature T of the fixing unit 13 after a predetermined time T_dev from the start of charging bias application. At the same time, the application of the developing bias is started (D in FIG. 4, steps S503 and S504 in FIG. 5). When the contact operation of the developing roller 8S is started, the developing roller 8S completely contacts the photosensitive drum 1 after a predetermined time T_D_R-on (E in FIG. 4, step S505 in FIG. 5).

  Here, the system controller 211 determines whether the temperature T of the fixing unit 13 has reached a predetermined temperature T2. If the predetermined temperature T2 is kept at the fixing temperature control, the fixing unit can maintain a sufficient temperature even when the image forming apparatus 100 is in a low temperature environment or when the supplied power supply voltage is at the lower limit. This is the temperature that is expected to be reached. That is, it is expected that the temperature of the fixing unit 13 can reach a temperature sufficient for fixing the recording medium 2 from the timing when the image formation on the photosensitive drum 5 is started until the recording medium 2 reaches the fixing unit 13. Temperature.

  If the temperature T of the fixing unit 13 has reached T2, image formation on the photosensitive drum 5 is started (E in FIG. 4, steps S506 and S507 in FIG. 5). At this time, if the temperature T of the fixing unit 13 has not reached T2, the temperature of the fixing unit 13 is continuously monitored, and after waiting for the temperature to reach T2, image formation on the photosensitive drum 5 is started.

  As described above, in the FPOT shortening sequence of this embodiment, the image forming preparation operation is started in parallel with the pressing operation of the fixing roller 14 of the fixing unit 13. The image forming preparation operation such as rotation / contact of the developing roller 8S is performed regardless of the temperature rise of the fixing unit 13 (hereinafter referred to as “second preparation operation mode”). As a result, if the temperature of the fixing unit 13 when receiving the print start command is a high temperature as shown by the solid line in FIG. 4, the effect of shortening the FPOT compared to the conventional example described above is achieved. is there.

  However, there are the following problems. That is, when the temperature of the fixing unit 13 when receiving the print start command is a low temperature as shown by the broken line in FIG. 4, the contact operation of the developing roller 8S is started and the predetermined time D_R− is started. After the ON, the temperature T of the fixing unit 13 does not reach T2, and image formation on the photosensitive drum 5 may not be started. In this case, the developing roller 8S of the developing unit 8 waits for the temperature of the fixing unit 13 to reach T2 in a state where the developing roller 8S rotates, resulting in unnecessary wear of the developing roller 8S.

[Selecting an image formation preparation sequence according to the life of the process cartridge]
In the present embodiment, in order to avoid the above problem, the lifetime of each consumable part of the process cartridge 22 is read, and the above-described FPOT shortening sequence is performed only when the lifetime of the process cartridge 22 is not affected.

  The life management of the process cartridge 22 in this embodiment will be described in detail. The system controller 211 reads values related to the lifetime of each consumable part of the process cartridge 22 from the nonvolatile memory 221 (221Y, 221M, 221C, 221K) as needed. Then, when the lifetime of any consumable part, which is a factor for determining the lifetime, has reached a predetermined threshold, it is assumed that the lifetime of the process cartridge 22 has been reached. It is carried out.

  In the process cartridge 22 of this embodiment, it is assumed that the life of the process cartridge 22 is determined by the life of two components, “toner” and “developing roller 8S”. The toner life refers to the remaining amount of toner filled in the developing container 11, and the remaining toner life (hereinafter referred to as “toner remaining life”) decreases as the remaining amount decreases. The life of the developing roller 8S (developer carrier life) refers to the total rotation time of the developing roller 8S, and the remaining life of the developing roller 8S (hereinafter referred to as “developing roller life”) increases as the rotation time increases. I think it will be less.

  Here, the remaining life of the toner and the life of the developing roller differ depending on how the image forming apparatus 100 is used. In general, for a user who prints a large amount of printing such as graphics and photographs, the amount of toner consumption increases, so the remaining toner life is often lost and the life of the process cartridge 22 is often reached. On the other hand, under a user who prints a small amount of text or the like and prints a document with a low printing rate in a small number of units, the rotation time of the developing roller 8S of the developing unit 8 becomes longer than the toner consumption amount. In many cases, the life of the process cartridge 22 is reached with the end of the roller life.

  As described above, the unnecessary wear of the lifetime mentioned as a problem when performing the FPOT shortening sequence is that the temperature of the fixing unit 13 reaches T2 in a state where the developing roller 8S of the developing unit 8 is rotated. This is the consumption of the developing roller life due to waiting. That is, wasteful consumption of the remaining toner life due to the execution of the FPOT shortening sequence does not occur.

  As described above, in the present invention, when the life of the developing roller is sufficiently longer than the remaining life of the toner among the two components of the process cartridge 22, the FPOT shortening sequence is performed. . As a result, if the temperature of the fixing unit 13 when the print start command is received is high, the FPOT may be shortened. On the other hand, if the temperature of the fixing unit 13 when the print start command is received is low, the life of the developing roller is wasted, but it is not possible to determine the end of the life of the process cartridge 22. It can be said that there is no influence.

  Hereinafter, a method for determining whether or not to execute the FPOT shortening sequence according to the embodiment of the present invention will be described. That is, a method for selecting an image forming preparation operation in the first preparation operation mode and the second preparation operation mode will be described.

  Let L_d be the rotation possible time of the developing roller 8S at the start of the printing operation at a certain time. Further, the remaining amount of toner filled in the toner cartridge 11 at the same time is denoted by L_t. Needless to say, the rotatable time L_d of the developing roller 8S is proportional to the developing roller life, and the remaining toner amount L_t is proportional to the remaining toner life.

  The number of pages P_d [page] that can be printed in the rotation possible time L_d [msec] of the developing roller 8S at a certain time is calculated by the following equation. X [msec / page] is a coefficient and represents the rotation time of the developing roller 8S necessary for printing one page.

P_d = L_d / X (1)

  Further, the number of printable pages P_t [page] with the remaining toner amount L_t [gram] at a certain time is calculated by the following equation. A [gram / page] is a coefficient, and is proportional to an assumed average printing rate of an image in subsequent printing.

P_t = L_t / A Expression (2)

  Here, when the system controller 211 receives the print start command from the video controller 201, the system controller 211 performs the calculation of the following equation (3).

P_d> P_t Expression (3)

  When receiving the print start command from the video controller 201, the system controller 211 determines that there is no influence on the life of the process cartridge 22 when the expression (3) is satisfied, and executes the FPOT shortening sequence. . That is, when the number P_d of pages that can be printed in the rotation time of the developing roller 8S at a certain time is larger than the number P_t of pages that can be printed with the remaining amount of toner at the same time, the developing roller lifetime is the remaining toner lifetime. There is room compared to. In this case, it is determined that the life of the process cartridge 22 is not affected even if the life of the developing roller is consumed, and the FPOT shortening sequence is performed (second preparation operation mode is performed). On the other hand, when Expression (3) does not hold, it is considered that the developing roller life is dominant with respect to the life of the process cartridge 22. In this case, since it is not allowed to waste the life of the developing roller, the normal FPOT shortening sequence is not performed and the normal image forming preparation sequence is performed (first preparation operation mode is performed).

  Here, the coefficient A for obtaining the number of printable pages P_t based on the remaining toner life in the equation (2) will be described. The coefficient A is a number proportional to the assumed average printing rate of images in subsequent prints. The print rate indicates the print rate of the toner image in the printable area on the paper of the recording medium 2, and when the whole surface of the paper is printed, the print rate is 100%. Further, in the case of a text-centered word processor document considered to be the most general usage situation, the printing rate is about 5% to 10%. In the determination of the execution of the FPOT shortening sequence of this embodiment, the coefficient A is set according to the life of the process cartridge 22 at that time.

  However, when the remaining life of the process cartridge 22 is 100%, that is, when the process cartridge 22 is nearly new, it cannot be determined which of the developing roller 8S and the toner is consumed earlier. For this reason, it is desirable to avoid the unnecessary consumption of the developing roller life due to the execution of the FPOT shortening sequence. Therefore, until the first half of the life of the process cartridge 22, a coefficient A corresponding to a printing rate smaller than that in a general use state, such as an assumed average printing rate of about 1%, is used. As a result, the value of the right side P_t of Equation (3) becomes relatively large, and the possibility that the FPOT shortening sequence is executed is reduced.

  On the other hand, after the second half of the life of the process cartridge, for example, when the remaining life falls below 20%, a coefficient A corresponding to a very general printing rate such as an assumed average printing rate of 5% to 10% is used. Thereby, since the value of the right side P_t of Expression (3) is relatively small, the possibility that the FPOT shortening sequence is executed is increased.

  In this way, useless consumption of the developing roller is not allowed to occur until the first half of the life of the process cartridge 22, and is sufficient for the life of the developing unit 8 in the latter half of the life in normal use. Only when it is determined that there is room, the FPOT shortening sequence can be executed.

  Next, with reference to FIG. 6, a description will be given of the coefficient A selection method and the FPOT shortening sequence execution determination performed when the system controller 211 receives a print start command from the video controller 201 in this embodiment. .

  Upon receiving the print start command from the video controller 201, the system controller 211 sets the value of the coefficient A used in equation (2) according to the life value of the process cartridge 22 in step S601. In this embodiment, if the remaining life is 20% and the remaining life of the process cartridge 22 is 20% or more, the value of the coefficient A is set to a value corresponding to a low printing rate such as a printing rate of 1% (step S602). Set to the first value). On the other hand, if the remaining life of the process cartridge 22 in the second half of the process cartridge is less than 20% in this embodiment, the value of the coefficient A is set to a value corresponding to a high printing rate such as a printing rate of 10% (second value) in step S603. Value). After that, the calculation of Expression (3) is performed in Step S604, and when Expression (3) is satisfied, it is assumed that the developing roller life is sufficiently larger than the remaining toner life, and the FPOT shortening sequence is performed ( Step S605). On the other hand, if the expression (3) is not satisfied, it is determined that the developing roller life is not sufficient with respect to the remaining toner life, and the normal sequence is performed (step S606). Needless to say, the setting values described above, for example, the life threshold value of the process cartridge 22 in step S601 and the value of the printing rate related to the coefficient A in steps S602 and S603 are merely examples, and are designed. It can be set arbitrarily at each stage.

  As described above, in this embodiment, when starting the image forming preparation operation, as a result of comparing the difference between the remaining toner life and the developing roller life, it is determined that the life as the process cartridge 22 is not affected. The FPOT shortening sequence is executed. This makes it possible to shorten the image formation preparation operation time, that is, the FPOT, without wasting the life of the process cartridge 22. In determining whether to execute the FPOT shortening sequence, the coefficient A used in the determination formula is set according to the life of the process cartridge 22 at that time. Thus, it is possible to set so as not to allow useless consumption of the developing roller life until the latter half of the life of the process cartridge 22. As a result, the FPOT shortening sequence can be appropriately selected while maintaining the balance between shortening the FPOT and suppressing the consumption of the life of the process cartridge 22.

[Example 2]
In the first embodiment, the coefficient A is set according to the life of the process cartridge 22 at that time, and the execution of the FPOT shortening sequence is determined. In the state where the process cartridge 22 is nearly new, the possibility that the FPOT shortening sequence is executed is lowered. On the other hand, a method has been described in which the FPOT shortening sequence can be executed only when it is determined that there is a sufficient margin in the life of the developing roller 8S in the latter half of the life of the process cartridge 22.

  Next, a second embodiment of the present invention will be described.

  In the present embodiment, the default operation is set so that the FPOT shortening sequence is easy to be executed in the first half of the life of the process cartridge 22 and the possibility that the FPOT shortening sequence is executed in the second half of the life of the process cartridge 22 is low. . Then, a method of setting that does not allow useless consumption of the developing roller life will be described.

  Based on the flowchart of FIG. 7, the coefficient A selection method and the FPOT shortening sequence execution determination performed when the system controller 211 receives a print start command from the video controller 201 in this embodiment will be described.

  When receiving the print start command from the video controller 201, the system controller 211 sets the value of the coefficient A used in the equation (2) according to the life value of the process cartridge 22 in step S701. In this embodiment, if the remaining life is 20% and the remaining life of the process cartridge 22 is 20% or more, the value of the coefficient A is set to a value corresponding to a high printing rate such as a printing rate of 30% in step S702. Set to (first value). Thereby, since the value of the right side P_t of Expression (3) is relatively small, the possibility that the FPOT shortening sequence is executed is increased. On the other hand, if the remaining life of the process cartridge 22 in the second half of the process cartridge is less than 20% in this embodiment, the value of the coefficient A is set to a value corresponding to a very general printing rate such as a printing rate of 5% (step S703). 2nd value). Thereafter, the calculation of Expression (3) is performed in Step S704, and when Expression (3) is satisfied, that is, when the developing roller life is sufficiently larger than the remaining toner life, the FPOT shortening sequence is performed. (Step S705). On the other hand, if it is determined that the developing roller life is not sufficient with respect to the remaining toner life, a normal sequence is performed (step S706).

  As described above, in the present embodiment, the setting of the coefficient A used to determine whether or not to execute the FPOT shortening sequence is set to a value that increases the possibility that the FPOT shortening sequence will be performed in the first half of the process cartridge life. As a result, for example, a user who severely uses the developing means for a long time, such as frequently repeating a small number of copies at a low printing rate, has an opportunity to receive the benefits of the FPOT shortening sequence until the life of the process cartridge is exhausted. It is thought that it will increase.

[Example 3]
In the first and second embodiments, when there are a plurality of process cartridges, there is no particular mention as to which process cartridge developing means and the remaining life of the toner are used to determine whether to execute the FPOT shortening sequence. For this reason, the method described in the first and second embodiments is used only when printing in a single black color even if a monochrome printer having only one process cartridge 22 or a color printer having a plurality of process cartridges 22 is used. Applicable.

  In the third embodiment of the present invention, a description will be given of a method of performing execution determination of an FPOT shortening sequence when color printing is performed by the image forming apparatus 100 having a plurality of process cartridges 22.

  In the present embodiment, when a plurality of process cartridges 22 are provided, the execution value of the FPOT shortening sequence is determined using the life value of the process cartridge 22 having the shortest developing roller life. This is because when the FPOT shortening sequence is performed, there is a risk of wasting the developing roller life.

  The present embodiment will be described based on the flowchart of FIG. When the system controller 211 receives the print start command from the video controller 201, in step S800, the system controller 211 reads a value related to the lifetime of each consumable part of the process cartridge 22 from the nonvolatile memory 221 (221Y, 221M, 221C, 221K). . Then, the process cartridge 22i having the shortest developing roller life is determined. In the following description, the subscript i is used to represent the parameters relating to the process cartridge 22i having the smallest developing roller life determined as described above.

  Subsequent processing is the same as that in the first embodiment, and Expression (4), Expression (5), and Expression (6) can be expressed as follows.

P_d [i] = L_d [i] / X (4)
P_t [i] = L_t [i] / A (5)
P_d [i]> P_t [i] (6)

  In step S801, the value of the coefficient A used in equation (5) is set according to the lifetime value of the process cartridge 22i. In this embodiment, if the remaining life is 20% and the remaining life of the process cartridge 22i is 20% or more, the value of the coefficient A is changed to a value corresponding to a low printing rate such as 1% in step S802. Set. On the other hand, if the remaining life of the process cartridge 22i is less than 20% in this embodiment, the value of the coefficient A is set to a value corresponding to a high printing rate such as a printing rate of 10% in step S803. . After that, the calculation of Expression (6) is performed in Step S804, and when Expression (6) is satisfied, the FPOT shortening sequence is performed assuming that the developing roller life is sufficiently larger than the remaining toner life. (Step S805). On the other hand, if Equation (6) is not satisfied, it is determined that the developing roller life is not sufficient with respect to the remaining toner life, and the normal sequence is performed (step S806).

  As described above, in this embodiment, when color printing is performed by an image forming apparatus having a plurality of process cartridges 22, the lifetime value of the process cartridge 22i having the smallest developing roller lifetime is used. The difference between the remaining toner life of the process cartridge 22i and the life of the developing roller is compared, and if it is determined that there is no effect on the life of the process cartridge 22, the FPOT shortening sequence is performed, and the life is wasted. FPOT can be shortened without any problem.

1 Recording material (recording medium) storage cassette 2 Recording material (recording medium)
5 Photosensitive drum (image carrier)
7S primary charging means 8 developing means 8S developing roller (developer carrier)
11 Developing container 22 Process cartridge 10 Scanner unit 12 Intermediate transfer belt (intermediate transfer member)
13 Fixing means

Claims (7)

An image carrier;
A developer accommodating portion for accommodating the developer;
Developing means for forming an image on the image carrier by carrying the developer contained in the developer container on a developer carrier;
Transfer means for transferring the image to a recording medium;
Fixing means for fixing the image transferred to the recording medium;
Detecting means for detecting the temperature of the fixing means;
In an image forming apparatus having
Of the image formation preparation operations for starting image formation, a first preparation operation mode in which the start timing of the preparation operation relating to the developing unit is determined by the temperature of the fixing unit;
Among the image formation preparation operations, the start timing of the preparation operation related to the developing unit is determined regardless of the temperature of the fixing unit, and the second preparation is started earlier than the first preparation operation mode. The operation mode is executable,
The value proportional to the remaining amount of the developer accommodated in the developer accommodating portion is compared with the value proportional to the lifetime of the developer carrier, and the value proportional to the lifetime of the developer carrier is When the value is smaller than a value proportional to the remaining amount of developer accommodated in the developer accommodating portion, the image forming preparation operation is performed in the first preparation operation mode, and a value proportional to the life of the developer carrier is An image forming apparatus, wherein the image forming preparation operation is performed in the second preparation operation mode when the value is larger than a value proportional to the remaining amount of the developer stored in the agent storage portion. Proportional to the remaining amount of the developer carrying member and the number of pages that can be printed by the life of the developer carrying member of the printing operation at the start of a value proportional to the lifetime, the developer accommodated in said developer accommodating portion The number of printable pages is compared with the remaining amount of developer at the start of the printing operation as a value,
When the number of pages that can be printed due to the life of the developer carrier is less than the number of pages that can be printed due to the remaining amount of the developer, the image formation preparation operation is performed in the first preparation operation mode, and the development When the number of pages that can be printed due to the life of the agent carrier is greater than the number of pages that can be printed due to the remaining amount of the developer, the image formation preparation operation is performed in the second preparation operation mode. The image forming apparatus according to claim 1. At least the image carrier and the developing unit are integrated, and a process cartridge that can be attached to and detached from the image forming apparatus,
3. The predetermined coefficient is set for the number of pages according to the life of the process cartridge when calculating the number of printable pages based on the remaining amount of developer at the start of a printing operation. Image forming apparatus.   When the life of the process cartridge is larger than the threshold, a first value is set to the predetermined coefficient. When the life of the process cartridge is smaller than the threshold, the predetermined coefficient is smaller than the first value. The image forming apparatus according to claim 3, wherein a value of 2 is set.   When the life of the process cartridge is larger than the threshold, a first value is set to the predetermined coefficient, and when the life of the process cartridge is smaller than the threshold, the predetermined coefficient is larger than the first value. The image forming apparatus according to claim 3, wherein a value of 2 is set.   The fixing unit includes a fixing roller and a pressure roller, and fixes and fixes the toner image by sandwiching and transporting the recording medium by the fixing roller and the pressure roller. The rotation of the image carrier and the rotation of the developer carrier are not started at least as a preparatory operation relating to the developing unit before the timing at which the fixing roller and the pressure roller come into contact with each other and the pressure operation is completed. The second preparatory operation mode is a preparatory operation relating to at least the developing unit before the timing when the fixing roller and the pressure roller come into contact with each other and the pressure operation is completed. 2. The mode for shortening an image formation preparation operation time in which rotation of the image carrier and rotation of a developer carrier are started. The image forming apparatus according to any one of. An image forming apparatus having a plurality of image carriers, a plurality of developer accommodating portions for accommodating a developer, and a plurality of developing means, and forming a color image,
A value proportional to the remaining amount of developer accommodated in the developer accommodating portion with the least remaining amount among the plurality of developer accommodating portions and the shortest remaining lifetime among the plurality of developer carriers. A comparison is made with a value proportional to the life of the developer carrying member, and the image forming preparation operation is selected to be started in either the first preparation operation mode or the second preparation operation mode. Item 7. The image forming apparatus according to any one of Items 1 to 6.

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