JP2010228334A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the shortening of an apparatus life while realizing shortening of FPOT.
An image forming apparatus that starts a preparatory operation of the image forming unit according to an instruction from the outside before processing data by a controller, and starts an image forming preparatory operation according to an instruction from the outside Based on the value of the difference between the elapsed time from the start of image formation to the start of image formation and a predetermined time, it is selected whether or not to perform the preparation operation of the image forming means in accordance with an instruction from the outside. .
[Selection] Figure 6

Description

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

  2. Description of the Related Art Conventionally, as an example of an image forming apparatus that forms an image on a recording medium, apparatuses such as an electrophotographic laser beam printer, a copying machine, and a facsimile are known. In such an image forming apparatus, a first printout time (hereinafter referred to as FPOT), which is a time from when a print instruction is given until printing of one page of recording medium is completed, is as short as possible for the user who gives the print instruction. Better. This FPOT is determined by the time for preparing image data to be used in the image forming unit, the preparation time in the image forming unit, and the time taken to actually form the image by transporting the recording medium. As a technique for shortening the FPOT, for example, Patent Document 1 and Patent Document 2 propose a technique for starting a preparation operation in an image forming unit simultaneously with the start of image data preparation processing. In these patent documents, simultaneously with the start of image development as image data preparation processing, the start of the scanner motor and the start-up of the fixing device, which are one of the preparations of the image forming unit, are started at the same time. The FPOT is shortened compared to the case of execution.

JP 2006-221254 A JP 2007-310365 A

  However, when the start processing of the image data and the start operation of the image forming unit are simultaneously performed as in the conventional example, for example, the start processing of the scanner motor and the fixing device is simultaneously performed, FPOT can be shortened. However, if the time for the image data preparation process becomes long even if the image data preparation process is started simultaneously, the image forming unit is unnecessarily driven until the image data preparation process is completed even after the preparation operation of the image forming unit is completed. . That is, there is a possibility that the driving time of the scanner motor and the fixing device that are started at the same time becomes long, and the life of the scanner motor and the fixing device is shortened. In addition to the scanner motor and the fixing device, for example, if a replaceable member is driven by a preparatory operation in the image forming unit, the replacement frequency of the replacement member may increase.

  SUMMARY OF THE INVENTION An object of the present invention is to reduce a period in which parts and members of an apparatus driven to shorten the FPOT operate unnecessarily in an image forming apparatus capable of shortening the FPOT.

  In order to solve the above problems, an image forming apparatus of the present invention has a controller for processing data, and forms an image on a recording medium in the image forming apparatus that starts image formation in response to a print instruction from the controller. An image forming unit for controlling the image forming unit and a control unit for starting a preparatory operation of the image forming unit in response to an instruction from the outside before the data is processed by the controller. In response to an instruction from the outside, based on the value of the difference between the elapsed time from the start of the preparatory operation of the image forming unit to the start of image formation by the image forming unit and a predetermined time. It is selected whether or not to perform the preparation operation of the image forming unit.

  As described above, according to the present invention, in the image forming apparatus capable of shortening the FPOT, it is possible to reduce the period during which the parts and members of the apparatus operate unnecessarily.

1 is a schematic diagram of a laser beam printer of Examples 1 and 2. FIG. FIG. 2 is a block diagram of a control system according to the first embodiment. FIG. 3 is a drive system connection diagram of the first and second embodiments. 6 is a time chart regarding print control in the first and second embodiments. 3 is a flowchart illustrating a control method according to the first embodiment. 3 is a flowchart illustrating a control method according to the first embodiment. FIG. 6 is a block diagram of a control system according to a second embodiment. 6 is a flowchart illustrating a control method according to the second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Here, a mode applied to a laser beam printer is shown as an example, but the present invention is also applicable to other image forming apparatuses such as a copying machine and a facsimile. Further, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are intended to limit the technical scope of the present invention only to those unless otherwise specified. is not.

  As a configuration to which the invention of Embodiment 1 is applied, an example applied to a laser beam printer as an image forming apparatus will be described. FIG. 1 shows a schematic diagram of a laser beam printer 100. The laser beam printer 100 can be attached and detached with a cartridge 101 in which members for image formation are integrated. The cartridge 101 is a photosensitive drum 102 that is an image carrier on which an electrostatic latent image is formed, a charging roller 107 that uniformly charges the photosensitive drum 102, and the electrostatic latent image formed on the photosensitive drum 102 is developed with toner. The developing roller 108 is integrated. Further, a semiconductor laser 103 as an exposure unit for forming an electrostatic latent image on the photosensitive drum 102, a rotary polygon mirror 105 that scans the laser beam 106 from the semiconductor laser 103, and a scanner motor 104 that rotates the rotary polygon mirror 105 are provided. Have. Further, a transfer roller 109 that transfers the toner image developed on the photosensitive drum by the developing roller 108 to a sheet as a recording medium, and a fixing heater 110 of a fixing unit 124 that heats and pressurizes the toner image transferred to the sheet and fuses it. And a fixing film 111 and a pressure roller 112.

  In addition, a paper feed cassette 113 that stores paper, a paper feed pickup roller 114 that feeds the paper from the paper feed cassette 113 and sends it to the conveyance path, and a paper feed roller 115 that feeds the paper sent out by the pickup roller 114 are provided. . A retard roller 116 is provided so as to face the paper feed roller 115, and this retard roller 116 is a roller for separating the fed sheets one by one and feeding them to the conveyance path.

  A sheet fed from the sheet feeding cassette 113 is conveyed to an image forming unit by an intermediate roller pair 117, and a pre-transfer roller pair 118 for feeding the conveyed sheet to a transfer unit formed by the photosensitive drum 102 and the transfer roller 109. Have. Immediately after the pre-transfer roller pair 118, a top sensor 119 is provided to synchronize the sheet conveyance with the image formation on the photosensitive drum 102. The top sensor 119 is also a sensor that measures the length of the fed paper in the transport direction. The sheet on which the image is transferred is detected by the paper discharge sensor 120 after the image is fixed by the fixing device 124. Thereafter, the paper is transported by a pair of transport rollers 121 and discharged by a paper discharge roller 122 to a paper discharge tray 123 on which the paper is stacked.

  Next, a block diagram of a control system for controlling the operation of the laser beam printer 100 is shown in FIG. In FIG. 2, a printer controller 201 receives code data sent from an external device 200 such as a host computer and develops it into bitmap data (image data) necessary for printing. The printer controller 201 also has a function of reading and displaying information in the printer.

  In accordance with an instruction from the printer controller 201, the engine control unit 202 controls the operation of the image forming unit. The operation of the image forming unit is an operation including all of the above-described latent image formation on the photosensitive drum 102, toner development, transfer to paper, fixing, and paper transport. Then, the printer controller 201 is notified of internal information indicating the state of each unit of the image forming unit.

  The high voltage control unit 203 executes high voltage output control in each process of charging, development, and transfer, which are operations of the image forming unit, in accordance with an instruction from the engine control unit 202. The optical system control unit 204 controls driving / stopping of the scanner motor 104 and lighting of the laser beam in accordance with an instruction from the engine control unit 202. The fixing device control unit 205 performs on / off of energization to the fixing heater 110 in accordance with an instruction from the engine control unit 202. The sensor input unit 206 notifies the engine control unit 202 of paper presence / absence states such as a top sensor 119, a paper discharge sensor 120, and a paper surface position sensor (not shown). The paper transport control unit 207 controls the operation of a motor for driving / stopping the rollers for paper transport in accordance with an instruction from the engine control unit 202. The sheet conveyance control unit 207 causes the pickup roller 114, paper feed roller 115, retard roller 116, intermediate roller pair 117, pre-transfer roller pair 118, photosensitive drum 102, fixing film 111, pressure roller 112, and conveyance roller pair in FIG. 121, controlling the driving / stopping of the paper discharge roller 122. The nonvolatile memory 208 stores the latest control parameters related to the states of the printer controller 201 and the engine control unit 202.

  Next, FIG. 3 shows a drive system connection diagram of each roller for conveying paper in the laser beam printer 100 as the image forming apparatus in this embodiment. The drum motor 301 drives / stops the photosensitive drum 102, the charging roller 107, the developing roller 108, and the transfer roller 109 based on an instruction from the paper conveyance control unit 207. The transport motor 302 stops driving the rollers related to paper feeding and transport upstream of the photosensitive drum 102 based on an instruction from the paper transport control unit 207. The clutch 303 turns on / off transmission of the drive of the carry motor 302 to the paper feed roller 115, the retard roller 116, and the intermediate roller pair 117 based on an instruction from the paper carry control unit 207. The solenoid 304 drives the paper feed roller 115 based on the driving of the transport motor 302 transmitted through the clutch 303. The fixing motor 305 drives / stops the fixing film 111, the pressure roller 112, the conveyance roller pair 121, and the paper discharge roller 122 based on an instruction from the paper conveyance control unit 207.

  Next, FIG. 4 shows a time chart when the printer controller 201 executes a printing operation using only a printing instruction (hereinafter referred to as a printing instruction), and in response thereto, a printing operation preparation instruction is given before the printing instruction. FIG. 2 shows two time charts in a case where a print operation is also executed using an activation instruction (command) for the purpose. The print instruction is a command for causing the engine control unit 202 to start an operation, and is executed by transmitting a command from the printer controller 201 to the engine control unit 202.

  The time chart of FIG. 4A is a time chart when the printer controller 201 uses only a print instruction as a print start trigger to the engine control unit 202. Reference numeral 401 denotes a timing at which the external apparatus 200 instructs the printer to start printing (for example, a timing at which the user instructs printing using application software on the PC). Reference numeral 402 denotes a timing at which the data processing of the external apparatus 200 ends, and transmits print data to the printer controller 201 and issues a print instruction. The printer controller 201 that has received the print data starts developing the received print data into bitmap data (start of image development). Then, at the timing of 403, when the printer controller 201 is about to finish image development, it instructs the engine control unit 202 to print. The printer controller 201 can predict the remaining development time during execution of image development (before completion of development), and can issue a print instruction to the engine control unit 202 before completion of image development based on the predicted time. The engine control unit 202 instructed to print in 403 starts driving the fixing device 124 and the scanner motor 104. Specifically, the fixing device 124 starts driving the fixing motor 305 and starts energizing the fixing heater 110 to start the fixing device 124 so as to reach a predetermined temperature (for example, 180 ° C.). Further, the driving of the scanner motor 104 is started, and the start-up is started so as to reach a predetermined rotational speed. Reference numeral 404 denotes a timing for driving the drum motor 301 in accordance with the start completion timing 406 of the fixing device 124 and the scanner motor 104. The drum motor 301 is driven to rotate the photosensitive drum 102 for a predetermined time, and in accordance with an instruction from the high voltage control unit 203, a print preparation operation is performed to make each high voltage output in a printable state in each step of charging, developing, and transfer. . This timing is a timing at which a predetermined time Tα has elapsed from the timing 403. Reference numeral 405 denotes a timing at which a predetermined time Tβ has elapsed from 404, and is a timing to start feeding paper. In step 405, the clutch 303 and the solenoid 304 are driven in synchronization with the start of driving of the transport motor 302 to start feeding and transporting paper from the paper feed cassette 113. Reference numeral 406 denotes a timing when the start of the fixing device 124, the completion of the start of the scanner motor 104, and the completion of preparation for high-pressure output printing by the engine control unit. It is also the timing when is detected. In synchronization with this timing 406, the printer controller 201 transmits the developed bitmap data (image data) to the engine control unit 202 to form and develop a latent image on the photosensitive drum 102 and to transfer the image onto the sheet. A forming operation is performed. Reference numeral 407 denotes a timing at which the transmission of the bitmap data for one page is completed and the top sensor 119 detects the trailing edge of the conveyed paper. Reference numeral 408 denotes a timing at which the engine control unit 202 has finished discharging the paper on which the image forming operation has been completed to the paper discharge tray 123.

  In the time chart of FIG. 4B, the printer controller 201 uses a print instruction as a print start trigger to the engine control unit 202 and a start instruction for giving a print operation preparation instruction before the print instruction. It is a time chart in the case. Since 401, 402, and 403 have the same timing as the time chart of FIG. The difference from the time chart of FIG. 4A is that the printer controller 201 issues an activation instruction to the engine control unit 202 at 401. The engine control unit 202 instructed to start in 401 starts driving of the fixing device 124 and the scanner motor 104. Reference numeral 403 denotes a timing when a print instruction is received from the printer controller 201. At the timing of 403, the engine control unit 202 drives the drum motor 301 and starts control in order to make each high voltage output in each process such as charging, development, transfer, etc. printable according to an instruction from the high voltage control unit 203. . Reference numeral 409 denotes a timing at which a predetermined time Tβ has elapsed from the start of driving the drum motor, and is a timing at which paper feeding starts. 410 is the same timing as 406 described above, 411 is the same timing as 407, and 412 is the same timing as 408.

  Comparing the time charts of FIGS. 4A and 4B, the time taken to complete the paper discharge is shorter in (b) using the activation instruction in 401 than in (a). Specifically, it was Tb1 time in (a), but in Tb2 in (b), Tb3 (= Tb1-Tb3) time can be shortened. That is, in the case of (b), Tb3 time can be shortened compared with (a) FPOT.

  On the other hand, in the time chart of FIG. 4A in which the activation instruction is not used, the time from when the fixing device 124 and the scanner motor 104 are activated until the actual image formation is started is Ta1 time. On the other hand, in the time chart of FIG. 4B using the start instruction, the time is Ta2. That is, it can be seen that Ta2> Ta1, and the driving time of the fixing device 124 and the scanner motor 104 is longer in (b). For example, in (b), when the image processing time by the external apparatus 200 and the image development time by the printer controller 201 become longer, this Ta2 becomes longer. That is, in the case of (b), the FPOT can be shortened, but the life of the apparatus may be shortened depending on the situation. Therefore, this embodiment proposes a mechanism for restricting the execution of the start instruction. It is possible to control so as to reduce the shortening of the apparatus life by limiting the execution of the start instruction. That is, control is performed so as to extend the life of the apparatus as compared with the case where the control for executing the start instruction and shortening the FPOT is continued.

  Hereinafter, a method for limiting the number of executions of the start instruction will be described in detail.

  FIG. 5 is a flowchart for calculating the difference between the driving time of the fixing device 124 and the scanner when the engine control unit 202 does not give a start instruction when the print operation is started by the start instruction. In FIG. 5, control is started, and it is confirmed in S <b> 501 whether an activation instruction has been received from the printer controller 201. When an activation instruction is received from the printer controller 201, the timing 401 in FIG. In step S502, the fixing unit 124 is activated. In step S503, the scanner motor 104 is activated. In S504, time measurement is started simultaneously with the activation of the fixing device 124 in S503 and the activation of the scanner motor 104 in S504. In step S <b> 505, it corresponds to the timing 403 in FIG. 4B and is waiting for reception of a print instruction from the printer controller 201. Upon receiving a print instruction from the printer controller 201 in step S505, the engine control unit 202 starts driving the photosensitive drum and starts preparation for printing in step S506 (corresponding to timing 403 in FIG. 4B). In S507, the process waits for Tβ time from S506, and when Tβ time elapses, in S508, the paper feeding and conveyance from the paper feeding cassette 113 is started (at timing 409 in FIG. 4B). Correspondence). In S509, it is confirmed whether or not the top sensor 119 detects the leading edge of the fed paper. When the top sensor 119 detects the leading edge of the paper, image formation is started on the photosensitive drum in S510 (FIG. 4 ( corresponding to timing 410 of b)).

In S511, the time measurement started in S504 is terminated, and the measured elapsed time is set to Ta2. In S512, Tα + Tβ + paper feeding time, which is experimentally obtained in advance, is Ta1, and the time Ta2 measured in S511 is obtained as Ta3 as the difference as shown in the following equation, and is notified to the printer controller 201.
Ta3 = Ta2-Ta1 (Formula 1)
The difference time Ta3 is a time during which the fixing device 124 and the scanner motor 104 are driven excessively by the start instruction, as compared to when printing is performed without the start instruction. As will be described in detail below, this difference time Ta3 is accumulated and stored as Ta4 in the nonvolatile memory 208 of the printer controller 201.

  Next, FIG. 6 shows a flowchart for determining whether to give a start instruction from Ta4 (accumulated time of difference time Ta3) obtained by the engine control unit 202 and stored in the nonvolatile memory 208. In FIG. 6, control is started, and in step S <b> 601, the printer controller 201 confirms whether there is an activation instruction from the external device 200. When an activation instruction is received from the external device 200, Ta4 (Ta3 accumulated time) stored in the nonvolatile memory 208 is compared with a preset threshold value. As a result of this comparison, if threshold> Ta4, control is performed so as not to instruct activation. If the threshold value <Ta4, a start instruction is given to the engine control unit 202 in S603. The activation instruction in S603 corresponds to the timing 401 in FIG. Further, the above-described threshold value is set in advance by predicting the actual use status of the printer, and the difference between the lifetime of the image forming apparatus, the lifetime of the fixing device 124, and the lifetime of the scanner motor 104.

  For example, assuming that the FPOT per page is 10 seconds, when printing 2 pages, if printing is divided into 2 jobs for each page, 10 × 2 = 20 seconds. Assume that it takes 12 seconds to print as a job.

  Here, the paper feed interval differs between when printing in two jobs and when printing as one job. In other words, the paper feed interval when printing as one job is smaller than the paper feed interval when printing separately as two jobs.

  Assuming that the number of prints set as the life of the device is 100,000 pages, when all pages are printed one by one (corresponding to the case where printing is divided into the above two jobs), the total number of fixing units 124, The scanner motor 104 is driven. On the other hand, when printing as one job (corresponding to the case of printing as one job described above), the fixing device 124 and the scanner motor 104 are driven for a total of 600,000 seconds. Due to the difference in usage, the total driving time of the fixing device 124 and the scanner motor 104 differs even when the same number of pages are printed.

  In general, the device life is set on the basis of the number of pages. In this way, when the apparatus life is set on a page basis (for example, when the above-mentioned 100,000 pages are set as the apparatus life), the fixing device 124 and the scanner motor 104 that can be driven for 1 million seconds are originally 60. It is determined that it is at the end of life when driven for 10,000 seconds. Therefore, assuming this, the difference time of 400,000 seconds (1 million seconds to 600,000 seconds) may be set as the above-described threshold value and set as a reference for control selection. In this embodiment, the threshold value is set by comparing the case of printing one page at a time and the case of printing two pages as one job. It can be appropriately changed based on the actual use state.

In S604 of FIG. 6, the image development is completed (corresponding to the timing 403 of FIG. 4). In step S605, a print instruction is issued to the engine control unit 202. Thereafter, in S606, the fed paper and the image are synchronized (corresponding to timing 410 in FIG. 4B), and in S607, it is confirmed whether printing has been completed (timing in FIG. 4B). 411). In step S608, the Ta3 value obtained by the engine control unit is acquired. In S609, the integration time Ta4 is calculated as shown in the following equation 2.
Ta4 (n) = Ta4 (n-1) + Ta3 (Formula 2)
In S609, the calculated Ta4 is stored in the nonvolatile memory 208, and the sequence is terminated. As described above, Ta4 is an integrated value of the time during which the fixing device 124 and the scanner motor 104 are excessively driven by the start instruction.

  As described above, the accumulated time of the extra driving time of the fixing device and the scanner motor generated by the activation instruction is stored, and the activation instruction is given until the accumulated time exceeds the threshold value, and priority is given to shortening the FPOT. To do. When the integration time exceeds the threshold value, control is performed so as not to give a start instruction, and thereafter, control is performed with priority on the device life. As a result, it is possible to reduce the period during which the parts and members of the apparatus operate unnecessarily and to shorten the apparatus life while realizing shortening of the FPOT.

  In the first exemplary embodiment, the printer controller 201 determines whether to start driving the fixing device and the scanner motor based on the start instruction before the print instruction. The present embodiment is characterized in that the engine control unit 202 makes this determination. This will be described below.

  Note that the configuration of the image forming apparatus, the electrical connection diagram of the image forming apparatus, and the basic printing operation in the present embodiment are the same as those in the first embodiment (FIGS. 1, 3, and 4), and thus description thereof is omitted. .

  A block diagram of the circuit configuration of the control system in the present embodiment is shown in FIG. This embodiment is different from the first embodiment in that a nonvolatile memory 708 is provided in the engine control unit 202. The operations of the external device 200, printer controller 201, engine control unit 202, high voltage control unit 203, optical system control unit 204, fixing device control unit 205, sensor input unit 206, and paper transport control unit 207 are the same as those in FIG. Since there is, explanation is omitted. The nonvolatile memory 708 of the engine control unit 202 stores / stores the latest control parameters regarding the state of the engine control unit 202.

  Next, the control by the engine control unit 202 for determining whether or not the start instruction can be performed in the present embodiment will be described based on the flowchart of FIG. In FIG. 8, control is started, and in step S <b> 801, it is confirmed whether there is an activation instruction from the printer controller 201. When an activation instruction is issued, Ta4 (same as the integrated value of Ta3 described in the first embodiment) stored in the nonvolatile memory 708 in S802 is compared with a threshold (same as the threshold described in the first embodiment). The start instruction timing corresponds to the timing 401 in FIG. As a result of the comparison, if threshold> Ta4, the activation instruction is ignored and this sequence ends. When the threshold value <Ta4, the sequence after S803 is continued.

  This threshold value is the same as that described in the first embodiment, and is a value set in advance by experimentally determining the difference between the life of the image forming apparatus, the life of the fixing device 124, and the life of the scanner motor 104. The value can be set as appropriate according to the lifetime of each component of the image forming apparatus.

  In step S <b> 803, the engine control unit 202 activates the fixing device 124 and the scanner motor 104. In S804, time measurement is started simultaneously with the activation of the fixing device 124 and the scanner motor 104 in S803. In step S805, a print instruction is received from the printer controller 201 (corresponding to the timing 403 in FIG. 4). Upon receiving a print instruction from the printer controller 201 in step S805, the engine control unit 202 starts driving the drum and starts preparation for printing in step S806 (corresponding to the timing 403 in the lower diagram of FIG. 4). In S807, the process waits for Tβ time to elapse, and when Tβ time elapses, in S808, paper feeding and conveyance from the paper feeding cassette 113 are started (corresponding to timing 409 in FIG. 4B). In S809, it is confirmed whether the top sensor 119 detects the leading edge of the fed paper. When the top sensor 119 detects the leading edge of the paper, image formation on the photosensitive drum 102 is started in S810 (FIG. 4B). Corresponding to the timing 410 of FIG.

  In S811, the time measurement started in S804 is terminated, and the measured elapsed time is set to Ta2. In S812, Tα + Tβ + paper feeding time obtained experimentally in advance is Ta1, and Ta2 measured in S811 is obtained as a difference time based on (Equation 1) in the same manner as in the first embodiment. As in the first embodiment, the difference time Ta3 is a time when the fixing device 124 and the scanner motor 104 are driven excessively compared to the case where printing is performed without the activation instruction due to the activation instruction. Further, in S814, the integrated time of Ta3 is calculated based on Equation 2 described in the first embodiment. Then, the calculated integration time Ta4 is stored in the nonvolatile memory 708, and the sequence is terminated.

  As described above, in this embodiment as well, in the same manner as in the first embodiment, the accumulated time of the extra driving time of the fixing device and the scanner motor generated by the start instruction is stored, and until the accumulated time exceeds the threshold value. Controls to shorten the FPOT by giving an activation instruction. When the integration time exceeds the threshold value, control is performed so as not to give a start instruction, and thereafter, control is performed with priority on the device life. Thereby, while realizing shortening of FPOT, it is possible to reduce the period in which the parts and members of the apparatus operate unnecessarily, and to reduce the life of the apparatus.

DESCRIPTION OF SYMBOLS 100 Laser beam printer 200 External apparatus 201 Printer controller 202 Engine control part

Claims (5)

In an image forming apparatus having a controller for processing data and starting image formation in response to a print instruction from the controller,
An image forming means for forming an image on a recording medium;
Control means for starting a preparatory operation of the image forming means in accordance with an instruction from outside before processing the data by the controller;
Based on the value of the difference between the elapsed time from the start of the preparatory operation of the image forming unit in response to an instruction from the outside to the start of image formation by the image forming unit and a predetermined time, An image forming apparatus that selects whether or not to perform a preparatory operation of the image forming means in response to an instruction from the image forming apparatus.   2. The predetermined time is a time from when a printing instruction is received from the controller to when an image formation is started after a preparatory operation of the image forming unit is started. The image forming apparatus described in 1. Storage means for storing an integrated value of the difference values;
Until the integrated value stored in the storage means exceeds a threshold value, the preparation operation is started in accordance with an instruction from the outside,
2. The preparatory operation is started according to a print instruction from the controller without starting the preparatory operation according to an instruction from the outside after the integrated value exceeds a threshold value. The image forming apparatus according to 2. The image forming means includes an image carrier,
Performing a preparatory operation for forming an image on the image carrier in accordance with a print instruction from the controller;
The elapsed time is a time period from the start of the preparation operation of the image forming unit according to an instruction from the outside to the completion of the preparation operation for forming an image on the image carrier. The image forming apparatus according to claim 1. The image forming unit further includes an exposure unit that forms an electrostatic latent image on the image carrier, and a fixing unit that fixes the image formed on the recording medium.
5. The image forming apparatus according to claim 4, wherein the preparation operation of the image forming unit in response to an instruction from the outside is an operation of starting the exposure unit and the fixing unit.