JP2012101419A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make service life of consumables longer by making the time for converting print data to image data and the time for forming an image of image data on recording paper 100 closer to each other to the utmost extent, thereby preventing idle rotation of, for example, the photoreceptor drum 23 of an image forming section 20 which is a consumable article.SOLUTION: An image forming apparatus 10 receives print data relating to a plurality of print pages from a host computer 200 via a communication section 71. The received print data are converted into image data by a data analyzing section 72. Further, a maximum processing-time calculating section 87 clocks a processing time required for image data conversion for each print page and also calculates the maximum processing time, which is the maximum value of the processing time. A printing-speed switching section 83 switches the image forming speed of the image forming section 20 according to the maximum processing time.

Description

  The present invention relates to a technique for extending the life of consumables in an image forming apparatus.

  Conventionally, in an image forming apparatus, if it is predicted that the processing time for converting the print data related to the next print page into image data is longer than the image formation time, the image forming apparatus is adapted to the conversion processing time for image data for each print page. A technique is known in which the image forming speed on a recording medium is controlled to reduce the total number of revolutions of a roller, a photoconductor, and the like constituting the image forming unit.

JP 2005-178138 A

  However, the conventional image forming apparatus has a problem that it is necessary to adjust the fixing temperature in order to switch the image forming speed for each print page. Furthermore, there is a problem that the performance is deteriorated by the fixing temperature adjustment, and the total number of rotations of the rollers and the photosensitive members constituting the image forming unit is increased.

  An image forming apparatus according to the present invention includes a communication unit that receives print data relating to a plurality of print pages from a host computer, a data analysis unit that converts the print data into image data, and the image data for each print page. A maximum processing time calculation unit that measures a processing time to be converted and calculates a maximum processing time that is the maximum value of the processing time, and a speed switching unit that switches a printing speed according to the maximum processing time. To do.

  According to the image forming apparatus of the present invention, the image forming speed is set according to the maximum value of the image data conversion time of a plurality of print pages in the print job. This has the effect of reducing the idling time of the image forming unit and extending the life of the consumables.

FIG. 1 is a schematic configuration diagram illustrating a control unit according to the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram illustrating the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a flowchart showing the printing outline operation by the control unit of FIG. FIG. 4 is a flowchart showing the operation of setting the consumable life extension mode in FIG. FIG. 5 is a flowchart showing the operation of the consumables simple life extension mode setting in FIG. FIG. 6 is a flowchart showing the printing operation of each page in FIG. FIG. 7 is a time chart in the printing operation of the first embodiment of the present invention. FIG. 8 is a diagram illustrating the relationship between the image processing time and the printing speed according to the first embodiment of the present invention. FIG. 9 is a diagram illustrating the printing time of each mode and the rotational speed of the photosensitive drum of the image forming unit at the time of sample data. FIG. 10 is a schematic configuration diagram illustrating a control unit according to the second embodiment of the present invention. FIG. 11 is a flowchart showing the printing operation of each page in the second embodiment of the present invention.

  Modes for carrying out the present invention will become apparent from the following description of the preferred embodiments when read in light of the accompanying drawings. However, the drawings are only for explanation and do not limit the scope of the present invention.

(Configuration of Example 1)
FIG. 2 is a schematic configuration diagram illustrating the image forming apparatus according to the first embodiment of the present invention.

  The image forming apparatus 10 is a tandem printer device, and includes a paper feeding unit 11 that supplies a recording medium (for example, recording paper) 100, an image forming unit 20 that forms a toner image on the recording paper 100, and a recording paper 100. A fixing unit 40 for fixing the toner image, a paper discharge unit 50 for discharging the recording paper 100, and a stacker unit 53 for storing the discharged recording paper 100. Further, the image forming apparatus 10 includes a motor (not shown) for rotating each roller, a clutch for turning on / off the power transmission to the rollers of the conveyance path 101, a charging roller 24 of the image forming unit 22, a transfer roller 21, and the like. It has a high-voltage power supply that supplies a high voltage of 200V to 5000V and a low-voltage power supply that supplies 5V DC and 24V DC to circuits and motors.

  The paper cassette 110 is a storage unit that stores the recording paper 100. The fixing unit 40 is a fixing unit that supplies heat to the recording paper 100. The paper feed mechanism is a medium transport unit that transports the recording paper 100 to the fixing unit.

  The paper feed unit 11 is a combination of a paper cassette 110 mounted at the bottom of the image forming apparatus 10, a recording paper 100 stored in the paper cassette 110, and a separating tongue from the paper cassette 110. A pickup roller 12 for separating and taking out the recording paper 100 one by one, a paper feed roller 13a and a retard roller 13b, a paper feed sensor 14, a pair of registration rollers 15a and 15b, and a writing position sensor 16 are provided. ing.

  The paper cassette 110 is a cassette for storing a plurality of recording papers 100 and is attached to the lower part of the image forming apparatus 10 so as to be removable. The recording paper 100 is a high-quality paper, recycled paper, glossy paper, matte paper, or an OHP (OverHead Projector) film having a predetermined size for recording a monochrome or color image.

  The pickup roller 12 rotates while being pressed against the recording paper 100, and on the downstream side of the conveyance path 101, a paper feed roller 13 a and a retard roller 13 b are arranged to face each other with the recording paper 100 interposed therebetween, and downstream thereof. Is provided with a paper feed sensor 14.

  The registration rollers 15a and 15b are arranged opposite to each other so as to sandwich the recording paper 100 on the downstream side of the conveyance path 101 with the paper feed roller 13a and the retard roller 13b, and a writing position sensor 16 is provided on the downstream side. ing.

The registration roller 15a is driven by a registration motor (not shown).
The image forming unit 20 includes four image forming units 22 (= 22-1 to 22-) arranged in the order of black (K), yellow (Y), magenta (M), and cyan (C) from the right side of the drawing. 4), a transfer roller 21 (= 21-1 to 21-4) disposed under the image forming unit 22, rollers 31 and 32, and the rollers 31 and 32, respectively. A transfer belt 30. Each image forming unit 22 corresponding to four colors of black (K), yellow (Y), magenta (M), and cyan (C) includes a photosensitive drum 23 and a photosensitive drum 23 that carry an electrostatic latent image based on image information. A charging roller 24 for charging, a light emitting diode (hereinafter referred to as “LED”) head 25 for irradiating the surface of the photosensitive drum 23 with light corresponding to image information, and a developing roller for developing an electrostatic latent image on the surface of the photosensitive drum 23 with toner. 26, a supply roller 27 for supplying toner to the developing roller 26, a separable toner cartridge 28, a toner regulating member (not shown), and a cleaning device (not shown) for writing off the toner remaining on the photosensitive drum 23. The transfer belt 30 is a transfer body that conveys the recording paper 100 and transfers the toner image formed on the photosensitive drum 23 to the recording paper 100. The photosensitive drum 23 and the transfer roller 21 are in contact with each other via the transfer belt 30. The image forming unit 20 is a developing unit that develops, for example, a developer image, which is a toner image, on the recording paper 100.

  The photosensitive drum 23 includes a photosensitive layer made of a photoconductive layer and a charge transport layer on a conductive base layer made of aluminum or the like. The photosensitive drum 23 has a cylindrical shape and is rotatably supported. The photosensitive drum 23 is disposed so that the charging roller 24, the transfer roller 21, and the developing roller 26 are in contact with each other, and the tip of a cleaning device (not shown) is in contact with the photosensitive drum 23. The photosensitive drum 23 functions as an image carrier that carries a toner image by accumulating electric charges on the surface, and rotates in the clockwise direction in the figure. Hereinafter, the configuration of the image forming unit 22 will be described in the order of the rotation direction of the photosensitive drum 23.

  The charging roller 24 has a conductive metal shaft covered with a semiconductive rubber such as silicone and has a cylindrical shape. The charging roller 24 is rotatably supported by being pressed against the photosensitive drum 23. The charging roller 24 is charged by a power source (not shown), rotates while being pressed against the photosensitive drum 23, thereby applying a predetermined voltage to the photosensitive drum 23, and thus uniformly storing charges on the surface.

  The LED head 25 includes a plurality of LEDs, a lens array, and LED drive elements, and is disposed above the photosensitive drum 23. The LED head 25 irradiates the surface of the photosensitive drum 23 with light corresponding to image information, and forms an electrostatic latent image on the surface of the photosensitive drum 23.

  The supply roller 27 is made by covering a metal shaft having conductivity with rubber, and has a cylindrical shape. The supply roller 27 is disposed so as to contact the developing roller 26. The supply roller 27 is charged by a power source (not shown) and presses against the developing roller 26 to supply toner to the developing roller 26.

  The developing roller 26 is made by coating a conductive metal shaft with a semiconductive urethane rubber material or the like. The developing roller 26 has a cylindrical shape, abuts against the supply roller 27 and the photosensitive drum 23, and a tip of a toner regulating member (not shown). The parts are arranged to contact each other. The developing roller 26 is charged by a power source (not shown), and is supplied with toner by being in pressure contact with the supply roller 27.

  A toner regulating member (not shown) is made of stainless steel or the like, has a plate shape, and is arranged so that the tip portion contacts the surface of the developing roller 26. A toner regulating member (not shown) scrapes off the toner exceeding a certain amount on the surface of the developing roller 26, thereby regulating the thickness of the toner formed on the surface of the developing roller 26 to be always uniform.

  The cleaning device (not shown) is made of a rubber material or the like, has a plate shape, and is arranged so that the tip portion contacts the surface of the photosensitive drum 23. A cleaning device (not shown) scrapes and cleans the toner remaining on the photosensitive drum 23 after transferring the toner image formed on the photosensitive drum 23 onto the recording paper 100.

  The fixing unit 40 includes a fixing roller 41, a backup roller 42, a temperature detection sensor 43, and a halogen heater 44. Inside the fixing roller 41, a halogen heater 44 typified by a halogen lamp is disposed. Above the fixing roller 41, a temperature detection sensor 43 constituted by a thermistor is disposed, and detects the surface temperature of the fixing roller 41. The fixing unit 40 is a fixing unit that fixes the toner image by pressurizing and heating the recording paper 100.

  The paper discharge unit 50 includes a paper travel path sensor 51 and discharge rollers 52a and 52b. The discharge rollers 52a and 52b are arranged opposite to each other so as to sandwich the recording paper 100 on the downstream side of the conveyance path 101 of the fixing unit 40, and are driven by motors (not shown).

FIG. 1 is a schematic configuration diagram illustrating a control unit according to the first embodiment of the present invention.
The image forming apparatus 10 according to the first exemplary embodiment includes a communication unit 71, a data analysis unit 72, a data buffer 73, and a control unit 80. The control unit 80 includes a fixing control unit 81, a conveyance control unit 82, a printing speed switching unit 83, a data transfer unit 84, a processing time measurement unit 85, a timer 86, a maximum processing time calculation unit 87, and a processing. And a time storage unit 88.

  The image forming apparatus 10 is communicably connected to an external host computer 200 and receives print data relating to a plurality of print pages from the host computer 200 via the communication unit 71.

  The output side of the communication unit 71 is connected to the data analysis unit 72. The data analysis unit 72 converts the print data received via the communication unit 71 into image data for each print page. The output side of the data analysis unit 72 is connected to the control unit 80 and the data buffer 73. The output side of the data buffer 73 is connected to the image forming unit 20 via the data transfer unit 84.

  The output side of the data transfer unit is connected to the image forming unit 20 and to the processing time measuring unit 85. The output side of the timer 86 is connected to the processing time measuring unit 85. The processing time measuring unit 85 measures the image processing time for each print page based on the data transfer unit 84 and the timer 86.

  The output side of the processing time measuring unit 85 is connected to the maximum processing time calculating unit 87. The maximum processing time calculation unit 87 calculates the maximum processing time in the print job based on the image processing time for each print page. The maximum processing time calculation unit 87 is connected to the processing time storage unit 88 in a readable / writable manner. The processing time storage unit 88 is a maximum processing time storage unit that stores the value calculated by the maximum processing time calculation unit 87.

  The output side of the processing time storage unit 88 is connected to the printing speed switching unit 83. The printing speed switching unit 83 instructs the conveyance control unit 82 on the printing speed based on the value stored in the processing time storage unit 88. The output side of the printing speed switching unit 83 is connected to the conveyance control unit 82.

  The output side of the conveyance control unit 82 is connected to the fixing unit 40 via the fixing control unit 81, and further connected to the medium conveyance unit 60 and the image forming unit 20.

(Operation of Example 1)
A printing operation of the image forming apparatus 10 will be described with reference to FIG.

  The recording paper 100 is transported along the transport path 101 from the upstream side to the downstream side. The paper cassette 110 is the most upstream side, and the stacker unit 53 is the most downstream side.

  The image forming apparatus 10 is connected to a host device through a cable or wirelessly. When the printing data is transferred from the host device and a printing instruction is received, a pickup motor (not shown) rotates the pickup roller 12 to separate a plurality of recording sheets 100 one by one and send them to the downstream side of the conveyance path 101. . The four image forming units 22 (= 22-1 to 22-4) arranged in the order of black (K), yellow (Y), magenta (M), and cyan (C) from the right side of FIG. The rollers start rotating almost simultaneously with the start of the paper, and the photosensitive drum 23 is rotated one or more times until the recording paper 100 reaches the photosensitive drum 23.

  When a motor (not shown) rotates the paper feed roller 13a, the retard roller 13b in contact with the paper feed roller 13a is rotated. The recording paper 100 conveyed from the pickup roller 12 is nipped and conveyed between the paper supply roller 13a and the retard roller 13b, and the paper supply sensor 14 is turned on. After that, it is conveyed to the registration rollers 15 a and 15 b on the downstream side of the conveyance path 101. The recording paper 100 turns on the writing position sensor 16. The LED head 25 of each of the image forming units 22 for black (K), yellow (Y), magenta (M), and cyan (C) four colors starts exposure after a certain period of time after the writing position sensor 16 is turned on. An electrostatic latent image corresponding to the color is formed on the photosensitive drum 23.

  When a registration motor (not shown) rotates the registration roller 15 a, the registration roller 15 b contacts and rotates, and the recording paper 100 is conveyed to the transfer belt 30 on the downstream side of the conveyance path 101. When the roller 31 rotates, the transfer belt 30 stretched around the rollers 31 and 32 is driven along the conveyance path 101. The recording paper 100 is sequentially conveyed to the image forming units 22 arranged in the order of black (K), yellow (Y), magenta (M), and cyan (C) by driving the transfer belt 30.

  The photosensitive drums 23 of the four image forming units 22 of black (K), yellow (Y), magenta (M), and cyan (C) rotate in the clockwise direction. It is charged like this. The uniformly charged photosensitive drum 23 is irradiated with light based on image information received from the host device by the LED head 25 to form an electrostatic latent image. The photosensitive drum 23 on which the electrostatic latent image is formed develops the toner image by the supply roller 27 and the developing roller 26. The photosensitive drum 23 having developed the toner image sandwiches and conveys the transfer belt 30 and the recording paper 100 together with the transfer roller 21, and the toner on the photosensitive drum 23 is transferred to the recording paper 100 by a voltage of about +3000 V applied to the transfer roller 21. The toner image is drawn to the side, and the toner image is transferred to the recording paper 100. The recording paper 100 onto which the toner image has been transferred is sent to the fixing unit 40 to fix the toner image. The toner remaining on the photosensitive drum 23 is scraped off by a cleaning device (not shown) to prepare for the formation of a new toner image.

  A recording sheet 100 on which toner images of four colors of black (K), yellow (Y), magenta (M), and cyan (C) are transferred is a nip formed by a fixing roller 41 and a backup roller 42 in a fixing unit 40. The region is nipped and conveyed. The recording paper 100 is heated by the heat of the fixing roller 41 and pressure by the urging force of the backup roller 42 in the nip region, and the toner image is fixed by melting the toner.

  The recording paper 100 on which the toner image has been fixed is conveyed by the rotation of the discharge rollers 52a and 52b after the leading edge of the recording paper 100 is detected by the paper travel path sensor 51. The conveyed recording paper 100 is discharged to the stacker unit 53.

FIG. 3 is a flowchart showing the printing outline operation by the control unit of FIG.
When the process starts, the control unit 80 receives print data from the host computer 200 via the communication unit 71 and the data analysis unit 72 in step S1, and determines the print mode in step S2. If the print mode is the consumable life extension mode, the process of step S3 is performed. If the print mode is the consumable life extension mode, the process of step S4 is performed.

  In step S3, a consumable life extension mode shown in FIG. 4 to be described later is set. In step S6, a printing operation shown in FIG. 6 to be described later is performed, and the processing in FIG.

  In step S4, a consumable simple life extension mode shown in FIG. 5 to be described later is set. In step S6, a printing operation shown in FIG. 6 to be described later is performed, and the processing in FIG.

  In step S5, the standard printing speed is set. In step S6, a printing operation shown in FIG. 6 described later is performed, and the processing in FIG. 3 is terminated.

  FIG. 4 is a flowchart showing the operation of setting the consumable life extension mode in FIG.

  When the process starts, the control unit 80 stores 0 in the processing time storage unit 88 in step S10. In steps S11 to S18, the process is repeated from the first page to the last page of the print data. In this repetitive processing, the print data currently being processed is the nth page.

  In step S12, the processing time measuring unit 85 starts measuring the processing time. For example, the timer 86 is initialized or the value of the timer 86 is stored.

  In step S <b> 13, the data analysis unit 72 starts a process for converting the print data of the nth page to be processed into image data. In step S14, the processing time measuring unit 85 waits until the image data conversion processing is completed, and reads the processing time via the timer 86 in step S15.

  In step S <b> 16, the maximum processing time calculation unit 87 compares the current processing time with the time stored in the processing time storage unit 88. If the current processing time is longer than the time stored in the processing time storage unit 88, the current processing time is stored in the processing time storage unit 88 in step S17.

  If the process for the last page of the print data has been completed in step S18, the process of step S19 is performed.

  In step S19, if the time in the processing time storage unit 88 is smaller than N [seconds], the process of step S20 is performed, and if it is N [seconds] or longer, the process of step S21 is performed. Here, N [seconds] is an image processing time during which continuous printing is possible at the standard printing speed. The standard printing speed of the first embodiment is 190.4 [mm / SEC], and the image processing time capable of continuous printing is 1.8225 [seconds].

  In step S20, the printing speed switching unit 83 sets the printing to the standard speed and ends the process of FIG.

  In step S21, the printing speed switching unit 83 sets the printing to a low speed based on the relationship shown in FIG. 8 described later according to the value of the processing time storage unit 88, and ends the process of FIG.

  FIG. 5 is a flowchart showing the operation of the consumables simple life extension mode setting in FIG.

  When the process starts, the conveyance control unit 82 reads the time stored in the processing time storage unit 88. The processing time storage unit 88 stores the maximum processing time among the image processing times of each print page in the previous print job.

  In step S19, if the time in the processing time storage unit 88 is smaller than N [seconds], the process of step S20 is performed, and if it is N [seconds] or longer, the process of step S21 is performed.

  In step S20, the printing speed switching unit 83 sets the printing to the standard speed and ends the process of FIG.

  In step S21, the printing speed switching unit 83 sets the printing to a low speed based on the relationship shown in FIG. 8 to be described later according to the value of the processing time storage unit 88, and ends the process of FIG.

FIG. 6 is a flowchart showing the printing operation of each page in FIG.
When the processing starts, the control unit 80 stores 0 in the processing time storage unit 88 in step S30. In steps S31 to S43, the process is repeated from the first page to the last page of the print data. In this repetitive processing, the print data currently being processed is the nth page.

  In step S32, the processing time measuring unit 85 starts measuring the processing time. For example, the timer 86 is initialized or the value of the timer 86 is stored.

  In step S33, the data analysis unit 72 starts processing for converting the print data of the nth page to be processed into image data. In step S34, the data analysis unit 72 starts storing image data in the data buffer 73 and notifies the start address. .

  In step S35, the processing time measuring unit 85 waits until the image data conversion processing is completed, and reads the processing time via the timer 86 in step S36.

  In step S <b> 37, the maximum processing time calculation unit 87 compares the current processing time with the time stored in the processing time storage unit 88. If the current processing time is longer than the time stored in the processing time storage unit 88, the current processing time is stored in the processing time storage unit 88 in step S38.

  In step S39, the control unit 80 instructs the conveyance control unit 82 to start conveyance, determines whether conveyance control can be started, and waits until conveyance is possible.

  If it is determined that conveyance is possible, the conveyance of the recording paper 100 is started in step S40, the image forming unit 20 is instructed to form image data in step S41, and the fixing unit 40 is instructed to fix in step S42. If the process for the last page of the print data has been completed in step S43, the process in FIG. 6 is terminated.

  FIGS. 7A to 7C are time charts in the printing operation according to the first embodiment of the present invention, in which the horizontal axis indicates time and the numbers indicate print pages.

  FIG. 7A is a time chart in the printing speed priority mode. If the received data consists of the first page and the second page, the image data conversion process for each page is performed when the reception of each page is completed. When the image data conversion process for each page is completed, the image forming unit 20 is driven.

  In the example shown in FIG. 7A, since the image data conversion process for the second page is longer than the drive time of the image forming unit 20 per page, the second page after the image formation for the first page is completed. Until the image formation of the page starts, the image forming unit 20 idles.

  FIG. 7B is a time chart in the consumable life extension mode. If the received data consists of the first page and the second page, when the reception of each page is completed, the image data conversion process for each page is performed, and the maximum processing time is measured.

  The same data is received again, image data conversion processing for each page is performed, the image forming unit 20 is driven in accordance with the maximum processing time, and idling of the image forming unit 20 is suppressed. In this case, there is an effect that the idling of the image forming unit 20 can be suppressed, but there is a problem that the printing time becomes long.

  FIG. 7C is a time chart in the consumable simple life extension mode. If the received data consists of the first page and the second page, the image data conversion process for each page is performed when the reception of each page is completed. Further, the image forming unit 20 is driven in accordance with the maximum processing time measured in the previous print job, and the idling of the image forming unit 20 is suppressed. In this case, if the previous print job is similar to the current print job, the idling of the image forming unit 20 can be suppressed, and the overall printing time is not different from the printing speed priority mode. There is.

  FIG. 8 is a diagram illustrating the relationship between the image processing time and the printing speed according to the first embodiment of the present invention.

  FIG. 8 shows that if the maximum image processing time is 1822.5 [mSEC] or less, the standard printing speed of 190.4 [mm / SEC] is selected. If the maximum image processing time is 1822.5 [mSEC] to 1944.0 [mSEC], it indicates that 178.5 [mm / SEC] of the low speed printing speed 1 is selected. If the maximum image processing time is 1944.0 mSEC to 2082.8 mSEC, it indicates that 166.6 [mm / SEC] of the low speed printing speed 2 is selected. Similarly, a lower printing speed is selected in response to an increase in the maximum image processing time.

  FIG. 9 is a diagram showing the printing time of each mode and the photosensitive drum rotation speed of the image forming unit at the time of sample data.

  The premise of this sample data is that 4400 [mSEC] is stored in the processing time storage unit 88, the received data of the first page is 2000 [mSEC], and the received data of the second page is 4000 [mSEC]. It is. The image data conversion time for the first page is 3800 [mSEC], and the image data conversion time for the second page is 5000 [mSEC]. The distance from the paper feed tray to the discharge port is 476.44 [mm], and the paper length is 297 [mm]. The continuous printable interval is 347 [mm], and the circumferential distance of the photosensitive drum 23 is 94.2 [mm].

  When the sample data was printed in the printing speed priority mode, the printing time was 15124 [mSEC], and the rotational speed of the photosensitive drum 23 of the image forming unit 22 was 18.8. When the sample data was printed in the consumable life extension mode, the printing time was 33719 [mSEC], and the rotational speed of the photosensitive drum 23 of the image forming unit 22 was 11.8. When the sample data was printed in the consumable simple life extension mode, the printing time was 20799 [mSEC], and the rotational speed of the photosensitive drum 23 of the image forming unit 22 was 12.3.

  In the consumables life extension mode, the printing time is slightly longer than in the printing speed priority mode, but the rotational speed of the photosensitive drum 23 of the image forming unit 22 is suppressed to be almost the same as that of the consumables life extension mode. be able to.

(Effect of Example 1)
The image forming apparatus 10 according to the first exemplary embodiment has the following effects (A) and (B).

  (A) The image forming speed is set according to the maximum value of the image data conversion time for a plurality of print pages in the print job. Thereby, the idling time of the image forming unit 20 is reduced, and the life of the consumables is extended.

  (B) The image forming speed is set according to the maximum value of the image data conversion time for a plurality of print pages in the previous print job. As a result, the idling time of the image forming unit 20 can be reduced, the life of the consumables can be extended, and printing can be completed in a relatively short time.

(Configuration of Example 2)
FIG. 10 is a schematic configuration diagram illustrating a control unit according to the second embodiment of the present invention. Elements common to those in FIG. 1 illustrating the first embodiment are denoted by common reference numerals.

The image forming apparatus 10A according to the second exemplary embodiment includes a control unit 80A illustrated in FIG.
The control unit 80A of the second embodiment includes an average processing time calculation unit 89 and a processing time array storage unit 90 in addition to the control unit 80 of the first embodiment, and the output side of the maximum processing time calculation unit 87 is an average process. The processing time storage unit 88 is connected via the time calculation unit 89. Further, the processing time array storage unit 90 is connected to the average processing time calculation unit 89 in a readable / writable manner. Other configurations are the same as those of the control unit 80 of the first embodiment.

  The processing time array storage unit 90 has an array structure that can store M values, and is a maximum processing time array storage unit that can store the maximum processing time in the most recent M print jobs.

(Operation of Example 2)
FIG. 11 is a flowchart showing the printing operation of each page in the second embodiment of the present invention. Elements common to the elements in FIG. 6 showing the first embodiment are denoted by common reference numerals.

  When the process starts, the control unit 80A stores 0 in a temporary storage unit (not shown) in step S30A. In steps S31 to S43, the process is repeated from the first page to the last page of the print data. In this repetitive processing, the print data currently being processed is the nth page.

The processing in steps S32 to S36 is the same as the processing in the first embodiment shown in FIG.
In step S37A, the maximum processing time calculation unit 87 compares the current processing time with the time stored in the temporary storage unit. If the current processing time is longer than the time in the temporary storage unit, the current processing time is stored in the temporary storage unit in step S38.

  The processing of step S39 to step S43 is the same as the processing of the first embodiment shown in FIG.

  In step S50, the average processing time calculation unit 89 stores the value of the temporary storage unit (not shown) in the processing time array storage unit 90. In step S 51, the average processing time calculation unit 89 calculates the average value of the maximum processing times in the most recent M print jobs stored in the processing time array storage unit 90 and stores the average value in the processing time storage unit 88. Then, the process of FIG.

(Effect of Example 2)
According to the image forming apparatus 10A of the second embodiment, the maximum value of the image data conversion time for a plurality of print pages is calculated in the most recent print job, and the average value of the plurality of maximum values is calculated. The image forming speed is set according to the average value of the maximum values of the image data conversion time. Thereby, the idling time of the image forming unit 20 is averaged, and there is an effect of extending the life of the consumables.

(Modification)
The present invention is not limited to the above-described embodiments, and various usage forms and modifications are possible. For example, there are the following forms (a) and (b) as usage forms and modifications.

  (A) Embodiments 1 and 2 are examples applied to the image forming apparatus 10, but may be applied to a multifunction machine having any one of a fax function, a copy function, and a copy function.

  (B) In the first and second embodiments, the printing speed is determined based on the maximum image processing time and the correspondence between the continuous printable time and the printing speed shown in FIG. The printing speed may be determined based on a mathematical expression indicating the relationship between Thereby, there exists an effect that idle time can be reduced more correctly.

DESCRIPTION OF SYMBOLS 10,10A Image forming apparatus 11 Paper feeding part 20 Image forming part 22 Image forming unit 23 Photosensitive drum 40 Fixing part 50 Paper discharge part 60 Medium conveyance part 71 Communication part 72 Data analysis part 73 Data buffer 80, 80A Control part 81 Fixing control Unit 82 Conveyance control unit 83 Printing speed switching unit 84 Data transfer unit 85 Processing time measurement unit 86 Timer 87 Maximum processing time calculation unit 88 Processing time storage unit 89 Average processing time calculation unit 90 Processing time array storage unit 100 Recording paper 200 Host computer

Claims (6)

A communication unit that receives print data relating to a plurality of print pages from a host computer;
A data analysis unit for converting the print data into image data;
A maximum processing time calculating unit that measures a processing time for converting to the image data for each print page and calculates a maximum processing time that is a maximum value of the processing time;
A speed switching unit that switches the printing speed according to the maximum processing time;
An image forming apparatus comprising:   The print data received by the data analysis unit is converted into the image data, and the maximum processing time calculation unit measures the maximum processing time, and then the data analysis unit converts the print data again into the image data. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1 further includes:
When the data analysis unit has converted all the print data, a maximum processing time storage unit that calculates a maximum of the processing time related to the print data and stores it as the maximum processing time,
The image forming apparatus, wherein the speed switching unit switches a printing speed according to the maximum processing time related to the latest print data stored in the maximum processing time storage unit.   The image forming apparatus according to claim 1, wherein the speed switching unit switches to a predetermined printing speed when the maximum processing time is longer than a predetermined processing time. The image forming apparatus according to claim 3, further comprising:
A maximum processing time array storage unit that calculates the maximum processing time for the print data and stores it as the maximum processing time when the data analysis unit has converted all the print data;
An average processing time calculating unit that calculates an average maximum processing time that is an average of the maximum processing times related to the plurality of print data stored in the maximum processing time array storage unit,
The image forming apparatus, wherein the speed switching unit switches a printing speed according to the average maximum processing time.   The image forming apparatus according to claim 5, wherein the speed switching unit switches to a predetermined printing speed when the average maximum processing time is longer than a predetermined processing time.

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