JP2006072236A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of restraining the power consumption of a fixing device to the utmost and realizing rapid rise, and a control method therefor. <P>SOLUTION: At starting by a main switch 414, the fixing device is set to a standby state (S503). After starting, control to start fixing only when printing is required from a user or external equipment is performed (S504 and S505). At reset from an energy saving mode, preheating control is performed because it is clear to apply a job by the user immediately after the reset. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and a control method thereof.

  In general, in an image forming apparatus such as a copying machine, a printer, or a facsimile machine, a fixing device is provided that heats and pressurizes a sheet on which a toner image is formed and thermally fixes the toner image on the sheet surface. In such an image forming apparatus, immediately after the main switch is turned on, energization to the heater in the fixing device is started regardless of the operation of the user, and the image forming operation is accepted after the heater reaches the set temperature. ing.

  During the standby time due to such a fixing device preparation operation (warm-up operation), image formation is also performed at locations other than the fixing device such as a developing device, a photoconductor, a charging device, a transfer device, and a main control unit. Each preparatory operation is performed.

  However, in general, the preparatory operation for parts other than the fixing device is completed in a relatively short time (about 5 to 30 seconds), while the waiting time for the preparatory operation of the fixing device is 5 minutes or more. The long waiting time required for the fixing device preparation operation has been a problem from the viewpoint of speeding up the rise time of the image forming apparatus. In particular, for a user who does not need an image forming operation such as copying immediately after turning on the main switch of the image forming apparatus (for example, facsimile transmission), the warm-up operation of the fixing device delays the rise time of the image forming apparatus. This not only deteriorates operability, but also consumes unnecessary power.

  Accordingly, various proposals have been made as techniques for shortening the startup time of the fixing device as follows.

  (1) There is a technique that shortens the rise time of the fixing device by controlling the energization current to the heater in the fixing device while maintaining the input current of the image forming apparatus below a predetermined value (prior art 1).

  (2) Preheating control for the heater in the fixing device is performed even during normal operation while waiting for a user operation, and the upper limit of the power consumed by the fixing device is switched between when the image forming apparatus is started and during normal operation. There is one that shortens the rise time of (Prior Art 2).

  (3) In the method of Patent Document 1, in order to reduce the power consumption of the image forming apparatus during standby and to shorten the time from standby until it can be used, the power supply device is effectively used to perform standby. Three modes are provided: time (energy saving mode), start-up (start-up mode), and print (print mode). There are two types of start-up modes: start-up of the fixing device and start-up of the image forming unit, which are collectively referred to as start-up mode.

  The operation of Patent Document 1 will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the conventional image forming apparatus disclosed in Patent Document 1.

  First, when the main switch of the image forming apparatus is turned on (step S601), a transition is made to the energy saving mode which is a standby state (step S602). When the energy saving cancel switch is pressed in this state, the mode is shifted to the startup mode (step S603), and the fixing device is started up. Then, after the fixing device rises to the set temperature, the standby state is maintained with the fixing standby power.

  When the start-up operation is completed, the print mode is entered (step S604), and print processing is executed. When printing is completed and a preset condition (for example, when the next print processing operation is not performed for a predetermined time from the end of printing) is reached, the printer returns to the energy saving mode and enters the standby state. Become.

By such an operation, when the image forming apparatus is started up, it is possible to optimize the distribution of power consumption other than the fixing unit and the input power to the fixing unit, and shorten the start-up time of the image forming apparatus. Can do.
JP 2001-022334 A

  However, although the conventional technique 1 has an effect of shortening the start-up time to some extent, it is difficult to further reduce the start-up time due to the limitation of the input current of the image forming apparatus.

  In the above prior art 2, the waiting time can be shortened when the image forming operation is necessary by performing the preheating control to the heater in the fixing device even during the standby of the user operation, but the frequency of the image forming operation is low. For a small number of users, there is a problem that power is wasted by preheating control.

  In the technique of Patent Document 1, startup control is performed in response to a user's cancellation of energy saving. However, the predetermined time after the start-up of the fixing device and the end of the printing operation is maintained in the standby state of the fixing device. There was a problem that power consumption increased.

  An object of the present invention is to provide an image forming apparatus capable of suppressing power consumption of a fixing device as much as possible and enabling quick start-up, and a control method thereof.

  In order to solve the above problems, an image forming apparatus according to the present invention includes a power supply apparatus to which an AC power input is supplied when a power switch of the apparatus main body is turned on, an image forming means for performing image formation, and the power supply apparatus. Image forming apparatus comprising: fixing means for fixing an image formed by the image forming means to a sheet surface to which an AC power input is supplied; and a fixing control means for performing warm-up operation by energization control on the fixing means. In the apparatus, the fixing control unit does not perform the warm-up operation for the fixing device when the power switch is turned on, and starts the warm-up operation in response to an input of a job request. To do.

  According to the image forming apparatus control method of the present invention, the AC power input is supplied when the power switch of the apparatus main body is turned on, the image forming means for forming an image, and the AC power input from the power supply. And a fixing means for fixing the image formed by the image forming means on the surface of the sheet. When the power switch is turned on, a warming by energization control is performed on the fixing apparatus. The warm-up operation is started in response to the input of a job request without performing the up operation.

  According to the present invention, the power consumption of the fixing unit can be suppressed as much as possible, and the image forming apparatus can be quickly started up.

  Embodiments of an image forming apparatus and a control method thereof according to the present invention will be described with reference to the drawings.

[First Embodiment]
<Overall structure of image forming apparatus>
FIG. 1 is a cross-sectional view showing the overall structure of the image forming apparatus according to the first embodiment of the present invention.

  The image forming apparatus includes a scanner unit B, an image forming unit C, and a sheet deck D in each unit of the image forming apparatus main body A. The image forming apparatus main body A has a scanner unit B as an image reading unit that reads image information of a book document at the upper part thereof, an image forming unit C as an image forming unit at a lower part thereof, and a sheet at the lower part thereof. The deck D is assembled.

  More specifically, the scanner unit B reads image information on a document surface, and includes a scanning light source 201, a platen glass 202, a document pressure plate 203 that can be opened and closed with respect to the image forming apparatus main body A, a mirror 204, The lens 205 includes a light receiving element (photoelectric conversion element) 206, an image processing unit, and the like. A book original such as a book / thick paper / curled paper or a sheet-like original is placed on the platen glass 202 with the original surface facing down, and the back side is pressed by the original pressure plate 203 and set in a stationary state. When is pressed, the scanning light source 201 scans the lower part of the platen glass 202 in the direction of the arrow a to read image information on the document surface. The document image information read by the scanning light source 201 is processed by an image processing unit (not shown), converted into an electrical signal, and transmitted to the laser scanner 111 of the image forming unit C.

  Here, the image forming apparatus main body A functions as a copying machine, a printer, a facsimile machine, or the like. That is, if a processing signal of the image processing unit is input to the laser scanner 111 of the image forming unit C, it functions as a copying machine, and if an output signal of an external device (computer) is input, it functions as a printer. The image forming apparatus main body A also functions as a facsimile apparatus if it receives a signal from another facsimile apparatus or transmits a signal from the image processing unit to another facsimile apparatus.

  On the other hand, a sheet cassette 51 is mounted below the image forming unit C, and a sheet (recording material) accommodated in the cassette is fed to the image forming unit C in synchronization with the image forming operation. Is done. Two sheet cassettes 51, a lower cassette 51a and an upper cassette 51b, are configured as one feeding unit. In the present embodiment, two supply units U1 and U2 are mounted and four cassettes are mounted. One feeding unit U1 positioned above is detachably attached to the image forming apparatus main body A, and the lower feeding unit U2 is detachably attached to the sheet deck D.

  The sheets (recording materials) accommodated in the lower cassette 51a and the upper cassette 51b are fed by the pickup roller 53, and separated and fed one by one by the cooperative action of the feed roller 54 and the retard roller 55. After that, the paper is transported by the transport rollers 104 and 105, guided by the registration roller 106, and fed to the image forming unit C by the registration roller 106 so as to be synchronized with the image forming operation.

  In addition to the sheet cassette 51 described above, the manual feed tray 10 is disposed on the side surface of the image forming apparatus main body A, and the sheets on the manual feed tray 10 are fed out to the registration rollers 106 by the manual feed roller 11.

  The image forming unit C forms an image on the sheet surface, and includes an electrophotographic photosensitive drum 112, an image writing optical system 113, a developing device 114, a transfer charger 115, and the like. Laser light corresponding to the image information emitted from the laser scanner 111 is scanned by the image writing optical system 113 on the surface of the photosensitive drum 112 uniformly charged by the transfer charger 115 to form a latent image. A toner image is formed on the latent image by the developing device 114, and the toner image is transferred by the transfer charger 115 to the first surface of the sheet conveyed by the registration roller 106 in synchronization with the rotation of the photosensitive drum 112. .

  In the figure, reference numeral 117 denotes a conveyance unit that conveys a sheet on which a toner image is formed, 118 denotes a fixing unit, and 119 denotes a discharge roller. The sheet on which the toner image is formed is conveyed to the fixing unit 118 by the conveyance unit 117 and is heated and pressurized, and the toner image is fixed on the sheet surface. The sheet on which the image is formed in this manner is discharged and stacked on the sorter 120 arranged outside the apparatus by the discharge roller 119.

  When recording images on both sides of the sheet, the sheet discharged from the fixing unit 118 is held between the discharge rollers 119, and the discharge rollers 119 are reversed when the trailing edge of the sheet passes the branch point 207. Then, the sheet is temporarily placed on the sheet double-sided tray 121. Thereafter, the sheet is conveyed by the conveying rollers 104 and 105 to reach the registration roller 106, and the inverted sheet is formed on the second surface in the same manner as described above, and then discharged and stacked on the sorter 120.

<Structure of fuser unit>
FIG. 2 is a sectional view showing the structure of the fixing unit 118 shown in FIG.

  The fixing unit 118 of the image forming apparatus includes a stay 11, an endless heat-resistant film (hereinafter, a fixing film) 12, a ceramic heater 13, a thermistor 15, and a pressure roller 18. The ceramic heater 13 having a resistance heating element is pressed against the pressure roller 18 with the fixing film 12 interposed therebetween, and is in contact with the nip N. The pressure roller 18 is rotated in the direction of the arrow “Rot” by a driving source (not shown), and causes the fixing film 12 to move in a heavy motion.

  Further, when the paper on which the toner image is placed passes through the nip portion N in the direction of the arrow “Paper”, it is heated by the ceramic heater 13 to fix the toner image. A thermistor 15 is in contact with the ceramic heater 13 so that the temperature of the ceramic heater 13 can be detected.

<Fixing temperature control related parts>
Next, the configuration of the fixing temperature control related part that controls the temperature of the fixing unit 118 will be described with reference to FIG. FIG. 3 is a block diagram illustrating the configuration of the fixing temperature control related unit according to the first embodiment.

  As shown in FIG. 3, the image forming apparatus main body A in the present embodiment includes a fixing unit 118 equipped with a ceramic heater 13 as a fixing heater, and a triac 410 as a switching control element, as shown in FIG. And a fixing control unit 405 which is a part of the control unit 402 of the image forming apparatus main body A.

  An AC input is supplied to the image forming apparatus main body A from an AC power supply 404. The AC input is, for example, a household 100V / 50 Hz AC power input. The AC input is supplied to the image forming apparatus A through the main switch 414, and the user turns on / off the apparatus main body with the main switch 414. Then, an activation signal for notifying activation of the apparatus main body A is output from the activation signal generation unit 411 of the power supply unit 403 to the control unit 402 in accordance with on / off of the main switch 414.

  The AC input is supplied to the power supply unit 403 and input to the fixing relay 409 and the triac 410 via a filter (not shown). The AC input input to the fixing relay 409 is controlled to be on or off in accordance with the RDRV signal output from the fixing control unit 405. The AC input is supplied to the ceramic heater 13 via the fixing relay 409.

  On the other hand, the triac 410 is a switching control element for turning on / off the energization of the ceramic heater 13, and turns on / off the energization of the ceramic heater 13 in accordance with the HDRV signal from the fixing control unit 405.

  The on / off control of the triac 410 using the HDRV signal is performed by setting the energization amount (AC half wave) from the input of the ZX signal (zero cross signal) to the input of the next ZX signal as one control amount. Executed according to Here, the zero cross (ZX) detection unit 406 detects a zero cross detection range set at several volts above and below the zero cross point of the power supply voltage, and outputs a zero cross signal ZX according to the set zero cross detection range. That is, the ZX detection unit 406 connected to the AC input line outputs a ZX signal to the fixing control unit 405 via the photocoupler 407 for each zero cross point of the AC input. The fixing control table is stored in advance in a ROM (not shown) in the fixing control unit 405.

  The thermistor 15 is brought into contact with the ceramic heater 13 in the fixing device unit 118, and the thermistor 15 outputs a Tdet signal, which is temperature information of the ceramic heater 13, to the fixing control unit 405. The fixing control unit 405 converts the Tdet signal into digital data by an analog / digital conversion unit (not shown). Then, the energization amount of the ceramic heater 13 is obtained based on the difference between the digital Tdet signal, which is current temperature information of the ceramic heater 13, and the control target temperature value, and the on / off pattern corresponding to the energization amount is controlled for fixing. Select from the table. The fixing control unit 405 controls the on / off of the triac 410 by outputting the on / off pattern selected in this way to the triac 410 as an HDRV signal. The fixing control unit 405 continuously performs such energization control (hereinafter referred to as fixing temperature control) for the ceramic heater 13 so that the temperature of the ceramic heater 13 is controlled to a predetermined target temperature. ing.

<Operation of First Embodiment>
FIG. 4 is a flowchart showing the operation of the image forming apparatus according to the first embodiment. This operation is executed by the control unit 402.

  First, when the main switch 414 is turned on (step S501), an activation signal for notifying activation of the image forming apparatus main body A is output to the control unit 402 (step S502). Upon receiving the activation signal, the control unit 402 activates the image forming apparatus main body A and sets it to a standby state (a state waiting for a user operation) (step S503). At the start-up, as a preparatory operation for image formation, the preparatory operation of the fixing unit 118, that is, the fixing temperature control (warm-up operation) for the ceramic heater 13 is not performed. In the image forming unit such as the drum 112, the transfer charger 115, and the main control unit, an image forming preparation operation (toner remaining amount check, pre-rotation of the photosensitive member, initialization of each part by the main control, abnormality check, etc.) is performed. Each done. In addition, initialization of the program, initial check, etc. are performed also in the controller system connected to an external device such as a network or a facsimile.

  Thereafter, the standby state is maintained until a job request (job request) such as a user operation on the operation unit of the image forming apparatus main body A, a print request from an external host computer or the like, or facsimile reception is input to the control unit 402. (Step S504).

  When the job request is input, fixing temperature control is started by the fixing controller 405 in the controller 402. That is, as described above, energization to the ceramic heater 13 is started, and energization control is performed so that the ceramic heater 13 reaches a predetermined target temperature (step S505).

  After it is determined that the ceramic heater 13 has reached the predetermined target temperature, the above-described series of image forming operations is started (step S506). After the image formation is completed (step S507), the process returns to step S503, the image forming apparatus main body A again enters the standby state, and maintains the standby state until a job request is input to the control unit 402.

  According to the present embodiment, when the image forming apparatus main body A to which the main switch 414 is turned on is started, the fixing temperature control is not performed and the standby state is set, and the image forming operation request (job request) is not input thereafter. As long as the fixing temperature control (preheating control) is not performed, the standby state is maintained. Thereby, the startup time of the image forming apparatus can be shortened. Further, if the fixing temperature control is performed at the time of starting the image forming apparatus, the power that would have been consumed by the fixing unit 118 can be reduced, and the consumption of the fixing unit 118 after the image forming apparatus is started up. It becomes possible to suppress electric power as much as possible.

[Second Embodiment]
FIG. 5 is a block diagram showing the configuration of the fixing temperature control related section according to the second embodiment. Elements common to those in FIG. 3 are given the same reference numerals and explanation thereof is omitted.

  The difference between the fixing temperature control related portion of the present embodiment and the first embodiment described above is that in the configuration of FIG. 3, an energy saving mode such as a sleep mode can be set, and the energy saving mode is canceled. By providing the energy saving cancel switch 601 and depressing the energy saving cancel switch 601 when the energy saving mode is set, a return signal is notified to the control unit 402 in the image forming apparatus main body A, and the image forming apparatus main body A is It is a point that can be restored from the energy saving mode to the standby state.

  Here, the energy saving mode is a mode in which only a predetermined portion of the image forming apparatus is energized to maintain a waiting state for an input from a user or an external device or an interrupt signal. This is a switch for manually operating the release of the energy saving mode or the like by direct operation by the user.

  At the time of returning to the standby state by the operation of the energy saving cancel switch 601, since the user is expected to input a job immediately after that, the fixing control unit 405 controls the fixing temperature for the ceramic heater 13 in the fixing unit 118. It is like that. In addition, when there is a job request from a peripheral external device 602 connected to the image forming apparatus A in the energy saving mode, a return to the standby state is performed in the same manner as when the energy saving cancel switch 601 returns.

  On the other hand, when the energy saving cancel switch 601 is pressed in the standby state, the return signal is notified to the control unit 402 as an energy saving transition signal, so that some units in the control unit 402 are switched to shift to the energy saving mode. The energization control by the power supply unit 403 is performed so as to stop the remaining energization.

  For example, when the energy saving mode automatic transition setting such as auto sleep is performed, a state in which no operation from the user or an external device or an interrupt signal is input to the image forming apparatus main body A has elapsed for a predetermined set time. After that, it automatically shifts to the energy saving mode.

<Operation of Second Embodiment>
FIG. 6 is a flowchart illustrating the operation of the image forming apparatus according to the second embodiment. Elements common to those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. This operation is executed by the control unit 402.

  After performing the processing of step S501 to step S503 in the same manner as in the first embodiment, the process proceeds to step S701.

  In step S701, in a standby state, whether a state where no operation or interrupt signal or the like from the user or an external device is input to the image forming apparatus (no operation state) has passed a predetermined set time (counted by an internal timer). If it has not yet elapsed, the process proceeds to the job request interruption waiting state (step S504). If the standby state in the non-operation state has elapsed for a predetermined set time, the image forming apparatus main body A automatically shifts to the energy saving mode (step S702). In the energy saving mode, only a predetermined portion is energized to maintain a state waiting for an input from the user or an external device or an interrupt signal.

  When the energy saving cancel switch 601 is pressed in this energy saving mode, a return signal is notified to the control unit 402, and the control unit 402 performs control for shifting to the standby state. At that time, the fixing control unit 405 performs fixing temperature control that was not performed at the time of activation. This is because it is obvious that the user has input a job immediately after that, and the ceramic heater 13 in the fixing unit 118 is raised to the set temperature in advance, thereby shortening the waiting time for image formation. In addition, when there is a job request from the external device 602 in this energy saving mode, a return to the standby state is performed in the same manner as when the energy saving cancel switch 601 returns.

  After detecting the temperature rise of the ceramic heater 13 to the set temperature, the process proceeds to the standby state (step S503), and the return operation is completed. The above series of operations is repeated.

  According to the present embodiment, as in the first embodiment, since the fixing temperature control is not performed when the image forming apparatus main body A is started by the main switch, the fixing unit 118 is used when the image forming apparatus is started up. It is possible to reduce power consumption and shorten the startup time of the image forming apparatus.

  In addition, after startup, the fixing temperature control is performed only when a print request is received from the user or an external device. When returning from the energy saving mode, a request for an image forming operation is expected immediately, so the fixing temperature control (preheating control) is performed. Do. Thereby, power consumption can be suppressed as much as possible in consideration of a user's practical aspect.

  In addition, this invention is not limited to each above-mentioned embodiment, A various deformation | transformation is possible. Examples of such modifications include the following.

  (1) In the second embodiment, after making it possible to set a single energy saving mode, one energy saving release switch 601 for releasing this is provided, and the energy saving release switch 601 is operated to operate the energy saving. Returning from the mode, the components of the image forming apparatus shown in FIG. 1 are divided into a plurality of blocks according to the amount of power consumption, and an energy saving mode is set for each block. You may take the structure which provided the some energy-saving cancellation switch corresponding to each energy-saving mode. In this case, the return from each of the energy saving modes is performed by operating the corresponding energy saving release switch. The fixing control unit 405 sets the energization rate at the time of fixing temperature control in response to the notification of each return signal from each energy saving release switch.

  Further, the fixing means is not limited to the resistance (surface) heat generation method, and the present invention can also be applied to a device using a halogen heater or a device using a fixing device such as an induction heating fixing method.

1 is a cross-sectional view showing an overall structure of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a structure of a fixing device unit 118 shown in FIG. 1. FIG. 3 is a block diagram illustrating a configuration of a fixing temperature control related unit according to the first embodiment. FIG. 5 is a flowchart showing the operation of the image forming apparatus according to the first embodiment. FIG. 10 is a block diagram illustrating a configuration of a fixing temperature control related unit according to a second embodiment. FIG. 10 is a flowchart illustrating an operation of the image forming apparatus according to the second embodiment. FIG. 10 is a flowchart showing the operation of a conventional image forming apparatus.

Explanation of symbols

13 Ceramic heater 15 Thermistor 118 Fixing unit 402 Control unit 405 Fixing control unit 410 Triac 411 Activation signal generation unit 414 Main switch

Claims (6)

A power supply device to which an AC power input is supplied when the power switch of the apparatus main body is turned on, an image forming means for performing image formation, and an AC power input from the power supply device to form the image forming means. In an image forming apparatus comprising: a fixing unit that fixes an image on a sheet surface; and a fixing control unit that performs a warm-up operation by energization control on the fixing unit.
The fixing control means does not perform the warm-up operation for the fixing device when the power switch is turned on, and starts the warm-up operation in response to an input of a job request. apparatus.   The image forming apparatus includes: an energy saving mode with less power consumption; and a return notification unit that notifies the fixing control unit of a return from the energy saving mode to a standby state with more power consumption than the energy saving mode. The image forming apparatus according to claim 1, wherein the warm-up operation for the fixing device is performed when a return from the energy saving mode is notified by the return notification unit.   The image forming apparatus further includes a plurality of energy saving modes corresponding to the amount of power consumption, and a plurality of return notification means for notifying the fixing control means of the return from the plurality of energy saving modes to the standby state, The image forming apparatus according to claim 2, wherein the fixing control unit performs the warm-up operation on the fixing device when a return from the energy saving mode is notified by the return notification unit.   The image forming apparatus according to claim 3, wherein the fixing control unit sets an energization rate of the warm-up operation in accordance with each return notification from the plurality of return notification units. A power supply device to which an AC power input is supplied when the power switch of the apparatus main body is turned on, an image forming means for performing image formation, and an AC power input from the power supply device to form the image forming means. In a control method of an image forming apparatus including a fixing unit that fixes an image on a sheet surface,
When the power switch is turned on, the warm-up operation by energization control is not performed on the fixing device.
A control method for an image forming apparatus, wherein the warm-up operation is started in response to an input of a job request. The image forming apparatus includes an energy saving mode with low power consumption, and a return notification unit that notifies the fixing control unit of a return from the energy saving mode to a standby state with higher power consumption than the energy saving mode,
6. The method of controlling an image forming apparatus according to claim 5, wherein the warm-up operation for the fixing device is performed when a return from the energy saving mode is notified by the return notification unit.

Images