JP2011158698A - Fixing control device, image forming apparatus, fixing control method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing control device configured to reduce power consumption of a heat source part of a fixing roller, and to provide an image forming apparatus, a fixing control method, a program and a recording medium. <P>SOLUTION: The fixing control device is configured to make a transfer medium pass through a gap between a fixing roller with a heating part provided therein and a pressure roller to fix a toner image transferred onto the transfer medium. The fixing control device includes: a calculating means that calculates the area of the unfixed region of the transfer medium passing through the gap between the fixing roller and the pressure roller; a detecting means that detects the temperature in the vicinity of the fixing roller; and a control means that shuts off the power supply to the heating part based on the area of the unfixed region and the temperature in the vicinity of the fixing roller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing control device, an image forming apparatus, a fixing control method, a program, and a recording medium, and in particular, a fixing control device, an image forming apparatus, a fixing control method, a program, and a recording medium that reduce power consumption of a heat source unit of a fixing roller. About.

  A fixing heater used in a fixing device of an electrophotographic image forming apparatus requires a large amount of electric power. In the case of a fixing device using a halogen heater as a fixing heater, the temperature of the fixing roller does not cool immediately even when the heater is turned off, and the temperature is a temperature at which the toner can be fixed for a certain time even when the heater is turned off. Is in range. However, conventionally, since the fixing heater of the fixing device is turned off after the trailing edge of the transfer paper has completely passed through the fixing device, there is a disadvantage that excessive power is consumed.

  Therefore, in order to reduce the power consumption of the fixing heater, a technique has been proposed in which the heater is turned off before the transfer paper completely passes through the fixing device, and fixing is performed by the residual heat of the fixing roller (see, for example, Patent Document 1). . In the image forming apparatus described in Patent Document 1, for the purpose of reducing the power consumption of the fixing heater, a predetermined time elapses after the printer engine control unit detects the trailing edge of the transfer paper passing through the fixing device by the registration sensor. In this case, a configuration is disclosed in which the halogen heater of the fixing device is turned off before the trailing edge of the transfer paper passes through the fixing device, and fixing is performed by the residual heat of the fixing roller.

  However, the above-mentioned technology that uniformly turns off the halogen heater when a certain period of time has passed after the transfer paper passes through a predetermined position detected by a registration sensor or the like, turns off the halogen heater at an optimal timing for optimal power reduction. I can't say.

  That is, depending on the surrounding environment (ambient temperature, humidity, etc.), fixing device status (fixing roller temperature), transfer paper type (paper thickness, etc.), etc. Since whether or not the area of the unfixed area can be fixed is different, an optimal power reduction cannot be realized only by turning off uniformly as in the above technique.

  The present invention has been made in view of such a situation, and an object of the present invention is to reduce the power consumption of the heating unit as much as possible in the control for fixing the toner onto the transfer paper by the residual heat of the fixing roller.

  A fixing control device according to the present invention is a fixing control device that fixes a toner image transferred to a transfer medium by passing the transfer medium between a fixing roller having a heating unit therein and a pressure roller. A calculating means for calculating an area of an unfixed area of the transfer medium passing between the fixing roller and the pressure roller; a detecting means for detecting a temperature near the fixing roller; and the unfixed area And a control means for turning off the power supply to the heating unit based on the area of the fixing roller and the temperature in the vicinity of the fixing roller.

  An image forming apparatus according to the present invention includes the fixing control device according to the present invention.

  A fixing control method according to the present invention is a fixing control device for fixing a toner image transferred to a transfer medium by passing the transfer medium between a fixing roller having a heating unit therein and a pressure roller. A fixing control method, comprising: calculating an area of an unfixed area of a transfer medium passing between the fixing roller and a pressure roller; detecting a temperature in the vicinity of the fixing roller; And a step of turning off the power supply to the heating unit based on the area of the contact area and the temperature in the vicinity of the fixing roller.

  A fixing control program according to the present invention is a fixing control device for fixing a toner image transferred to a transfer medium by passing the transfer medium between a fixing roller having a heating unit therein and a pressure roller. A fixing control program, a process for calculating an area of an unfixed area of a transfer medium passing between the fixing roller and a pressure roller, a process for detecting a temperature in the vicinity of the fixing roller, and the undetermined The computer is caused to execute a process of turning off the power supply to the heating unit based on the area of the contact area and the temperature in the vicinity of the fixing roller.

  The recording medium according to the present invention is a computer-readable recording medium for recording the process of the fixing control program according to the present invention.

  According to the present invention, it is possible to control the power supply to the heating unit of the fixing roller based on the temperature of the fixing roller and the area of the unfixed area in the control for fixing the toner to the transfer paper by the residual heat of the fixing roller The power consumption of the heating unit can be reduced as much as possible.

1 is a diagram illustrating a schematic configuration of an image forming process unit 3 and an engine control unit 1 of an image forming apparatus according to an embodiment of the present invention. It is a figure for demonstrating temperature control of a fixing roller. FIG. 5 is a schematic cross-sectional view for explaining a fixed area and an unfixed area of a transfer sheet during paper passing. FIG. 5 is a schematic perspective view for explaining a fixed area and an unfixed area of a transfer sheet during paper passing. 5 is a flowchart showing a control operation process of a fixing heater according to an embodiment of the present invention. It is a figure which shows the heater extinction timing judgment reference table which concerns on embodiment of this invention. It is a figure which shows the specific example of the heater extinction timing judgment reference table which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  The image forming apparatus according to the present embodiment has the following characteristics in control for fixing toner onto a transfer sheet, which is an example of a transfer medium, by residual heat of the fixing roller. In short, the present embodiment is based on the area of an unfixed area (the area of the transfer paper where the toner image transferred to the transfer paper is not yet fixed) and the temperature of the fixing roller (near temperature). The power supply to the heating unit of the fixing roller is turned off.

  For example, a judgment reference temperature indicating the temperature of the fixing roller corresponding to the area of the unfixed area of the transfer paper that can be fixed by the residual heat of the fixing roller is provided as predetermined data in association with the area of the unfixed area and detected. When the temperature of the fixing roller is equal to or higher than the judgment reference temperature corresponding to the area of the unfixed area, control is performed to turn off the heating unit, and the toner is fixed to the transfer paper with the remaining heat of the fixing roller. Hereinafter, it will be specifically described with reference to the drawings.

〔Constitution〕
FIG. 1 is a diagram illustrating a schematic configuration of an image forming process unit 3 and an engine control unit 1 of the image forming apparatus according to the present embodiment. The engine control unit 1 realizes control of the image forming process unit 3 (control unit), calculation of an area of a transfer sheet unfixed area (calculation unit), which will be described later, and timing determination (determination unit) of power supply off to the fixing heater. CPU (Central Processing Unit) 11, ROM (Read Only Memory) 12 and RAM (Random Access Memory) 13 as storage means. Reference numeral 2 schematically indicates a control command from the CPU 11 to the image forming process unit 3 and a control signal such as a response from the image forming process unit 3 (for example, a detection signal from a sensor) (hereinafter, control signal 2). Called).

  The image forming process unit 3 includes a photosensitive drum 31 that forms a toner image to be transferred to a transfer paper, a transfer roller 32 for transferring to the transfer paper, and a fixing for fixing the toner image transferred to the transfer paper. And a fixing inlet sensor 33 which is a passage detecting means for detecting that the transfer paper has entered the fixing device 34. The fixing device 34 includes a fixing roller (heating roller) 341 having a heating unit therein and a pressure roller 342. The fixing roller 341 is heated by a fixing heater that is a heating unit provided therein, for example, a halogen heater 343 that is an electric heater (hereinafter also simply referred to as a heater). Further, the fixing device 34 includes a fixing temperature detection sensor 344 that is a detection unit that detects the temperature in the vicinity of the fixing roller 341. The fixing temperature detection sensor 344 is, for example, a thermistor or a thermopile.

[Operation processing]
As described above, the fixing heater used in the fixing device of the electrophotographic image forming apparatus requires a large amount of electric power. Also, in the case of a fixing device using an electric heater such as a halogen heater as a fixing heater, the temperature of the fixing roller does not cool immediately even when the heater is turned off. It is within a temperature range in which toner can be fixed. Therefore, in this embodiment, in order to reduce the power consumption of the fixing heater, the heater is turned off before the transfer paper finishes passing through the fixing device, and fixing is performed by the residual heat of the fixing roller.

  First, the temperature control of the fixing roller that is normally performed will be described with reference to FIG. FIG. 2 is a diagram for explaining temperature control of the fixing roller. The temperature of the fixing roller 341 that is a fixing roller is controlled by the engine control unit 1. During image formation, the temperature of the fixing roller 341 is controlled so as to approach the control target temperature. The temperature control of the fixing roller 341 is controlled by turning on / off an electric heater 343 such as a halogen heater provided in the fixing roller 341 based on fixing roller temperature information obtained from the fixing temperature detection sensor 344.

  Since the temperature control of the fixing roller is controlled by turning on / off the heater, the temperature of the fixing roller generates a temperature ripple with respect to the control target temperature as time passes as shown in FIG. The temperature of the fixing roller during the temperature control of the fixing roller to the control target temperature at the time of image formation must always be equal to or higher than the temperature at which the toner image formed on the transfer paper can be fixed on the transfer paper. Further, temperature control is performed so that the lower limit of the temperature ripple is equal to or higher than the fixable temperature.

  That is, the relationship of “control target temperature> temperature ripple lower limit of fixing roller temperature> fixable temperature of toner image formed on transfer paper” is established during image formation.

  Patent Document 1 discloses “For the purpose of reducing the power consumed by the fixing heater, the printer engine control unit detects the position of the transfer paper passing through the fixing device and detects the trailing edge of the paper with a registration sensor. When the predetermined time has elapsed, the halogen heater of the fixing device is turned off before the trailing edge of the transfer paper passes through the fixing device, and the fixing time is indicated by the residual heat of the fixing roller. However, since the current fixing roller temperature that causes temperature ripple is not taken into consideration, the predetermined time is assumed assuming the area of the transfer paper unfixed area that can be fixed by the residual heat of the fixing roller in the case of the lower limit value of the temperature ripple. It is prescribed. In other words, the area that can be fixed by the residual heat of the fixing roller in the case of the lower limit value is the minimum area, and if the actual temperature of the fixing roller when the heater is off is higher than the lower limit value, fixing is possible with the residual heat Since this area is larger than the assumed area, the heater may be turned off at an earlier stage, and power consumption can be reduced by heating off at an earlier stage.

  Therefore, in the present embodiment, the heater-off timing is appropriately determined from the current temperature of the fixing roller causing the temperature ripple and the area of the unfixed area of the transfer paper that can be fixed by the residual heat of the fixing roller, thereby reducing the power consumption. Can be further reduced.

  Next, the unfixed area of the transfer paper will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view for explaining the fixed area and the non-fixed area of the transfer paper during paper passing. FIG. 4 is a schematic perspective view for explaining the fixed area and the non-fixed area of the transfer paper during paper passing. The speed at which the transfer paper advances through the image forming process section is constant, and the speed (linear speed) is v. A portion where the fixing roller 341 and the pressure roller 342 are in contact is referred to as a fixing roller nip, and a distance from the fixing roller nip to the fixing inlet sensor 33 is defined as l. Further, the width of the transfer paper in the main scanning direction is x, and the width of the sub scanning direction is y.

FIG. 4 is a schematic perspective view for explaining the fixed area and the non-fixed area of the transfer paper during paper passing. The area S of the toner image non-fixed area on the transfer paper is obtained by the following formula (1).
S = xy − (vt − l) x (1)
v: linear velocity, l: distance from the fixing roller nip to the fixing inlet sensor 33, x: width in the main scanning direction of the transfer paper, y: width in the sub-scanning direction, t: after the leading edge of the transfer paper reaches the fixing inlet sensor 33 Elapsed time

  Next, control of the fixing heater according to the present embodiment will be described with reference to the drawings. FIG. 5 is a flowchart showing a control operation process of the fixing heater according to the present embodiment. When there is an image formation request (printing request) (step S1 / Yes), the engine control unit 1 starts temperature control with the temperature of the fixing roller 341 of the fixing device being set to the control target temperature (step S2). In other words, the fixing heater is turned on to heat the fixing roller 341, and the temperature of the fixing roller 341 is brought close to the control target temperature.

  When the temperature of the fixing roller 341 reaches a prescribed temperature (fixable temperature) (step S3 / Yes), toner image formation is started on the photosensitive drum 31, and further, from the paper feed tray to the image forming process unit 3. The transfer paper starts to be conveyed (step S4).

  When the leading edge of the final transfer paper reaches the fixing entrance sensor 33 in response to the print request (step S5 / Yes), the CPU 11 of the engine control unit 1 calculates the area S of the unfixed area of the final transfer paper. Start (step S6). The area S of the unfixed area is calculated by the above formula (1).

  The CPU 11 determines the timing for turning off the fixing heater based on the calculated area S of the unfixed area of the final transfer paper (steps S7 to S9). The timing determination for fixing heater OFF will be described in detail. First, the ROM 12 stores a heater turn-off timing determination reference table in advance. FIG. 6 is a diagram illustrating a heater turn-off timing determination criterion table. The heater turn-off timing determination reference table shows the "unfixed area area" of the final transfer paper and the fixing roller that can fix the toner to the unfixed area area of the transfer paper with the residual heat of the fixing roller when the fixing heater is turned off. Is associated with “determination reference temperature” (indicated as “fixing roller temperature” in FIG. 6).

The CPU 11 determines the timing at which the heater of the fixing device is turned off using the heater turn-off timing determination reference table stored in the storage unit, for example, the ROM 12, and the information on the area S of the unfixed area of the final transfer paper calculated in step S6. To do. Not area S of the fixing area is S _{n (n} = 1,2,3 ...) in the following (FIG. 5 step S7 / Yes) and the temperature T of the fixing roller when the calculated area S of the unfixed region T _{If n} (n = 1, 2, 3...) or more (step S8 / Yes), the heater of the fixing device is turned off (step S9), and the toner image on the transfer paper is fixed by the residual heat of the fixing roller.

  Next, a specific example of the processing in steps S7 and S8 will be described below. FIG. 7 is a diagram illustrating a specific example of the heater turn-off timing determination criterion table. The ROM 12 of the engine control unit 1 stores a heater turn-off timing determination reference table shown in FIG.

For example, when the calculated area S of the unfixed area of the transfer paper is S = 140 [cm ² ], since S = 140 [cm ² ] <S ₁ = 148.50 [cm ² ], fixing at that time When the roller temperature T is T> T ₁ = 160 [° C.], the fixing heater is turned off, and the toner image on the transfer paper can be fixed by the residual heat of the fixing roller.

On the other hand, when the calculated area S of the unfixed area of the transfer paper is S = 100 [cm ² ], since S = 100 [cm ² ] <S ₄ = 103.95 [cm ² ], fixing at that time When the roller temperature T is T> T ₄ = 157 [° C.], the fixing heater is turned off, and the toner image on the transfer paper can be fixed by the residual heat of the fixing roller.

The “fixing roller temperature at that time” is the fixing roller temperature detected at the timing when the area of the unfixed area is calculated, but is not limited to exactly the same timing. For example, when the calculated S corresponds to S <S _1, it is sufficient if the timing is shifted so as to correspond to S <S ₂ when the fixing roller temperature is detected.

  As described above, in the fixing heater control of the image forming apparatus according to the above-described embodiment, it is possible by turning off the fixing heater when the temperature is equal to or higher than the determination reference temperature corresponding to the area of the unfixed area of the final transfer paper. As much as possible, power consumption can be reduced.

  In the above embodiment, a fixing device using a halogen heater as a fixing heater as a heat source has been described as an example. However, the present invention is also effective in a carbon heater, a ceramic heater, an IH (Induction Heating) method, and an on-demand fixing device. Needless to say.

  As another embodiment of the present invention, it is conceivable that the storage means includes a plurality of determination criterion tables, and the table to be referred to varies depending on the surrounding environment, the state of the fixing device, the type of transfer paper, and the like. For example, depending on the thickness of the transfer paper, the density of the transfer paper, the amount and type of toner image formed on the transfer paper, the transfer speed of the transfer paper, the heat capacity of the fixing roller of the fixing device, the ambient temperature, the ambient humidity, etc. Make them different.

  Note that the program for the CPU to execute the processing shown in the flowcharts of the drawings constitutes a program according to the present invention. As a recording medium for recording the program, a semiconductor storage unit, an optical and / or magnetic storage unit, or the like can be used. By using such a program and a recording medium in a system having a configuration different from that of each of the above-described embodiments and causing the CPU to execute the program, substantially the same effect as the present invention can be obtained.

  Although the present invention has been specifically described above based on the preferred embodiments, it is needless to say that the present invention is not limited to the above-described ones and can be variously modified without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 Engine part 2 Control signal 3 Image formation process part 11 CPU
12 ROM
13 RAM
31 Photosensitive drum 32 Transfer roller 33 Fixing inlet sensor 34 Fixing device 341 Fixing roller (heating roller)
342 Pressure roller 343 Electric heater (fixing heater)
344 Fixing temperature detection sensor

Japanese Patent Laid-Open No. 08-171307

Claims (10)

A fixing control device for fixing a toner image transferred to the transfer medium by passing the transfer medium between a fixing roller provided with a heating unit and a pressure roller,
A calculating means for calculating an area of an unfixed area of the transfer medium passing between the fixing roller and the pressure roller;
Detecting means for detecting a temperature near the fixing roller;
Control means for turning off the power supply to the heating unit based on the area of the unfixed region and the temperature near the fixing roller;
A fixing control device comprising: Provided with passage detection means for detecting that the transfer medium has passed upstream from the position where the fixing is performed;
The calculation means includes distance information l from the position of the passage detection means to a position where the fixing is performed, time information t after the leading edge of the transfer medium passes through the passage detection means, and conveyance of the transfer medium. 2. The fixing according to claim 1, wherein the area of the unfixed area is calculated by the following formula based on the speed information v, the information x on the width in the main scanning direction of the transfer medium, and the information y on the width in the sub scanning direction. Control device.
S = xy − (vt − l) x Storage means for storing a judgment reference table in which the area of the unfixed area and the judgment reference temperature are associated with each other;
Determination means for determining whether a temperature near the fixing roller is equal to or higher than a determination reference temperature corresponding to an area of the unfixed region with reference to the determination reference table;
With
The control unit turns off the power supply to the heating unit when the determination unit determines that the temperature near the fixing roller is equal to or higher than a determination reference temperature corresponding to the calculated area of the non-fixed region. The fixing control apparatus according to claim 1, wherein:   4. The fixing control device according to claim 1, wherein the determination reference temperature is a lower limit temperature at which an area of the unfixed area can be fixed by residual heat of the fixing roller. 5.   The fixing control device according to claim 3, wherein the storage unit includes a plurality of the determination criterion tables, and the reference table varies depending on the situation.   The situation is at least one of the thickness of the transfer medium, the density of the transfer medium, the toner amount and type of the toner image formed on the transfer medium, the transfer speed of the transfer medium, the heat capacity of the fixing roller, the ambient temperature, and the ambient humidity. The fixing control device according to claim 5, wherein the fixing control device is in one or more situations.   An image forming apparatus comprising the fixing control device according to claim 1. A fixing control method of a fixing control device for fixing a toner image transferred to the transfer medium by passing the transfer medium between a fixing roller provided with a heating unit and a pressure roller,
Calculating the area of the unfixed area of the transfer medium passing between the fixing roller and the pressure roller;
Detecting the temperature in the vicinity of the fixing roller;
Turning off the power supply to the heating unit based on the area of the unfixed area and the temperature near the fixing roller;
A fixing control method comprising: A fixing control program of a fixing control device for fixing a toner image transferred to the transfer medium by passing the transfer medium between a fixing roller provided with a heating unit and a pressure roller,
A process of calculating the area of the unfixed area of the transfer medium passing between the fixing roller and the pressure roller;
A process for detecting the temperature near the fixing roller;
A process of turning off the power supply to the heating unit based on the area of the unfixed region and the temperature near the fixing roller;
A fixing control program for causing a computer to execute the above.   A computer-readable recording medium for recording the process of the fixing control program according to claim 9.

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