WO2019031674A1

WO2019031674A1 - Range based operation of image forming apparatus

Info

Publication number: WO2019031674A1
Application number: PCT/KR2018/003007
Authority: WO
Inventors: Jong Choon Kim; Jeong Seob Kim
Original assignee: HP Printing Korea Co Ltd
Current assignee: HP Printing Korea Co Ltd
Priority date: 2017-08-08
Filing date: 2018-03-14
Publication date: 2019-02-14
Anticipated expiration: 2020-02-08
Also published as: KR20190016288A

Abstract

An image forming apparatus is provided. The image forming apparatus includes a paper conveying unit configured to supply a printing paper to an image forming unit along a conveying path of the printing paper, a heating roller heated through a heater unit, a sensor configured to detect a temperature of a central surface region of the heating roller, and a processor configured to, in response to a printing paper having a narrower width than a general printing paper being printed in the image forming apparatus, estimate a temperature of a side surface region of the heating roller using the detected temperature of the central surface region and a pre-stored relation table and control a printing speed of the image forming unit based on the estimated temperature of the side surface region.

Description

RANGE BASED OPERATION OF IMAGE FORMING APPARATUS

Image forming apparatuses may refer to apparatuses which print printing data generated in a printing control terminal apparatus such as a computer. The image forming apparatus may include a printer, a copier, a facsimile, a multifunction peripheral (MFP) in which functions of the printer, the copier, and the facsimile are integrated into one apparatus, and the like.

The image forming apparatuses may form an image through various methods. An electrophotography has been used as one of the various image forming methods. The image forming apparatus employing the electrophotography such as a copier or a printer may form an image by entirely charging a drum type photoreceptor, forming an electrostatic latent image on the photoreceptor by exposing the photoreceptor through light controlled according image information, forming a visible image (toner image) through selective adsorption of toner with the electrostatic latent image, transferring the toner image into a recording medium, and fusing the toner image to the recording medium by allowing the recording medium into which the toner image is transferred to pass through a fuser.

The image forming apparatuses may employ a configuration for finally fusing the image to a printing paper. The configuration may refer to a fuser. In general, the fuser may be configured of a heating roller including a heater and a pressing roller which is in pressure contact with the heating roller and is disposed to be rotatably driven.

The above and/or other aspects of the present invention will be more apparent by describing certain embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment;

FIG. 2 is a detailed diagram illustrating a configuration of an image forming apparatus according to an embodiment;

FIG. 3 is a configuration diagram illustrating an image forming unit of FIG. 1 according to an embodiment;

FIGS. 4 and 5 are diagrams illustrating a configuration of a fuser according to an embodiment;

FIG. 6 is a diagram illustrating a temperature distribution of a central surface region and a side surface region of a fuser in printing of a narrow paper according to an embodiment;

FIG. 7 is a diagram illustrating a dual lamp according to an embodiment;

FIG. 8 is a diagram illustrating a temperature distribution of a side surface region of a fuser over time in printing of a narrow paper according to an embodiment;

FIG. 9 is a diagram illustrating a temperature rising curve of a side surface region of a fuser according to a condition according to an embodiment;

FIG. 10 is a diagram illustrating a temperature rising curve of a side surface region of a fuser according to an embodiment;

FIG. 11 is a diagram illustrating a temperature rising curve of a side surface region of a fuser according to an inter-paper distance according to an embodiment;

FIG. 12 is a diagram illustrating a temperature variation of a side surface region of a fuser according to an initial temperature according to an embodiment;

FIG. 13 is a diagram illustrating a temperature falling curve of a side surface region of a fuser according to an embodiment;

FIG. 14 is a diagram illustrating a temperature falling curve according to an operation state of a fuser according to an embodiment;

FIG. 15 is a diagram illustrating conversion output performance comparison according to an embodiment;

FIG. 16 is a diagram illustrating a relation table stored in a storage unit according to an embodiment;

FIG. 17 is a flowchart explaining an operation of determining an output condition in printing according to an embodiment;

FIG. 18 is a flowchart explaining an operation of estimating a temperature of a side surface region of a fuser in printing according to an embodiment

FIG. 19 is a flowchart explaining an operation of calculating a temperature of a side surface region of a fuser in a standby mode according to an embodiment; and

FIG. 20 is a flowchart explaining a temperature estimation method of a heating roller according to an embodiment.

Hereinafter, embodiments of the invention will be described more fully with reference to the accompanying drawings, in which the embodiments of the invention are shown to understand a configuration and an effect of the invention. This invention may, however, be embodied and modified in many different forms and should not be construed as limited to the embodiments set forth herein. To more clearly describe features of the embodiments, detailed description for contents widely known to those skilled in the art will be omitted for clarity.

It will be understood that when an element (for example, a first element) is referred to as being “coupled with/to” or “connected to” another element (for example, a second element), it can be directly connected or coupled to the other element or intervening elements (for example, third elements) may be present. Unless otherwise described, any portion including any element may refer to the portion further including other elements not excluding the other elements.

In the specification, the term “image forming job” may refer to various jobs (for example, print, scan, or facsimile) related to an image such as image formation or generation/storage/transmission of an image file and the term “job” may refer to an image forming job as well as a series of processes required for performing the image forming job.

The term “image forming apparatus” may refer to an apparatus which prints printing data generated in a terminal apparatus such as a computer in a recording paper. For example, the image forming apparatus may include a printer, a copier, a facsimile, a multifunction peripheral (MFP) in which functions of the printer, the copier, and the facsimile are integrated into one apparatus, and the like. The image forming apparatus may refer to any apparatus which may perform an image forming job such as the printer, the copier, and the facsimile, the MFP, a display apparatus, and the like.

The term “hard copy” may refer to an operation which outputs am image to a printing medium such as paper and the term “soft copy” may refer to an operation which outputs an image to a display apparatus such as a television (TV) or a monitor.

The term “content” may refer to all types of data which are to be subjects for image forming jobs such as photo, an image, or a text file.

The term “printing data” may refer to data converted into a format printable in a printer. For example, in response to direct printing being supported in the printer, a file itself may be the printing data.

The term “user” may refer to a person who performs an operation related to an image forming job using an image forming apparatus or a device coupled to the image forming apparatus in a wireless or wired form. The term “manager” may be a person who has authority to access all functions of the image forming apparatus and a system. The “user” and the “manager” may be the same person.

Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment.

Referring to FIG. 1, an image forming apparatus 100 according to an embodiment may include a processor 110 and a fuser 200.

The processor 110 may control an overall operation of the image forming apparatus 100 and include a processor such as a central processing unit (CPU). The processor 110 may control other configurations included in the image forming apparatus 100 to perform an operation corresponding to a user input received through an operation input unit (see 140 of FIG. 2).

For example, the processor 110 may execute a program stored in a storage unit (see 150 of FIG. 2), read a file stored in a memory, or store a new file in the memory.

The processor 110 may estimate a temperature of a side surface region of a heating roller using a detected temperature of a central surface region of the heating roller and a pre-stored relation table and control a printing speed of an image forming unit based on the estimated temperature of the side surface region in response to a printing paper having a narrower width than a general printing paper being printed in the image forming apparatus.

A method of controlling a printing speed of an image forming unit may include a method of controlling driving speed of a fuser and a method of controlling an inter-paper distance.

The processor 110 may determine the printing speed and the inter-paper distance corresponding to the estimated temperature of the side surface region and control a paper conveying unit and the image forming unit to move the printing paper to a conveying path based on the determined printing speed and inter-paper distance.

For example, the processor 110 may update a counter value stored in the storage unit according to a printing job and estimate the temperature of the side surface region of the heating roller based on estimated temperature information corresponding to the counter value in the relation table.

In this example, the counter value may refer to the accumulated number of copies. The term “update” may refer to an operation which stores the accumulated number of copies as a current accumulated value for the number of copies in the storage unit. The number of currently printed copies may be determined based on the stored counter value and simultaneously the temperature variation according to the accumulated number of copies may be estimated. In general, as the accumulated number of copies is increased, the temperature of the heating roller may be increased.

The processor 110 may control the paper conveying unit to provide the printing paper based on the inter-paper distance corresponding to the counter value.

The processor 110 may count a standby time of a fuser and estimate the current temperature of the side surface region based on the temperature of the side surface region estimated during a printing job and the counter value in response to the printing job being terminated.

In general, in response to the printing job being terminated, the heat supply to the heating roller may be interrupted and the surface temperature of the heating roller may be reduced. Accordingly, the temperature reduction over time may be determined by measuring the standby time of the fuser. The standby mode of the fuser may merely refer to another mode according to idle speed in addition to a stop mode and detailed description thereof will be made later.

The processor 110 may estimate the temperature of the side surface region of the heating roller according to operation states of a plurality of heating units. The plurality of heating units may refer to a plurality of heating lamps constituting the heating roller. The processor 110 may heat the heating roller through the plurality of heating units by dividing the heating roller into the central surface region and the side surface region and the processor 110 may control the operations of the central surface region and the side surface region.

The fuser 200 may fuse charged toner on the printing paper to the printing paper by applying heat and pressure to the printing paper. For example, the fuser 200 may be configured of the heating roller 210 heated through a heater unit and a sensor 230 configured to detect the temperature of the central surface region of the heating roller 210. Detailed configuration and operation of the fuser 200 will be described later with reference to FIG. 4.

The heating roller 210 may be heated to a preset temperature and provide the heat to the printing paper so that the charged toner on the printing paper is easily fused to the printing paper. For example, a heater unit (see 211 of FIG. 4) may be located in the inside of a cylindrical base member of the heating roller 210 and an elastic layer and a release layer may be disposed on the base member.

The heating roller 210 may include a plurality of heating units. The plurality of heating units will be described in detail with reference to FIG. 7.

The sensor 230 may detect the temperature of the central surface region of the heating roller 210. For example, the central surface region may be a paper-passing region which the printing paper passes therethrough. In this example, the central surface region may be the paper-passing region and thus the sensor 230 may be a non-contact temperature sensor which is in non-contact with the heating roller 210 to prevent image failure due to sensor contact.

As described above, referring to FIG. 1, through one sensor, the temperature of the central surface region may be detected and the temperature of the side surface region may be estimated. The printing speed may be controlled based on the estimated temperature of the side surface region. For example, the printing paper may be printed at the printing speed corresponding to the temperature of the side surface region and thus the efficient printing operation may be performed.

The image forming apparatus 100 according to the embodiment may estimate the temperature of the side surface region of the heating roller through one sensor as described above, and thus the side surface region of the heating roller may be controlled through only one sensor. In response to the printing job being performed on the narrow printing paper according to a condition set through the user, the printing speed may not be set to be lowered and the printing speed may be controlled based on the temperature of the side surface region of the heating roller.

FIG. 2 is a detailed block diagram illustrating a configuration of an image forming apparatus according to an embodiment.

Referring to FIG. 2, the image forming apparatus 100 according to an embodiment may include the processor 110, a communication interface 120, a display 130, the operation input unit 140, the storage unit 150, an image forming unit 160, and a paper conveying unit 170.

The processor 110 and the fuser 200 may have the same configuration and operation as those of the processor 110 and the fuser 200 of FIG. 1 and thus overlapping description thereof will be omitted.

The communication interface 120 may be configured to couple the image forming apparatus 100 to an external apparatus. For example, the communication interface 120 may couple the image forming apparatus 100 to the external apparatus using a local area network (LAN) and an Internet network. In another example, the communication interface 120 may couple the image forming apparatus 100 to the external apparatus using a universal serial bus (USB) port and a wireless module. In this example, the wireless module may be WiFi, WiFi Direct, near field communication (NFC), Bluetooth, and the like.

The communication interface 120 may receive a job execution command from a host apparatus (not shown). The communication interface 120 may receive and transmit data related to the job execution command. For example, in response to the job execution command of the user being a print command for a specific file, the communication interface 120 may receive the printing file. In this example, the printing file may be a printer language of data such as postscript (PS) or printer control language (PCL). The printing file may be a file itself such as PDF, XPS, BMP, or JPG.

In response to the job execution command of the user being a scan command, the communication interface 120 may transmit scan data as a result of a scanning job to a host apparatus (not shown) or another storage site (not shown).

The communication interface 120 may inform a host apparatus (not shown) of a processing state for the requested job command.

The display 130 may display various types of information supported in the image forming apparatus 100. For example, the display 130 may be implemented with a monitor such as a liquid crystal display (LCD) or a cathode-ray tube (CRT). In another example, the display 130 may be implemented with a touch screen which simultaneously performs a function of the operation input unit 140 to be described later.

The display 130 may display a screen for controlling a function of the image forming apparatus 100. The display 130 may display an error occurring in the image forming apparatus 100. For example, in response to the fuser being overheated, the display 130 may display the occurrence of the error.

The operation input unit 140 may include a plurality of function keys which the user may set or select various functions supported in the image forming apparatus 100 therethrough. For example, the operation input unit 140 may be implemented with a device such as a mouse or a keyboard. In another example, the operation input unit 140 may be implemented with a touch screen which simultaneously perform the function of the display 130.

The storage unit 150 may store a printing file. For example, the storage unit 150 may store the printing file received through the communication interface 120. The storage unit 150 may store a target temperature of the central surface region and a target temperature of the side surface region required for fusing or may store a look-up table having a plurality of surface temperature ranges and target temperatures of a first heater roller and a second heater roller according to the plurality of surface temperature ranges. The storage unit 150 may be implemented with a storage medium inside the image forming apparatus 100 or an external storage medium, for example, a removable disc including a USB memory, a web server through a network, and the like.

The image forming unit 160 may print printing data. For example, the image forming unit 160 may perform a job such as parsing or rendering on the printing data, transfer toner corresponding to the rendered data to the printing paper through an electrophotographic manner, fuse the toner transferred into the printing paper using the fuser 200, and output the toner-fused printing paper. The detailed configuration and operation of the image forming unit 160 will be described later with reference to FIG. 3.

The paper conveying unit 170 may perform a job for conveying a paper fed to the fuser and the printing paper supplied to the fuser may be fed at certain intervals. For example, the paper conveying unit may serve to control the printing paper fed to the fuser. The inter-paper distance may be maintained by adjusting a paper feeding distance constantly.

In this example, the inter-paper distance of a printing paper may be controlled through a control command. For example, in response to a command for increasing the inter-paper distance being received from the processor, the paper printing unit (image forming unit) may receive the command and control the distance between the printing papers.

FIG. 3 is a configuration diagram illustrating the .image forming unit of FIG. 1 according to an embodiment.

Referring to FIG. 3, the image forming unit may include a photosensitive drum 161, a charger 162, an exposure unit 163, a developing unit 164, a transfer unit 165, and a fuser 200.

The image forming unit may further include a paper-feed unit (not shown) configured to supply a recording medium P. An electrostatic latent image may be formed in the photosensitive drum 161. The photosensitive drum 161 may be referred to as a photosensitive drum or a photosensitive belt, and the like according to a type thereof.

Hereinafter, for clarity, only a configuration of the image forming unit 110 corresponding to one color will be exemplarily described, but this is not limited thereto. For example, the image forming unit may be implemented to include a plurality of photosensitive drums 161, a plurality of chargers 162, a plurality of exposure unit 163, and a plurality of developing units 164 corresponding to a plurality of colors.

The charger 162 may charge a surface of the photosensitive drum 161 with a uniform potential. The charger 162 may be implemented in a form of a corona charger, a charge roller, a charge brush, and the like.

The exposure unit 163 may form an electrostatic latent image in the surface of the photosensitive drum 161 by changing the surface potential of the photosensitive drum 161 according to image information to be printed. For example, the exposure unit 163 may form the electrostatic latent image by radiating light modulated according to the image information to be printed into the photosensitive drum 161. This type of exposure unit 163 may be referred to as a light radiator and the like and a light emitting diode (LED) may be used as a light source.

The developing unit 164 may receive a developing agent in the inside thereof and develop the electrostatic latent image as a visible image by supplying the developing agent to the electrostatic latent image. The developing unit 164 may include a developing roller 167 configured to supply the developing agent to the electrostatic latent image. For example, the developing agent may be supplied to the electrostatic latent image formed in the photosensitive drum 161 from the developing roller 167 through a developing electric field formed between the developing roller 167 and the photosensitive drum 161.

The visible image formed in the photosensitive drum 161 may be transferred into the recording medium P through a transfer unit 165 or an intermediate transfer belt (not shown). The transfer unit 165 may transfer the visible image into the recording medium, for example, through an electrostatic transfer method. The visible image may be attached to the recording medium P through electrostatic attraction.

For example, the developing agent may be used whenever the image forming job is performed and the developing agent may be exhausted in response to the developing agent being used for a fixed time or more. In this example, a unit (for example, the developing unit 164) configured to store the developing agent itself needs to be newly replaced. The parts or elements replaceable in the using process of the image forming apparatus may refer to a consumable unit or a replaceable unit. A memory (or customer replaceable unit monitoring memory (CRUM) chip) may be attached to the consumable unit to suitably manage the consumable unit.

FIGS. 4 and 5 are diagrams illustrating a configuration of the fuser 200, wherein FIG. 4 is a diagram illustrating a configuration of the fuser 200 when viewed in a side and FIG. 5 is a diagram illustrating an arrangement form of the sensor 230 configured to detect a temperature of the heating roller 210.

Referring to FIGS. 4 and 5, the fuser 200 may fuse the charged toner on the printing paper to the printing paper by applying heat and pressure to the printing paper. For example, the fuser 200 may be configured of the heating roller 210, the pressing roller 22, and the sensor 230.

The heating roller 210 may be heated to a preset temperature and may provide the heat to the printing paper so that the charged toner on the printing paper may be easily fused.

The pressing roller 220 may provide high pressure to the printing paper so that the charged toner on the printing paper is easily fused to the printing paper. For example, the heating roller 210 may be attached to a surface of the pressing roller 220 and thus a fixed nip may be maintained between the pressing roller 220 and the heating roller 210. An elastic layer and a release layer may be disposed on a cylindrical core of the pressing roller 220.

The heater unit 211 may be disposed in the center on the basis of a direction perpendicular to a moving direction of the printing paper (for example, an axial direction of the heating roller 210). For example, the heater unit 211 may have a length corresponding to a narrow length of an A4 paper.

The paper-passing region may refer to a portion of the printing paper which is in contact with the fuser in response to a general printing paper being printed and the paper-non-passing region may refer to a portion of the printing paper which is in noncontact with the fuser in response to the general printing paper being printed.

FIG. 6 is a diagram illustrating a temperature distribution of a central region 610 and a side surface region 620 of the fuser 200 in narrow width printing. The phrase “narrow width printing” may refer to an operation of printing a printing paper having a narrower width than a general printing paper.

For example, the fuser 200 may be configured of one lamp 640 and one sensor 230.

While the paper passes through the heating roller 210 in printing, the heat of the heating roller 210 is transmitted to the paper. In the narrow paper printing, the heat in only a portion (for example, 50 to 60 %) of the entire width of the heating roller 210 being transmitted to the printing paper and the heat in the side surface region 620 may be continuously accumulated. For example, in response to one sensor 230 being disposed in the central surface region 610, the heat in the central surface region 610 may be drained to the paper and thus the temperature in the central surface region 610 may be lower than that of the side surface region 620. In this example, in response to the heating roller 210 being controlled through only the sensor 230 in the central surface region 610, the heat may be further accumulated in the side surface region 620.

Tvs in FIG. 6 may mean that temperature of the side surface region 620 is estimated may not mean that actually, a sensor is physically present in the side surface region 620.

FIG. 7 is a diagram illustrating a dual lamp according to an embodiment. For example, a heating roller 210’ of the image forming apparatus may be configured of a first lamp 212 and a second lamp 213. The first lamp 212 and the second lamp 213 may refer to a plurality of heating units.

Referring to FIG. 7, to prevent the temperature of the side surface region 620 from being increased, the fuser may heat the printing paper using the first lamp 212 and the second lamp 213 in response to the general printing paper being output and heat the printing paper only using the second lamp 213 in response to the narrow printing paper being printed.

FIG. 8 is a diagram illustrating a temperature distribution over time in response to a narrow printing paper being printed. For example, the graph in FIG. 8 may be obtained through narrow width printing experiment.

Referring to FIG. 8, a temperature 810 of the central surface region 610 over a time that the printing operation is performed is illustrated. A temperature 820 of the side surface region 620 over the time that the printing operation is performed is illustrated.

A temperature variation in the temperature 810 of the central surface region 610 may be repeatedly maintained according to the printing of the narrow printing paper. However, the temperature 820 of the side surface region 620 is continuously increased and reach the limit. In the graph, the time elapsed to a saturation temperature, rising speed, and the like may be changed according to various line speeds of the image forming apparatus.

FIG. 9 is a diagram illustrating a temperature rising curve of the side surface region 620 according to a condition. The graph of FIG. 9 illustrates temperatures measured through different control methods and a temperature 910 in a first condition, a temperature 920 in a second condition, and a temperature 930 in a third condition are illustrated. Steps in FIG. 9 may refer to conditions.

For example, Tstep1 in FIG. 9 may refer to a time operating in the first condition and step1 may refer to an operation in the first condition.

In this example, the condition may refer to a printing speed predetermined by the user or a printing data processing rate. The printing speed may be changed according to the conditions and thus a temperature rising rate of the side surface region may be changed according to the condition.

For example, the first condition may be a condition that the printing speed is fastest and thus the temperature 910 in the first condition may be fastest increased per unit time.

The second condition may be a condition that the printing speed is middle and thus it can be seen that increase of the temperature 920 in the second condition per unit time is smaller than increase of the temperature 910 in the first condition per unit time. Similarly, the third condition may be a condition that the printing speed is slowest.

For example, through control of the processor 110, the heating roller may first operate in the first condition and then the heating roller may operate in the second condition in response to the temperature reaching the preset first temperature. Similarly, the processor 110 may control the heating roller to operate in the third condition in response to the temperature reaching the preset second temperature while the heating roller operates in the second condition.

In this example, the condition that cannot reach the saturation temperature may be determined through an experiment in advance so that the printing is not intermitted.

Tstep1 may refer to a time operating in the first condition, Tstep2 may refer to a time operating in the second condition, and Tstep3 may refer to a time operating in the third condition. The relationship among Tstep1, Tstep2, and Tstep3 will be described later with reference to FIG. 10.

The temperature variation according to a condition may be expressed in an exponential function through the following equation 1 and a plurality of the number of copies and pieces of estimated temperature information corresponding to the plurality of the number of copies may be calculated based on the following Equation 1.

[Equation 1]

Here,

is the temperature of the central surface region detected through the sensor, x is the number of copies, m and K are constant values according to an operation condition, and T is the temperature of the side surface region of the heating roller.

In Equation 1, x is the number of copies, but x is not limited to the number of copies and x may be time. For example, the number of copies output per minute is constant in the image forming apparatus in which a printing paper is printed at constant speed and thus the number of copies may be in proportion to the time. Accordingly, x in Equation 1 may refer to the number of copies or the time.

K and m in Equation 1 may be constant values calculated through experimental measurement values. For example, the image forming apparatus may be set to operate at a specific operation speed and K and M may be measured through experiment. The temperature in the side surface region 620 according to the number of copies may be directly measured and experimental data between the measured temperature of the side surface region 620 and the number of copies may be obtained. An empirical formula may be determined by performing curve fitting on the experimental data.

The term “curve fitting” may refer to a process of, in response to the measurement values having a constant tendency, expressing the measurement values in an equation form by determining the most fit curve to the constant tendency.

The operation of determining an empirical formula by performing curve fitting on the experimental data may refer to an operation of specifying K and m in Equation 1. In response to K and m being specified as described above, the temperature of the side surface region 620 may be estimated as a value calculated through the empirical formula in the printing speed set by the user.

The temperature rising curve of the fuser may be changed according to the printing speed, the inter-paper distance, and a size and a thickness of the printing paper.

FIG. 10 is a diagram illustrating a temperature rising curve of the side surface region 620 according to an embodiment. Unlike FIG. 9 that illustrates the temperature variations according to the operation conditions, FIG. 10 illustrates a process of changing an operation condition to a first condition, a second condition, and a third condition according to a preset temperature over time in the processor 110.

Referring to FIG. 10, the first condition may be operated during a time that seven pieces of paper are printed and the time required may be 24.7 seconds and the second condition may be operated during a time that seven pieces of paper are printed and the time required may be 28 seconds. Next, the temperature may be maintained by changing the operation condition to the third condition.

This may refer to an operation of controlling a printing operation without intermission by coupling operation times according to operation conditions of Tstep1, Tstep2, and Tstep3 described above in FIG. 9.

FIG. 11 is a diagram illustrating a temperature rising curve of the side surface region 620 according to the inter-paper distance according to an embodiment. In FIG. 11, the temperature variation may be compared by constantly keeping the line speed to 55 % and controlling the inter-paper distance.

Referring to FIG. 11, the temperature variation according to printing may be compared by differently setting the inter-paper distance to 85 mm, 130 mm, and 227 mm. In response to the inter-paper distance being 85 mm, a temperature 1110 is fast increased.

It can be seen in FIG. 11 that through comparison between a temperature 1120 in the inter-paper distance of 130 mm and a temperature 1130 in the inter-paper distance of 227 mm, a temperature variation changed per unit time may be reduced as the inter-paper distance is increased.

Accordingly, it can be seen in FIG. 11 that as the inter-paper distance is reduced, the temperature of the side surface region 620 may be abruptly changed.

FIG. 12 is a diagram illustrating a temperature variation according to an initial temperature according to an embodiment.

It can be seen from FIG. 12 that even in response to initial temperatures being different, the quantity of heat and a coefficient of convection transfer (cooling rate) are constant in the same line speed and inter-paper distance and thus the temperature rising curves are coincide with each other.

For example, a curve that the temperature rises to 20 degrees until t* seconds in response to the temperature being measured by setting the initial temperature to 0 (zero) degree (1210) is coincide with a curve of the temperature in response to the temperature being measured by setting the initial temperature to 20 degrees (T*) (1220).

FIG. 13 is a diagram illustrating a temperature falling curve 1310 of the side surface region 620 according to an embodiment. FIG. 13 illustrates a cooling temperature of the side surface region 620 over time after the printing job is terminated.

The plurality of the number of copies and the pieces of estimated temperature information corresponding to the plurality of the number of copies may be calculated based on the following equation 2.

[Equation 2]

Here,

is the temperature of the heated central surface region a point of printing termination time,

is a time that the fuser is stopped, m and K are constant values according to a standby mode of the fuser, and T is the temperature of the side surface region of the heating roller.

K and m in Equation 2 may be constant values obtained through the experimental measurement value. For example, an experiment which obtains the temperature of the side surface region 620 may be performed while the fuser is idling at a specific speed. The temperature of the side surface region 620 over time may be directly measured and the experimental data between the measured temperature of the side surface region 620 and the time may be obtained. The empirical formula may be determined by performing curve fitting on the experimental data.

The term “curve fitting” may refer to a process of, in response to measurement values having a constant tendency, expressing the measurement values in an equation form by determining the most fit curve to the constant tendency.

The operation of determining an empirical formula by performing curve fitting on the experimental data may refer to an operation of specifying K and m in Equation 1. In response to K and m being specified as described above, the temperature of the side surface region 620 may be estimated as a value calculated through the empirical formula in the same mode as an operation set by the user.

FIG. 14 is a diagram illustrating a temperature falling curve according to an operation state of the fuser 200 according to an embodiment.

In FIG. 14, the operation state may refer to the standby mode of the fuser and a comparison result of a temperature 1410 in response to the fuser being idling at a line speed of 100 %, a temperature 1420 in response to the fuser being idling at a line speed of 55 %, a temperature 1430 in response to the fuser being idling at a line speed of 45 %, a temperature 1440 in response to the fuser being idling at a line speed of 33 %, and a temperature 1450 in response to the fuser being stopped is illustrated.

In general, in response to the idle speed being increased, the temperature falling width per unit time may be largely increased. Accordingly, a difference between the temperature 1410 in response to the fuser being idling at the line speed of 100 % and the temperature 1450 in response to the fuser being stopped may be largest.

The operation state of the fuser may have various states such as a standby mode other than the mode that the fuser idles at various line speeds and the stop mode and thus the temperature falling curve according to the operation state of the fuser may be derived from Equation 2 described above.

The temperature falling curve of the fuser may be changed according to the printing speed, the inter-paper distance, and the size and thickness of the printing paper.

FIG. 15 is a diagram illustrating conversion output performance comparison result according to an embodiment.

In FIG. 15, a comparison result of a conversion output performance 1530 in response to the line speed being changed to 22 pages per minute (ppm), 15 ppm, and 8 ppm, a conversion output performance 1520 in response to the line speed being changed to 17 ppm, 15 ppm, and 12 ppm, and a conversion output performance 1510 in response to the line speed being fixed to 4 ppm is illustrated.

The conversion output performance 1530 in response to the line speed being changed to 22 ppm, 15 ppm, and 8 ppm is maintained to at high ppm until first 30 seconds, but the conversion output performance 1530 has to be maintained at low ppm after 30 seconds due to abrupt temperature rise and the like.

Accordingly, in the user’s point of view, it may be further efficient to select “the conversion output performance 1520 in response to the line speed being changed to 17 ppm, 15 ppm, and 12 ppm”, that the printing output is persistently maintained at the same speed, in consideration of the effect such as output speed change due to the change of line speed and noise according to the output speed change.

The user may store the relation table illustrated in FIG. 16 by analyzing the graph.

FIG. 16 is a diagram illustrating the relation table stored in a storage unit according to an embodiment. The relation table may have setting values different according to the inter-paper distance and may be divided into a first condition step1, a second condition step2, a third condition step3, and the like according to the inter-paper distance.

The printing paper may be divided into a narrow printing paper and a general printing paper according to a size and the printing paper may be divided into a thin printing paper Thin, a plain printing paper Plain, a thick printing paper Thick, and the like according to a thickness. The estimated temperature values of the side surface region may be changed according to the size and thickness of the printing paper.

In FIG. 16, the division according to the condition (e.g.step1, step2, step3) may be made according to the inter-paper distance and the setting values may be divided based on factors affecting the printing speed, for example, the operation condition according to the type of the relation table.

The relation table and a counter value for the number of copies may be stored in the storage unit and the plurality of the number of cores and the pieces of estimated temperature information corresponding to the plurality of the number of copies may be included in the relation table. The relation table may further include pieces of inter-paper distance information corresponding to the plurality of the number of copies.

The plurality of the number of copies in the relation table may be divided into a plurality of groups and the plurality of groups may have pieces of inter-paper distance information different from each other.

For example, the temperature may be differently estimated according to the thickness of the printing paper (for example, the thin printing paper Thin, the plain printing paper Plain, and the thick printing paper Thick) in the first condition that the inter-paper distance is 0 (zero) in response to the size of the printing paper being a narrow printing paper. The group may be designated according to the size of the printing paper in response to the printing paper being a narrow printing paper.

The group may be used to indicate the size of the printing paper and the group may indicate a printing paper having a specific size or the group may refer to a specific range.

The narrow printing paper may refer to a printing paper having a narrower width than the general printing paper and the narrow printing paper may be determined in the image forming apparatus. For example, the user may determine the narrow width range of the printing paper which is to be determined as the narrow printing paper in the image forming apparatus, by setting a specific size in advance. In this example, the user may determine the narrow width range of the printing paper to 70 % or less of the basic printing paper or to 15 cm or less in a lateral width of the basic printing paper.

For example, the temperature of the side surface region 620 may be determined through a counter value for determining the accumulated number of copies. For example, in response to the counter value being increased, the temperature of the side surface region 620 may also be increased.

In the relation table, Tstep may correspond to a value for calculating the temperature and the value of the general temperature may be obtained by dividing Tstep by 1000. For example, in response to Tstep being 130000, the temperature may refer to 130 degrees. In response to the unit of temperature in the relation table being expressed in degree Celsius, the temperature may be stored as 130.

The inter-paper offset in the related table may refer to a value indicating a distance, for example, cm, mm, and like.

The process of calculating the relation table may include measuring temperature data of the side surface region 620 according to the operation condition through experiments, calculating an empirical formula by finally performing curve fitting on the measured temperature data, and calculating the relation table that maps the temperature of the side surface region 620 to the number of copies or time based on the empirical formula corresponding to the condition through various experiments.

In relation to Equation 1, the K and m values may be different in step1, step2, and step3 and thus the K and m values may have different constant values according to the steps.

The relation table between the number of copies and the temperature of the side surface region 620 may be stored in the storage unit after the empirical formula is derived and the processor 110 may control the printing speed using the stored relation table.

The estimated temperature information may be changed according to at least one of the size and thickness of the printing paper.

The relation table according to the number of copies may be changed according to the image forming apparatus, the user, and the like and the inter-paper distance according to the condition may also be changed according to an operation of the user.

Referring to FIG. 16, in response to a thin printing paper Thin being selected in a paper size of Group1, the image forming apparatus may be controlled by setting the inter-paper offset to 0 (zero) until the accumulated number of copies is 7, setting the inter-paper offset to 46 until the accumulated number of copies is 8 to 13, and setting the inter-paper offset to 142 after the accumulated number of copies is 14.

FIG. 17 is a flowchart explaining an operation of determining an output condition in printing according to an embodiment.

First, Tvs may indicate the temperature value of the side surface region 620. Tvs,init may refer to the temperature of the central surface region 610 measured through the sensor 230 and n may indicate the accumulated number of copies.

In response to power being applied to the image forming apparatus, the processor may detect the temperature of the central surface region 610 through the sensor 230 and estimate the temperature of the side surface region 620 using the detected temperature of the central surface region 610.

Just in response to the power being applied to the image forming apparatus, the processor may estimate that the temperature in the central surface region of the fuser is equal to that in the side surface region 620 of the fuser (1705). In general, this is because the central surface region and the side surface region 620 are equally cooled to a low temperature in response to the power being not applied for a long time.

Next, the image forming apparatus may stand by (1710) and in response to a printing command being received in the image forming apparatus (1715), the processor 110 may determine whether or not a printing paper is a preset narrow printing paper (1720) and in response to the printing paper being not the narrow printing paper, the processor 110 may control another mode to be selected (S7).

The preset narrow printing paper may refer to the printing paper having the same size as Group1 illustrated in FIG. 16 and the group may include a plurality of groups (for example, Group1, Group2, Group3, and the like) according to a size of the printing paper.

In response to the size of the printing paper being corresponding to a preset size, the processor may determine a thickness of the printing paper (1725) and in response to the printing paper being not the narrow printing paper, the processor may control another mode to be selected (S7).

In response to the thickness of the printing paper being in a preset range, the processor may initialize the n value indicating the number of copies to 0 (zero) (1730). The processor may compare the initial temperature value Tvs of the side surface region 620 and the temperature value Tstep(n) corresponding to the relation table (1735). In response to the initial temperature value Tvs of the side surface region 620 being smaller than or equal to the temperature value Tstep(n), the processor may directly store the accumulated number of copies and estimate the temperature value Tstep(n) corresponding to the relation table as the temperature of the side surface region 620 (1750).

For example, in response to the number of copies being 0 (zero), n=0. An example that Tvs is smaller than the temperature of Tstep(0) may refer to an example that the side surface region is previously cooled and thus Nvs=0 and Tvs=Tstep(0). Tstep(0) may refer to the lowest temperature and thus Tvs may be referred to as Tstep(0).

In response to the initial temperature value Tvs of the side surface region 620 being larger than the temperature value T_step(n) corresponding to the relation table, the processor may compare the accumulated number of copies and the maximum number of copies n,max (1740).

In response to the accumulated number of copies being larger than or equal to the maximum number of copies, the processor may perform operation 1750 and in response to the accumulated number of copies being smaller than the maximum number of copies, the processor may increase the accumulated number of copies by one (1745).

In response to the initial temperature value Tvs of the side surface region 620 being larger than Tstep(n) by repeatedly performing

operations

1735, 1740, and 1745, the processor may output Nvs and Tvs after operation 1750 (1755) and the processor may enter operation S1 for estimating the temperature of the side surface region 620 in printing.

For example, in response to the number of copies being increased and n=10, the processor may determine whether or not Tvs is smaller than Tstep(10). Tvs having the temperature value larger than Tstep(9) and smaller than Tstep(10) may mean that the temperature of the central surface region is the same as a temperature of the central surface region after 10 pieces of printing paper are printed.

Through the determination process, even in response to the size of the printing paper being changed during the printing operation (S4), the processor may continuously estimate the temperature of the side surface region 620.

The temperature value Tstep(n) corresponding to the relation table may be obtained from the relation table of FIG. 16. Although not shown in the flowchart of FIG. 17, Tstep(n) may have different values according to the size or thickness of the printing paper. For example, Tstep(1) in the thin printing paper Thin may have a different value from Tstep(1) in the plain printing paper Plain.

FIG. 18 is a flowchart explaining an operation of estimating a temperature of the side surface region 620 in printing according to an embodiment.

V may refer to a line speed, ti may refer to a printing time, L_p,j may refer to a paper length, and L_GO,j may refer to a basic inter-paper distance.

The inter-paper distance corresponding to the relation table may be expressed as L_Goffset,j and the offset-applied inter-paper distance may be expressed as L_G,j.

The processor may determine the line speed V and initialize the printing time ti in operation S1 (1805). Next, the values of the paper length L_P,j and the basic inter-paper distance L_GO,j may be allocated (1810). For example, the values of the paper length L_P,j and the basic inter-paper distance L_GO,j may be directly input by the user or the automatically determined values may be allocated as the values of the paper length L_P,j and the basic inter-paper distance L_GO,j.

The paper conveying unit may pick up an i-th paper (1815) and the processor may calculate the inter-paper distance L_Goffset,j corresponding to the relation table by adding the accumulated number Nvs of printing paper previously stored and the number i(1820). In general, in response to the power being applied to the image forming apparatus, i may be initialized to 0 (zero) and in response to the power being interrupted in a state that the previous printing operation is not terminated, i may include the information for the previously accumulated number of copies.

The image forming apparatus may output the printing paper based on the changed inter-paper distance (1830). The output elapsed time may be calculated using the paper length, the inter-paper distance, and the line speed V (1835) and the calculation processor may be expressed as the following Equation 3.

[Equation 3]

The processor may newly estimate the temperature of the side surface region 620 by reflecting the accumulated number of printing which is updated (1840) and the calculation processor may be Tvs=Tstep(N_VS+i).

The processor may output the number i of printing papers printed after the processor newly estimates the temperature of the side surface region 620, the printing time ti, and the temperature Tvs of the side surface region 620 (1845).

In response to a printing operation on one piece of printing paper being terminated, the processor may determine whether or not next printing paper to be output is present (1850) and in response to the next printing paper to be output being present, the processor may determine whether or not a size of the next printing paper to be printed is changed (1855).

In response to the size of the next printing paper being changed, the processor may enter operation S4 and operation S4 may refer to an operation of entering operation 1720 of FIG. 17.

In response to the printing paper being not changed, the processor may increase the number i of printing numbers by one (1860) and processor may proceed to operation 1815.

In response to the next printing paper to be printed being not present as the determination result in operation 1850, the processor may enter operation S3 and operation S3 may refer to an operation of entering operation (see FIG. 19) of calculating the temperature of the side surface region 620 in response to the fuser being in the standby mode,

Referring to FIG. 18, the number i of printing papers, the printing time ti, and the temperature Tvs of the side surface region 620 may be stored and even in response to the printing operation being interrupted due to the abrupt shut-off of the power or an operation mistake of the user, the processor may estimate the temperature of the side surface region 620 by reflecting the previously stored information.

FIG. 19 is a flowchart explaining an operation of calculating a temperature of the side surface region 620 in response to the fuse 200 being in a standby mode according to an embodiment.

In general, in response to the fuser 200 being in the standby mode, no heat may be further supplied and the temperature over time may be lowered.

First, in response to all the printing papers being output and no printing paper to be printed being present, the processor may enter operation S3 and the mode of the fuser may be changed to the standby mode (1905). For example, the standby mode of the fuser may refer to the idle mode at a different speed or the stop mode as described above and other various modes.

In response to the mode of the fuser being changed to the standby mode, the processor may stop the fuser and shut off the power of the lamp (1910). The processor may set the temperature of the side surface region 620 to Td.

Td may refer to the temperature of the side surface region at a point of cooling time. In general, Td may refer to the temperature of the side surface region 620 at a point of time that the printing job is terminated. Td may refer to the heated temperature of the side surface region 620 at a point of time that the printing job is terminated in FIG. 18. The processor may initialize Tr indicating the time that the fuser is stopped (1920).

The processor may calculate the fuser stop time (1935). The processor may measure the stop time that the fuser is stopped from the initial time and update the measured stop time (1940). The processor may estimate the temperature of the side surface region 620 by substituting the stop time into the Equation 2 (1945). T in Equation 2 may refer to the temperature of the side surface region 620 like Tvs.

After the temperature of the side surface region 620 is estimated, the processor may determine whether or not next printing paper being present (1950). In response to the next printing paper being present, the processor may enter operation S4. Operation S4 may refer to an operation of entering operation 1720 of FIG. 17.

In response to the next printing paper being not present, the processor may determine whether or not the temperature of the side surface region 620 is equal to or smaller than a preset temperature Tend (1955). For example, the preset temperature Tend may refer to a temperature that the fuser is sufficiently cooled. The preset temperature Tend may be a temperature directly input by the user or may be a temperature at a point of time that the temperature of the side surface region 620 is equal to the temperature of the central surface region 610.

In response to the temperature of the side surface region 620 being larger than the preset temperature Tend, the processor may proceed to operation 1935 and may estimate the temperature of the side surface region 620 over time until the temperature of the side surface region is equal to or smaller than the preset temperature Tend.

In response to the temperature of the side surface region 620 being equal to or smaller than the preset temperature Tend, the processor may estimate the temperature of the side surface region 620 by substituting the temperature of the central surface region 610 detected through the sensor 230 into the temperature of the side surface region 620 (1960). The processor may enter operation S6 and operation S6 may refer to an operation of entering operation 1710 of FIG. 17.

The processor may determine whether or not intermittent heating is present. For example, the intermittent heating may refer to a heating operation of supplying the heat to the fuser at regular time intervals so that the temperature of the fuser is maintained at a certain level and thus next printing operation starts in a short time.

In this example, in response to the intermittent heating being present, the processor may perform a specific mode and the specific mode may refer to a mode that the fuser operates under a condition preset by the user.

FIG. 20 is a flowchart explaining a fuser control method according to an embodiment.

The fuser control method may include heating the heating roller 210 using the heater unit 211, detecting the temperature of the central surface region 610 of the heating roller (2010), estimating the temperature of the side surface region of the heating roller using the detected temperature of the central surface region 610 and the pre-stored relation table in response to a printing paper having a narrower width than the general printing paper being printed in the image forming apparatus (2020), and controlling a printing speed of the image forming unit based on the estimated temperature of the side surface region (2030).

The controlling may include determining printing speed and an inter-paper distance corresponding to the estimated temperature of the side surface region and controlling the image forming unit and a paper conveying unit to move the printing paper to a conveying path based on the determined printing speed and inter-paper distance.

The method may further include storing the relation table and a counter value for the number of copies. The relation table may include a plurality of the number of copies and pieces of estimated temperature information corresponding to the plurality of the number of copies. The estimating may include updating the counter value stored according to a printing job and estimating the temperature of the side surface region of the heating roller based on estimated temperature information corresponding to the counter value in the relation table.

The relation table may further include pieces of inter-paper distance information corresponding to the plurality of the number of copies. The controlling may include controlling the paper conveying unit to provide the printing paper to the conveying path depending on an inter-paper distance corresponding to the inter-paper distance information based on the inter-paper distance information corresponding to the counter value.

The estimated temperature information may be changed according to at least one of a size and a thickness of the printing paper.

The estimating may include counting a time in response to the printing job being terminated and estimating a current temperature of the side surface region based on a temperature of the side surface region estimated during the printing job and the counter value.

The heating of the heating roller may include heating the heating roller using a plurality of heating units and the controlling of the printing speed of the image forming unit may include estimating the temperature of the side surface region of the heating roller according to operation states of the plurality of heating units.

The fuser control method according to an embodiment may estimate the temperature of the side surface region of the heating roller using one sensor and control the side surface region of the heating roller using the one sensor. The fuser control method may not set the printing speed to be lowered in the narrow printing paper printing according to the condition setting of the user and may control the printing speed according to the temperature of the side surface region of the heating roller.

The fuser control method as described above may be implemented with at least one execution program for executing the fuser control method and the execution program may be stored in a non-transitory computer-readable recording medium.

The non-transitory computer-recordable medium is not a medium configured to temporarily store data such as a register, a cache, or a memory but an apparatus-readable medium configured to semi-permanently store data. Specifically, the above-described various applications or programs may be stored in the non-transitory apparatus-readable medium such as a compact disc (CD), a digital versatile disc (DVD), a hard disc, a Blu-ray disc, a universal serial bus (USB), a memory card, or a read only memory (ROM), and provided.

It has been described that all elements constituting the embodiment in the present disclosure may be combined in one or operate in a combined form, but this is not limited thereto. For example, one or more elements among the all elements may be selectively combined and operate within the object scope of the present disclosure. Further, all the elements may be individually implemented with pieces of hardware, but all or a portion of the elements may be selectively combined and may be implemented with a computer program having program modules which perform all or a portion of functions combined in one piece of hardware or a plurality of pieces of hardware. Program codes and code segments constituting the computer program may be derived by those skilled in the art of the present disclosure. The computer program may be stored in non-transitory computer-readable media and read and executed to implement the embodiment.

The foregoing embodiments and advantages are merely and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. Also, the description of the embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.

Claims

An image forming apparatus comprising:

a paper conveying unit configured to supply a printing paper to an image forming unit along a conveying path of the printing paper;

a heating roller heated through a heater unit;

a sensor configured to detect a temperature of a central surface region of the heating roller; and

a processor configured to, in response to a printing paper having a narrower width than a general printing paper being printed in the image forming apparatus, estimate a temperature of a side surface region of the heating roller using the detected temperature of the central surface region and a pre-stored relation table and control a printing speed of the image forming unit based on the estimated temperature of the side surface region.
The image forming apparatus as claimed in claim 1, wherein the processor determines the printing speed and an inter-paper distance corresponding to the estimated temperature of the side surface region and controls the paper conveying unit and the image forming unit to move the printing paper to the conveying path based on the determined printing speed and inter-paper distance.
The image forming apparatus as claimed in claim 1, further comprising a storage unit configured to store the relation table and a counter value for the number of copies,

wherein the relation table includes a plurality of the number of copies and pieces of estimated temperature information corresponding to the plurality of the number of copies, and

the processor updates the counter value stored in the storage unit according to a printing job and estimates the temperature of the side surface region of the heating roller based on estimated temperature information corresponding to the counter value in the relation table.
The image forming apparatus as claimed in claim 3, wherein the relation table further includes pieces of inter-paper distance information corresponding to the plurality of the number of copies, and

the processor controls the paper conveying unit to provide the printing paper to the conveying path according to an inter-paper distance based on inter-paper distance information corresponding to the counter value.
The image forming apparatus as claimed in claim 4, wherein the plurality of the number of copies in the relation table are divided into a plurality of groups and the plurality of groups have pieces of inter-paper distance information different from each other.
The image forming apparatus as claimed in claim 3, wherein the estimated temperature information is changed according to at least one of a size and a thickness of the printing paper.
The image forming apparatus as claimed in claim 3, wherein the plurality of the number of copies and the pieces of estimated temperature information corresponding to the plurality of the number of copies are calculated based in the following equation.

,

wherein
is the temperature of the central surface region detected through the sensor, x is the number of copies, m and K are constant values according to an operation condition, and T is the temperature of the side surface region of the heating roller.
A method for controlling a fuser of an image forming apparatus, the method comprising:

heating a heating roller using a heater unit;

detecting a temperature of a central surface region of the heating roller;

estimating a temperature of a side surface region of the heating roller using the detected temperature of the central surface region and a pre-stored relation table in response to a printing paper having a narrower width than a general printing paper being printed through an image forming unit of the image forming apparatus; and

controlling a printing speed of the image forming unit based on the estimated temperature of the side surface region.
The method as claimed in claim 8, wherein the controlling includes:

determining a printing speed and an inter-paper distance corresponding to the estimated temperature of the side surface region; and

controlling the image forming unit and a paper conveying unit to move the printing paper to a conveying path based on the determined printing speed and inter-paper distance.
The method as claimed in claim 8, further comprising storing the relation table and a counter value for the number of copies,

wherein the relation table includes a plurality of the number of copies and pieces of estimated temperature information corresponding to the plurality of the number of copies, and

the estimating includes updating the counter value stored according to a printing job and estimating the temperature of the side surface region of the heating roller based on estimated temperature information corresponding to the counter value in the relation table.
The method as claimed in claim 10, wherein the relation table further includes pieces of inter-paper distance information corresponding to the plurality of the number of copies, and

the controlling includes controlling a paper conveying unit to provide the printing paper to a conveying path according to an inter-paper distance corresponding to inter-paper distance information based on the inter-paper distance information corresponding to the counter value.
The method as claimed in claim 11, wherein the plurality of the number of copies in the relation table are divided into a plurality of groups and the plurality of groups have pieces of inter-paper distance information different from each other.
The method as claimed in claim 10, wherein the estimated temperature information is changed according to at least one of a size and a thickness of the printing paper.
The method as claimed in claim 10, wherein the plurality of the number of copies and the pieces of estimated temperature information corresponding to the plurality of the number of copies are calculated based in the following equation.

,

wherein
is the temperature of the side surface region heated at a point of printing termination,
is a stop time of the fuser, m and K are constant values according to a standby mode of the fuser, and T is the temperature of the side surface region of the heating roller.
A computer-readable recording medium including a program for executing a method for controlling a fuser of an image forming apparatus, the method comprising:

receiving a signal corresponding to a temperature of a central surface region of a heating roller;

estimating a temperature of a side surface region of the heating roller using the temperature of the central surface region corresponding to the received signal and a pre-stored relation table in response to a printing paper having a narrower width than a general printing paper being printed through an image forming unit of the image forming apparatus; and

controlling a printing speed of the image forming unit based on the estimated temperature of the side surface region.