JP2006126430A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a space-saving and low-cost image forming apparatus capable of fixing a transfer material having a wide paper passing width. <P>SOLUTION: The image forming apparatus is equipped with a fixing device having a heat roller which rotates along a conveyance direction X of the transfer material, a pressure roller which forms a nip portion with the heat roller while conveying the transfer material, a heater which heats the heat roller, and a primary body control section which drives, wherein the heater comprises a plurality of a first heater 731, a 2nd heater 732 and a 3rd heater 33 which are so divided as to heat the heat roller independently by mutually different heating widths along the axis, and the primary body control section selects the heat sources according to the paper passing width of the carried transfer material so that the total width of the combined heat sources is larger than the paper passing width of the transfer material to be heated and closest to the width the paper passing width. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that includes a fixing device capable of fixing transfer materials of a plurality of sizes, and more particularly to heating control of the fixing device.

  Image forming apparatuses such as copying machines, facsimile machines, and printers are provided with a fixing device that fixes a toner image on a transfer material by heating and pressing. The fixing device includes a heating roller provided with a heat source on the inside, and a pressure roller that presses the heating roller to form a nip portion.

  The heat source is provided so that a region corresponding to the maximum sheet passing width of the transfer material is heated, and heats the entire heating roller (maximum sheet passing width). For this reason, when a transfer material having a width smaller than the maximum sheet passing width is passed, the non-sheet passing area where the transfer material is not passed passes through a predetermined heat generation in the same manner as the sheet passing area even though no heat energy is consumed. Since heat is generated with an amount, the temperature of the non-sheet passing area rises higher than that of the sheet passing area. Due to this temperature rise phenomenon in the non-sheet passing area, a temperature difference occurs between the sheet passing area and the non-sheet passing area, and the temperature distribution of the heating roller in the direction orthogonal to the transfer material conveyance direction becomes non-uniform. Therefore, there is a problem that a difference in toner fixing rate occurs in a direction orthogonal to the transfer material conveyance direction and the life of the heating roller is reduced.

  As a measure for solving such a problem, conventionally, there has been disclosed a fixing device that includes a plurality of heaters having different heat generation lengths according to the sheet passing width and switches the heater according to the sheet passing width.

For example, it has a heater that can be selectively switched between a full-length heating element that generates heat over the entire length of the roller and a partial heating element that generates heat only at a predetermined portion. 2. Description of the Related Art A fixing device that performs fixing by pinching and transporting a transfer paper carrying a toner image is disclosed that switches a heater energizable range between a full heat generation state and a partial heat generation state every predetermined time (see Patent Document 1). ).
JP 63-92979 A

  However, since a heat source having a heat generation length corresponding to each sheet passing width is provided, it is necessary to select a heat source corresponding to each sheet passing width and select a transfer material having a large sheet passing width. In this case, a heat source must be provided for each sheet passing width, which causes problems such as an increase in cost and an increase in installation space.

  An object of the present invention is to provide an image forming apparatus capable of fixing a transfer material having a large sheet passing width with a small space and a low cost.

  According to the first aspect of the present invention, a heating member that rotates along a transfer material conveyance direction, a pressure member that forms a nip portion with the heating member while conveying the transfer material, and heats the heating member. In an image forming apparatus including a fixing device including a heating unit and a control unit that performs drive control of the heating unit, the heating unit heats each heating width that is different from each other in the axial direction of the heating member. The control means is configured such that the total width of the heating widths of the combined heat sources is larger than the sheet passing width of the transfer material to be heated according to the sheet passing width of the transfer material to be conveyed. The image forming apparatus is characterized in that the heat source is selected so as to have a width closest to the sheet passing width.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the heating width of any one of the plurality of heat sources is a plurality of types of transfer materials conveyed to the fixing device. It corresponds to the width of any transfer material.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, when the control unit selects the heat source, the heat source is selected based on a writing start position in a main scanning direction. It is characterized by.

  According to the first aspect of the present invention, it is possible to provide an image forming apparatus capable of fixing a large number of sheet passing width transfer materials at a low cost by combining heat sources having different heating widths.

  According to the second aspect of the present invention, it is possible to efficiently design the heating width of each heat source at a low cost as well as the same effect as the first aspect.

  According to the first or second aspect of the invention, the same effect as that of the first or second aspect can be obtained, and the paper passing reference position can be easily set. Thus, the reference position of each part in the image forming apparatus can be set, and an image having no deviation in the direction orthogonal to the transport direction can be accurately formed on the transfer material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration will be described.
FIG. 1 is a cross-sectional view of the internal configuration of the image forming apparatus 1 according to the present embodiment.
The image forming apparatus 1 reads an image from a document WP, receives image data from a copy function for forming the read image on a transfer material or a personal computer, and forms an image represented by the image data on the transfer material. This is a digital multi-function peripheral equipped with a printer function for output. As shown in FIG. 1, the image forming apparatus 1 includes an image reading unit 10 and a printing unit 20.

The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder) and a reading unit 12.
The automatic document feeder 11 includes a paper feed roller 11a that sequentially conveys the documents WP stacked on the document tray T1 from the top, and a contact roller for allowing the document WP to pass through a contact glass that is a reading portion of the document while being in close contact therewith. 11b, and a guide roller 11c for guiding the document WP conveyed by the paper feed roller 11a along the contact roller 11b. A switching claw 11d for switching the transport direction of the document that has passed through the contact glass, a reversing roller 11e for reversing the front and back of the document, and a discharge tray 11f for discharging the document that has been read are provided.

  The reading unit 12 includes a scanner including a light source, a lens, a contact glass, a CCD (Charge Coupled Device), and the like. The reading unit 12 forms an image of the reflected light of the light irradiated on the document and photoelectrically converts the image of the document. Read and output to the print unit 20. Here, the image means not only image data such as graphics and photographs but also text data such as characters and symbols.

  A document image (analog image signal) read by the reading unit 12 is output to a main body control unit, which will be described later, and after A / D conversion and various image processing are performed in the main body control unit, the print data is sent to the printing unit 20 as print data. Is output.

  The print unit 20 performs electrophotographic image formation based on input print data, and includes an image forming unit 30, a cleaning unit 40, a paper feeding unit 50, a transport unit 60, and a fixing device. 70.

The image forming unit 30 includes a photosensitive drum 31, a charging device 32, a laser output unit 33a that outputs laser light representing image data, and an exposure device 33 that includes a polygon mirror 33b that scans the laser light in the main scanning direction. , A developing device 34 and a transfer device 35 are provided.
Specifically, the photosensitive drum 31 charged by the charging device 32 is irradiated with laser light by the exposure device 33 to form an electrostatic latent image. The developing device 34 develops the electrostatic latent image by attaching charged toner to the surface of the photosensitive drum 31 on which the electrostatic latent image is formed. The toner image formed on the photosensitive drum 31 by the developing device 34 is transferred to the transfer material P by the transfer device 35.

  After the toner image is transferred to the transfer material P, the cleaning unit 40 removes residual charges and residual toner on the surface of the photosensitive drum 31.

  The paper feed unit 50 includes a plurality of paper feed units 51a, 51b, 51c,... And a manual feed tray T2. The plurality of paper feeding units 51a, 51b, 51c,... Are at the paper passing reference position through which the intra-standard transfer material P1 identified in advance for each paper size, printing direction, and type for each paper feeding unit. The standard transfer material P1 that is set in advance and stored by the paper feed rollers 52a, 52b, 52c... Is transported one by one from the top to the transport unit 60.

  The manual feed tray T2 can be loaded with various types of non-standard transfer materials P2 according to user needs each time, and the non-standard recording medium P2 loaded by the paper feed roller 53 is loaded from the top. One sheet is conveyed toward the conveyance unit 60. The manual feed tray T2 includes a width regulating plate (not shown) and a width detection sensor 54 that detect the maximum sheet passing width in a direction orthogonal to the conveyance direction X in which the stacked nonstandard transfer material P2 is conveyed. Further, a mechanism (not shown) that transports the non-standard transfer material P2 to a sheet passing reference position that is predetermined according to the detected maximum sheet passing width on the transport path that is transported to the transport unit 60 by the sheet feeding roller 53. ) Is provided.

  The adjustment mechanism for the paper passing reference position of the nonstandard transfer material P2 placed on the manual feed tray T2 is not limited to the case where it is provided between the paper feed roller 53 and the transport unit 60, and the nonstandard transfer material P2 is used. The manual feed tray T2 may be provided before reaching the transfer device 35, and after detecting the maximum sheet passing width, the manual feed tray T2 is provided so that the non-standard transfer material P2 is provided at the sheet passing reference position determined according to the maximum sheet passing width. It may be moved, or the user may place it again at the paper passing reference position.

  The non-standard transfer material P1 and the non-standard transfer material P2 are collectively referred to as a transfer material P hereinafter.

  The transport unit 60 transfers the transfer material P transported from the paper feed units 51a, 51b, 51c,..., The manual feed tray T2, through a plurality of intermediate rollers 61a, 61b, 61c,. Transport to.

  The fixing device 70 includes a heating member having a heat source therein, and a pressure member that forms the nip portion N together with the heating member while conveying the transfer material P, and presses the transfer material P against the heating member.

  As the heating member, a belt, a roller, or the like for heating the toner can be used.

  The pressurizing member needs to have a predetermined nip width with the heating member, and thus is configured with elasticity. As the pressure member, a belt, a pad, a roller, or the like can be used.

  As the heat source, an electric heating means such as a halogen lamp or a nichrome wire or an induction heating means for heating using an eddy current can be used. A plurality of heat sources are provided in a direction substantially perpendicular to the transfer direction X of the transfer material P. Yes.

  A fixing device 70 shown in FIG. 1 includes a heating roller 71 as a heating member provided so as to extend in a direction substantially orthogonal to the conveyance direction X of the transfer material P, and a heat source provided inside the heating roller 71. A heater 73 and a pressure roller 72 as a pressure member are provided. The toner image transferred to the transfer material P transported by the transport unit 60 is fixed by passing through the nip portion N.

  The transfer material P that has been subjected to the fixing process is sandwiched between the paper discharge rollers 63 and output onto the paper discharge tray 64.

  The rotational operation speeds of the laser output unit 33a, the polygon mirror 33b, the photosensitive drum 31, and the fixing device 70 of the image forming apparatus 1 (hereinafter collectively referred to as image forming speeds) are controlled by a main body control unit described later.

FIG. 2 shows a layout example of a plurality of heaters 73 provided in the heating roller 71.
The heater 73 of the present invention is divided into a first heater 731 that is divided so as to be heated independently for each different heating width in the longitudinal direction Y of the heating roller 71 (direction substantially orthogonal to the transfer direction X of the transfer material P). The second heater 732 and the third heater 733 are provided.

  In the longitudinal direction Y of the heating roller 71, the length (heating width) at which each of the first heater 731, the second heater 732, and the third heater 733 generates heat is designed based on the sheet passing width of the transfer material P to be passed. Has been.

  The heating width of each heater corresponds to at least one paper passing width in the heating width of each individual heater, and corresponds to at least one paper passing width in the heating width obtained by combination with the adjacent heater. Designed to be able to.

  The heating width (first heating width W1) of the first heater 731 is the first sheet passing area E1, the heating width (second heating width W2) of the second heater 732 is the second sheet passing area E2, and the third heating width W3 is The fourth heating width W4 corresponding to the different sheet passing widths in the third sheet passing area E3 and obtained by the combination of the adjacent first heater 731 and second heater 732 is the first to third heating width W1. The fifth heating width W5 obtained by combining the adjacent second heater 732 and the third heater 733 corresponds to a paper passing area (fourth paper passing area E4) different from .about.W3. Corresponding to a paper passing area (fifth paper passing area E5) different from the widths W1 to W4, the sixth heating width W6 obtained by the combination of the adjacent first to third heaters 731, 732, 733 is the first ~ 5 Heating width W1 to W5 different from the paper passing area (sixth paper passing area E6 It is set to correspond to.

  For example, in order to correspond to the paper passing widths of 10 types of transfer materials P1 within the standard of A3 to A6 paper, B4 to B7 paper, postcard paper, and business card paper, the first heating width W1 is set to 80 mm as shown in FIG. A heater in which the second heating width W2 is set to 105 mm and the third heating width W3 is set to 130 mm can be used.

  In addition, a sheet passing reference position at which the transfer material P is conveyed to the fixing device 70 is set in advance for each sheet passing area. The paper passing reference position is a paper passing reference position corresponding to the writing start position side in the main scanning direction of the laser beam of the exposure device 33.

  For example, as shown in FIG. 2, when the writing start position side in the main scanning direction of the laser beam of the exposure device 33 is the left end in the conveyance direction X of the transfer material P, the first sheet passing area E1 and the fourth sheet passing area. The sheet passing reference position (first reference position) of E2 and the sixth sheet passing area E6 is Y1 corresponding to the writing start position for each sheet passing area. The sheet passing reference position (second reference position) of the second sheet passing area E2 and the fifth sheet passing area E5 is Y2 corresponding to the writing start position for each sheet passing area. The sheet passing reference position (third reference position) of the third sheet passing area E3 is Y3 corresponding to the writing start position for the third sheet passing area E3.

  In the present invention, the sheet passing reference position of the transfer material P conveyed to the fixing device 70 according to the sheet passing width and the writing start position of the latent image written on the photosensitive drum 31 have a correspondence relationship.

FIG. 3 shows a schematic configuration diagram of the photosensitive drum 31 and the exposure device 33.
In order to simplify the description, the lens system is omitted.

  As shown in FIG. 3, the laser beam output from the laser output unit 33a based on the drive signal of the laser drive unit 310 is reflected by the polygon mirror 33b rotating at high speed, and the reflected laser beam is SOS ( Start of Scan) is detected by the sensor 330. A detection signal detected by the SOS sensor 330 is output to the main body control unit 100. The main body control unit 100 instructs the laser driving unit 310 to stop the output of the laser beam based on the detection signal of the laser beam input from the SOS sensor 330. In addition, the main body control unit 100 instructs the laser driving unit 310 to restart the output of the laser light after measuring the reference time ts according to the sheet passing area set based on the sheet passing width. The laser driving unit 310 outputs laser light from the laser output unit 33 a to form a scanning line (latent image) on the photosensitive drum 31.

  The reference time ts is set according to the sheet passing area set based on the sheet passing width (sheet passing area) of the transfer material P conveyed to the fixing device 70, and is set at the sheet passing reference position of each sheet passing area. The scanning line (latent image) is set to be formed from the corresponding position on the photosensitive drum 31 (writing start position). As a method for calculating the reference time ts, for example, it can be calculated based on the scanning speed of the laser beam.

  For example, as shown in FIG. 3, each writing start position corresponds to the first writing start position Z1 and the second reference position Y2 corresponding to the first reference position Y1 from the scanning start position side in the laser beam scanning direction. The second writing start position Z2 and the third writing start position Z3 corresponding to the third reference position Y3 are set.

FIG. 4 shows a control block diagram of the image forming apparatus 1.
The image forming apparatus 1 includes an image reading unit 10, a printing unit 20, an operation display unit 80, a communication unit 90, and a main body control unit 100 as a control unit. In addition, the same code | symbol is attached | subjected to the structure same as each part demonstrated in FIG. 1, and the description is abbreviate | omitted.

  The printing unit 20 includes an image forming unit 30, a cleaning unit 40, a paper feeding unit 50, a transport unit 60, and a fixing device 70. Each unit includes a driving unit and various sensors.

  In order to realize the present embodiment, the image forming unit 30 includes a laser driving unit 310 that operates the exposure device 33, a polygon driving unit 320, an SOS sensor 330, and a laser output unit 33a. The laser drive unit 310 drives the laser output unit 33a based on an instruction signal from the main body control unit 100 to output laser light. The polygon drive unit 320 rotates the polygon mirror 33b at high speed based on the instruction signal from the main body control unit 100. The SOS sensor 330 detects the laser beam reflected from the polygon mirror 33 b and outputs a detection signal to the main body control unit 100.

  In order to realize this exemplary embodiment, the paper feeding unit 50 includes electric clutches 55a, 55b, 55c,... That drive the width detection sensor 54 and paper feeding rollers 52a, 52b, 52c,. It has the drive motor M as a drive source of 52a, 52b, 52c .... The width detection sensor 54 is a means for detecting the maximum sheet passing width of the non-standard transfer material P2 placed on the manual feed tray T2, and outputs a signal indicating the detected maximum sheet passing width to the main body control unit 100. The electric clutches 55a, 55b, 55c,... Transmit the driving force of the drive motor M to the paper feed rollers 52a, 52b, 52c,. The transferred transfer material P is fed to the transport unit 60.

  The fixing device 70 includes an AC power supply unit 75, a first drive circuit unit 741, a second drive circuit unit 742, and a third drive circuit unit 743 in order to realize the present embodiment. The AC power supply unit 75 is a power supply for the first heater 731, the second heater 732, and the third heater 733, and power is supplied via the first drive circuit unit 741, the second drive circuit unit 742, and the third drive circuit unit 743. Supply. The first drive circuit unit 741 is a power supply drive circuit for the first heater 731, the second drive circuit unit 742 is a second heater 731, and the third drive circuit unit 743 is a third heater 733. Based on the above, the power supply from the AC power supply unit 75 is turned ON / OFF. As the first drive circuit unit 741, the second drive circuit unit 742, and the third drive circuit unit 743, SSR (Solid State Relay) can be used.

  The operation display unit 80 includes an LCD (Liquid Crystal Display), an operation display control unit, and other operation key groups. A touch panel is provided on the LCD so as to cover the LCD, and the operation display control unit according to a display signal input from the main body control unit 100, a basic screen for inputting print conditions, various processing results, and the like. Is displayed on the LCD. In addition, an operation signal input from the operation display control unit, the operation key group, or the touch panel is output to the main body control unit 100.

  Printing conditions input from the operation display unit 80 include the size of the transfer material P (paper size) on which an image is formed, the direction in which the transfer material P is conveyed to form an image (printing direction), and instructions such as enlargement / reduction Includes signal.

  The communication unit 90 includes a modem, a TA, a router, and the like, and controls communication with an external device connected to the network. The communication unit 90 outputs information such as image data, paper size, and printing direction input from an external device to the main body control unit 100.

  The main body control unit 100 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a nonvolatile RAM, and the like, and stores programs and data stored in the ROM and the nonvolatile RAM such as a RAM. The data is expanded in a temporary storage area (not shown), and is connected so that various types of information can be transmitted to and received from each unit in the image forming apparatus 1 based on the program. The received information is judged, information such as an operation instruction as a judgment result is output to each part, and each part is controlled in an integrated manner.

  The main body control unit 100 reads the image data of the original WP input from the image reading unit 10, the original size, the print condition such as the paper size input from the operation display unit 80, the print direction, or the image input from the communication unit 90. A transfer material P storing the paper size and the printing direction instructed based on data, information on the paper size, printing direction, or the detection signal from the width detection sensor 54 provided on the manual feed tray T2 is fed to the paper feeding unit 50. Alternatively, control is performed such that the toner image is transferred from the manual feed tray T2 and transferred to the transferred transfer material P and fixed to form an image.

  In order to realize the present embodiment, the main body control unit 100 sets the sheet passing width of the transferred transfer material P, and sets the writing start position, that is, the reference time ts based on the set sheet passing width. To control the laser driver 310. Further, the main body control unit 100 performs setting of the sheet passing reference position and selection of a combination of heaters to be heated based on the sheet passing width.

  When the transfer material P on which an image is formed from the instructed paper size and printing direction is the standard transfer material P1, the main body control unit 100 sets the paper passing width and the paper passing width based on the paper size and the printing direction. There is a data table in which a corresponding sheet passing area, a sheet passing reference position set for each sheet passing area, and a heater combination corresponding to the sheet passing area are set in advance. Select the combination.

FIG. 5 shows an example of a data table according to the present embodiment.
As shown in FIG. 5, in the data table, the total width of the heating widths of the combined heat sources is larger than the sheet passing width of the standard transfer material P1 to be heated according to the sheet passing width of the standard transfer material P1 being conveyed. In addition, the heat source is set in advance so as to be the width closest to the sheet passing width.

  For example, the data table shown in FIG. 5 has a preset size (width × length) for each type of standard transfer material P (A3 to A6, B4 to B7, postcard, and business card) as the paper size. ) And the printing direction (vertical, horizontal), the paper passing width is determined, the paper passing area corresponding to the determined paper passing width and the paper passing reference position are set, and the set paper passing area is also supported. A combination of heaters to be selected is set.

  The printing direction “vertical” indicates the case where the conveyance direction X and the length direction of the transfer material P are the same, and the printing direction “horizontal” indicates the case where the conveyance direction X and the width direction of the transfer material P are the same. Indicates.

  For example, when A4 paper (210 mm × 297 mm) is set as the paper size and vertical is set as the printing direction, the paper passing width is determined to be 210 mm, and the paper passing area where 210 mm can pass is the fifth paper passing area E5 (235 mm). ), And the second reference position Y2 is set as the sheet passing reference position of the fifth sheet passing area E5. Further, as the heaters selected to heat the set fifth paper passing area E5, the second heater 732 and the third heater 733 are selected, and the power supply is set to be in an ON state.

  When the transfer material P on which an image is to be formed is a non-standard transfer material P2, that is, when an image is formed on the non-standard transfer material P2 placed on the manual feed tray T2, the main body control unit 100 detects that the manual feed tray Based on the detection signal from the width detection sensor 54 provided at T2, the maximum sheet passing width of the non-standard transfer material P2 is detected, and the total width of the heating widths of the combined heat sources is determined according to the detected maximum sheet passing width. A heat source is selected so as to be larger than the sheet passing width of the nonstandard transfer material P2 to be heated and closest to the sheet passing width.

Next, the operation of the present embodiment will be described.
FIG. 6 shows a flowchart of write start preparation in the present embodiment.
The main body control unit 100 performs a write start preparation operation so that the exposure starts from the write start position corresponding to the set sheet passing width with respect to the exposure apparatus 33 of the present embodiment.

  The main body control unit 100 selects a reference time ts set in advance based on the writing start position corresponding to the set sheet passing width (step S1), and sets the reference time ts (step S2).

  After setting the reference time ts, the main body control unit 100 drives the laser driving unit 310 to output laser light from the laser output unit 33a to the polygon mirror 33b (step S3).

  When detecting the laser beam reflected from the polygon mirror 33b, the SOS sensor 330 outputs a detection signal to the main body control unit 100. The body control unit 100 determines whether a detection signal is input from the SOS sensor 330 (step S4). When the detection signal is not input from the SOS sensor 330 (step S4; No), the main body control unit 100 waits until the detection signal is input from the SOS sensor 330 (returns to step S4).

  When it is determined that the detection signal is input from the SOS sensor 330 (step S4; Yes), the main body control unit 100 drives the laser driving unit 310 to stop the emission of the laser light from the laser output unit 33a (step S5). ).

  The main body control unit 100 stops measuring the laser light and starts measuring time (step S6). The main body control unit 100 determines whether or not the measured time t is equal to or greater than the reference time ts (step S7). When determining that the time t is not equal to or greater than the reference time ts (step S7; No), the main body control unit 100 waits until the time t is equal to or greater than the reference time ts (return to step S7).

  When the main body control unit 100 determines that the time t is greater than or equal to the reference time ts (step S7; Yes), the writing start operation is started after the writing start preparation is completed, and the latent image on the photosensitive drum 31 is An image is formed.

  As described above, the writing start position can be changed in correspondence with the different sheet passing reference position for each sheet passing width.

7 and 8 show the heater selection operation flow in the present embodiment.
The main body control unit 100 performs a heater selection operation on the heater 73 according to the present embodiment in accordance with the sheet passing area corresponding to the set sheet passing width.

  The heater selection operation flow shown in FIG. 7 is a flowchart in the case where the transfer material P to be passed is the standard transfer material P1.

  The main body control unit 100 reads the set sheet passing width and data table (step S11). The main body control unit 100 reads the heater combination (heater selection data) selected corresponding to the paper passing area set based on the paper passing width set with reference to the data table (step S12).

  The main body control unit 100 determines whether or not the first heater 731 is selected based on the read heater selection data (step S13). When determining that the first heater 731 is selected (step S13; Yes), the main body control unit 100 drives the first drive circuit unit 741 to supply power from the AC power supply unit 75 (step S14). ).

  When determining that the first heater 731 is not selected (step S13; No), the main body control unit 100 determines whether the second heater 732 is selected based on the read heater selection data (step S13; No). Step S15). When determining that the second heater 732 is selected (step S15; Yes), the main body control unit 100 drives the second drive circuit unit 742 to supply power from the AC power supply unit 75 (step S16). ).

  When determining that the second heater 732 is not selected (step S15; No), the main body control unit 100 determines whether or not the third heater 733 is selected based on the read heater selection data (step S15; No). Step S17). When determining that the third heater 733 has been selected (step S17; Yes), the main body control unit 100 drives the third drive circuit unit 743 to supply power from the AC power supply unit 75 (step S18). ).

  When the main body control unit 100 determines that the third heater 733 is not selected (step S17; No), the main body control unit 100 ends the heater selection operation.

  As described above, the image forming apparatus 1 capable of fixing a large number of sheet passing widths can be realized by selecting a combination of heaters that are heated according to the sheet passing area with respect to the sheet passing width.

  The heater selection operation flow shown in FIG. 8 is a flowchart in the case where the transfer material P to be passed is the non-standard transfer material P2 placed on the manual feed tray.

  The main body control unit 100 calculates the length of the maximum sheet passing width based on the detection signal detected from the width detection sensor 54 (step S21).

  The main body control unit 100 determines whether or not the calculated maximum sheet passing width is equal to or less than the first heating width W1 (step S22).

  When determining that the maximum sheet passing width is equal to or less than the first heating width W1 (step S22; Yes), the main body control unit 100 sets the first sheet passing area E1 as the sheet passing area (step S23). The main body control unit 100 selects the first heater 731 as the heater corresponding to the first sheet passing area E1, drives the first drive circuit unit 741, and supplies power from the AC power supply unit 75 (step S24). .

  When determining that the maximum sheet passing width is larger than the first heating width W1 (step S22; No), the main body control unit 100 determines whether the maximum sheet passing width is equal to or less than the second heating width W2 (step S25). ).

  When determining that the maximum sheet passing width is equal to or less than the second heating width W2 (step S25; Yes), the main body control unit 100 sets the second sheet passing area E2 as the sheet passing area (step S26). The main body control unit 100 selects the second heater 732 as a heater corresponding to the second sheet passing area E2, drives the second drive circuit unit 742, and supplies power from the AC power supply unit 75 (step S27). .

  When determining that the maximum sheet passing width is larger than the second heating width W2 (step S25; No), the main body control unit 100 determines whether the maximum sheet passing width is equal to or smaller than the third heating width W3 (step S28). ).

  When determining that the maximum sheet passing width is equal to or smaller than the third heating width W3 (step S28; Yes), the main body control unit 100 sets the third sheet passing area E3 as the sheet passing area (step S29). The main body control unit 100 selects the third heater 733 as the heater corresponding to the third sheet passing area E3, drives the third drive circuit unit 743, and supplies power from the AC power supply unit 75 (step S30). .

  When the main body control unit 100 determines that the maximum sheet passing width is larger than the third heating width W3 (step S28; No), the maximum sheet passing width is the sum of the first heating width W1 and the second heating width W2. It is determined whether or not the following is true (step S31).

  When the main body control unit 100 determines that the maximum sheet passing width is equal to or less than the sum of the first heating width W1 and the second heating width W2 (step S31; Yes), the fourth sheet passing area is set as the sheet passing area. E4 is set (step S32). The main body control unit 100 selects the first heater 731 and the second heater 732 as heaters corresponding to the fourth sheet passing area E4, drives the first drive circuit unit 741 and the second drive circuit unit 742, and each supplies AC power. Power is supplied from the unit 75 (step S33).

  When the main body control unit 100 determines that the maximum sheet passing width is larger than the sum of the first heating width W1 and the second heating width W2 (step S31; No), the maximum sheet passing width is the second heating width W2. It is determined whether or not the heating width is equal to or less than the sum of the third heating width W3 (step S34).

  When the main body control unit 100 determines that the maximum sheet passing width is equal to or less than the sum of the second heating width W2 and the third heating width W3 (step S34; Yes), the fifth sheet passing area is set as the sheet passing area. E5 is set (step S35). The main body control unit 100 selects the second heater 732 and the third heater 733 as heaters corresponding to the fifth sheet passing area E5, drives the second drive circuit unit 742 and the third drive circuit unit 743, and respectively supplies AC power. The power is supplied from the unit 75 (step S36).

  When the main body control unit 100 determines that the maximum sheet passing width is larger than the sum of the second heating width W2 and the third heating width W3 (step S34; No), the sixth sheet passing area is set as the sheet passing area. E6 is set (step S37). The main body control unit 100 selects the first heater 731, the second heater 732, and the third heater 733 as the heaters corresponding to the sixth sheet passing area E6, and the first drive circuit unit 741, the second drive circuit unit 742, and the third. The drive circuit unit 743 is driven to supply power from the AC power supply unit 75 (step S38).

  As described above, it is possible to provide the image forming apparatus 1 capable of fixing a transfer material having a large sheet passing width with a space saving and low cost by combining heaters having different widths. In addition, the heating width of each heater can be easily designed, the paper passing reference position can be easily set, and the reference position of each part in the image forming apparatus 1 is set corresponding to the paper passing reference position. Therefore, it is possible to accurately form an image having no deviation in the direction orthogonal to the transport direction on the transfer material.

  Further, the present invention is not limited to the contents of the above embodiment, and can be appropriately changed without departing from the gist of the present invention.

1 is a cross-sectional view of an internal configuration of an image forming apparatus 1 in the present embodiment. FIG. 6 is an example of an arrangement diagram of a plurality of heaters 73 provided in a heating roller 71. 2 is a schematic configuration diagram of a photosensitive drum 31 and an exposure device 33. FIG. 2 is a control block diagram of the image forming apparatus 1. FIG. It is an example of the data table of this Embodiment. It is a flowchart of the writing start preparation in this Embodiment. It is a heater selection operation | movement flow in case the transfer material P passed through is the standard transfer material P1. It is a heater selection operation flow when the transfer material P to be passed is a nonstandard transfer material P2 placed on the manual feed tray.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image reading part 11 ADF part 11a Paper feed roller 11b Contact roller 11c Guide roller 11d Switching claw 11e Reversing roller 11f Paper discharge tray 12 Reading part 20 Printing part 30 Image forming part 31 Photosensitive drum 32 Charging device 33 Exposure Device 33a Laser output unit 33b Polygon mirror 34 Development device 35 Transfer device 40 Cleaning unit 50 Paper feed unit 51a, 51b, 51c Paper feed unit 52a, 52b, 52c, 53 Paper feed roller 54 Width detection sensors 55a, 55b, 55c Electric clutch 60 Conveying parts 61a, 61b, 61c Intermediate roller 62 Registration roller 63 Paper discharge roller 64 Paper discharge tray 70 Fixing device 71 Heating roller 72 Pressure roller 73 Heater 75 AC power supply part 80 Operation display part 90 Communication part 100 Main body control part 310 Laser Drive unit 320 Rigon drive section 330 SOS sensor 731 1st heater 732 2nd heater 733 3rd heater 741 1st drive circuit section 742 2nd drive circuit section 743 3rd drive circuit section E1 1st sheet passing area E2 2nd sheet passing area E3 1st 3 sheet passing area E4 4th sheet passing area E5 5th sheet passing area E6 6th sheet passing area M Drive motor P Transfer material P1 In-standard transfer material P2 Non-standard transfer material T1 Document tray T2 Manual feed tray t Time count ts Reference time W1 First heating width W2 Second heating width W3 Third heating width X Transport direction Y Longitudinal direction Y1 First reference position Y2 Second reference position Y3 Third reference position Z Laser scanning direction Z1 First writing start position Z2 Second writing Start position Z3 Third write start position

Claims (3)

A heating member that rotates along a transfer material conveyance direction, a pressure member that forms a nip portion with the heating member while conveying the transfer material, a heating unit that heats the heating member, and a drive of the heating unit In an image forming apparatus comprising a fixing device having a control means for performing control,
The heating means is composed of a plurality of heat sources divided so as to heat independently for each different heating width in the axial direction of the heating member,
In accordance with the sheet passing width of the transfer material to be conveyed, the control unit is configured such that the total heating width of the combined heat sources is larger than the sheet passing width of the transfer material to be heated and closest to the sheet passing width. Selecting a heat source,
An image forming apparatus. The image forming apparatus according to claim 1.
The heating width of any one of the plurality of heat sources corresponds to the width of any one of the plurality of types of transfer materials conveyed to the fixing device;
An image forming apparatus. The image forming apparatus according to claim 1, wherein
The control means, when selecting the heat source, to select the heat source with reference to the writing start position in the main scanning direction;
An image forming apparatus.

Images