Image forming device and control method

Abstract

The present invention discloses an image forming device and a control method. The image forming device of an embodiment has a transfer unit, a heating unit, and a control unit. The transfer unit transfers a colorant image representing an image onto a sheet. The heating unit is arranged at a position downstream of the transfer unit in the conveying direction of the sheet, and a plurality of heating components for heating the sheet are arranged in a width direction orthogonal to the conveying direction. The control unit determines the heating component corresponding to the width direction end of the sheet as an end heating component, determines whether the end heating component can be made not to be heated by shifting the image or reducing a specified area of ​​the image, and when it is determined that the end heating component can be made not to be heated, performs special control to shift the image or reduce a specified area of ​​the image and make the end heating component not to be heated.

Description

Technical Field

[0001] The present invention relates to an image forming device and a control method. Background Art

[0002] There is an image forming apparatus including an on-demand fixing device capable of reducing power consumption. Since only a portion of a sheet sometimes passes through an end portion of the on-demand fixing device in a main scanning direction, the temperature is likely to rise.

[0003] When the temperature has risen, in order to lower the temperature, the image forming speed must be lowered, so there is a problem of reduced performance of the image forming apparatus. In addition, when a fan is provided to prevent the temperature from rising, there is a problem of reduced cost performance. Summary of the invention

[0004] An image forming device involved in one embodiment of the present invention comprises: a transfer unit that transfers a colorant image representing an image onto a sheet; a heating unit that is arranged at a position downstream of the transfer unit in the conveying direction of the sheet, and a plurality of heating components that heat the sheet are arranged in a width direction orthogonal to the conveying direction; and a control unit that determines the heating component corresponding to the width-direction end of the sheet as an end heating component, determines whether the end heating component can be prevented from being heated by shifting or reducing a specified area of ​​the image, and when it is determined that the end heating component can be prevented from being heated, performs special control to shift or reduce a specified area of ​​the image and prevent the end heating component from being heated.

[0005] A control method involved in one embodiment of the present invention is a control method for an image forming device, wherein the image forming device comprises: a transfer unit that transfers a colorant image representing an image onto a sheet; and a heating unit that is arranged at a position downstream of the transfer unit in the conveying direction of the sheet, and a plurality of heating components that heat the sheet are arranged in a width direction orthogonal to the conveying direction. The control method includes the following steps: determining the heating component corresponding to the width-direction end of the sheet as an end heating component, determining whether the end heating component can be made not to be heated by shifting or reducing a specified area of ​​the image, and when it is determined that the end heating component can be made not to be heated, controlling the end heating component to be shifted or reduced in a specified area of ​​the image and not to be heated. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 1 is an external view showing an example of the overall configuration of the image forming apparatus 100 according to the embodiment.

[0007] Figure 21 is a hardware block diagram of the image forming apparatus 100 according to the embodiment.

[0008] Figure 3 It is a front cross-sectional view of the fixing device 30 according to the embodiment.

[0009] Figure 4 is a schematic diagram of the heater unit 40 .

[0010] Figure 5 This is a diagram showing an overview of normal control.

[0011] Figure 6 This is a diagram showing an overview of normal control.

[0012] Figure 7 It is a diagram showing an example of shift in special control.

[0013] Figure 8 The diagram shows a reduced example of a partial area of ​​an image.

[0014] Fig. 9 It is a diagram showing an example of reduction of the entire image area.

[0015] Fig.10 It is a diagram for explaining the control method.

[0016] Fig.11 : is a flowchart showing the control flow by the control unit 160 .

[0017] Fig.12 : is a flowchart showing the control flow by the control unit 160 .

[0018] Fig.13 This is a diagram showing an example of a region to be removed.

[0019] Fig.14 It is a diagram showing an example of change when the entire image area is reduced.

[0020] Fig.15 This is a diagram showing an example in which a sheet is divided into two areas, the upper half and the lower half, and special control is performed.

[0021] Fig.16 It is a figure which shows the selection screen. DETAILED DESCRIPTION

[0022] The image forming apparatus of the embodiment includes a transfer unit, a heating unit, and a control unit. The transfer unit transfers a toner image representing an image onto a sheet. The heating unit is disposed at a position downstream of the transfer unit in the conveying direction of the sheet, and a plurality of heating components for heating the sheet are disposed in a width direction orthogonal to the conveying direction. The control unit determines the heating component corresponding to the width direction end of the sheet as an end heating component, determines whether the end heating component can be made not to be heated by shifting the image or reducing a specified area of ​​the image, and when it is determined that the end heating component can be made not to be heated, performs special control to shift the image or reduce a specified area of ​​the image and make the end heating component not to be heated.

[0023] Figure 1 1 is an external view showing an example of the overall configuration of the image forming apparatus 100 according to the embodiment. Figure 2 1 is a hardware block diagram of an image forming apparatus 100 according to an embodiment. The image forming apparatus 100 is, for example, a multifunction peripheral and includes a display 110 , a control panel 120 , an image forming unit 130 , a sheet storage unit 140 , a storage unit 150 , a control unit 160 , and an image reading unit 200 .

[0024] The image forming apparatus 100 forms an image on a sheet using a developer such as a toner. The developer is fixed on the sheet by being heated. The sheet is, for example, paper or label paper. The sheet may be any sheet as long as the image forming apparatus 100 can form an image on its surface.

[0025] The display 110 is an image display device such as a liquid crystal display, an organic EL (Electro Luminescence) display, etc. The display 110 displays various information related to the image forming apparatus 100 .

[0026] The control panel 120 has a plurality of buttons. The control panel 120 receives user operations. The control panel 120 outputs a signal corresponding to the user operations to the control unit 160 of the image forming apparatus 100. In addition, the display 110 and the control panel 120 may be configured as an integrated touch panel.

[0027] The image forming unit 130 forms an image on a sheet based on image information generated by the image reading unit 200 or image information received via a communication path. The image forming unit 130 includes, for example, a developer 10, a transfer device 20, and a fixer (fixing device) 30. The image forming unit 130 forms an image, for example, by the following process. The developer 10 of the image forming unit 130 forms an electrostatic latent image on a photosensitive drum based on the image information. The developer 10 of the image forming unit 130 forms a visible image by attaching a developer to the electrostatic latent image. As a specific example of a developer, there is a colorant. As an example of a colorant, there are decolorizing toners, non-decolorizing toners (normal toners), decorative toners, etc. Some developers become lighter (disappear) when heated. In the following description, such a developer is referred to as a decolorizing developer. Decolorizing toner is a specific example of a decolorizing developer.

[0028] The transfer device 20 of the image forming unit 130 transfers a toner image representing an image onto a sheet. The transfer device 20 is an example of a transfer unit. The fixing device 30 of the image forming unit 130 fixes the visible image onto the sheet by heating and pressing the sheet. In addition, the sheet on which the image is formed may be a sheet stored in the sheet storage unit 140 or a sheet fed manually.

[0029] The sheet storage section 140 stores sheets used for image formation in the image forming unit 130 .

[0030] The storage unit 150 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The storage unit 150 stores data required when the image forming apparatus 100 operates. The storage unit 150 may also temporarily store data of an image formed in the image forming apparatus 100 .

[0031] The control unit 160 is configured using a processor such as a CPU (Central Processing Unit) and a memory. The control unit 160 reads out and executes a program pre-stored in the storage unit 150. The control unit 160 controls the operation of each device included in the image forming apparatus 100.

[0032] The control unit 160 controls Figure 3 The power supplied by the heating element group 45 shown in the figure. Specifically, the power control can also be achieved by controlling the amount of power supplied. The amount of power supplied can be controlled by, for example, phase control or frequency control.

[0033] The image reading unit 200 reads the image information of the read object as the brightness of light. The image reading unit 200 records the read image information. The recorded image information can be sent to other information processing devices via a network. The recorded image information can be formed into an image on a sheet by the image forming unit 130. The image reading unit 200 can be equipped with an ADF (Auto Document Feeder).

[0034] Figure 3 2 is a front cross-sectional view of the fixing device 30 according to the embodiment. The fixing device 30 according to the embodiment includes a pressure roller 30p and a film unit 30h.

[0035] The pressure roller 30p can press the surface of the film unit 30h and be driven to rotate. When the pressure roller 30p presses the surface of the film unit 30h, a gap N is formed between the pressure roller 30p and the film unit 30h. The pressure roller 30p presses the visible image of the sheet entering the gap N. When the pressure roller 30p is driven to rotate, the sheet is conveyed along with the rotation. The pressure roller 30p has, for example, a core 32, an elastic layer 33, and a release layer (not shown).

[0036] The core metal 32 is formed into a cylindrical shape by a metal material such as stainless steel. Both ends of the core metal 32 in the axial direction are supported so as to be rotatable. The core metal 32 is rotationally driven by a motor (not shown). The core metal 32 abuts against a cam member (not shown).

[0037] The elastic layer 33 is formed of an elastic material such as silicone rubber. The elastic layer 33 is formed with a certain thickness on the outer peripheral surface of the core metal 32. A release layer (not shown) is formed on the outer peripheral surface of the elastic layer 33. The release layer is formed of a resin material such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).

[0038] The fixing belt 35 of the film unit 30h rotates with the pressure roller 30p rotating while the gap N is formed. The fixing belt is formed of a cylindrical film. The pressure roller 30p rotates with the sheet disposed in the gap N, thereby conveying the sheet in the conveying direction W.

[0039] The film unit 30 h heats the visible image of the sheet entering the gap N. The film unit 30 h includes a fixing belt 35 , a heater unit 40 , a heat transfer member 49 , a support member 36 , a bracket 38 , a heater thermometer 62 , a thermostat 68 , and a film thermometer 64 .

[0040] The fixing belt 35 is formed into a cylindrical shape. The fixing belt 35 has a base layer, an elastic layer and a release layer in order from the inner peripheral side. The base layer is formed into a cylindrical shape by a material such as nickel (Ni). The elastic layer is stacked on the outer peripheral surface of the base layer. The elastic layer is formed by an elastic material such as silicone rubber. The release layer is stacked on the outer peripheral surface of the elastic layer. The release layer is formed by a material such as PFA resin.

[0041] Figure 4 2 is a schematic diagram of the heater unit 40. The heater unit 40 is an example of a heating unit. The heater unit 40 is provided at a position downstream of the transfer device 20 in the conveyance direction of the sheet.

[0042] The heater unit 40 includes a substrate (heating element substrate) 41 and a heating element group 45. The substrate 41 is formed of a metal material such as stainless steel, nickel, or a ceramic material such as aluminum nitride. The substrate 41 is formed in an elongated rectangular plate shape. The substrate 41 is arranged on the radial inner side of the fixing belt 35. The substrate 41 has the axial direction of the fixing belt 35 as its length direction.

[0043] A heating element group 45 is formed on the surface of the substrate 41. The heating element group 45 includes a plurality of heating elements 46. The heating element 46 is an example of a heating member for heating the sheet. Each heating element 46 is formed using a heating resistor such as a silver-palladium alloy. Figure 4 In the example of FIG. 4 , the heating element group 45 includes five heating elements 46 ( 46 a to 46 e ). The amount of current supplied to each heating element 46 is independently controlled by the control unit 160 . Figure 4 As shown, the plurality of heat generating elements 46 are provided in the width direction perpendicular to the conveying direction.

[0044] like Figure 3 As shown, the heater unit 40 is arranged on the inner side of the fixing belt 35. A lubricant (not shown) is applied to the inner peripheral surface of the fixing belt 35. The heater unit 40 contacts the inner peripheral surface of the fixing belt 35 via the lubricant. When the heater unit 40 generates heat, the viscosity of the lubricant decreases. Thus, the sliding property of the heater unit 40 and the fixing belt 35 is ensured. In this way, the fixing belt 35 is a belt-shaped film that contacts the heater unit 40 on one side and slides on the surface of the heater unit 40.

[0045] The support member 36 is formed of a resin material such as a liquid crystal polymer. The support member 36 supports the heater unit 40. The support member 36 supports the inner peripheral surface of the fixing belt 35 at both end portions of the heater unit 40.

[0046] The bracket 38 is formed of a steel plate material or the like. The cross section of the bracket 38 may be formed into a U-shape, for example. The bracket 38 is installed so that the opening of the U-shape is blocked by the support member 36. Both ends of the bracket 38 are fixed to the housing of the image forming apparatus 100. Thus, the film unit 30h is supported by the image forming apparatus 100.

[0047] The heater thermometer 62 is disposed near the heater unit 40 . The heater thermometer 62 measures the temperature of the heater unit 40 .

[0048] The thermostat 68 is arranged similarly to the heater thermometer 62. The thermostat 68 cuts off the supply of electricity to the heating element group 45 when the measured temperature of the heater unit 40 exceeds a predetermined temperature.

[0049] The control unit 160 performs normal control and special control as control related to the heating element 46. First, the normal control will be described. Figure 5 , Figure 6 1 is a diagram showing an overview of normal control. In normal control, the control unit 160 determines the heating element 46 corresponding to the width direction end of the sheet as the end heating component. The control unit 160 heats the end heating component and the heating element 46 sandwiched between the end heating components. That is, the heating element 46 corresponding to the area where the sheet passes is heated.

[0050] In the following description, the area where the sheet passes is sometimes referred to as a "paper passing area". In addition, the heating of the heating element 46 is sometimes referred to as "ON". In addition, the amount of current supplied to the heating element 46 is sometimes referred to as 0 and the heating element 46 is not heated as "OFF".

[0051] exist Figure 5 and Figure 6 In the example, the size of the sheet S is different. Figure 5 In the embodiment, the end heating components are heating elements 46b and 46d. In addition, the heating element sandwiched between the end heating components is heating element 46c. Therefore, the control unit 160 heats the heating elements 46b, 46c, and 46d. The heating elements 46b, 46c, and 46d are heating elements corresponding to the paper passing area.

[0052] exist Figure 6 In the embodiment, the end heating components are heating elements 46a and 46e. In addition, the heating elements sandwiched between the end heating components are heating elements 46b, 46c and 46d. Therefore, the control unit 160 heats the heating elements 46a, 46b, 46c, 46d and 46e. The heating elements 46a, 46b, 46c, 46d and 46e are heating elements corresponding to the paper passing area.

[0053] Thus, in normal control, the heating element 46 is controlled according to the size of the sheet. On the other hand, in special control, image data in which the image is shifted or reduced is generated according to not only the size of the sheet but also the image to be formed on the sheet.

[0054] Special control is described. In the special control, the control unit 160 determines the heating element 46 corresponding to the end portion parallel to the conveying direction of the sheet as the end heating component. The control unit 160 determines whether the end heating component can be prevented from heating by shifting the image formed on the sheet or reducing the specified area of ​​the image. When the control unit 160 determines that the end heating component can be prevented from heating, the image is shifted or reduced in the specified area of ​​the image, and the end heating component is prevented from heating. This special control is also a control as follows: when there is no colorant image in the area of ​​the sheet heated by the heating component, the heating component is prevented from heating.

[0055] Figure 7 is a diagram showing an example of shifting in special control. In this embodiment, shifting means shifting the image in a direction perpendicular to the sheet conveying direction. The direction perpendicular to the sheet conveying direction is the sub-scanning direction. Figure 7 In the figure, the shaded portion indicates the image area in which the image is formed in the sheet. Before the image is shifted, the heating elements 46 corresponding to the image area are heating elements 46a, 46b, 46c, and 46d. Among them, the heating elements 46a and 46d at the end correspond to a part of the image area. Therefore, the control unit 160 shifts the image to the right. As a result, the image area is shifted.

[0056] By shifting the image area, the heating element 46 corresponding to the image area becomes the heating element 46b, 46c, and 46d. The control unit 160 can turn off the heating element 46a. By turning off the heating element 46a, the temperature rise is suppressed.

[0057] In addition, the control unit 160 may also limit the shift amount. Specifically, the control unit 160 may shift when the shift amount required to turn off the heating element 46 at the end is below a certain value, and not shift when it is not. This is because if the shift amount is large, the position of the image area will be greatly different from the original position. Specifically, for example, when the shift amount is represented by the number of dots in the main scanning direction, the shift is performed when the necessary number of dots is less than N dots, and when it exceeds N dots, the shift is not performed. In the following description, when the shift amount is limited, the range of the shift amount that can be shifted is sometimes expressed as the allowable shift range.

[0058] Next, a reduction example in special control is described. The reduction control includes a control for reducing a part of an image area and a control for reducing the entire image area. First, the control for reducing a part of an image area is described.

[0059] Figure 8This is a diagram showing a reduced example of a part of an image in a reduced example in special control. As a part of the image, an area including an upstream end and a downstream end along the conveying direction of the sheet can be cited. This area is used as a specified area to determine whether the end heating component can be stopped from heating by reducing the length in the width direction of the sheet. In addition, the above-mentioned area is also expressed as a rejection target area. As the rejection target area, an area where a colorant image is not formed can be cited. Sometimes, the rejection target area where a colorant image is not formed is specifically expressed as a "white area".

[0060] exist Figure 8 In FIG. 1 , a white area is shown as an area sandwiched between two image areas. The white area is an area including an upstream end and a downstream end in the conveying direction of the sheet S. As a specific example of the white area, an area provided in the center of a sheet when printing images of two or more pages on one sheet can be cited.

[0061] Before the white area is reduced, the heating element 46 corresponding to the image area is Figure 8 The heating elements 46a, 46b, 46c, 46d, and 46e are shown. The heating elements 46a and 46e at the end portions correspond to a part of the image area. Therefore, the control unit 160 reduces the white area in the main scanning direction to narrow the interval of the image area.

[0062] Thus, the heating elements 46 corresponding to the image area become the heating elements 46b, 46c, and 46d. Therefore, the control unit 160 can turn off the heating elements 46a and 46e. By turning off the heating elements 46a and 46e, the temperature rise is suppressed.

[0063] The above-mentioned elimination target area may also be an area where a toner image of the same colorant is formed. Here, the same toner refers to a toner in which the proportions of the respective toners of CMYK are the same, for example. Therefore, an area where a toner image of the same colorant is formed is an area with uniform color.

[0064] Fig. 9 1 is a diagram showing an example of reduction of the entire image area in the reduction example in special control. Before reduction, the heating elements 46 corresponding to the image area are heating elements 46a, 46b, 46c, 46d, and 46e. Among them, the heating elements 46a and 46e at the end portions correspond to a part of the image area. Therefore, the control unit 160 reduces the entire image area.

[0065] Thus, the heating elements 46 corresponding to the image area become the heating elements 46b, 46c, and 46d. Therefore, the control unit 160 can turn off the heating elements 46a and 46e. By turning off the heating elements 46a and 46e, the temperature rise is suppressed.

[0066] In addition, the control unit 160 may also limit the reduction. That is, the control unit 160 may also decide whether to reduce based on the reduction amount required to turn off the heating element 46 at the end. Here, it is assumed that the larger the reduction amount, the smaller the image becomes. Therefore, for example, in the case of reducing by eliminating points in the main scanning direction, a large reduction amount means a large number of eliminated points. On the other hand, in the case of reducing based on the reduction ratio, a large reduction amount means a small reduction ratio. In the following description, the range of the reduction amount that can be reduced is sometimes expressed as the reduction allowable range.

[0067] The specific control methods of the normal control and special control described above are explained. Fig.10 is a diagram for explaining the control method. Fig.10 In FIG. 1 , the X-axis parallel to the main scanning direction, the X-coordinates A and B of the heating element 46 at the end, and the coordinates P and Q of the end of the image area in the main scanning direction are shown. The coordinate P is the minimum coordinate of the image area in the main scanning direction, and the coordinate Q is the maximum coordinate of the image area in the main scanning direction. Fig.10 In , QP is set to the picture width R and BA is set to the cell width C.

[0068] Use in Fig.10 The control method is explained using the coordinates described in . Fig.11 1 is a flowchart showing the control flow based on the control unit 160. This flowchart shows the processing flow when an image is formed on a sheet. Therefore, when there are multiple sheets to form an image, the number of times corresponding to the number of sheets is repeated. In addition, Fig.11 The flowchart shows the processing when limiting the shift and reduction.

[0069] When the control unit 160 receives a request for image formation such as copying, the control unit 160 obtains the size of the sheet (ACT 101). The control unit 160 obtains the X coordinates A and B of the heating element 46 at the end (ACT 102). The heating element 46 corresponding to the end is determined according to the size of the sheet. The coordinates of each heating element 46 are stored in advance in the storage unit 150. The control unit 160 calculates BA as the unit width C (ACT 103).

[0070] The control unit 160 acquires image data representing an image formed on the sheet (ACT 104). The control unit 160 acquires coordinates P and Q of the ends of the image region in the main scanning direction from the image data (ACT 105). The control unit 160 calculates QP as the image width R (ACT 106).

[0071] The control unit 160 determines whether the image width R is less than the cell width C (ACT 107). When the image width R is less than the cell width C (ACT 107: Yes), the control unit 160 determines whether the coordinate P is greater than the coordinate A and the coordinate Q is less than the coordinate B (ACT 108). This determination is whether the control unit 160 can turn off the heating element 46 at the end without performing special control.

[0072] When the coordinate P is above the coordinate A and the coordinate Q is below the coordinate B (ACT108: YES), the control unit 160 turns off the heating element 46 at the end (ACT111). Here, when there are other heating elements 46 outside the heating element 46 at the end, they are also controlled to be turned off. The control unit 160 performs image formation (ACT112), and then ends the process.

[0073] The case where a negative determination is made in ACT 108 is described below. A negative determination in ACT 108 means that coordinate P is smaller than coordinate A or coordinate Q is larger than coordinate B. This means that the image width R is smaller than the cell width C, but the image area corresponds to any one of the heating elements 46 at the two ends. In this case, by shifting the image, coordinate P can be made greater than coordinate A and coordinate Q can be made less than coordinate B.

[0074] Therefore, the control unit 160 determines whether the shift is possible (ACT109). Specifically, the control unit 160 determines whether the shift amount required to turn off the heating element 46 at the end is within the allowable shift range. When the shift is possible (ACT109: Yes), the control unit 160 generates the image data after the shift (ACT110). The control unit 160 turns off the heating element 46 at the end (ACT111). Here, in the case where there is another heating element 46 outside the heating element 46 at the end, of course, they are also controlled to be turned off. The control unit 160 forms an image based on the shifted image data (ACT112), and then ends the processing.

[0075] If the paper cannot be displaced in ACT 109 (ACT 109: No), the control unit 160 performs normal control to heat the heating element 46 corresponding to the paper passing area (ACT 113). The control unit 160 performs image formation based on the image data (ACT 112), and then ends the process.

[0076] In ACT 107, when the image width R is not less than the cell width C (ACT 107: No), the control unit 160 enters Fig.12 ACT201. Fig.12In ACT 201, the control unit 160 determines whether culling is possible (ACT 201). Specifically, the control unit 160 determines whether there is a culling target area, whether the reduction amount when culling is performed is within the reduction allowable range, and whether the image width R is less than the cell width C when culling is performed.

[0077] When it is determined that the image can be eliminated (ACT 201: Yes), the control unit 160 generates image data after the elimination (ACT 202). Thus, image data is generated in which the image width R is less than the unit width C. However, it is not limited to that the minimum coordinate P of the image area in the main scanning direction is greater than the coordinate A and the maximum coordinate Q of the image area in the main scanning direction is less than the coordinate B.

[0078] Therefore, the control unit 160 obtains the coordinates P and Q of the image area of ​​the image represented by the image data after the elimination (ACT 203), and enters Fig.11 ACT 108 is performed. In ACT 108, it is determined whether the coordinate P is above the coordinate A and whether the coordinate Q is below the coordinate B. In the case of a negative determination, the above-mentioned shift is performed.

[0079] If it is determined in ACT 201 that the image cannot be culled (ACT 201: No), the control unit 160 determines whether the entire image area can be reduced (ACT 204). Specifically, the control unit 160 determines whether the reduction amount required to turn off the heating element 46 at the end is within the reduction allowable range (ACT 204).

[0080] If it is determined that the image can be reduced (ACT 204: Yes), the control unit 160 generates reduced image data (ACT 205). Thus, image data is generated in which the image width R is less than the unit width C. However, it is not limited to that the minimum coordinate P of the image area in the main scanning direction is greater than the coordinate A and the maximum coordinate Q of the image area in the main scanning direction is less than the coordinate B.

[0081] Therefore, the control unit 160 obtains the coordinates P and Q of the image area represented by the image data after the elimination (ACT 203), and enters Fig.11 ACT 108 is performed. In ACT 108, it is determined whether the coordinate P is greater than or equal to the coordinate A and whether the coordinate Q is less than or equal to the coordinate B. In the case of a negative determination, the shift is performed as described above.

[0082] In ACT 204, when it is determined that the image cannot be reduced (ACT 204: No), it is determined that neither displacement nor reduction is possible. Therefore, the control unit 160 performs normal control to heat the heating element 46 corresponding to the paper passing area (ACT 113). The control unit 160 performs image formation based on the image data (ACT 112), and then ends the processing.

[0083] Fig.13 FIG. 1 is a diagram showing an example of a region to be removed. Fig.13 In the figure, the shaded area indicates the image area where the image is formed on the sheet. Fig.13 As shown, the number of the elimination target regions may be two or more. By setting a plurality of regions as the elimination target regions, the reduction can be performed more effectively. Thus, the control unit 160 can prevent the heating element 46 at the end from generating heat.

[0084] Fig.14 is a diagram showing an example of changes when the entire image area is reduced. Fig.14 In the figure, the shaded part represents the image after reduction, and the part surrounded by the single-dot dash line represents the image before reduction. Fig.14 As shown in FIG. 1 , the image width becomes shorter after the reduction. Thus, the control unit 160 can prevent the heating element 46 at the end from generating heat.

[0085] Next, an example will be described in which an image is divided into a plurality of regions and special control is performed on each of the divided regions. Fig.15 1 is a diagram showing an example of performing special control by dividing a sheet into two regions, the upper half and the lower half. The control unit 160 shifts the image of the upper half to the right and reduces the image of the lower half in the entire image area. In this way, by shifting the image or reducing the specified area of ​​the image for each divided area, the control unit 160 can prevent the heating element 46 at the end from generating heat. Fig.15 In the example, although the divided areas are two, the area may be divided into more than two areas depending on the image.

[0086] In the above embodiment, the reduction of the white area and the reduction of the image area as a whole are described. This embodiment does not limit the reduction amount, but introduces a preferred method for the reduction amount. It is preferably configured so that the reduction amount for the image area as a whole is smaller than the reduction amount for the white area and the reduction amount for the image area as a whole.

[0087] The reason is as follows. That is, since the white area is an area where nothing is recorded originally, even if the reduction amount is relatively large, the effect on the image is slight. On the other hand, the reduction amount for the entire image area has a large effect on the image because the image itself is reduced. Therefore, it is preferable to configure so that, between the reduction amount for the white area and the reduction amount for the entire image area, the reduction amount for the entire image area is smaller. In addition, as an example of the reduction amount in the white area, a reduction rate of 90% or more can be cited. As an example of the reduction amount for the entire image area, a reduction rate of 99% or more can be cited.

[0088] You can also set the reduction amount. By setting the reduction amount, you can respond more flexibly. For example, in many cases, the style of internal company documents is not very important. In such a case, you can set a relatively large reduction amount. On the other hand, in many cases, since the style of documents for outside the company is very important, you can also set the reduction amount to 0 or set a relatively small reduction amount.

[0089] It is also possible to decide whether to perform special control based on the temperature detected by the heater thermometer 62. That is, when the temperature is less than A% (e.g., 50%) of the specified temperature at which the power supply to the heating element group 45 is cut off, the control unit 160 only performs normal control. On the other hand, when the temperature becomes, for example, B% (A<B: for example, 70%) or more of the specified temperature, the control unit 160 may switch the control in a manner of performing special control. In addition, even when the switching control is performed, it is not preferable to switch in the middle of executing a job. This is because the style of the image formed on the sheet changes in the middle.

[0090] Alternatively, the user may select whether to perform the above-mentioned special control. In this case, for example, a selection screen that the user can select may be provided. In the selection screen, when the user selects to perform the special control, the control unit 160 performs the special control.

[0091] The control unit 160 may also control whether to perform special control in association with the operating mode of the image forming apparatus 100. For example, the image forming apparatus 100 has a normal mode and a power saving mode that consumes less power than the normal mode. At this time, the control unit 160 may also display a selection screen that allows the user to select either the normal mode or the power saving mode. Fig.16 2 is a diagram showing a selection screen. The selection screen is displayed on the display 110. In the selection screen, the user can select either the normal mode or the power saving mode using a radio button.

[0092] When the power saving mode is selected on the selection screen, the control unit 160 performs special control.

[0093] Special control is a control that affects the appearance of the image. Therefore, sometimes the user does not want to perform special control. Therefore, it is very effective to allow the user to choose whether to perform special control or to perform control in association with the working mode.

[0094] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope and subject matter of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

1. An image forming device, characterized in that: have: A transfer section that transfers a toner image representing an image onto a sheet; a heating section disposed downstream of the transfer section in the conveying direction of the sheet, wherein a plurality of heating members for heating the sheet are disposed in a width direction orthogonal to the conveying direction; and The control unit determines the heating component corresponding to the end portion in the width direction of the sheet as an end heating component, determines whether the end heating component can be prevented from being heated by shifting the image or reducing a specified area of ​​the image, and when it is determined that the end heating component can be prevented from being heated, performs special control to shift the image or reduce a specified area of ​​the image and prevent the end heating component from being heated.

2. The image forming apparatus according to claim 1, wherein: The control unit determines whether the end heating member can be prevented from performing heating by shifting the image in the width direction.

3. The image forming apparatus according to claim 1, wherein: The control unit sets the entire region of the image as the predetermined region, and determines whether the end heating member can be prevented from performing heating by reducing the predetermined region.

4. The image forming apparatus according to claim 1, wherein: In the case where there is an area including an upstream end and a downstream end along the conveying direction of the sheet as an area where the colorant image representing the image is not formed, the control unit sets the area as the prescribed area and determines whether the end heating component can be prevented from being heated by reducing the length of the prescribed area in the width direction.

5. The image forming apparatus according to claim 1, wherein: In the case where there is an area including an upstream end and a downstream end along the conveying direction of the sheet as an area where a colorant image representing the image is formed with the same colorant, the control unit sets the area as the prescribed area and determines whether the end heating component can be prevented from being heated by reducing the length of the prescribed area in the width direction.

6. The image forming apparatus according to claim 1, wherein: The control unit determines that the heating member can be made not to perform heating when a toner image does not exist in a region of the sheet heated by the heating member.

7. The image forming apparatus according to claim 1, wherein: have: a strip-shaped film that contacts the heating member on one side and slides on the surface of the heating member; and The rotating body can be pressed against the other surface of the film and can rotate.

8. The image forming apparatus according to claim 1, wherein: The control unit divides the image into a plurality of regions, and determines, for each of the divided regions, whether the end heating member can be prevented from performing heating by shifting or reducing a predetermined region of the image.

9. The image forming apparatus according to claim 1, wherein: The image forming apparatus has a normal mode and a power saving mode in which power consumption is lower than that in the normal mode as operating modes. The control unit performs the special control when a user selects the power saving mode on a selection screen that allows selection of either the normal mode or the power saving mode.

10. A control method, characterized in that: A method for controlling an image forming apparatus, The image forming device comprises: a transfer unit that transfers a toner image representing an image onto a sheet; and The heating section is arranged at a position downstream of the transfer section in the conveying direction of the sheet, and a plurality of heating components for heating the sheet are arranged in a width direction orthogonal to the conveying direction. The control method includes the following steps: determining the heating component corresponding to the end portion in the width direction of the sheet as an end heating component, determining whether the end heating component can be made not to be heated by shifting the image or reducing a specified area of ​​the image, and if it is determined that the end heating component can be made not to be heated, shifting the image or reducing a specified area of ​​the image and controlling the end heating component not to be heated.

Images