JP7124469B2 - Image forming device and control program - Google Patents

Description

The present invention relates to an image forming apparatus and control program.

There is a demand for a fixing device that can stably fix a high-quality image on paper. In addition to high quality, recent fixing devices are required to achieve a wider range of glossiness, from low glossiness suitable for plain paper to high glossiness suitable for photographic images. . Generally, in an electrophotographic image forming apparatus, a sheet of paper on which a toner image is formed in an image forming section is passed through a fixing nip portion of a fixing device, and heat and pressure are applied to fix the toner image on the sheet. do. The fixing nip portion is formed between the fixing belt and the pressure roller, which are stretched over the heating roller and the fixing roller, in the configuration having the fixing belt, and is formed between the fixing roller and the pressure roller in the configuration having no fixing belt. formed between

In relation to this, Japanese Patent Application Laid-Open No. 2002-200000 discloses a technique for changing the glossiness of an output image according to the temperatures of the fixing roller and the pressure roller.

JP-A-9-106210

However, the technique disclosed in Japanese Patent Laid-Open No. 2002-200000 has a problem that high-temperature offset occurs in the high-gloss mode, degrading the image quality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an image forming apparatus and a control program capable of realizing a wide range of glossiness from low glossiness suitable for plain paper to high glossiness suitable for photographic image quality. intended to provide

The above objects of the present invention are achieved by the following means.

(1) An image forming unit that forms a toner image on paper using a toner containing wax, a fixing member, and a pressure member that presses against the fixing member and forms a fixing nip portion with the fixing member. and a wax removal section for removing wax transferred from the toner image formed on the paper and on the fixing member, the fixing section for fixing the toner image formed on the paper, and the fixing section. a glossiness acquiring unit for acquiring a glossiness required for the toner image on the sheet to be fixed; and the wax removing unit adjusts removal performance for removing wax from the fixing member according to the glossiness. a wax removal adjustment unit; and a storage unit that stores the relationship between the amount of wax to be removed from the fixing member by the wax removal unit and the glossiness of the fixed image, wherein the wax removal adjustment unit is 7. The image forming apparatus, wherein the removal performance of the wax removing section is adjusted based on the relationship between the amount of wax stored in the storage section and the glossiness .

( 2 ) a fixing driving section that rotationally drives the fixing member, a pressure driving section that rotationally drives the pressure member, a drive control section that controls rotational driving of the fixing driving section and the pressure driving section; The image forming apparatus according to (1 ) , wherein the wax removal adjustment section adjusts the removal performance by changing the difference between the peripheral speed of the fixing member and the peripheral speed of the pressure member. .

( 3 ) The image forming apparatus according to ( 2 ), wherein the wax removal adjustment unit performs control such that the larger the difference in peripheral speed, the lower the wax removal performance.

( 4 ) The wax removing section has a web that removes wax on the fixing member, and a web winding section that winds up the web. The image forming apparatus according to (2) or (3 ) above, wherein the web winding speed is controlled by the web winding section.

( 5 ) The drive control unit limits the peripheral speed of the fixing member to within ±10% of the peripheral speed of the pressure member, and the absolute value of the speed difference is set in advance. The image forming apparatus according to ( 4 ) above, wherein the winding amount of the web is reduced when the threshold value is exceeded.

( 6 ) The image forming apparatus according to any one of (1) to ( 5 ) above, further comprising a leveling member that contacts the surface of the fixing member and levels the wax.

( 7 ) The image forming apparatus according to any one of (1) to ( 6 ) above, wherein the wax content of the toner is 5 to 20% by mass with respect to the entire toner.

( 8 ) The wax removal adjusting section calculates an absolute value of a difference between the peripheral speed of the fixing member and the peripheral speed of the pressure member at predetermined time intervals, and the rate of change of the absolute value exceeds a predetermined threshold. In this case, the image formation according to any one of (1) to ( 7 ) above, wherein another paper for supplying wax is passed through the fixing nip portion to increase the amount of wax in the fixing member. Device.

( 9 ) an image forming unit that forms a toner image on paper using a toner containing wax, a fixing member, and a pressure member that presses against the fixing member and forms a fixing nip portion with the fixing member. and a wax removal section for removing the wax of the fixing member transferred from the toner image formed on the paper, wherein the fixing section for fixing the image formed on the paper and the wax removal section A control program for an image forming apparatus having a storage unit for storing a relationship between the amount of wax to be removed from a fixing member and the glossiness of an image after fixing, the control program for the sheet to be fixed by the fixing unit. a step (a) of acquiring glossiness required for an image ; a step (b) of determining the removal performance of the wax removing unit based on the relationship between the amount of wax stored in the unit and the glossiness of the fixed image; and a step of forming a toner image on the paper. A control program for causing the image forming apparatus to execute (c) and a procedure (d) of fixing the toner image formed on the paper.

According to the present invention, the image forming apparatus suppresses the removal of wax from the fixing member and leaves the wax on the fixing member for an image that requires high glossiness. It improves the sliding between the pressurizing member. Therefore, smoothing of the toner layer on the paper is promoted, and the achievable range of glossiness is widened on the high gloss side. For images that require low gloss, increasing the amount of wax removed from the fixing member reduces slippage between the fixing member and pressure member at the fixing nip, lowering the glossiness. do. Therefore, the image forming apparatus can control glossiness in a wider range from low glossiness to high glossiness.

1 is a schematic cross-sectional view illustrating the configuration of an image forming apparatus according to a first embodiment; FIG. 2 is a schematic block diagram illustrating the configuration of the image forming apparatus shown in FIG. 1; FIG. 2 is a schematic diagram illustrating the main configuration of a fixing section shown in FIG. 1; FIG. 4 is a flowchart illustrating the procedure of a method for controlling the image forming apparatus according to the first embodiment; 4 is a schematic diagram showing a chart used in a fixing experiment of Example 1. FIG. 4 is a graph of experimental results showing the relationship between the web winding amount and the glossiness in Example 1. FIG. 9 is a graph of experimental results showing the relationship between the web winding amount and the glossiness of an image when the difference in peripheral speed between the fixing belt and the pressure roller is changed in Example 2. FIG. 9 is a graph of experimental results showing the relationship between the web winding amount and the glossiness of an image when the difference in peripheral speed between the fixing belt and the pressure roller is changed in Example 2. FIG. 10 is a graph illustrating glossiness when the amount of wax contained in toner is changed in Example 3. FIG. 10 is a graph illustrating the glossiness of an image with and without a wax-supplying paper in Example 4. FIG. FIG. 10 is a schematic diagram showing the main configuration of an example of a fixing section according to the second embodiment; FIG. 11 is a schematic diagram showing a chart used in a fixing experiment of Example 5; 10 is a graph of experimental results showing the relationship between the web winding amount and the glossiness in Example 5. FIG. FIG. 8 is a schematic diagram showing the main configuration of another example of the fixing section in the second embodiment;

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

(First embodiment)
<Image forming apparatus 100>
FIG. 1 is a schematic cross-sectional view illustrating the configuration of the image forming apparatus 100 of the first embodiment, and FIG. 2 is a schematic block diagram illustrating the configuration of the image forming apparatus 100 shown in FIG.

The image forming apparatus 100 is called a tandem-type color image forming apparatus, reads an image from a document, and forms (prints) the read image on paper. The image forming apparatus 100 also receives a print job including print data in PDL (Page Description Language) format and print setting information from an external client terminal via a network, and forms a toner image on paper based on the print job. A client terminal may be, for example, a personal computer, a tablet terminal, a smartphone, or the like.

As shown in FIG. 2, the image forming apparatus 100 includes an image reading unit 110, an image processing unit 120, an image forming unit 130, a paper feeding unit 140, a paper conveying unit 150, a fixing unit 200, a communication unit 300, and an operation display unit 400. , and a control unit 500 . These components are communicably connected to each other via an internal bus 101 .

Image reading unit 110 reads an original and outputs an image information signal. An image of a document placed on the document platen 111 is scanned and exposed by the optical system of the scanning exposure device of the image reading device 112, and is read by the line image sensor. The photoelectrically converted image information signal is subjected to analog processing, A/D conversion, shading correction, image compression processing, etc. in the image processing section 120, and then is processed as print image data by the optical writing section 3Y of the image forming section 130, Input to 3M, 3C, 3K (described later).

The image forming unit 130 forms a toner image on paper based on print image data using a well-known image forming process such as electrophotography including charging, exposure, development, and transfer steps. Image forming section 130 includes four sets of subunits 13Y, 13M, and 4 sets of subunits 13Y, 13M, and 13M for forming toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. It has a unit 13C and a subunit 13K.

The subunit 13Y includes a photosensitive drum 1Y, a charging section 2Y arranged around the photosensitive drum 1Y, an optical writing section 3Y, a developing device 4Y, and a drum cleaner 5Y.

Similarly, the subunit 13M includes the photosensitive drum 1M, the charging section 2M arranged therearound, the optical writing section 3M, the developing device 4M and the drum cleaner 5M. The subunit 13K includes the photosensitive drum 1K, the charging unit 2K, the optical writing unit 3K, and the developing unit 13K. It comprises a device 4K and a drum cleaner 5K.

Photoreceptor drums 1Y, 1M, 1C, 1K, charging units 2Y, 2M, 2C, 2K, optical writing units 3Y, 3M, 3C, 3K, developing devices 4Y, 4M in subunits 13Y, 13M, 13C, 13K, respectively , 4C, 4K, and drum cleaners 5Y, 5M, 5C, 5K have common contents. In the following description, the symbols Y, M, C, and K will be omitted unless a distinction is particularly necessary.

The image forming unit 130 writes the print image data onto the photoreceptor drum 1 with the optical writing unit 3 and forms a latent image on the photoreceptor drum 1 based on the print image data. The latent image is developed by the developing device 4 to form a toner image, which is a visible image, on the photosensitive drum 1 . The developing device 4 can use toner containing wax as a releasing agent.

The wax is not particularly limited, and known waxes can be used. Specifically, for example, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; plant waxes such as synthetic ester wax, carnauba wax, rice wax, candelilla wax, wood wax and jojoba oil; montan wax and paraffin wax. , microcrystalline wax, minerals such as Fischer-Tropsch wax, petroleum-based waxes; modified products thereof, and the like.

As will be described later, the amount of wax added is usually 5 to 20% by mass, preferably 7 to 14% by mass, based on the total toner. As for the size of the wax, the volume average particle diameter is preferably 10 to 1000 nm, 50 to 500 nm, and particularly preferably 80 to 300 nm.

Yellow (Y), magenta (M), cyan (C), and black (K) colors are respectively applied to the photosensitive drums 1Y, 1M, 1C, and 1K of the subunits 13Y, 13M, 13C, and 13K. A toner image is formed.

The intermediate transfer belt 6 is wound around a plurality of rollers and supported so as to be able to run. The toner images of respective colors formed by the subunits 13Y, 13M, 13C, and 13K are sequentially transferred onto the running intermediate transfer belt 6 by the primary transfer portions 7Y, 7M, 7C, and 7K, and Y (yellow) and M (magenta) are transferred onto the intermediate transfer belt 6. ), C (cyan), and K (black) to form a color toner image.

Paper feeding unit 140 supplies paper 10 as a recording material to image forming unit 130 . The paper feeding unit 140 has an upper tray 141, a middle tray 142, and a lower tray 143, and each tray accommodates sheets of different sizes, such as A4 size and A3 size.

The paper transport section 150 transports the paper 10 . The paper 10 supplied from the upper tray 141, the middle tray 142, or the lower tray 143 is conveyed to the secondary transfer portion 7A through the registration rollers 151, and the color toner image on the intermediate transfer belt 6 is transferred onto the paper 10. be transcribed.

In addition, the paper conveying unit 150 includes a paper reversing unit 152. It is possible to guide the fixed paper 10 to the paper reversing unit 152, turn it over, and discharge it, or to form images on both sides of the paper 10. and

The fixing section 200 fixes the toner image formed on the paper 10 . The paper 10 on which the color image is fixed is discharged to the outside of the image forming apparatus 100 through the paper discharging section 153 . Details of the fixing unit 200 will be described later.

Communication unit 300 connects to a client terminal such as a personal computer via a network, and transmits/receives data such as a print job.

The operation display section 400 has an input section and an output section. The input unit includes, for example, a keyboard and a touch panel, and is used by the user to perform various instructions (inputs) such as character input, various settings, and print instructions. The output unit has a display and is used to present the device configuration, print job execution status, occurrence status of an abnormality (jam) in paper transport, etc. to the user.

Control unit 500 controls image reading unit 110 , image processing unit 120 , image forming unit 130 , paper feeding unit 140 , paper conveying unit 150 , fixing unit 200 , communication unit 300 , and operation display unit 400 . The control unit 500 has a CPU 510 , an auxiliary storage unit 520 , a RAM 530 and a ROM 540 .

CPU 510 executes a control program. The control program is stored in auxiliary storage unit 520 and loaded into RAM 530 when executed by CPU 510 . Auxiliary storage unit 520 includes, for example, a large-capacity storage device such as a hard disk drive or flash memory. The RAM 530 stores calculation results and the like associated with the execution of the CPU 510 . Various parameters, various programs, and the like are stored in the ROM 540 . The CPU 510 implements various functions by executing the control program.

For example, in this embodiment, the image forming apparatus 100 has a gloss level adjustment mode for adjusting the gloss level of the fixed image in addition to the normal print mode. When the mode of the image forming apparatus 100 is the glossiness adjustment mode, the control section 500 functions as a wax removal adjustment section and adjusts the glossiness required for the toner image on the paper 10 fixed by the fixing section 200 . Accordingly, the amount of wax to be removed from the fixing belt 220, that is, the removal performance (removal strength) of the wax removing section 280, which will be described later, is adjusted. Control unit 500 acquires, for example, glossiness required for the toner image on paper 10 through operation display unit 400 . The operation display unit 400 and the control unit 500 function as a glossiness acquisition unit.

As will be described later, there is a correlation between the amount of wax removed from the fixing belt 220 and the glossiness of the image after fixing (hereinafter simply referred to as “image glossiness”). The higher the amount of , the higher the glossiness of the image. Also, there is a correlation between the difference between the peripheral speed of the fixing belt 220 and the pressure roller 240 and the glossiness of the image, and it was found that a high glossiness can be achieved in an area where the difference in peripheral speed is large. ing.

In this embodiment, the relationship between the amount of wax removed from the fixing belt 220 and the glossiness of the image is obtained in advance through experiments, and stored as a table in the auxiliary storage unit 520 or the RAM 530 . When fixing the paper 10, the control unit 500 obtains from the above table the amount of wax removal (removal performance) that can achieve the glossiness required for the toner image, and adjusts the amount of wax on the fixing belt 220. . At this time, image forming apparatus 100 suppresses the removal of wax from fixing belt 220 for a toner image that requires high gloss, and leaves the wax on fixing belt 220 so that the toner image is fixed at fixing nip portion N. To improve slippage between the belt 220 and the pressure roller 240. - 特許庁Therefore, smoothing of the toner layer on the paper 10 is promoted, and the achievable range of glossiness is widened on the high gloss side. Details of wax removal from the fixing belt 220 will be described later.

<Structure of Fixing Unit 200>
Next, a specific configuration of the fixing section 200 will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating the main configuration of the fixing section 200 shown in FIG.

Fixing section 200 includes non-contact temperature sensor 201 , heating roller 210 , fixing belt 220 , fixing roller 230 , pressure roller 240 , fixing drive section 250 , pressure drive section 260 , drive control section 270 , and wax removal section 280 . have.

Heating roller 210 is, for example, a cylindrical core made of metal such as aluminum as it is, or its outer peripheral surface is coated with fluorine resin or the like, and its outer diameter is, for example, 65 to 75 [mm]. degree. Heating roller 210 incorporates heater (for example, halogen heater) 211 as a heating unit for heating fixing belt 220 .

Fixing belt 220 is, for example, a polyimide (PI) substrate having a thickness of 70 [μm] whose outer peripheral surface is covered with an elastic layer and whose surface layer is covered with a heat-resistant resin. As the elastic layer, for example, heat-resistant silicone rubber (hardness JIS-A30 [°]) having a thickness of 200 [μm] can be used. Also, as the heat-resistant resin, for example, a PFA (perfluoroalkoxy) tube having a thickness of 50 [μm] can be used. Fixing belt 220 is an endless belt, and is stretched between heating roller 210 and fixing roller 230 with a predetermined belt tension (for example, 250 [N]).

Fixing belt 220 functions as a fixing member, contacts sheet 10 on which a toner image is formed, and heats sheet 10 at a fixing temperature. Here, the fixing temperature is a temperature (for example, 160 to 200 [° C.]) that can supply the amount of heat necessary to melt the toner on the paper, and varies depending on the paper type of the paper 10 on which the image is formed. . The surface temperature of the fixing belt 220 is detected by the non-contact temperature sensor 201, and the heating of the heater 211 is controlled by the controller 500 to maintain a predetermined set temperature.

The fixing roller 230 includes, in order from the inside, a core metal 231 made of a cylindrical metal, an elastic layer 232 made of a material such as silicone rubber or foamed silicone rubber formed on the surface of the metal core 231, and a release layer (not shown) made of a fluorine resin or the like. ). The outer diameter of fixing roller 230 can be, for example, about 50 to 60 [mm], and the thickness of elastic layer 232 can be, for example, about 15 to 25 [mm]. The length of fixing roller 230 in the axial direction is a length that sufficiently corresponds to the maximum sheet width that can be conveyed (for example, 300 [mm]).

Fixing roller 230 is rotationally driven, for example, in the direction of the arrow in FIG. The peripheral speed of fixing roller 230 can be set to about 200 [mm/s], for example. Fixing belt 220 rotates following the rotation of fixing roller 230 . Therefore, fixing roller 230 is indirectly heated by heater 211 through fixing belt 220 .

The pressure roller 240 functions as a pressure member, and includes, in order from the inside, a core metal 241 made of a cylindrical metal, an elastic layer 242 formed on the surface thereof and made of a material such as silicone rubber or foamed silicone rubber, and a separator. A mold layer (not shown) is provided. The axial length and release layer of the pressure roller 240 may be the same as those of the fixing roller 230 . On the other hand, in the present embodiment, the outer diameter of the pressure roller 240 is formed larger than the outer diameter of the fixing roller 230, and the thickness of the elastic layer 242 is smaller than that of the elastic layer 232 of the fixing roller 230. It can be formed in about 5 [mm].

In addition, the pressure roller 240 can be rotationally driven in a direction opposite to the R direction, that is, counterclockwise by power transmission from the pressure drive unit 260 .

Wax removing section 280 removes wax from fixing belt 220 transferred from the paper. The wax removing section 280 has a web 281 , a primary winding roller 282 , a pressing roller 283 and a winding roller 284 .

The web 281 is, for example, a nonwoven fabric using heat-resistant fibers such as aramid fibers, and has air permeability. The web 281 supplied from the main winding roller 282 is in sliding contact with the outer peripheral surface of the fixing roller 230 , is wound around the pressure roller 283 and is wound up by the winding roller 284 .

The take-up roller 284 functions as a web take-up unit and is rotated little by little by a motor (not shown) to take up the web 281 . The winding amount (winding speed) is, for example, about 0.01 to 0.5 [mm] for printing on one sheet of A3 size paper. In addition, the main winding roller 282 has braking means, which constantly brakes the advance of the web 167 to prevent the web 281 from becoming slack during the feeding operation.

The pressing roller 283 is a cylindrical roller made of a SUS metal core, and its outer peripheral surface is coated with an elastic member (foamed silicone rubber or the like). The pressing roller 283 can be moved toward or away from the fixing belt 220 by a pressing drive mechanism (not shown). When removing the wax from the fixing belt 220, the pressing roller 283 is moved to a predetermined position close to the fixing belt 220, and presses the web 281 against the outer peripheral surface of the fixing belt 220 by a biasing means such as a spring (not shown). do. As a result, the web 281 abuts or presses against the fixing belt 220 , and the outer peripheral surface of the rotating fixing belt 220 is rubbed by the web 281 . As a result, the wax or the like adhering to the outer peripheral surface of the fixing belt 220 is taken into the web 281, and the wax on the outer peripheral surface of the fixing belt 220 is removed.

<Method for Controlling Image Forming Apparatus 100>
FIG. 4 is a flowchart illustrating procedures of a control method for the image forming apparatus 100 according to the first embodiment. Before forming a toner image on the paper 10, the image forming apparatus 100 acquires the gloss level as a preparation stage for adjusting the gloss level, and determines the amount of wax to be removed from the fixing belt 220 according to the gloss level.

Specifically, the control unit 500 acquires the glossiness required for the toner image on the paper 10 fixed by the fixing unit 200 (step S101). The user inputs the glossiness to image forming apparatus 100 through operation display unit 400, for example. Alternatively, the user can select a low gloss mode or a high gloss mode instead of entering the gloss level directly. A predetermined low gloss value is preset for the low gloss mode, and a predetermined high gloss value is preset for the high gloss mode. Note that the gloss mode is not limited to the low gloss mode and the high gloss mode, and may be configured to include multi-level gloss levels such as a low gloss mode, a medium gloss mode, and a high gloss mode.

The user can also specify that the glossiness of the fixed image and the glossiness of the paper 10 should be the same. In this case, the control unit 500 acquires the glossiness based on the print setting information of the print job. For example, if the paper 10 is plain paper, a low glossiness value is acquired, and if the paper 10 is coated paper, a high glossiness value is acquired.

Alternatively, the reflectance of the paper 10 may be measured by an optical sensor or an in-line scanner installed on the paper transport path, and the glossiness may be calculated and acquired based on the reflectance.

Next, the amount of wax to be removed from fixing belt 220 is determined according to the degree of gloss (step S102). The amount of wax removed from the fixing belt 220 by the wax remover 280 (hereinafter referred to as “wax removal amount”) is related to the winding amount of the web 281 . The amount of wax removed is roughly proportional to the winding amount of the web 281, except when a large amount of wax adheres to the fixing belt 220 and the removal by the web 281 has reached a saturated state. are uniquely associated with. The control unit 500 obtains the winding amount of the web 281 from the glossiness acquired in step S101 using a table that holds the correspondence relationship between the winding amount of the web 281 and the glossiness of the image. The relationship between the amount of winding of the web 281 and the glossiness of the image is experimentally acquired in advance in Examples 1 to 4 described later, and the above table is created based on these experimental results. is stored in the auxiliary storage unit 520 of

Next, a toner image is formed on the paper 10 (step S103). The control unit 500 controls the image forming unit 130 to form a toner image on the paper 10 based on the print job.

Next, the toner image is fixed on the paper 10 (step S104). The control unit 500 controls the fixing unit 200 to fix the toner image on the paper 10 . The fixing unit 200 removes the wax from the fixing belt 220 by the wax removal unit 280 according to the wax removal amount obtained in step S102, and fixes the toner image on the paper 10. FIG. The paper 10 on which the toner image is fixed is discharged to the outside of the image forming apparatus 100 through the paper discharging section 153 . Then, the control unit 500 ends the processing (END).

<Example 1>
The relationship between the winding amount of the web 281 and the glossiness of the image will be described below with reference to FIGS. 5 and 6. FIG. FIG. 5 is a schematic diagram showing a chart used in the fixing experiment of this embodiment, and FIG. 6 is a graph of experimental results showing the relationship between the web winding amount and the glossiness. In FIG. 6, the horizontal axis of the graph is the winding amount of the web 281 per 10 A3 sheets, and the vertical axis is the glossiness of the image. In addition, the glossiness of the image was measured at 60 degree glossiness.

In this embodiment, an experiment was conducted using the fixing unit 200 shown in FIG. 3 to obtain the relationship between the amount of winding of the web 281 and the glossiness of the image. The experimental conditions are as follows.

As shown in FIG. 5, the image forming unit 130 formed a solid chart on A3 size coated paper (Esprit C209g) using YM toner (red). The amount of wax in the toner was 10 mass % with respect to the entire toner. Further, the temperature of the fixing belt 220 before the fixing nip portion N was 170[° C.], and the nip time was 50[ms].

In this embodiment, only the pressure roller 240 of the fixing unit 200 is driven, and the fixing belt 220 and the fixing roller 230 are rotated following the pressure roller 240. I tried to take him around. As a result, the peripheral speed of fixing belt 220 became slower than the peripheral speed of pressure roller 240 . The peripheral speed of fixing belt 220 can be measured, for example, by attaching markers at regular intervals in the circumferential direction along the widthwise end of fixing belt 220 and reading the markers with an optical sensor. The circumferential speed of pressure roller 240 can also be measured in the same manner as the circumferential speed of fixing belt 220 .

As a result of the measurement, the peripheral speed of fixing belt 220 was slower than the peripheral speed of pressure roller 240 by about 1%. In this specification, the case where the peripheral speed of fixing belt 220 is slower than the peripheral speed of pressure roller 240 is referred to as a “brake”. % slower is called "brake 1%". When fixing roller 230 is rotationally driven by fixing drive unit 250, for example, if the peripheral speed of fixing belt 220 is 1% higher than the peripheral speed of pressure roller 240 with respect to pressure roller 240, "assist 1% ”.

In this embodiment, the amount of wax removed from the fixing belt 220 is adjusted by adjusting the winding amount of the web 281 . As shown in FIG. 6, the smaller the winding amount of the web 281, that is, the lower the removal performance, the higher the glossiness of the image. , the glossiness of the image decreased. It is considered that this is due to the following reasons. The smaller the winding amount of the web 281, that is, the larger the amount of wax remaining on the fixing belt 220, the lower the coefficient of friction between the fixing belt 220 and the paper 10, improving the slippage. Therefore, when the paper 10 is conveyed along with the rotation of the pressure roller 240, the toner layer on the paper 10 receives a shearing force due to the speed difference with the fixing belt 220 and is smoothed. As a result, the glossiness of the image increases. On the other hand, as the amount of winding of the web 281 increases, the amount of wax remaining on the fixing belt 220 decreases, so the glossiness of the image decreases.

By adjusting the winding amount of the web 281 in this manner, it is possible to control the glossiness of the image within a predetermined range. In the example shown in FIG. 6, the glossiness of the image can be controlled in the range of 20.5 to 15.5 by changing the winding amount of the web 281 in the range of 0 to 4 [mm]. Therefore, the gloss control width is 5 (=20.5-15.5).

Also, when the user requests a glossiness close to the glossiness of the paper as the glossiness of the image, as in offset printing, the winding amount of the web 281 is adjusted so that the glossiness is close to the glossiness of the paper. may Further, if a high-gloss image is required regardless of the glossiness of the paper, a mode or configuration for suppressing wax removal by the wax removal section 280 may be provided. Further, regarding the adjustment of the removal performance of the wax removal unit 280 , it is possible to adjust the pressing force of the web 281 against the fixing belt 220 , etc., in addition to the winding amount of the web 281 .

<Example 2>
In the first embodiment, the relation between the winding amount of the web 281 and the glossiness of the image is described in the case where the pressure roller 240 and the fixing belt 220 are driven with the brake of 1%. In Example 2, when the difference between the circumferential speed of the pressure roller 240 and the circumferential speed of the fixing belt 220 (hereinafter simply referred to as “difference in circumferential speed”) is changed, the winding amount of the web 281 and the image size are different. A relationship with glossiness will be described.

FIG. 7 is a graph of experimental results showing the relationship between the web winding amount and the image glossiness when the brake is changed from no difference in peripheral speed between the fixing belt 220 and the pressure roller 240 to 4%. FIG. 8 shows the web winding amount and image gloss when the web winding amount is set to 0 or 4 [mm] and the brake is changed to 4 to 12% and the assist is changed to 4 to 12%. It is a graph of the experimental results showing the relationship with degree.

The experimental conditions in this example are the same as in Example 1, except that the difference in peripheral speed is set to a different value. In this embodiment, the speed difference between the toner image on the paper 10 and the fixing belt 220 is set by adjusting the peripheral speeds of the fixing roller 230 and the pressure roller 240 . If there is a difference between the circumferential speed of pressure roller 240 and the circumferential speed of fixing belt 220, wax is released when the toner on paper 10 is crushed, and the amount of wax increases as the difference increases. As a result, the sliding between the fixing belt 220 and the paper 10 is also improved.

As shown in FIG. 7, the relationship between the web take-up amount and the glossiness of the image was determined for the cases of no peripheral speed difference and brakes of 1, 2, 3, and 4%. In all cases of no difference in peripheral speed and brakes of 1, 2, 3, and 4%, the glossiness of the image is maximized when the web take-up amount is 0 [mm], and increases as the web take-up amount increases. Decreased. Without the difference in peripheral speed, the degree of change in the glossiness of the image with respect to the change in the amount of web take-up was small. However, as the difference in peripheral speed increased, that is, as the brake percentage increased, the degree of change in image gloss with respect to the change in web winding amount increased.

Thus, the glossiness of the image changes according to the amount of web winding. Also, even if the web winding amount is the same, the glossiness of the image increases as the difference in peripheral speed increases. Therefore, it is possible to realize a wider range of glossiness by utilizing the fact that the glossiness of the image changes according to the difference between the web winding amount and the peripheral speed. For example, by removing the wax using P1 to P5 surrounded by "o" in FIG. In the example shown in FIG. 7, the glossiness can be controlled in the range of 35 to 13 by changing the winding amount of the web 281 in the range of 0 to 4 [mm]. Therefore, the gloss control width is 22 (=35-13).

In addition, instead of adjusting the glossiness in multiple stages like P1 to P5 described above, P1 is used in the high gloss mode and P5 is used in the low gloss mode, and the glossiness is adjusted in two stages. can be configured to

As shown in FIG. 8, when the peripheral speed of the fixing belt 220 is higher than the peripheral speed of the pressure roller 240, that is, in the assist case, the smoothing effect of the toner and the release of wax from the toner are the same as in the case of the brake. The glossiness of the image can be adjusted. However, the change in gloss due to the difference in peripheral speed was saturated at approximately ±10% for both the assist and brake, and further changes in the difference in peripheral speed had almost no effect on the gloss. Therefore, the drive control unit 270 can limit the difference in peripheral speed between the fixing belt 220 and the pressure roller 240 to within ±10%, that is, the absolute value of the difference in peripheral speed is within 10. The control unit 500 performs control to reduce the winding amount of the web 281 when the absolute value of the difference in peripheral speed is greater than a predetermined threshold value.

<Example 3>
The glossiness of the image also depends on the amount of wax contained in the toner. In Examples 1 and 2, the relationship between the amount of winding of the web 281 and the glossiness of the image is described in the case where the toner contains 10% by mass of wax. In Example 3, the relationship between the amount of wax and the glossiness of an image when the amount of wax contained in toner is changed will be described.

FIG. 9 is a graph illustrating the glossiness when the amount of wax contained in the toner is changed in this embodiment. The experimental conditions of this example are the same as those of Example 1 except that the amount of wax contained in the toner is changed.

The range in which the glossiness of an image can be reproduced (hereinafter also referred to as “gloss reproduction range”) depends on the amount of wax contained in the toner. It is preferable to use wax in a range that is neither too little nor too much. For example, if the amount of wax is less than 5% by mass with respect to the entire toner, the separability is low and the glossiness is significantly lowered, which may make it difficult to control the glossiness.

On the other hand, if the amount of wax exceeds 20% by mass with respect to the entire toner, the amount of wax is too large and the fluidity at the time of fixing becomes significantly high. As a result, a minute high-temperature offset occurs to disturb the image, and it may become difficult to control the glossiness by smoothing the toner layer in the fixing nip portion N. FIG. Therefore, the content of wax in the toner is preferably 5 to 20% by mass based on the total toner.

In this example, the amount of wax contained in the toner was changed, and the glossiness of the fixed image was measured. First, fixing was performed under the condition that the web winding amount was 4 [mm] with no difference in the peripheral speed as the condition that the glossiness was minimized, and the glossiness of the fixed image was measured. The measurement results of glossiness are shown in Table 1 below.

In addition, fixing was performed under the condition that the brake was 10% and the web winding amount was 0 [mm] (winding was stopped) as the conditions for maximizing the glossiness, and the glossiness of the fixed image was measured. The measurement results of glossiness are shown in Table 2 below.

As shown in FIG. 9, as the amount of wax contained in the toner increases, the minimum and maximum glossiness tend to increase. However, the minimum value is saturated at about 7% wax by weight and the maximum value is saturated at 14% wax by weight.

The gloss control range C1 is the difference between the maximum and minimum values of the glossiness of the image for each amount of wax, and represents the range of gloss that can be imparted to the image. In order to ensure a large gloss control range C1, it is desirable to use 7% by mass when targeting low glossiness (low gloss) and 14% by mass when targeting high glossiness (high gloss). If it is less than 7% by mass, the lower limit of the gloss reproduction range is saturated, and if it exceeds 14%, the upper limit of the gloss reproduction range is saturated, so a wide gloss control width C1 cannot be secured. However, since it swings to the part lower than the upper limit of the gloss reproduction range or the part higher than the lower limit of the gloss reproduction range, when those parts are targeted, less than 7% by mass and 14% by mass You can also use regions larger than .

Therefore, from the viewpoint of widening the range in which the gloss can be controlled, the content of the wax in the toner is more preferably 7 to 14% by mass with respect to the entire toner.

<Example 4>
With reference to FIG. 10, the case of adjusting the amount of wax on fixing belt 220 by passing paper for supplying wax will be described. FIG. 10 is a graph showing an example of the glossiness of an image when the paper for supplying wax is passed and when it is not passed in this embodiment.

For example, when general business documents are printed on paper, the ratio of the area of the paper 10 to which toner is adhered, that is, the coverage, is often relatively low. In addition, in the case of general business texts, which are mainly written texts, the glossiness of the image is often relatively low. Hereinafter, such an image is referred to as a "low gloss image" in this specification. On the other hand, when a photographic quality image is printed on paper, its coverage and gloss are often relatively high. Such an image is called a "high gloss image".

As an actual usage of the image forming apparatus 100, there is a case where a high-gloss image is fixed after fixing a low-gloss image. In this embodiment, in such a case, after fixing the low-gloss image and before fixing the high-gloss image, a paper on which a solid image is formed, for example, is passed as the paper for supplying wax.

More specifically, control unit 500 calculates the absolute value of the difference between the peripheral speed of fixing belt 220 and the peripheral speed of pressure roller 240 every predetermined time. If the rate of change in the absolute value exceeds a predetermined threshold value, another sheet for supplying wax is passed through the fixing nip portion N to increase the amount of wax on the fixing belt 220 . After fixing, this paper is treated as waste paper. A specific procedure of the fixing experiment of this embodiment is as follows.

First, 10 low gloss images with 1% coverage were fixed in the low gloss mode (P5 of Example 2).

Next, in order to replenish the wax onto the fixing belt 220, one sheet of paper having a solid image formed thereon was fed as a paper for supplying wax, and fixing was carried out.

Next, in the high gloss mode (P1 of Example 2), a sheet of high gloss image (solid image) was fixed.

Further, as a comparative example, a similar fixing experiment was conducted in the case where the paper for supplying wax was not passed.

As shown in FIG. 10, the glossiness of the fixed high-gloss image was higher when the wax supply paper was passed before fixing the high-gloss image than when the paper was not passed. Therefore, even if the remaining amount of wax on the fixing belt 220 after fixing the low-gloss image is small, the wax is supplied onto the fixing belt 220 by passing the wax-supplying paper, thereby The glossiness required for the image can be secured.

The image forming apparatus 100 of this embodiment described above has the following effects.

Image forming apparatus 100 suppresses the removal of wax from fixing belt 220 for an image that requires high glossiness, and leaves the wax on fixing belt 220 . It improves sliding with the pressure roller 240 . Therefore, smoothing of the toner layer on the paper 10 is promoted, and the achievable range of glossiness is widened on the high gloss side. Further, by increasing the amount of wax removed from the fixing belt 220 for an image that requires low gloss, the slippage between the fixing belt 220 and the pressure roller 240 at the fixing nip portion N is reduced. Reduces glossiness. Therefore, the image forming apparatus 100 can control glossiness in a wider range from low glossiness to high glossiness.

(Second embodiment)
In the second embodiment, in addition to the configuration of the first embodiment, the fixing section 200 has a leveling roller.

FIG. 11 is a schematic diagram showing the main configuration of one example of the fixing section in the second embodiment. 12 is a schematic diagram showing a chart used in the fixing experiment of Example 5, and FIG. 13 is a graph showing experimental results showing the relationship between the web winding amount and the glossiness. In FIG. 13, the horizontal axis in the graph is the web winding amount per 10 A3 sheets, and the vertical axis is the glossiness of the image. In addition, the glossiness of the image was measured at 60 degree glossiness. Also, FIG. 14 is a schematic diagram showing the main configuration of another example of the fixing section in the second embodiment.

As shown in FIG. 11, the fixing section 200 further includes a leveling roller 290 (leveling member) in this embodiment. Leveling roller 290 is, for example, a cylindrical core made of metal such as aluminum whose outer peripheral surface is coated with resin or the like, or a rubber roller. placed in position. Note that the position of the leveling roller 290 is not limited to the position facing the heating roller 210 , and may be any position after the fixing nip portion N on the fixing belt 220 and before the wax removal portion 280 .

Further, leveling roller 290 is configured such that the outer peripheral surface thereof can contact or separate from fixing belt 220 . Leveling roller 290 may be configured to rotate following fixing belt 220 when the outer peripheral surface is in contact with fixing belt 220 . Alternatively, leveling roller 290 may be configured to rotate in a counter direction to the rotation of fuser belt 220 .

The wax on the fixing belt 220 promotes sliding between the paper 10 and the fixing belt 220 and improves glossiness. Even if the wax does not exist uniformly on the surface of the fixing belt 220 , the glossiness of the image is improved, but the wax is dispersed in the width direction of the fixing belt 220 , that is, the axial direction of the fixing roller 230 . It is possible to efficiently improve the glossiness by existing. On the other hand, when reducing the glossiness, the leveling roller 290 is separated from the fixing belt 220 and the operation is stopped.

Depending on the pattern of the toner image formed on the paper 10 , the wax may concentrate and adhere to a portion of the fixing belt 220 in the width direction. In such a case, the fixing unit 200 can spread the wax evenly in the width direction of the fixing belt 220 by the leveling roller 290 .

<Example 5>
In this embodiment, an experiment was conducted using the fixing unit 200 shown in FIG. 11 to obtain the relationship between the amount of winding of the web 281 and the glossiness of the image.

As shown in FIG. 12, an image pattern was generated in which the central portion was filled in a rectangular shape, and the image forming section 130 formed a solid central band chart toner image on A3 size coated paper (Esprit C209g). . By fixing such a toner image, the amount of residual wax on the surface of the fixing belt 220 is increased in the central portion and decreased in the peripheral portion.

In this embodiment, only the pressure roller 240 of the fixing section 200 is driven, and the fixing belt 220, the fixing roller 230, and the leveling roller 290 are rotated following the pressure roller 240, that is, rotated together with the pressure roller 240. I made it Other experimental conditions are the same as in Example 1.

As shown in FIG. 13, when the leveling roller 290 was operated, the glossiness of the image was improved compared to when it was not operated.

Further, as shown in FIG. 14, even when the leveling roller 290 was arranged between the wax removing section 280 and the fixing belt 220, the effect of improving the glossiness of the image was the same.

The image forming apparatus 100 of the second embodiment described above has the following effects in addition to the effects of the first embodiment.

Even if the wax is concentrated on a part of the fixing belt 220 in the width direction, the leveling roller 290 can level and disperse the wax so that it spreads in the width direction of the fixing belt 220. can improve the glossiness of

As described above, the image forming apparatus 100 and the control program have been described in the embodiments. However, it goes without saying that those skilled in the art can appropriately add, modify, and omit the present invention within the scope of its technical ideas.

For example, the control program for image forming apparatus 100 may be provided by a computer-readable recording medium such as a USB memory, flexible disk, or CD-ROM, or may be provided online via a network such as the Internet. . In this case, the program recorded on the computer-readable recording medium is usually transferred and stored in a memory, storage, or the like. Further, the control program may be provided, for example, as independent application software, or may be incorporated into the software of each device as one function of image forming apparatus 100 .

100 image forming apparatus,
110 image reading unit;
120 image processing unit,
130 image forming unit;
140 paper feeding unit,
150 paper transport unit,
200 fixing unit;
201 non-contact temperature sensor,
210 heated roller,
211 heater,
220 fixing belt,
230 fuser roller,
240 pressure roller,
250 fixing drive unit;
260 pressure drive,
270 drive control unit,
280 wax remover,
281 Web,
282 original winding roller,
283 pressure roller,
284 take-up roller,
290 leveling roller,
300 Communication Department,
400 operation display unit,
500 control unit,
510 CPUs,
520 auxiliary storage unit,
530 RAM,
540 ROMs.

Claims (9)

an image forming unit that forms a toner image on paper using toner containing wax;
a fixing member, a pressing member that presses against the fixing member and forms a fixing nip portion between the fixing member and the fixing member, and removes wax on the fixing member transferred from the toner image formed on the paper. a wax removal unit for fixing the toner image formed on the paper;
a glossiness acquisition unit that acquires the glossiness required for the toner image on the paper that is fixed by the fixing unit;
a wax removal adjustment unit that adjusts the removal performance of the wax removal unit for removing wax from the fixing member according to the glossiness;
a storage unit that stores the relationship between the amount of wax to be removed from the fixing member by the wax removal unit and the glossiness of the fixed image;
The image forming apparatus , wherein the wax removal adjustment section adjusts the removal performance of the wax removal section based on the relationship between the amount of wax stored in the storage section and the glossiness . a fixing drive unit that drives the fixing member to rotate;
a pressurizing drive unit that rotationally drives the pressurizing member;
a drive control unit that controls rotational driving of the fixing drive unit and the pressure drive unit;
The wax removal adjustment unit
2. The image forming apparatus according to claim 1 , wherein said removing performance is adjusted by changing a difference between a peripheral speed of said fixing member and a peripheral speed of said pressing member. The wax removal adjustment unit
3. The image forming apparatus according to claim 2 , wherein control is performed such that the greater the difference in peripheral speed, the lower the removal performance. The wax removal unit
a web for removing wax on the fusing member;
a web winding unit for winding the web,
4. The image forming apparatus according to claim 2 , wherein said wax removal adjusting section controls a winding speed of said web wound by said web winding section according to said difference in peripheral speed. The drive control unit
The peripheral speed of the fixing member is limited to within ±10% of the peripheral speed of the pressure member, and when the absolute value of the speed difference is larger than a predetermined threshold, the web 5. The image forming apparatus according to claim 4 , wherein the winding amount of the film is reduced. The image forming apparatus according to any one of claims 1 to 5 , further comprising a leveling member that contacts the surface of the fixing member and levels the wax. The image forming apparatus according to any one of claims 1 to 6 , wherein the wax content of the toner is 5 to 20% by mass with respect to the entire toner. The wax removal adjustment unit
calculating the absolute value of the difference between the peripheral speed of the fixing member and the peripheral speed of the pressure member at predetermined time intervals;
If the rate of change of the absolute value exceeds a predetermined threshold,
The image forming apparatus according to any one of claims 1 to 7 , wherein the amount of wax in the fixing member is increased by passing another paper for supplying wax through the fixing nip portion. an image forming unit that forms a toner image on paper using toner containing wax;
a fixing member, a pressing member that presses against the fixing member to form a fixing nip portion between itself and the fixing member, and wax that removes the wax from the fixing member transferred from the toner image formed on the paper. a fixing unit that fixes the image formed on the paper, and a removing unit;
A control program for an image forming apparatus having a storage unit that stores a relationship between the amount of wax to be removed from the fixing member by the wax removing unit and the glossiness of the fixed image ,
a step (a) of obtaining a gloss level required for the image on the paper to be fixed by the fixing unit;
A procedure for determining the removal performance of the wax removal unit for removing wax from the fixing member according to the glossiness , wherein the amount of wax stored in the storage unit and the glossiness of the image after fixing are determined. a step (b) of determining the removal performance of the wax removal unit based on the relationship of
a step (c) of forming a toner image on the paper;
a step (d) of fixing the toner image formed on the paper;
is executed by the image forming apparatus.

Images