Image forming apparatus, image forming method, and program

Abstract

To provide an image forming apparatus, an image forming method, and a program that can use normal toner and special toner and can more reliably remove fixing dirt.SOLUTION: An image forming apparatus uses normal toner and special toner, and the image forming apparatus has: an image forming unit that forms an unfixed image on a sheet; a fixing unit that has a fixing rotating body and a pressure member, and fixes the unfixed image to the sheet; a cleaning unit that cleans the fixing rotating body and / or the pressure member; and a control unit that controls to increase the cleaning force of the cleaning unit in printing using the special toner compared with printing not using the special toner.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, an image forming method, and a program.

Background Art

[0002] In an image forming apparatus that uses toner, there is a problem of fixing offset in which toner transfers from the paper to the members of the fixing unit when fixing an unfixed image on the paper. To solve such a problem of fixing stain, in the technique described in Patent Document 1, a mechanism for cleaning the fixing stain is provided by a cleaning roller that contacts the members of the fixing unit. In this mechanism, the cleaning operation time is controlled according to the toner concentration in the developing unit before passing through the fixing roller and the printed area ratio of the unfixed image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, in order to increase added value, an apparatus that uses special toner such as white toner in addition to conventional normal toner is known. However, it has been found that in the technique described in Patent Document 1, in a printing job using special toner, the above-described fixing stain generated during the job cannot be sufficiently cleaned. If the fixing stain cannot be sufficiently cleaned, problems such as the offset toner damaging the paper and the print image quality deteriorating occur.

[0005] The present invention has been made in view of the above situation. The problem to be solved by the present invention is to provide an image forming apparatus, an image forming method, and a program that can use normal toner and special toner and can more reliably eliminate fixing stain.

Means for Solving the Problems

[0006] The above problems can be solved by the following means.

[0007] 1. An image forming apparatus that uses normal toner and special toner, an image forming unit that forms an unfixed image on a sheet, a fixing unit that has a fixing rotator and a pressing member and fixes the unfixed image on the sheet, a cleaning unit that cleans the fixing rotator and / or the pressing member, and a control unit that controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing without using the special toner. The image forming apparatus has the control unit.

[0008] 2. The image forming apparatus according to claim 1, wherein at least one of color toner and black toner is used as the normal toner.

[0009] 3. The image forming apparatus according to claim 1, wherein at least one of white toner, clear toner, gold toner, and silver toner is used as the special toner.

[0010] 4. The image forming apparatus according to claim 1, wherein the control unit controls the cleaning force by controlling at least one of a cleaning amount in the cleaning unit, a time corresponding to the operation of the cleaning unit, a force corresponding to the operation of the cleaning unit, and a speed corresponding to the operation of the cleaning unit.

[0011] 5. The image forming apparatus according to claim 1, wherein the control unit controls the cleaning unit so that the cleaning force in a print job using the special toner is twice or more the cleaning force in a print job not using the special toner.

[0012] 6. The image forming apparatus according to claim 5, wherein the control unit controls the cleaning unit so that the cleaning force in a print job using the special toner is five times or more the cleaning force in a print job not using the special toner.

[0013] 7. The image forming apparatus according to claim 6, wherein the special toner includes white toner.

[0014] 8. The control unit increases or decreases the cleaning force based on the following formula (1), Formula (1) Y = (C1 × X1 + C2 × X2) × Z Y: Cleaning amount C1: Coverage rate of the special toner X1: Special toner coefficient C2: Coverage rate of the area with only normal toner X2: Normal toner coefficient Z: Arbitrary coefficient The image forming apparatus according to claim 1, wherein the special toner coefficient X1 is at least twice the normal toner coefficient X2.

[0015] 9. The image forming apparatus according to claim 8, wherein the special toner coefficient X1 is at least five times the normal toner coefficient X2.

[0016] 10. The image forming apparatus according to claim 9, wherein the special toner includes white toner.

[0017] 11. The image forming apparatus according to claim 1, wherein the cleaning unit has a first cleaning member that contacts the fixing rotator or the pressing member.

[0018] 12. The image forming apparatus according to claim 11, wherein the cleaning unit has a second cleaning member that contacts the first cleaning member.

[0019] 13. The image forming apparatus according to claim 12, wherein the second cleaning member is a web mechanism.

[0020] 14. The image forming apparatus according to claim 13, wherein the control unit controls the cleaning force by increasing or decreasing the web feed amount of the web mechanism as the cleaning amount.

[0021] 15. The image forming apparatus according to claim 4, wherein the control unit controls the cleaning force by increasing or decreasing the cleaning amount according to the paper size and / or the printing coverage rate.

[0022] 16. The image forming apparatus according to item 13, wherein the control unit varies the web feeding speed of the web mechanism.

[0023] 17. An image forming method using a normal toner and a special toner, comprising: an image forming step of forming an unfixed image on a sheet by an image forming unit; a fixing step of fixing the unfixed image on the sheet by a fixing unit having a fixing rotating body and a pressing member; a cleaning step of cleaning the fixing rotating body and / or the pressing member by a cleaning unit during or after the fixing step; and an image forming method in which, in the cleaning step, a control unit controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing not using the special toner.

[0024] 18. A computer of an image forming apparatus including an image forming unit that forms an unfixed image on a sheet, a fixing unit having a fixing rotating body and a pressing member that fixes the unfixed image on the sheet, and a cleaning unit that cleans the fixing rotating body and / or the pressing member, and using a normal toner and a special toner, a program that functions as a control unit that controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing not using the special toner.

Effects of the Invention

[0025] By the above means of the present invention, an image forming apparatus, an image forming method, and a program that can use a normal toner and a special toner and can more reliably eliminate fixing stains can be provided.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0027] Hereinafter, with reference to the drawings, some embodiments of the present invention will be described. The features and technical effects of the embodiments will be understood from the following detailed description and the drawings. However, the scope of the present invention is not limited to the embodiments disclosed below. Since the drawings are provided for illustrative purposes only, the scope of the present invention is not limited to the illustrations in the drawings.

[0028] FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the image forming apparatus 1. FIG. 2 is an enlarged view of the fixing unit 23 and the cleaning unit 24. FIG. 3 is a block diagram showing the functional configuration of an embodiment of the image forming apparatus 1.

[0029] The image forming apparatus 1 of the present embodiment includes a paper feeding unit 10, a main body unit 20, a post-processing unit 30, a control unit 40, a storage unit 50, a communication unit 60, an operation display unit 70, and a bus 80.

[0030] The paper feeding unit 10 includes a plurality of paper feeding trays 11 and paper feeding means (not shown) including a paper feeding roller, a separating roller, a paper feeding / separating rubber, a feeding roller, and the like. Papers of different paper types, basis weights, sizes, etc. are stored in each paper feeding tray 11. The papers are conveyed one by one from the paper feeding unit 10 to the main body unit 20.

[0031] The main body unit 20 includes a conveying unit 21, an image forming unit 22, a fixing unit 23, and a cleaning unit 24.

[0032] The conveying unit 21 conveys the paper supplied from the paper feeding unit 10 through the image forming unit 22 and the fixing unit 23 to the post-processing unit 30. The conveying unit 21 includes a plurality of conveying rollers and the like for conveying the paper provided along a predetermined paper conveying path. The conveying unit 21 includes a paper reversing mechanism for double-sided printing that reverses the front and back of the paper passing through the fixing unit 23 and sends it back to the conveying path upstream of the image forming unit 22 again.

[0033] The image forming unit 22 forms an unfixed image on the paper conveyed by the conveying unit 21 based on a print job or the like. The image forming unit 22 includes an intermediate transfer belt 221, a yellow toner image forming unit 222Y, a magenta toner image forming unit 222M, a cyan toner image forming unit 222C, a black toner image forming unit 222K, a white toner image forming unit 222W, and a secondary transfer roller 223.

[0034] Note that the types, numbers, arrangements, etc. of the image forming units are not limited to this. Since the image forming apparatus of the present disclosure uses normal toner and special toner, it may have an image forming unit corresponding thereto. Normal toner includes color toner and black toner. Color toner includes yellow toner, magenta toner, and cyan toner. Special toner is, for example, white toner, clear toner, gold toner, silver toner, etc.

[0035] Each image forming unit includes a rotating drum-shaped photoreceptor, a charging unit, an exposure unit, a developing unit, a primary transfer roller, and a photoreceptor cleaning unit that are sequentially arranged along the rotation direction of the photoreceptor in the outer peripheral surface region of the photoreceptor (not shown in the figure). The intermediate transfer belt 221 is rotated by a roller (not shown). In each image forming unit, toner images of each color are formed on the photoreceptor by an electrophotographic method. The toner images of each color are transferred to the intermediate transfer belt 221 by the primary transfer roller, and the toner images of each color are superimposed on the intermediate transfer belt 221. The superimposed toner image is transferred to the paper by the secondary transfer roller. Thereby, an unfixed image is formed on the paper.

[0036] The fixing unit 23 fixes the unfixed image on the paper by heating and pressurization. The fixing unit 23 includes a fixing rotating body 231 and a pressing member 232.

[0037] In the embodiments shown in FIGS. 1 and 2, the fixing rotating body 231 is a fixing belt. The fixing rotating body (fixing belt) 231 is stretched by a fixing roller 233, a heating roller 234, and a tensioning roller 235. A driving force is transmitted from a driving motor (not shown) to at least one of the rotating shafts of the fixing roller 233, the heating roller 234, and the tensioning roller 235. Thereby, the fixing rotating body (fixing belt) 231 rotates in the direction of the arrow in the figure.

[0038] The fixing rotating body (fixing belt) 231 may be configured by covering the outer peripheral surface of a polyimide substrate with heat-resistant silicone rubber as an elastic layer and further covering it with a tube of PFA (perfluoroalkoxyalkane), which is a heat-resistant resin. The thickness of the substrate is, for example, about 70 μm. The thickness of the silicone rubber is, for example, about 400 μm. The length of the fixing rotating body (fixing belt) 231 is, for example, about equivalent to an outer diameter of φ168 mm.

[0039] The fixing rotating body 231 is not limited to a fixing belt, and may be, for example, a roller-shaped fixing drum. The fixing drum is, for example, one in which an elastic layer and a release layer are arranged on the outer peripheral surface of a metal sleeve such as aluminum. When the fixing rotating body 231 is a fixing drum, the fixing roller 233, the heating roller 234, and the tensioning roller 235 are not required.

[0040] The heating roller 234 is composed of a metal core bar that is hollow, a coat layer located on the surface of the core bar, and a heater located in the internal space of the core bar. The outer diameter of the core bar is, for example, about φ80 mm. The thickness of the core bar is, for example, about 2.5 mm. The core bar is made of, for example, aluminum. The thickness of the coat layer is, for example, about 15 μm. The coat layer is made of PFA (perfluoroalkoxyalkane) or PTFE (polytetrafluoroethylene). The heater is composed of, for example, a plurality of halogen lamps.

[0041] The fixing roller 233 is formed by coating a core bar made of a metal such as iron with an elastic layer. As the elastic layer, for example, silicon rubber can be used. The elastic layer may be configured by coating heat-resistant silicon rubber with PTFE (polytetrafluoroethylene), which is a heat-resistant resin. The outer diameter of the fixing roller 233 is, for example, about φ90 mm. The thickness of the elastic layer is, for example, about 20 mm. The hardness of the elastic layer is, for example, about 35° (Asker C).

[0042] The tensioning roller 235 is a roller made of metal or the like. By changing the biasing force with a variable mechanism, the total tension on both sides of the end of the fixing rotating body (fixing belt) 231 can be appropriately set, for example, in the range of 100 to 400 N.

[0043] In the embodiments shown in FIGS. 1 and 2, the pressing member 232 is a pressing roller. The pressing member (pressing roller) 232 is formed by coating a core bar with an elastic layer, for example. As the elastic layer, for example, heat-resistant silicon rubber can be used. The elastic layer may be configured by coating heat-resistant silicon rubber with a PFA (perfluoroalkoxy alkane) tube as a surface release layer. The outer diameter of the pressing member 232 is, for example, about φ80 mm. The thickness of the elastic layer is, for example, about 10 mm. The hardness of the elastic layer is, for example, about 30° (Asker C).

[0044] The fixing roller 233 and the pressing member 232 are pressed against each other via the fixing rotating body 231, thereby forming a fixing nip N between the fixing rotating body 231 and the pressing member 232. The pressing load is, for example, about 2500 N.

[0045] The length in the rotation axis direction (longitudinal direction) of each member of the fixing unit 23 such as the fixing rotating body 231 is a length that sufficiently corresponds to the paper width.

[0046] Toner or wax may transfer from the unfixed image and stain the fixing rotating body 231. Toner or wax that adheres to the pressing member 232 and is not cleaned may transfer from the fixing rotating body 231 and stain it.

[0047] The cleaning unit 24 cleans the fixing rotating body 231 and / or the pressing member 232 of the fixing unit 23. The cleaning unit 24 may be provided to clean only one of the fixing rotating body 231 and the pressing member 232. A plurality of cleaning units 24 may be provided to clean both the fixing rotating body 231 and the pressing member 232. In the embodiments shown in FIGS. 1 and 2, the cleaning unit 24 is provided to clean only the fixing rotating body (fixing belt) 231.

[0048] The cleaning unit 24 may be configured to be separated from the fixing rotating body 231 or the pressing member 232 except during cleaning, and to contact and press against the fixing rotating body 231 or the pressing member 232 only during cleaning. By separating the cleaning unit 24 from the fixing rotating body 231 or the pressing member 232 except during cleaning, unnecessary member deterioration is reduced.

[0049] In the embodiments shown in FIGS. 1 and 2, the cleaning unit 24 includes a first cleaning member 241 that contacts the fixing rotating body (fixing belt) 231, and a second cleaning member 242 that contacts the first cleaning member 241. When the cleaning unit 24 cleans the pressing member 232, the first cleaning member 241 contacts the pressing member 232. The first cleaning member 241 only needs to contact the fixing rotating body 231 or the pressing member 232 at least during cleaning.

[0050] In the embodiments shown in FIGS. 1 and 2, the first cleaning member 241 is a cleaning roller. The first cleaning member (cleaning roller) 241 has, for example, lower releasability than the fixing rotating body (fixing belt) 231. Therefore, the toner and wax adhering to the fixing rotating body (fixing belt) 231 are likely to transfer to the first cleaning member (cleaning roller) 241. The first cleaning member (cleaning roller) 241 rotates in the direction of the arrow in the figure. The rotation speed of the first cleaning member (cleaning roller) 241 can be adjusted as appropriate.

[0051] Note that the first cleaning member 241 is not limited to a cleaning roller, and may be a scraper, a brush, or the like.

[0052] In the embodiments shown in FIGS. 1 and 2, the second cleaning member 242 is a web mechanism. A web mechanism is a mechanism for cleaning an object using a web. The second cleaning member (web mechanism) 242 is composed of a delivery roller 242a, a winding roller 242b, a pressing roller 242c, and a web 242d. The web 242d is, for example, a long sheet made of a non-woven fabric using heat-resistant fibers such as aramid fibers. The web 242d is sent out from the delivery roller 242a, pressed against the surface of the first cleaning member (cleaning roller) 241 by the pressing roller 242c, and wound around the winding roller 242b. The web 242d rubs against the surface of the first cleaning member (cleaning roller) 241 at the contact portion with the surface of the first cleaning member (cleaning roller) 241 to wipe off toner and wax. Thereby, the second cleaning member (web mechanism) 242 indirectly cleans the fixing rotating body (fixing belt) 231 via the first cleaning member (cleaning roller) 241. The feeding speed of the web 242d can be adjusted as appropriate.

[0053] Note that the second cleaning member 242 is not limited to a web mechanism, and may be a scraper, a brush, or the like. From the viewpoint of less toner scattering and less deterioration of each member, the second cleaning member 242 is preferably a web mechanism.

[0054] The post-processing unit 30 performs post-processing on the paper conveyed from the main body unit 20. Examples of the post-processing include staple processing, punching processing, folding processing, binding processing, and the like. The post-processing is not essential, and the post-processing is executed only when instructed from the control unit 40. When the post-processing unit 30 does not perform the post-processing, the conveyed paper is discharged as it is.

[0055] The control unit 40 comprehensively controls the operations of each functional component of the image forming apparatus 1. The control unit 40 includes a CPU (Central Processing Unit) 41, a RAM (Random Access Memory) 42, and a ROM (Read Only Memory) 43. The CPU 401 executes various control programs to drive and control the image forming apparatus 1 and performs various arithmetic processes. The RAM 402 provides a working memory space for the CPU 401 and stores temporary data. The RAM 402 may include a non-volatile memory. The ROM 403 stores various control programs, setting data, etc. to be executed by the CPU 401. A rewritable non-volatile memory such as a flash memory may be used instead of the ROM 403. As will be described later, the control unit 40 of the image forming apparatus 1 of the present disclosure controls at least the cleaning power of the cleaning unit 24 to be higher in printing using a special toner than in printing without using a special toner.

[0056] The storage unit 50 stores programs executed by the CPU 41, various setting data, etc. in a readable and writable manner. As the storage unit 50, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like is used in combination.

[0057] The communication unit 60 controls the transmission and reception of data (signals) with external devices, etc. according to a predetermined communication standard. The communication unit 60 controls communication according to, for example, the LAN (Local Area Network) standard. The communication unit 60 may be connectable to peripheral devices according to a standard such as USB (Universal Serial Bus).

[0058] The operation display unit 70 includes a display such as an LCD (Liquid Crystal Display) or an organic EL display. Further, the operation display unit 70 includes a touch panel and / or hard keys. The operation display unit 70 performs display of various setting screens, various buttons, the operation status of each function, etc. according to the display control signal input from the control unit 40. The user can operate the operation display unit 70 to execute settings related to image formation, paper conveyance instructions, startup and stop operations of the apparatus, etc. The settings related to image formation include image quality settings, magnification settings, application settings, output settings, paper settings, etc. A corresponding operation signal is output to the control unit 40 according to the user's operation.

[0059] The bus 80 is a path for transmitting and receiving signals between the control unit 40 and other functional components.

[0060] Each functional component may operate based on a control signal transmitted from a separate processor (such as a CPU) from the control unit 40.

[0061] Next, the control of the cleaning force of the cleaning unit 24 performed by the control unit 40 will be described.

[0062] The image forming apparatus 1 of the present disclosure uses normal toner and special toner. The control unit 40 included in the image forming apparatus 1 controls the cleaning force of the cleaning unit 24 to be higher in printing using special toner than in printing not using special toner.

[0063] The cleaning force of the cleaning unit 24 in the present disclosure refers to the ability of the cleaning unit 24 to clean the fixing rotator 231 or the pressing member 232. The cleaning force is determined by, for example, the following parameters. Therefore, the control unit 40 controls the cleaning force by increasing or decreasing the parameters exemplified below from the start of a certain printing to the start of the next printing. (1) Cleaning amount (web feed amount, etc.) (2) Time for the first cleaning member 241 to contact the fixing rotator 231 or the pressing member 232 (3) Time for the second cleaning member 242 to contact the first cleaning member 241 (4) The contact force between the first cleaning member 241 and the fixing rotating body 231 or the pressing member 232 (5) When the first cleaning member 241 is a cleaning roller, the rotation speed of the cleaning roller

[0064] The cleaning amount is, for example, the web feed amount when the first cleaning member 241 is a cleaning roller and the second cleaning member 242 is a web mechanism. The web feed amount refers to the length of the web 242d fed by the web mechanism. Since the web feed amount is easy to adjust, the control unit 40 can easily control the cleaning force appropriately by increasing or decreasing the web feed amount as the cleaning amount.

[0065] Special toner is more likely to transfer from the paper to the fixing rotating body 231 and become fixing stains due to differences in components, shape, size, etc. compared to normal toner. Therefore, by increasing the cleaning force of the cleaning unit 24 in printing using special toner compared to printing without using special toner, the cleaning unit 24 can more reliably eliminate fixing stains.

[0066] When the control unit 40 controls the cleaning force by increasing or decreasing the cleaning force, it may increase or decrease the cleaning amount according to the paper size and / or the printing coverage ratio. For example, it is preferable for the control unit 40 to increase the cleaning amount in printing with a larger paper size than in printing with a smaller paper size. Similarly, it is preferable for the control unit 40 to increase the cleaning amount in printing with a larger printing coverage ratio than in printing with a smaller printing coverage ratio. Thereby, the cleaning unit 24 can more reliably eliminate fixing stains. The printing coverage ratio includes, for example, the coverage ratio of special toner, the coverage ratio of the area with only normal toner, etc.

[0067] When the first cleaning member 241 is a cleaning roller and the second cleaning member 242 is a web mechanism, the control unit 40 may vary the web feed speed of the second cleaning member (web mechanism) 242. For example, by increasing the web feed speed, the amount of web fed within a certain period of time can be increased. Thereby, the control unit 40 can easily and appropriately control the cleaning force according to the required cleaning force.

[0068] The control unit 40 may increase or decrease the cleaning amount based on, for example, the following formula (1). Formula (1) Y = (C1 × X1 + C2 × X2) × Z Y: cleaning amount C1: coverage rate of special toner X1: special toner coefficient C2: coverage rate of the area with only normal toner X2: normal toner coefficient Z: arbitrary coefficient

[0069] The coverage rate C1 of the special toner is the ratio of the area of at least the area where the special toner is applied, when the printing area of the paper is taken as 100%.

[0070] The special toner coefficient X1 is a coefficient to be multiplied by the coverage rate C1 of the special toner and can be arbitrarily set.

[0071] The coverage rate C2 of the area with only normal toner is the ratio of the area where only normal toner is applied, when the printing area of the paper is taken as 100%.

[0072] The normal toner coefficient X2 is a coefficient to be multiplied by the coverage rate C2 of the area with only normal toner and can be arbitrarily set.

[0073] The arbitrary coefficient Z is a coefficient other than the above and can be arbitrarily set. The arbitrary coefficient Z may be a product of a plurality of coefficients. The arbitrary coefficient Z may include, for example, a paper size coefficient. The paper size coefficient is a coefficient determined according to the paper size, and is, for example, the area ratio of the paper when the area of A4 size is taken as 1.

[0074] The coverage rate C1 of the special toner is 0% in printing without using the special toner and is more than 0% in printing using the special toner. Therefore, when the coverage rate C2 of the area with only the normal toner is the same, the cleaning amount increased or decreased based on the above formula (1) is larger in printing using the special toner than in printing without using the special toner. As a result, the cleaning power becomes higher in printing using the special toner than in printing without using the special toner.

[0075] The special toner coefficient X1 is preferably at least twice the normal toner coefficient X2, and particularly preferably at least five times when the special toner is a white toner. Thereby, the cleaning unit 24 can more surely eliminate the fixing stain.

[0076] As a specific embodiment, when the normal toner is a yellow toner, a magenta toner, a cyan toner, and a black toner, and the special toner is a white toner, for example, by setting the special toner coefficient X1 to 6 and the normal toner coefficient X2 to 1, the cleaning unit 24 can more surely eliminate the fixing stain. At this time, the arbitrary coefficient Z is the product of the paper size coefficient and other coefficients.

[0077] FIG. 4 is a flowchart showing an example of the flow of the image forming method when the control unit 40 controls the cleaning power by increasing or decreasing the cleaning amount.

[0078] In step S1, a print job is started according to a control signal from the control unit 40.

[0079] In step S2, it is detected that the sheet on which the unfixed image is formed in the image forming unit 22 is conveyed to the conveying unit 21 and passes through the fixing unit 23.

[0080] In step S3, the control unit 40 calculates the cleaning amount (for example, web feed amount) in the printing of one sheet of paper for each sheet of paper according to the paper size, the type of toner used, the print coverage rate, etc., for example, based on the above formula (1).

[0081] In step S4, according to the cleaning amount calculated in step S3, the cleaning unit 24 cleans the fixing rotating body 231 of the fixing unit 23 and / or the pressing member 232.

[0082] In step S5, the control unit 40 determines whether there is a next printing job. If there is a next printing job, the next printing job is started in step S1. If there is no next printing job, the image formation ends.

[0083] The flowchart shown in FIG. 4 is an example, and the flow of the image forming method is not limited thereto. For example, the cleaning amount calculation in step S3 may be performed before step S2.

[0084] Further, the control unit 40 can also change the cleaning force for each printing job instead of calculating the cleaning amount for each sheet. For example, when a printing job using special toner is set, the control unit 40 may control the cleaning unit 24 to have a cleaning amount more than twice that of a printing job not using special toner. Furthermore, when a printing job using special toner including white toner is set, the control unit 40 may control the cleaning unit 24 to have a cleaning force more than five times that of a printing job not using special toner so as to be more surely cleaned.

[0085] As described above, the image forming apparatus of the present disclosure uses normal toner and special toner and includes an image forming unit, a fixing unit, a cleaning unit, and a control unit. The image forming unit forms an unfixed image on a sheet. The fixing unit has a fixing rotating body and a pressing member and fixes the unfixed image on the sheet. The cleaning unit cleans the fixing rotating body and / or the pressing member. The control unit controls the cleaning force of the cleaning unit to be higher in printing using special toner than in printing not using special toner. Thereby, the cleaning unit can more surely eliminate the fixing stain.

[0086] The image forming method of the present disclosure is an image forming method by an image forming apparatus that uses normal toner and special toner. The image forming method includes an image forming step, a fixing step, and a cleaning step. In the image forming step, an image forming unit forms an unfixed image on a sheet. In the fixing step, a fixing unit having a fixing rotator and a pressing member fixes the unfixed image on the sheet. In the cleaning step, a cleaning unit cleans the fixing rotator and / or the pressing member during or after the fixing step. In the cleaning step, a control unit controls the cleaning force of the cleaning unit to be higher in printing using special toner than in printing not using special toner.

[0087] The program of the present disclosure is a program that causes a computer of an image forming apparatus that uses normal toner and special toner to function as a control unit. The image forming apparatus includes an image forming unit, a fixing unit, and a cleaning unit. The image forming unit forms an unfixed image on a sheet. The fixing unit has a fixing rotator and a pressing member, and fixes the unfixed image on the sheet. The cleaning unit cleans the fixing rotator and / or the pressing member. The control unit controls the cleaning force of the cleaning unit to be higher in printing using special toner than in printing not using special toner.

Explanation of Reference Numerals

[0088] 1 Image forming apparatus 10 Paper feeding unit 11 Paper feed tray 20 Main body unit 21 Conveying unit 22 Image forming unit 221 Intermediate transfer belt 222Y Image forming unit for yellow toner 222M Image forming unit for magenta toner 222C Image forming unit for cyan toner 222K Image forming unit for black toner 222W Image forming unit for white toner 223 Secondary transfer roller 23 Fixing unit 231 Fixing rotator 232 Pressing member 233 Fixing roller 234 Heating roller 235 Tension roller 24 Cleaning section 241 First cleaning member 242 Second cleaning member 242a Feeding roller 242b Take-up roller 242c Pressing roller 242d Web 30 Post-treatment section 40 Control section 50 Memory section 60 Communication section 70 Operation display section 80 Bus

Claims

1. An image forming apparatus that uses normal toner and special toner, an image forming unit that forms an unfixed image on a sheet, a fixing unit that has a fixing rotator and a pressing member and fixes the unfixed image on the sheet, a cleaning unit that cleans the fixing rotator and / or the pressing member, and a control unit that controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing without using the special toner. An image forming apparatus having the same.

2. The image forming apparatus according to claim 1, wherein at least one of color toner and black toner is used as the normal toner.

3. The image forming apparatus according to claim 1, wherein at least one of white toner, clear toner, gold toner, and silver toner is used as the special toner.

4. The image forming apparatus according to claim 1, wherein the control unit controls the cleaning force by controlling at least one of the cleaning amount in the cleaning unit, the time corresponding to the operation of the cleaning unit, the force corresponding to the operation of the cleaning unit, and the speed corresponding to the operation of the cleaning unit.

5. The image forming apparatus according to claim 1, wherein the control unit controls the cleaning unit so that the cleaning force in a printing job using the special toner is at least twice the cleaning force in a printing job not using the special toner.

6. The image forming apparatus according to claim 5, wherein the control unit controls the cleaning unit so that the cleaning force in a printing job using the special toner is at least five times the cleaning force in a printing job not using the special toner.

7. The image forming apparatus according to claim 6, wherein the special toner includes white toner.

8. The control unit increases or decreases the cleaning force based on the following formula (1), Equation (1) Y = (C １ × X １ + C ２ × X ２ ) × Z Y: cleaning amount C １ : Coverage rate of special toner X １ : Special toner coefficient C ２ : Coverage ratio of the area with only normal toner X ２ : Normal toner coefficient Z: arbitrary coefficient The special toner coefficient X １ is more than twice the normal toner coefficient X ２ The image forming apparatus according to claim 1

9. The special toner coefficient X １ is five times or more the normal toner coefficient X ２ The image forming apparatus according to claim 8

10. The image forming apparatus according to claim 9, wherein the special toner includes white toner.

11. The image forming apparatus according to claim 1, wherein the cleaning unit has a first cleaning member that contacts the fixing rotator or the pressing member.

12. The image forming apparatus according to claim 11, wherein the cleaning unit has a second cleaning member that contacts the first cleaning member.

13. The image forming apparatus according to claim 12, wherein the second cleaning member is a web mechanism.

14. The image forming apparatus according to claim 13, wherein the control unit controls the cleaning force by increasing or decreasing the web feed amount of the web mechanism as the cleaning amount.

15. The image forming apparatus according to claim 4, wherein the control unit controls the cleaning force by increasing or decreasing the cleaning amount according to the paper size and / or the printing coverage ratio.

16. The image forming apparatus according to claim 13, wherein the control unit varies the web feed speed of the web mechanism.

17. An image forming method by an image forming apparatus using normal toner and special toner, comprising: an image forming step of forming an unfixed image on a sheet by an image forming unit; a fixing step of fixing the unfixed image on the sheet by a fixing unit having a fixing rotating body and a pressing member; a cleaning step of cleaning the fixing rotating body and / or the pressing member by a cleaning unit during or after the fixing step; and an image forming method, wherein in the cleaning step, a control unit controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing not using the special toner.

18. A computer of an image forming apparatus that includes an image forming unit that forms an unfixed image on a sheet, a fixing unit that has a fixing rotating body and a pressing member and fixes the unfixed image on the sheet, and a cleaning unit that cleans the fixing rotating body and / or the pressing member, and uses normal toner and special toner, a program that functions as a control unit that controls the cleaning force of the cleaning unit to be higher in printing using the special toner than in printing not using the special toner.

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