JP4663333B2 - Image prediction apparatus, image forming apparatus, and image prediction method - Google Patents

Description

  The present invention relates to an image prediction apparatus that predicts an image after fixing toner on a recording member, an image forming apparatus equipped with the image prediction apparatus, and image prediction that predicts an image after fixing toner on a recording member. Regarding the method.

  In a fixing device used in an electrophotographic apparatus such as a copying machine, a facsimile machine, or a printer, a fixing nip that is a pressure contact portion between a fixing roller or a fixing belt having a heating source disposed therein and a pressure roller or a pressure belt is provided. A so-called internal heating system is generally used in which a recording member carrying unfixed toner is carried in and the toner is fixed on the recording member by heating and melting.

  When toner is fixed on a recording member using an internal heating type fixing device, the degree of toner collapse varies depending on the temperature at the time of fixing. When the temperature at the time of fixing is high, the toner tends to spread in the horizontal direction with respect to the print surface, so that blurring and blurring of the image increase. On the other hand, if the temperature at the time of fixing is low, the toner is difficult to spread, and the image becomes sharp.

  When an image with large blurring or blur is fixed on the recording member, the recording member printed, labor cost, electricity cost, toner cost, etc. are wasted without satisfying the print creator's request.

  Japanese Patent Application Laid-Open No. 2005-228561 satisfies a specific formula in the relationship between the step of detecting the surface temperature of the pressure roller in the fixing device and at least the detected pressure roller detection temperature, the fixing nip time, and the fixing nip surface pressure. A target heating roller temperature acquisition operation including a step of calculating a target heating roller temperature to be performed, and a control for controlling an operation state of a heating source in the heating roller based on a target heating roller temperature obtained by the target heating roller acquisition operation. A device control method has been proposed.

  In Patent Document 2, a sheet temperature of an image fixing apparatus such as a copying machine, a printer, a facsimile machine, or the like is detected, and the fixing condition is automatically changed in accordance with the detected temperature of the sheet. In addition, an image fixing apparatus has been proposed that aims to always perform optimum fixing.

JP 2002-251099 A JP 05-333740 A

  However, since the surface temperature and the sheet temperature of the pressure roller change according to the use environment, a new method for preventing a bleeding at the time of fixing and forming a higher quality image is required. In the present invention, an image predicting device that predicts the interface temperature, focusing on the fact that the state when the toner is fixed on the recording member, such as blurring, is strongly influenced by the interface temperature between the toner and the recording member in the nip. It is an object to provide a forming apparatus and an image prediction method.

  Furthermore, a method for predicting how an image after fixing is formed depending on the interface temperature between the toner and the recording member has not been proposed yet. In the present invention, the image after fixing is fixed before fixing. If it is possible to predict, an image predicting apparatus that predicts the image after fixing based on the prediction of the interface temperature between the toner and the recording member, newly paying attention to the cost of the recording member, labor cost, electricity cost, toner cost, etc. An object is to provide an image forming apparatus and an image prediction method.

The image predicting apparatus according to the present invention predicts an interface temperature between a recording member at a nip between a fixing member and a pressure member and a toner to be fixed to the recording member according to a fixing condition , and on the recording member after fixing based on the interface temperature. In an image prediction apparatus that predicts an image, the interface temperature in the nip is determined based on the temperature of the fixing member, the temperature of the pressure member, and the temperature of the recording member before reaching the nip between the fixing member and the pressure member. An image to be fixed is predicted and displayed using the predicted interface temperature at the nip, the fixing pressure by the pressure member, and the point spread function indicating the degree of blurring of the image after fixing .

Image prediction apparatus of this invention, it is preferable to output an image predicted to outside. The image prediction apparatus according to the present invention may include an operation unit for setting fixing conditions. The image predicting apparatus according to the present invention may change the fixing condition based on the predicted image. The image prediction apparatus according to the present invention may include an operation unit that sets a reference for changing the fixing condition.

An image forming apparatus according to the present invention includes any one of the image prediction apparatuses described above. The image predicting method according to the present invention includes an interface temperature between a recording member at a nip between a fixing member and a pressure member and a toner to be fixed to the recording member according to a fixing condition , a temperature of the fixing member, a temperature of the pressure member, and a fixing. Point spread function that predicts based on the temperature of the recording member before reaching the nip between the member and the pressure member, and indicates the predicted interface temperature at the nip, the fixing pressure by the pressure member, and the degree of blurring of the image after fixing Are used to predict and display an image to be fixed .

  According to the image predicting apparatus, the image forming apparatus, and the image predicting method of the present invention, an image after fixing can be predicted, and an unsatisfactory image is printed, printed paper, labor cost, electricity cost, toner cost Can be prevented, and the environmental load can be reduced.

  As shown in the configuration diagram of FIG. 1, the image forming apparatus 1 according to the first embodiment includes a paper feed unit 10, a transfer unit 11, a fixing device 12, a paper discharge unit 13, and an image formation control unit 14. . The paper feeding unit 10 accommodates various recording members 15 such as plain paper accommodated in a tray, and feeds the recording unit 15 appropriately. The transfer unit 11 charges and exposes the photosensitive member to form a latent image, develops and develops the latent image, transfers the toner to the recording member 15, and cleans the transferred photosensitive member. The fixing device 12 fixes the toner 16 transferred to the recording member 15 to the recording member 15. The paper discharge unit 13 discharges and stores the recording member 15 on which the toner 16 is fixed. The image formation control unit 14 controls a series of operations related to image formation of the image forming apparatus 1. The configuration of the image forming apparatus 1 is not limited to this, and other methods may be used as long as the toner image is formed on the recording member 15. Further, the fixing device 12 is not limited to being incorporated in the image forming apparatus 1, but may be a single unit or may be incorporated in another device.

  2, the fixing device 12 includes a fixing member 20, a heater 21, a pressure member 22, a conveyance motor 23, a pressure mechanism 24, a recording member temperature sensor 25, a fixing member temperature sensor 26, and a pressure. A member temperature sensor 27, a fixing control unit 28, and an image prediction device 29 are provided to fix the toner 16 to the recording member 15.

  The fixing member 20 is a roller provided with a fixing member surface layer 31 on the surface of the fixing member core 30. Specifically, the fixing member core 30 is made of aluminum, and the fixing member surface layer 31 is made of Teflon (registered trademark). Is formed. The heater 21 heats the fixing member 20 at a variable temperature by generating heat inside the hollow of the fixing member core 30.

  The pressure member 22 is a roller that is disposed to face the fixing member 20 and has a pressure member surface layer 33 on the surface of the pressure member core metal 32. Specifically, the pressure member core metal 32 is made of aluminum. The pressure member surface layer 33 is formed of silicone. The conveyance motor 23 is constituted by a motor whose speed can be varied, such as a stepping motor, an AC motor, and a DC motor, and is rotated on the central axis of the pressure member 22.

  The pressure mechanism 24 forms a nip that sandwiches the recording member 15 by pressing the pressure member 22 against the fixing member 20 with a variable fixing pressure. Specifically, the pressure mechanism 24 includes a stepping motor 40, a cylinder 41, a spring 42, and a pressure lever 43. The tip of the stepping motor 40 has a screw shape and is inserted into the cylinder 41. The cylinder 41 reciprocates in the direction of the rotation axis by the rotation of the stepping motor 40. The spring 42 has one end connected to the cylinder 41 and the other end connected to a pressure lever 43. The pressure lever 43 is pulled by the elastic force of the spring 42 with one end serving as a fulcrum 44, contacts the shaft of the pressure member 22 between the fulcrum 44 and the spring 42, and applies pressure to the pressure member 22.

  The fixing member 20 and the pressure member 22 may have various shapes such as a belt shape and a plate shape in addition to a roller shape, and the fixing member 20 and the pressure member 22 are not necessarily in the same shape. The fixing member 20 may have a function as the pressing member 22, or the pressing member 22 may have a function as the fixing member 20.

  The recording member temperature sensor 25 detects the temperature of the recording member 15 before being conveyed to the nip. The fixing member temperature sensor 26 detects the surface temperature of the fixing member 20. The pressure member temperature sensor 27 detects the surface temperature of the pressure member 22. Specifically, the recording member temperature sensor 25, the fixing member temperature sensor 26, and the pressure member temperature sensor 27 are each a contact type temperature sensor such as a thermistor or a non-contact type temperature sensor such as an infrared radiation thermometer. It is configured using a sensor or the like.

  As shown in the block diagram of FIG. 3, the fixing control unit 28 includes a heating control unit 50, a speed control unit 51, and a pressure control unit 52, and is based on commands from the image forming control unit 14 and the image prediction device 29. To control the fixing temperature, fixing nip speed, and fixing pressure. The heating control unit 50 varies the fixing temperature by controlling the amount of heat generated by the heater 21. The speed controller 51 varies the speed of the carry motor 23 and drives the carry motor 23 so as to keep the set fixing speed. The pressure controller 52 controls the pressure mechanism 24 to control the fixing pressure. Specifically, the pressure control unit 52 adjusts the fixing pressure by rotating the stepping motor 40 of the pressure mechanism 24.

  The image prediction device 29 includes a constant storage unit 60, a heat conduction calculation unit 61, a prediction pattern storage unit 62, a prediction calculation unit 63, a display unit 64, and an operation unit 65.

The constant storage unit 60 includes, for example, the fixing member core metal 30, the fixing member surface layer 31, the toner 16, the recording member 15, the pressure member surface layer 33, and the pressure member core metal 32 in the form shown in the table of FIG. Specific values of thickness (μm), density (kg / m ³ ), specific heat (J / kg · K), and thermal conductivity (W / m · K) are stored. Each value may be input from the operation unit 65.

  The heat conduction calculation unit 61 performs heat conduction calculation and calculates an interface temperature between the recording member 15 and the toner 16 in the nip (hereinafter referred to as toner paper interface temperature). As shown in the conceptual diagram in which the vicinity of the nip in FIG. 5 is enlarged, the heat conduction calculation is performed in the x direction perpendicular to the recording member 15 in the nip, with the depth close to the recording member 15 as a range. In the heat conduction calculation, a one-dimensional heat conduction equation (1) expressed using temperature T, time t, thermal conductivity λ, density ρ, specific heat C, and distance x is used.

  For solving the heat conduction calculation, the material can be divided into meshes, and a difference method, a finite element method, or the like can be applied. The boundary condition of the heat conduction calculation may be one in which the temperature at both ends of the calculation area is fixed or the heat transfer boundary at both ends of the calculation area, and the fixing nip time is relatively short. Therefore, it can be calculated using any boundary condition.

  The heat conduction calculation unit 61 sets the surface temperature of the fixing member 20 detected by the fixing member temperature sensor 26 to the initial temperature of the fixing member core 30 and the fixing member surface layer 31, as shown in the table of FIG. The surface temperature of the recording member 15 detected by the recording member temperature sensor 25 is set to the initial temperature of the recording member 15 and the toner 16, and the surface temperature of the pressure member 22 detected by the pressure member temperature sensor 27 is pressurized. The initial temperatures of the member surface layer 33 and the pressure member core metal 32 are set, the thickness of each material and the thermal material constant are read from the constant storage unit 60, and the heat conduction calculation is performed.

  The relationship between the toner paper interface temperature and the time obtained by the heat conduction calculation is represented by a curve that rises with time as shown in the graph of FIG. The toner paper interface temperature when the fixing nip time has elapsed represents the interface temperature at which the temperature of the interface between the recording medium 15 and the toner 16 reaches during fixing. The interface arrival temperature is held in the memory in the heat conduction calculation unit 61 and further sent to the prediction calculation unit 63.

  The predicted pattern storage unit 62 stores the correspondence relationship between the interface arrival temperature, the fixing pressure, and the PSF (Point Spread Function) in the form of a table or a function in advance. PSF is a kind of blur function, and details are described in "Digital Image Processing" by Rafael C. Gonzalez. For example, the fine particles of the toner 16 adhering to a narrow area of the recording member 15 before fixing as shown in FIG. 8A keep the volume constant as shown in FIG. 8B by fixing. It spreads over a relatively wide area. The PSF represents how much each particle spreads by fixing, that is, how much the image after fixing is blurred. The lower the temperature at the interface, the less the toner 16 is crushed and the image is less blurred. Therefore, the degree of blur caused by PSF is set weaker. The higher the temperature at the interface, the more the toner 16 is crushed and spreads in the horizontal direction. Because it is easy, set the degree of blurring by PSF strongly. Also, the lower the fixing pressure, the less the toner 16 is crushed and the image is less blurred. Therefore, the degree of blurring in the PSF is set weaker, and the higher the fixing pressure, the more easily the toner 16 is crushed and spreads in the horizontal direction. Because it is easy to blur, set the degree of blurring by PSF strongly.

  The prediction calculation unit 63 predicts an image after fixing of the image data input from the image formation control unit 14 according to the interface arrival temperature and the fixing pressure input from the heat conduction calculation unit 61. Specifically, the prediction calculation unit 63 selects the PSF corresponding to the interface arrival temperature and the fixing pressure from the prediction pattern storage unit 62 by the built-in CPU, and is input based on the selected PSF. A process of blurring data is performed to form a predicted image.

  Note that the prediction calculation unit 63 is not limited to the one using the PSF, and predicts the image after fixing in some form, such as one that predicts the image after fixing using a blur filter that performs some averaging process. It may be.

  The display unit 64 displays the predicted image. It should be noted that the display unit 64 may be provided in the image prediction device 29, the image forming device 1, or the fixing device 12. It may be connected to the. Since the image predicting device 29 has the display unit 64, when the operator works in front of the image forming apparatus 1, the predicted image after fixing can be easily confirmed. Since the image prediction device 29 has an external terminal, the operator can freely select and connect the display unit 64.

  The operation unit 65 has a function of receiving fixing conditions such as a fixing temperature, a fixing pressure, and a fixing nip time, sets the fixing temperature in the heating control unit 50, sets the fixing pressure in the pressure mechanism 24, and sets the fixing nip. The time is set in the image formation control unit 14. Specifically, when the operator wants to reduce the degree of blurring of the image after fixing, if the operator sets the fixing temperature to be lowered by the operation unit 65, the heating control unit 50 that receives a command from the operation unit 65 causes the temperature of the heater 21 to be reduced. By lowering the fixing temperature, the fixing temperature is lowered, and blurring of the image after fixing is reduced.

  An image prediction method in the image prediction apparatus 29 will be described with reference to the block diagram of FIG. First, the image prediction device 29 inputs the temperature of the recording member 16 from the recording member temperature sensor 25 (step S1) and inputs the temperature of the fixing member 20 from the fixing member temperature sensor 26 in the heat conduction calculating unit 61 (step S1). S2) The temperature of the pressure member 22 is input from the pressure member temperature sensor 27 (step S3), the constants necessary for the heat conduction calculation are read from the constant storage unit 60 (step S4), and the temperature and fixing of the recording member 16 are fixed. The interface temperature is calculated based on the temperature of the member 20, the temperature of the pressure member 22, and the read constant (step S5). Next, the image predicting device 29 receives the fixing pressure from the fixing control unit 52 in the prediction calculating unit 63 (step S6), and reads out the PSF corresponding to the interface arrival temperature and the fixing pressure from the predicted pattern storage unit (step S7). ), The image after fixing is predicted to form a predicted image (step S8). Next, the image prediction device 29 displays a predicted image on the display unit 64 (step S9). Next, the image predicting device 29 determines whether or not there is an input for changing the fixing condition in the operation unit 65 (step S10), and if there is an input for changing the fixing condition, causes the fixing control unit 28 to change the fixing condition ( In step S11), if there is no input for changing the fixing condition, the process is terminated.

  According to the image forming apparatus 1 of the first embodiment, the operator predicts the image after fixing by inputting the fixing conditions with the operation unit 65 while confirming the predicted image displayed on the display unit 64. It is possible to print an unsatisfactory image and prevent the printed recording member, labor cost, electricity bill, toner bill, etc. from being wasted and reduce the environmental load. In particular, the state when the toner 16 is fixed to the recording member 15, such as blurring, is strongly influenced by the temperature in the vicinity of the interface between the toner 16 and the recording member 15 in the nip. According to the image forming apparatus 1 of the first embodiment, an image after fixing can be accurately predicted.

  The image predicting device 29 may be integrated into the image forming apparatus 1 or the fixing device 12 or may be formed detachably on the image forming apparatus 1 or the fixing device 12. Alternatively, a device that exists outside the image forming apparatus 1 and transmits / receives data to / from the image forming apparatus 1 may be used. By providing the image predicting device 29 inside the image forming apparatus 1, the space required as a whole can be reduced and the environmental load can be reduced. By providing the image predicting device 29 outside the image forming apparatus 1, the image forming apparatus 1 can be reduced in size and can be conveniently used when the image forming apparatus 1 is remotely operated.

  The image forming apparatus according to the second embodiment includes an image prediction apparatus 70 different from the image prediction apparatus 29 according to the first embodiment. As shown in the block diagram of FIG. 10, the image prediction device 70 includes a constant storage unit 60, a heat conduction calculation unit 61, a prediction pattern storage unit 62, and a prediction calculation unit 63 included in the image prediction device 29 of the first embodiment. Furthermore, it has the operation part 71, the reference | standard storage part 72, and the comparison part 73.

  The operation unit 71 inputs a reference for how much the image is spread, that is, how much blur is allowed. Specifically, the reference is specified by the ratio of the line width after fixing that the toner is crushed and thick with respect to the line width of the input image. The reference storage unit 72 stores the reference input from the operation unit 71. The comparison unit 73 compares the prediction image formed by the prediction calculation unit 63 with the reference stored in the reference storage unit 72, and reduces the blur when the blur of the prediction image is larger than the specified reference. In this manner, a command is issued to the fixing control unit 28, and when the blur of the predicted image falls within the specified standard, fixing is performed under the fixing conditions as they are. For example, when the line width of the predicted image is thicker than the reference and the blur is large, the comparison unit 73 causes the heating control unit 50 to lower the temperature of the heater 21 and reduce the fixing temperature to reduce the blur of the image after fixing.

  According to the image forming apparatus 2 of the second embodiment, an unsatisfactory image is automatically printed without the operator confirming the predicted image after fixing every time, and printed paper, labor costs, electricity It is possible to prevent waste and toner costs from being wasted and to reduce the environmental load. The present invention can also be applied to image prediction simulation using a computer.

1 is a configuration diagram of an image forming apparatus. It is a block diagram of a fixing device. FIG. 3 is a block diagram illustrating a fixing control unit and an image prediction apparatus according to the first embodiment. It is a figure which illustrates the content memorized by the constant memory part. It is the conceptual diagram which expanded the nip vicinity. It is a figure which shows allocation of the initial temperature of each member in a nip, and the example of a value. It is a figure which shows the relationship between interface temperature and time. FIG. 6 is a diagram illustrating a change in shape of toner particles before and after fixing. It is a flowchart of an image prediction method. It is a block diagram explaining the fixing control part and image prediction control part of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Image forming apparatus, 10; Paper feed part, 11: Transfer part, 12: Fixing apparatus, 13: Paper discharge part,
14; Image formation controller, 15; Recording member, 16; Toner, 20; Fixing member,
21; heater, 22; pressure member, 23; transport motor, 24; pressure mechanism,
25; recording member temperature sensor; 26; fixing member temperature sensor; 27; pressure member temperature sensor;
28; Fixing control unit 29; Image prediction device 30; Fixing member core 31; Fixing member surface layer
32; Pressure member core, 33; Pressure member surface layer, 40; Stepping motor,
41; cylinder, 41; spring, 43; pressure lever, 44; fulcrum, 50; heating control unit,
51; Speed control unit, 52; Pressurization control unit, 60; Constant storage unit, 61; Heat conduction calculation unit,
62; Prediction pattern storage unit; 63; Prediction calculation unit; 64; Display unit; 65;
70; Image prediction device, 71; Operation unit, 72; Reference storage unit, 73; Comparison unit.

Claims (7)

Image prediction for predicting the interface temperature between the recording member at the nip between the fixing member and the pressure member and the toner to be fixed to the recording member according to the fixing condition, and predicting the image on the recording member after fixing based on the interface temperature In the device
The interface temperature in the nip is predicted based on the temperature of the fixing member, the temperature of the pressure member, and the temperature of the recording member before reaching the nip between the fixing member and the pressure member. The image to be fixed is predicted and displayed using the predicted interface temperature at the nip, the fixing pressure by the pressure member, and the point spread function indicating the degree of blur of the image after fixing. Image prediction device . Image prediction device according to claim 1, wherein outputting the prediction image to the outside. The image prediction apparatus according to claim 1, further comprising an operation unit that sets a fixing condition. Image prediction apparatus according to any one of claims 1 to 3 for changing the fixing condition based on the predicted image. The image prediction apparatus according to claim 4 , further comprising an operation unit that sets a reference for changing the fixing condition. An image forming apparatus comprising the image prediction device according to claim 1, or the deviation of the claims 5. The interface temperature between the recording member in the nip between the fixing member and the pressure member and the toner to be fixed to the recording member in accordance with the fixing conditions , the temperature of the fixing member, the temperature of the pressure member, the fixing member and the pressure A point spread function that is predicted based on the temperature of the recording member before reaching the nip with the member and indicates the predicted interface temperature in the nip, the fixing pressure by the pressure member, and the degree of blur of the image after fixing. And predicting and displaying an image to be fixed using the method.

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