JP2018041013A - Temperature changing unit, image forming apparatus, and temperature changing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesiveness of coating compared with the prior art.SOLUTION: After fixing performed by a fixing unit that fixes an image on a recording material by applying heat and pressure to the recording material, when coating is carried out on the recording material, a temperature changing unit changes the temperature during fixing of the rear surface of a surface of the recording material on which the image is formed to a higher temperature compared with a case where coating is not carried out on the recording material after fixing. When a second fixing operation performing fixing at a second heating temperature is performed, the second temperature being higher than a first heating temperature at which a first fixing operation is performed, the temperature changing unit preferably changes the temperature of the rear surface to a higher temperature compared with a case where coating is not carried out on the recording material after fixing.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a temperature changer, an image forming apparatus, and a temperature change program.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus in which a recording material such as a sheet on which an image is formed with a color material such as toner is heated to fix the image, and thereafter a coating is applied by laminating or the like.

  For example, Patent Document 1 includes a mode for forming an image on a sheet and a mode for laminating a sheet sandwiched between laminates by heating / pressurizing means, and an image for releasing the separation operation of the separation unit in the laminating mode. A forming apparatus is disclosed.

JP 2006-078852 A

  However, there is a possibility that the release agent that exudes from the color material by heat fixing weakens the adhesion of the coating.

  An object of the present invention is to improve the adhesion of a coating to a recording material as compared with the case where the temperature of the recording material is not changed.

The temperature changer according to claim 1 is:
When the recording material is coated after fixing by a fixing device that fixes the image on the recording material by heating and pressurizing the recording material, the surface of the recording material on which the image is formed is fixed. The temperature of the back surface is changed to a higher temperature than when the recording material is not coated after fixing.

The temperature changer according to claim 2 is the temperature changer according to claim 1,
When the fixing device performs the second fixing operation in which the fixing is performed at the second heating temperature higher than the first fixing operation in which the fixing is performed at the first heating temperature, the temperature of the back surface is set to the recording after the fixing. It is characterized in that the temperature is changed to a higher temperature than when the material is not coated.

The temperature changer according to claim 3 is the temperature changer according to claim 1 or 2,
The temperature of the back surface is changed by changing the temperature of a pressure member that presses the recording material in contact with the back surface of the recording material.

The temperature changer according to claim 4 is the temperature changer according to claim 3,
The temperature of the back surface is changed by changing the temperature of the pressure member by the heat of a heating member that contacts the surface of the recording material and heats the recording material.

The temperature changer according to claim 5 is:
The higher the fixing temperature is set in the fixing device, the higher the temperature of the pressure member is set.

The temperature changer according to claim 6 is:
When the recording material is coated after fixing by a fixing device that fixes the image on the recording material by heating and pressurizing the recording material, the surface of the recording material on which the image is formed is fixed. The temperature of the back surface is changed so that the surface area of the image of the recording material becomes larger than when the recording material is not coated after fixing.

An image forming apparatus according to claim 7 is provided.
A former that forms an image on a recording material with a color material that melts by heating;
A fixing device for fixing the image by heating and pressurizing the recording material;
When the recording material is coated after fixing by the fixing device, the recording material is not coated after fixing the temperature of the back surface with respect to the surface on which the image is formed on the recording material during fixing. A temperature changer that changes to a higher temperature,
It is provided with.

The temperature change program according to claim 8 is:
It is incorporated in a control device that controls a fixing device that fixes an image on the recording material by heating and pressurizing the recording material.
When the recording material is coated after fixing by the fixing device, the temperature of the back surface of the recording material being fixed with respect to the surface on which the image is formed is not coated after fixing. It is characterized by operating as a temperature changer that changes to a higher temperature.

  According to the temperature changer according to claim 1, the temperature changer according to claim 6, the image forming apparatus according to claim 7, and the temperature change program according to claim 8, compared with the case where the temperature of the recording material is not changed. This improves the adhesion of the coating.

  According to the temperature changer according to claim 2, in the case of the fixing operation in which the adhesiveness of the coating is lower than that in the first fixing operation, the cover on the recording material is compared with the case where the temperature of the temperature changer is not changed to a high temperature. The process which improves the adhesiveness of can be performed.

  According to the temperature changer of the third aspect, the temperature of the back surface of the recording material can be changed with a small amount of heat compared to the case where the pressure member does not contact the back surface of the recording material.

  According to the temperature changer of the fourth aspect, the temperature of the pressure member can be improved without preparing a separate heat source for the pressure member. .

  According to the temperature changer according to the fifth aspect, compared with the case where the temperature changer is not set according to the setting of the fixing temperature, the temperature change according to the amount of the release agent exuded from the toner is set. It can be carried out.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. It is a figure which shows the structure of a fixing device. It is a figure which shows the control part in which the heating control program was integrated. It is the flowchart which showed the heating control procedure. It is a figure showing the mechanism of a gross fall. 4 is a graph showing the relationship between the temperature of a pressure roll and the gloss of a toner image. 6 is a graph showing the relationship between the gloss of a toner image and the adhesive strength of a laminate.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention.

  The image forming apparatus 10 of this embodiment is a so-called tandem color printer.

  The image forming apparatus 10 includes two casings, a first casing 10a and a second casing 10b, which are connected to each other, and each member constituting the image forming apparatus 10 is divided into the two casings. Built in.

  The image forming apparatus 10 is configured to form an image using toners of up to six colors (including transparent colors), and six toner cartridges 11V that store toners of the respective colors are disposed on the upper portion of the first housing 10a. , 11W, 11Y, 11M, 11C, 11K are arranged.

  Here, V of the alphabet in the code represents a first special color (for example, transparent color), W represents a second special color (for example, light magenta), Y represents yellow, M represents magenta, C represents cyan, and K represents black. In the following, as a code indicating the toner cartridge, when it is not necessary to distinguish between the colors, the alphabet representing the color is omitted and simply referred to as the toner cartridge 11, and when it is necessary to distinguish between the colors, It shall be represented with an alphabet representing the color. The same applies to each element other than the toner cartridge 11.

  The toner in each toner cartridge 11 is supplied to an image forming unit 13 described below. Each toner cartridge 11 is replaceably attached to the first housing 10a. When the toner in the toner cartridge 11 becomes empty, the toner cartridge 11 is replaced with a new toner cartridge 11 containing toner of the same color.

  Below the toner cartridge 11 in the first housing 10a, six exposure units 12 and six image forming units 13 corresponding to the six toner cartridges 11 are provided. In each image forming unit 13, a toner image is formed on the photoconductor by a so-called electrophotographic method.

  Under the six image forming units 13, an endless intermediate transfer belt 14 is provided. The intermediate transfer belt 14 is supported by a plurality of rolls 16 including a drive roll 16a and a backup roll 16b, and circulates in the direction of arrow B while contacting each photoconductor incorporated in each image forming unit 13. The toner image on each photoconductor is transferred so as to sequentially overlap the intermediate transfer belt 14 by the action of the primary transfer roll 15 provided corresponding to each image forming unit 13, and is transferred in the direction of arrow B by the intermediate transfer belt 14. Be transported.

  A secondary transfer roll 17 is provided at a position facing the backup roll 16b with the intermediate transfer belt 14 interposed therebetween. The toner image on the intermediate transfer belt 14 is secondarily transferred by the action of the secondary transfer roll 17 onto a sheet conveyed to a position sandwiched between the intermediate transfer belt 14 and the secondary transfer roll 17. As a result, an unfixed toner image is formed on the sheet. The components including the image forming unit 13, the intermediate transfer belt 14, and the secondary transfer roll 17 that form an unfixed toner image on the paper as described above correspond to an example of the forming device referred to in the present invention.

  Two sheet storage portions 18a and 18b are provided at the lower portion of the first housing 10a, and each of the sheet storage portions 18a and 18b stores a plurality of sheets P in a stacked state. . In the image formation, one of the sheet storage portions 18a and 18b, which is manually or automatically designated by the operator, is stored in one sheet P by the pickup roll 19a and the separating roll 19b. It is taken out. The taken-out paper is conveyed sequentially through the take-out conveyance path 20a, the horizontal conveyance path 20b, and the skew conveyance path 20c, and reaches the positioning roll 19c. Further, the first housing 10a is provided with a take-in port 50 for taking in paper from the outside of the first housing 10a. When the paper is taken in from the take-in port 50, the take-in port 50 is taken in. The sheet is conveyed sequentially through the take-in conveyance path 20d and the skew conveyance path 20c, and reaches the positioning roll 19c.

  The positioning roll 19c serves to correct the posture of the conveyed paper and to adjust the subsequent delivery timing of the paper and send it further downstream in the conveyance direction. In other words, the positioning roll 19c is configured so that the sheet is conveyed to the position of the secondary transfer roll 17 in synchronization with the timing when the toner image on the intermediate transfer belt 14 is conveyed to the position of the secondary transfer roll 17. Send out the paper.

  The sheet on which the toner image has been transferred by the action of the secondary transfer roll 17 is transported by the transport belt 21 and enters the second housing 10 b to reach the fixing device 22. The fixing device 22 includes a heating belt 221 and a pressure roll 222, and the paper conveyed to the fixing device 22 is sandwiched between the heating belt 221 and the pressure roll 222 to be heated and pressurized. The upper toner image is fixed on the sheet. The fixing device 22 corresponds to an example of a fixing device according to the present invention. The sheet that has passed through the fixing device 22 is naturally cooled while being conveyed to the decurler 25, the warp is corrected by the decurler 25, and the sheet is discharged onto the sheet discharge table 28 by the sheet discharge roll 27.

  The above is the process when an image is formed only on the first side of the paper, but when an image is formed on both sides of the paper, the image forming apparatus 10 goes through the following process.

  First, an image is formed on the first surface of the paper by the same process as described above, and the paper passes through the decurler 25. Then, the sheet that has passed through the decurler 25 enters the lower conveying path 20e just before reaching the paper discharge roll 27, is conveyed on the lower conveying path 20e, and further enters the reverse conveying path 20f. When a sheet enters the reversal conveyance path 20f, the rotation direction of the conveyance roll of the reversal conveyance path 20f is reversed, and the sheet is sent in the reverse direction from the reversal conveyance path 20f to the return conveyance path 20g. Return to body 10a. The sheet returned to the first housing 10a reaches the positioning roll 19c through the horizontal conveyance path 20b and the skew conveyance path 20c. The paper at this time is in a posture in which the second surface on which an image is not yet formed faces the intermediate transfer belt 14. The toner image of the image formed on the second surface of the sheet is formed on the intermediate transfer belt 14 on the image forming unit 13 side until the sheet reaches the positioning roll 19c through such a conveyance path. Transcribed.

  Thereafter, in the same manner as the image formation on the first surface of the paper, the paper is sent out from the positioning roll 19c, and the toner image is transferred to the second surface of the paper by the action of the secondary transfer roll 17, and the fixing device 22, after passing through the decurler 25, this time the paper is discharged onto the paper discharge tray 28 by the paper discharge roll 27.

  In addition, an upper portion of the second housing 10b of the image forming apparatus 10 includes a memory for storing image data sent from the outside, an arithmetic circuit for performing image processing on the image data, and the fixing device 22. Is provided with a control unit 30 that is responsible for controlling the heating temperature of the image forming apparatus 10 and for controlling the sheet conveyance speed at various locations in the image forming apparatus 10.

  Further, a monitor 31 for displaying various states of the image forming apparatus 10 and an operation panel 32 for receiving an operation by the operator are arranged so as to be placed on a lower part of the second casing 10b.

  A sheet on which an image is formed by the image forming apparatus 10 may be laminated by a laminator that is a separate apparatus from the image forming apparatus 10. The image forming apparatus 10 has both a laminating mode in which laminating is scheduled by a laminator and a normal mode in which laminating is not scheduled. The user of the image forming apparatus 10 selects a mode by operating the operation panel 32 described above.

  FIG. 2 is a diagram illustrating the structure of the fixing device 22.

  As described above, the fixing device 22 includes the heating belt 221 and the pressure roll 222. The heating belt 221 is an endless belt, is driven by being wound around three heating rolls 223_1, 223_2, and 223_3 and a plurality of guide rolls 225, and circulates in the direction of arrow C. Heat sources 224_1, 224_2, and 224_3 are incorporated in the heating rolls 223_1, 223_2, and 223_3, and the heating temperatures of the heat sources 224_1, 224_2, and 224_3 are controlled by the control unit 30 illustrated in FIG. As a result of this control, the temperature at which the heating belt 221 heats the surface of the paper P (that is, the surface on which the unfixed image is formed) (that is, the fixing temperature) is controlled.

  The pressure roll 222 has an elastic layer 227 around the cored bar 226 and rotates in the direction of arrow E. The pressure roll 222 applies pressure to the paper P by sandwiching (niping) the paper P that has advanced in the direction of the arrow D with the heating belt 221.

  In this embodiment, a heat source is not incorporated in the pressure roll 222, but the pressure roll 222 is heated by the heating belt 221 by contacting the heating belt 221 while the paper P is not sandwiched. The heating temperature for heating the pressure roll 222 is also controlled by the control unit 30 shown in FIG. 1. As a result of this control, the temperature of the pressure roll 222 that contacts the back surface of the paper P is controlled. Although a description of a specific control method is omitted, in the present embodiment, a known control method in which the temperature of the pressure roll 222 is controlled with a certain degree of freedom with respect to the fixing temperature is employed. And The heating control of the fixing device 22 by the control unit 30 is realized by incorporating a heating control program that causes the control unit 30 to operate as a heating control device into the control unit 30.

  FIG. 3 is a diagram illustrating the control unit 30 in which the heating control program is incorporated.

  The control unit 30 incorporates a heating control program including a mode acquisition unit 35, a temperature setting unit 36, and a heating control unit 37.

  The mode acquisition unit 35 acquires the mode selected by the user by operating the operation panel 32 shown in FIG.

  The temperature setting unit 36 sets the fixing temperature and the temperature of the pressure roll according to the mode acquired by the mode acquisition unit 35 and the number of colors of toner used for image formation.

  The heating control unit 37 realizes the temperature set by the temperature setting unit 36 by controlling the heating temperature of each of the heat sources 224_1, 224_2, and 224_3 and the circulation speed of the heating belt 221 shown in FIG.

  This heating control program corresponds to an embodiment of the temperature change program of the present invention, and the control unit 30 is an example of the temperature change device of the present invention and an example of the temperature changer according to the present invention by this heating control program. Function as. And the control part 30 performs the heating control procedure corresponded to one Embodiment of the temperature change method of this invention.

  FIG. 4 is a flowchart showing a heating control procedure.

  When this heating control procedure is started, first, in step S101, the image forming mode acquired by the mode acquiring unit 35 is confirmed, and then, in step S102 and step S107, the toner used in the current image formation. The color of is confirmed. The color of the toner is confirmed, for example, by specifying data indicating the color in the image data.

  As a result of these checks, if it is determined in the normal mode that the spot color is not included in the toner color (step S101; normal, step S102; N), the temperature setting unit 36 sets the fixing temperature to a low temperature. (Step S103), the temperature of the pressure roll 222 is also set to a low temperature (Step S104), and image formation is performed under heating control by the heating control unit 37. In recent years, low-temperature fixing type toners having a low temperature required for fixing (low glass transition temperature) have become widespread, and power saving can be achieved by setting the fixing temperature to a low temperature. Further, since the temperature of the pressure roll 222 is low, the gloss of the image is improved and the appearance is good as described later.

  As a result of the above-described confirmation, when it is determined in the normal mode that the spot color is included in the toner color (step S101; normal, step S102; Y), the fixing temperature is set to a high temperature by the temperature setting unit 36. (Step S105) The temperature of the pressure roll 222 is set to a low temperature (Step S106), and image formation is performed under heating control by the heating control unit 37. Unlike the process colors (CMYK colors), special color toners such as white and transparent colors have few low-temperature fixing type toners. When special color toners are used, the fixing temperature is set to a high temperature to make the image Sufficient fixation is achieved. Further, the gloss of the image is improved due to the low temperature of the pressure roll 222, and the appearance is good.

  As a result of the above-described confirmation, when it is determined that the toner color does not include a special color in the laminating mode (step S101; lamination, step S107; N), the fixing temperature is set to a low temperature by the temperature setting unit 36. In step S108, the temperature of the pressure roll 222 is set to an intermediate temperature (step S109), and image formation is performed under the heating control by the heating control unit 37. When the temperature of the pressure roll 222 rises, the gloss of the image decreases as will be described later, and the adhesive strength in the laminating process is improved.

  As a result of the above-described confirmation, when it is determined that the toner color includes a special color in the laminating mode (step S101; laminating, step S107; Y), the fixing temperature is set to a high temperature by the temperature setting unit 36. (Step S110), the temperature of the pressure roll 222 is set to a high temperature (Step S111), and image formation is executed under the heating control by the heating control unit 37. By setting the fixing temperature to a high temperature, sufficient fixing can be achieved even for an image using a special color toner. Further, the adhesive strength in the laminating process is further improved by further increasing the temperature of the pressure roll 222. Since it is considered that the amount of the release agent that exudes from the toner increases with a high fixing temperature, the adhesive strength is further improved.

  FIG. 5 is a diagram showing a mechanism of gloss reduction.

  The toner 41 at the nip in the fixing device 22 is crushed flat by pressure, and a residual stress 42 remains in the toner 41 at this time. When the temperature of the pressure roll 222 is a low temperature of 50 ° C. or lower, the low temperature of the back surface of the sheet is maintained even during the nip during fixing, and the illustration is omitted, but after the fixing (that is, after the nip). The toner 41 is quickly cooled. For this reason, deformation due to the residual stress 42 does not occur after the nip, and the grain boundary dent 43 formed at the boundary between the toners maintains the same narrowness as in the nip, and the gloss of the toner image is high.

  On the other hand, when the temperature of the pressure roll 222 is an intermediate temperature of 50 ° C. to 80 ° C., the back surface of the sheet is warmed to an intermediate temperature at the time of nip during fixing. Maintained. For this reason, the residual stress 42 increases the height of the toner after fixing, and the grain boundary dent 43 slightly spreads to reduce the gloss of the toner image.

  Further, when the pressure roll 222 is at a high temperature of 80 ° C. to 120 ° C., the back surface of the paper is warmed to a high temperature during the nip during fixing. For this reason, the temperature of the toner 41 is maintained high even after fixing, and it takes time to cool down. As a result, the shape of the toner 41 returns to a round shape after fixing due to the residual stress 42, the surface of the toner image becomes uneven, the grain boundary dent 43 is greatly expanded, and the gloss of the toner image is significantly reduced.

  FIG. 6 is a graph showing the relationship between the temperature of the pressure roll and the gloss of the toner image.

  The horizontal axis of the graph of FIG. 6 represents the temperature of the pressure roll 222, and the vertical axis represents the gloss of the image after fixing (60 degree gloss). Further, the triangle mark in the graph represents the gloss in the primary color image, the square mark represents the gloss in the secondary color image, and the diamond mark represents the gloss in the tertiary color image.

  As can be seen from the graph, the gloss of the primary color, secondary color, and tertiary color decreases as the temperature of the pressure roll increases. When the gloss is reduced in this way, the laminate film adhesive penetrates into the grain boundary dent 43 (see FIG. 5) when the lamination process is performed by a laminator. Adhesive strength is improved. Further, the surface area of the image is increased with the decrease in the gloss, and the adhesive strength of the laminate is improved by the increase in the adhesive area.

  FIG. 7 is a graph showing the relationship between the gloss of the toner image and the adhesive strength of the laminate.

  The horizontal axis of the graph of FIG. 7 indicates the gloss of the image after fixing (60 degree gloss), and the vertical axis indicates the adhesive strength of the laminate as a value of T-type peeling evaluation (JIS 6354-3).

  The graph of FIG. 7 shows the results when OS coated paper (127 gsm) is used as the paper and laminating is performed at 120 ° C. and 4.0 m / min as the laminating conditions.

  As can be seen from the graph, as the gloss of the image decreases from 35 to 20, the T-peel force increases greatly from about 5 N / 15 mm to about 7 N / 15 mm.

  As described above, it was confirmed that the adhesive strength of the laminate was improved by increasing the temperature of the pressure roll during fixing.

  In the above description, the controller 30 that indirectly changes the temperature of the pressure roll 222 through the heating control of the heating belt 221 is exemplified as the temperature changer referred to in the present invention. For example, the temperature changer may include a heater inside the pressure member according to the present invention, and the temperature of the pressure member may be directly changed by the heater. Furthermore, the temperature changer referred to in the present invention may be one that heats the back side of the paper.

  Further, in the above description, an image forming apparatus that switches the fixing temperature to a temperature corresponding to the type of toner used is exemplified, but the image forming apparatus of the present invention is not based on the type of toner used, for example, depending on the amount used. The fixing temperature may be switched to a different temperature, or the fixing temperature switching function may not be provided.

  In the above description, an apparatus having no laminator is illustrated as an embodiment of the image forming apparatus of the present invention. However, the image forming apparatus of the present invention may be an apparatus in which a laminator is incorporated.

  In the above description, a tandem type color printer is illustrated as an embodiment of the image forming apparatus of the present invention. However, the image forming apparatus of the present invention may be a revolver type color printer, and is dedicated to monochrome. It may be a machine (however, it has a function of forming a transparent color image), or may be a copying machine, a facsimile machine, or a multifunction machine.

  In the above description, as an embodiment of the image forming apparatus of the present invention, an indirect transfer type image forming apparatus in which a toner image is transferred onto a sheet from a photoreceptor via an intermediate transfer belt is illustrated. The image forming apparatus of the present invention may be a direct transfer type image forming apparatus in which a toner image is directly transferred from a photosensitive member onto a sheet.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 13 ... Image forming unit, 14 ... Intermediate transfer belt, 22 ... Fixing device, 221 ... Heating belt, 222 ... Pressure roll, 30 ... Control part

Claims (8)

  When the recording material is coated after fixing by a fixing device that fixes the image on the recording material by heating and pressurizing the recording material, the surface of the recording material on which the image is formed is fixed A temperature changer characterized in that the temperature of the back surface of the recording medium is changed to a temperature higher than that when the recording material is not coated after fixing.   When the fixing device performs a second fixing operation in which fixing is performed at a second heating temperature higher than the first fixing operation in which fixing is performed at the first heating temperature, the temperature of the back surface is set to the recording after fixing. 2. The temperature changer according to claim 1, wherein the temperature is changed to a higher temperature than when the material is not coated.   The temperature changer according to claim 1 or 2, wherein the temperature of the back surface is changed by changing the temperature of a pressure member that presses the recording material in contact with the back surface of the recording material.   The temperature of the back surface is changed by changing the temperature of the pressure member with the heat of a heating member that contacts the surface of the recording material and heats the recording material. Temperature changer.   5. The temperature changer according to claim 3, wherein the temperature of the pressure member is set higher as the setting of the fixing temperature in the fixing device is higher.   When the recording material is coated after fixing by a fixing device that fixes the image on the recording material by heating and pressurizing the recording material, the surface of the recording material on which the image is formed is fixed A temperature changer characterized in that the temperature of the back surface of the recording material is changed so that the surface area of the image of the recording material becomes larger than when the recording material is not coated after fixing. A former that forms an image on a recording material with a color material that melts by heating;
A fixing device for fixing the image by heating and pressurizing the recording material;
When the recording material is coated after fixing by the fixing device, the temperature of the back surface of the recording material during fixing with respect to the surface on which the image is formed is not coated after fixing. A temperature changer that changes to a higher temperature than the case,
An image forming apparatus comprising: Incorporated in a control device for controlling a fixing device for fixing an image on the recording material by heating and pressurizing the recording material,
When the recording material is coated after fixing by the fixing device, the temperature of the back surface of the recording material during fixing with respect to the surface on which the image is formed is not coated after fixing. A temperature change program that operates as a temperature changer that changes to a higher temperature than the case.

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