JP5621445B2 - Gloss imparting apparatus and image forming apparatus - Google Patents

Description

  The present invention further increases the glossiness of an image after fixing an unfixed image formed of a powder particle image forming substance (hereinafter referred to as toner) on a recording medium (hereinafter also referred to as recording paper or sheet). And an image forming apparatus such as a copying machine, a printer, a facsimile, and a printing machine having the gloss applying device.

In an electrophotographic image forming apparatus, a copy or a recorded product can be obtained by heating and fixing an unfixed image transferred and carried on a recording sheet. Recently, there are a wide variety of types of recording paper to be used, such as uncoated paper such as plain paper, and coated paper having a high gloss by coating the surface layer with a resin. Further, the basis weight of the paper used is wide, and there are cases where paper is passed from a thin paper to a thick paper of about 300 g / cm ² .

Under such circumstances, particularly in full-color images such as photographs and computer graphics, there is a strong demand for high-quality images having a uniform image glossiness in the surface.
For this purpose, for example, in Japanese Patent Application Laid-Open No. H11-260260, after the assumed wearing, the image gloss adjusting means provided on the downstream side is used to place the paper surface side with toner on the outer peripheral surface of the endless belt in the planar state. It is proposed that the toner image is flowed so as to be in the state of the outer peripheral surface of the endless belt by adjusting the gloss of the toner image by separating the sheet after being conveyed by a predetermined distance after being pressed. ing. In the apparatus disclosed in Patent Document 1, the toner image and the recording sheet are cooled through the belt from the inside of the stretch belt in contact with the image surface by air cooling of a cooling fin or a fan.

  In this case, if the heat capacity of the belt is large, the belt temperature rises due to the continuous passing of the assumed paper, the cooling efficiency is greatly reduced, and the glossiness of each page may vary greatly. In addition, if the heat capacity of the belt is small, the heat capacity of the paper itself is relatively large. In particular, when the belt is cooled, the belt length is increased to reduce the temperature to cool and solidify the toner even when the belt is cooled. There is a possibility that the apparatus becomes large because it is necessary. Furthermore, in the case of double-sided printing, since the temperature control on the back side is not performed, there is a possibility that the glossiness on the back side also changes when the toner is pressurized in a deformable state.

  On the other hand, in Patent Document 2 and Patent Document 3 which make proposals for obtaining an image quality with high glossiness and excellent toner transparency irrespective of the lamination method, recording with heating and pressure fixing performed simultaneously with transfer and fixing is performed. It is disclosed that cooling is performed by blowing a fan from the back side of a sheet using a fan provided outside the belt for conveying the sheet. Such an outer fan can efficiently cool the paper, and therefore the temperature can be lowered faster than the cooling from the inside of the belt, and the size of the apparatus can be prevented from being increased.

  However, by blowing air vertically from the back side of the paper (the side where no toner is placed), depending on the position of the paper, the wind flow acts to peel off the belt and the paper, and a partial end of the paper. In some cases, uneven gloss or conveyance failure may be a problem due to peeling from the belt.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gloss applicator capable of providing stable gloss without uneven gloss while preventing the enlargement of the apparatus by rapidly cooling the back surface of the paper, and capable of stable conveyance. .

  The above-described problems include an endless belt-like recording medium carrier that carries a recording medium on which fixing toner is placed on at least one surface, one of the stretching rollers that stretch the recording medium carrier, and a recording medium on the stretching roller. At least one cooling that is located outside the recording medium carrier on the downstream side in the recording medium conveyance direction from the pair of rollers and is pressed against the recording medium carrier and blows air to the recording medium carrier. This can be solved by configuring the gloss imparting device having the device so that the direction of the wind from the cooling device can be changed.

  It is preferable if the cooling device changes the wind direction and the wind speed according to the position of the recording medium on the recording medium carrier. Further, it is more effective if the cooling device changes at least one of the wind direction and the wind speed according to the type of the recording medium.

  An endless belt-like recording medium carrier that carries a recording medium on which fixing toner is placed on at least one surface, a tension roller that stretches the recording medium carrier, and a recording medium carrier sandwiched between the tension rollers A pair of pressure rollers that are pressed by each other, and at least one cooling device that is located outside the recording medium carrier downstream of the pair of rollers and that blows air toward the recording medium carrier. In the gloss applying device, the above problem can be solved even if the wind direction component from the cooling device is set larger on the recording medium conveyance direction side than the vertical direction with respect to the recording medium on the recording medium carrier.

  According to the present invention, the direction of the wind from the cooling device disposed outside the endless belt-like recording medium carrier can be changed, so that the recording medium on the recording medium carrier, particularly the tip, is moved by the air current from the cooling device. A situation where the recording medium carrier is peeled off can be avoided and gloss unevenness can be prevented.

  By changing the wind direction of the cooling device according to the position of the recording medium, the recording medium conveyance direction component of the wind direction is larger with respect to the recording medium conveyance direction component with respect to the leading end portion of the recording medium conveyed by the recording medium carrier. In the vertical direction, the airflow can be adjusted so that the component in the direction opposite to the recording medium conveyance direction is larger with respect to the trailing edge of the recording medium, and the separation of the recording medium from the recording medium carrier by the airflow is effectively avoided. Can prevent uneven gloss. By changing the wind speed of the cooling device depending on the position of the recording medium, it is possible to control the wind speed to be small for the leading and trailing edges of the recording medium and to increase the wind speed for the middle part, similar to changing the wind direction. Further, peeling of the recording medium from the recording medium carrier due to the air current can be effectively avoided, and uneven gloss can be prevented.

  The heat capacity of the recording medium itself varies depending on the type of recording medium, for example, the paper thickness and basis weight, and the air volume required for cooling varies. For a thick recording medium, it is possible to efficiently cool the recording medium by increasing the prevailing width in the wind direction or increasing the wind speed in order to increase the time for which the airflow is applied. The thicker or the higher the basis weight, the stronger the stiffness of the recording medium, so even when an air current strikes between the end of the recording medium and the recording medium carrier, it is less likely to peel off than a thin or low basis weight. It is possible to increase the swing width or increase the wind speed.

  Since the wind direction component from the cooling device arranged outside the endless belt-like recording medium carrier is set larger in the recording medium conveyance direction side than the perpendicular direction to the recording medium on the recording medium carrier, the cooling device The wind direction of the recording medium can be fixed, and a mechanism for changing the wind direction is no longer necessary. Nevertheless, the situation where the recording medium on the recording medium carrier, particularly the tip, is peeled off from the recording medium carrier by the airflow from the cooling device is avoided. Can prevent uneven gloss.

1 is a schematic configuration diagram of an image forming multifunction peripheral according to the present invention. FIG. 2 is a schematic configuration diagram of a fixing device and a gloss applying device in the image forming multifunction peripheral of FIG. 1. It is a figure explaining the operation | movement outline of a glossiness imparting apparatus. It is a schematic block diagram which shows another example of a glossiness imparting apparatus. It is a schematic block diagram which shows another example of a glossiness imparting apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall schematic configuration of an internal mechanism in a multifunction machine having a copying function, a printer function, and a facsimile function as an example of an image forming apparatus. In the apparatus main body 100, five image forming stations 10c, 10m, 10y, 10b, and 10cl of cyan, magenta, yellow, black, and clear are arranged in tandem. Each image forming station is provided with drum-shaped photoconductors 11c, 11m, 11y, 11b, and 11cl, respectively, and each charging device 12c, 12m, 12y, 12b, and 12cl is first rotated in the clockwise direction in the drawing. A bias voltage is applied to uniformly charge the surface of the photoreceptor. Next, in the case of a copying machine, it is sent via a reading signal from an image reading device 200 mounted on the apparatus main body 100, an image signal from a host computer in the case of a printer, and a telephone line in the case of a facsimile. Based on the transmission signal, writing is performed by irradiating laser light Lc, Lm, Ly, Lb, and Lcl from the common writing device 13, respectively, and electrostatic latent images are formed on the photoreceptors 11c, 11m, 11y, 11b, and 11cl. Form an image. Thereafter, toner is attached by the developing devices 14c, 14m, 14y, 14b, and 14cl to visualize the electrostatic latent images, and each color single-color image is formed on the photoreceptors 11c, 11m, 11y, 11b, and 11cl. . Then, the endless belt-shaped intermediate transfer body 15 is run counterclockwise in the drawing while being in contact with the photoconductors 11c, 11m, 11y, 11b, and 11cl, and is photosensitive by the primary transfer devices 16c, 16m, 16y, 16b, and 16cl. Each color single color image on the bodies 11c, 11m, 11y, 11b, and 11cl is primarily transferred onto the intermediate transfer body 15 in order from cyan, and the transfer images are superimposed to form a full color image on the intermediate transfer body 15.

  On the other hand, one of the feed rollers 20 is selectively rotated at an appropriate timing, the recording material P is fed out from the corresponding paper feed cassette 21 in the apparatus main body 100, and conveyed through the recording material conveyance path 23 to be paired. It stops by abutting between the registration rollers 24. Then, the pair of registration rollers 24 are rotated in synchronization with the full color image on the intermediate transfer body 15, and the full color image is secondarily transferred to the recording material P by the secondary transfer device 25. In particular, the clear toner layer is controlled so that it is uniformly transferred to the image forming area where the CMYK toner is not placed, or is transferred as the uppermost layer to the entire image area so that the toner amount is uniform.

  Thereafter, the recording material P after full-color image transfer is conveyed as it is through the recording material conveyance path 23, passes through the fixing nip of the fixing device 300, and the unfixed transfer toner is fixed to the recording material P. When the mode for improving the glossiness is selected or depending on the type of paper, the paper passes through the nip of the gloss applying device 301 and is stacked on the paper discharge stack device 27 on the apparatus main body 100. When the glossiness is not given, the paper is discharged in a state where the glossing belt 30 and the pressure roller 40 shown in detail in FIG.

  The photoreceptors 11c, 11m, 11y, 11b, and 11cl after the completion of the primary transfer are cleaned by the primary cleaning devices 17c, 17m, 17y, 17b, and 17cl, and are initialized by removing the transfer residual toner. Further, the intermediate transfer member 15 after the secondary transfer is finished is cleaned by the secondary cleaning device 18 to remove the transfer residual toner and is initialized. In the figure, reference numerals 28c, 28m, 28y, 28b, and 28cl denote color toner bottles that supply toner to the color developing devices 14c, 14m, 14y, 14b, and 14cl, respectively.

  Incidentally, in the above description, a case where a color image is recorded on the recording material P has been described. However, in the above-described image forming apparatus, the image forming stations 10c, 10m, 10y are appropriately selected according to the selected single color mode or multiple color mode. By selecting and using some of 10b and 10cl, a monochrome image or a color image which is not full color can be arbitrarily formed.

FIG. 2 shows an outline of the gloss applying device 301. The gloss imparting device 301 is provided on the recording material conveyance downstream side of the fixing device 300, and a gloss imparting belt 30 as a gloss imparting member is stretched around the heating roller 36 and the separation roller 37. A pressure roller 40 serving as a pressure member is disposed at a position facing the heating roller 36 with the gloss imparting belt 30 interposed therebetween. Further, a halogen heater 33 serving as a heat source is provided inside the heating roller 36, the temperature of the surface layer of the gloss imparting belt 30 is monitored by a non-contact temperature sensor 56, and is controlled to a constant temperature by a controller (not shown).

  In this example, the gloss applying device 301 is close to the downstream side of the fixing device 300, but the arrangement thereof is not essential. For example, even if it is located outside the image forming apparatus, there is no functional difference. The gloss imparting belt 30 is made of a heat-resistant resin such as polyimide having a thickness of 10 to 200 μm, or a metal such as nickel or SUS, and has an outer diameter of 80 to 300 mm. The surface layer may have an elastic layer made of silicone rubber with a thickness of 5 to 50 μm in order to improve adhesion to the conveyed image surface. Further, the outermost layer may have a release layer coated with a silicon-based or fluorine-based resin in order to ensure release during separation. The heating roller 36 has an outer diameter of φ30 to 90 mm and is made of Al, SUS, or Fe. In order to form a wide nip with the pressure roller 40, an elastic layer such as silicon rubber may be provided on the roller surface with a thickness of 0.5 to 5 mm. The separation roller 37 has an outer diameter of φ10 to φ30 mm and is made of Fe, Al, or SUS. The pressure roller 40 has a diameter of 30 to 90 mm, and an elastic layer such as 1 to 50 mm of fluororubber or silicon rubber is formed on a core metal such as Fe, Al, or SUS, and the outermost layer has a thickness of 5 to 50 μm. The release layer is made of a fluorine compound or the like with a thickness.

  The pressure roller 40 can be operated so as to be in contact with and away from the gloss imparting belt 30 by using a cam (not shown), and the nip width and load formed can be variably controlled by changing the distance between the shaft and the heating roller 36. it can. Further, the heating roller 36, the gloss imparting belt 30, and the separation roller 37 are driven to rotate by being connected to a motor (not shown) and driven to rotate.

  A cooling device such as a heat sink, a fan, a heat pipe, or a Peltier element may be provided inside the gloss imparting belt 30 to cool the gloss impart belt 30. In this example, the internal cooling fan 42 is arranged as an internal cooling device. Further, an external cooling fan 41 is provided below the gloss imparting belt 30. The external cooling fan 41 is controlled by a drive device (not shown) so that the wind direction can be changed in the direction of the arrow in the figure.

  A printing signal is input as a printing operation, and the recording material P on which the toner T produced in the image forming unit is placed passes through the fixing device 300, and then in a fixing state, the heating roller 36 via the gloss applying belt 30 is used. And a pressure roller 40. While pressure is applied at the nip portion, heat is applied from the gloss imparting belt 30, and the remelted toner adheres to the gloss imparting belt 30, and is conveyed together with the recording material in close contact with the gloss imparting belt 30. When the external cooling fan 41 is driven from the back side of the recording material when entering the nip portion, the air current from the fan hits the back side of the recording material, and the recording material is rapidly cooled. Further, the gloss imparting belt 30 is also cooled by the internal cooling fan 42, the molten toner image is solidified, the surface of the fixed image portion is smoothed along the belt surface, and glossiness is imparted. The recording material on which the toner image is placed is further conveyed in close contact with the gloss imparting belt 30, and is separated by the separation roller 37 and discharged.

  As shown in FIG. 3, the external cooling fan 41 changes the direction angle with respect to the recording material conveyance direction by a driving device (not shown) according to the position of the recording material P detected by a paper position sensor (not shown), and changes the wind direction. adjust. At this time, the wind direction is adjusted so as not to face the conveyance direction of the recording material or the end face of the recording material. By doing so, it is possible to prevent airflow from entering the gap between the gloss imparting belt 36 and the recording material P and peeling off the recording material P, and uneven gloss can be prevented. At that time, the wind direction of the external cooling fan 41 may be changed depending on the sheet thickness of the recording material. In this case, since the heat capacity is large when the paper is thick, the wind width in the wind direction is increased to cool for a longer time, and conversely, when the thickness is small, the stiffness of the recording material is reduced, so the width is decreased. Prevents peeling due to airflow from the end face of the recording material, and prevents gloss unevenness due to peeling of the recording material.

  Further, the wind speed may be changed according to the position of the recording material while changing the wind direction of the external cooling fan 41. For example, when the next recording material is transported after the preceding recording material has passed in the continuous printing process, the air velocity is reduced and control is performed so that the opposing airflow does not flow to the tip of the next recording material. Thus, uneven gloss due to peeling of the recording material can be prevented. Similarly to the change in the wind direction, the wind speed may be changed depending on the thickness of the recording material. When the paper thickness is thick, the wind speed is increased, and when the paper thickness is small, the wind speed is decreased to balance cooling and peeling, thereby improving both cooling efficiency and preventing gloss unevenness.

  As shown in FIG. 4, a plurality of external cooling fans 41 may be provided outside the gloss imparting belt 30 and fixedly arranged so that the wind directions are different from each other. In this case, by adjusting the wind speed of each external cooling fan 41 according to the position of the recording material, it is possible to prevent peeling due to the air current to the recording material end surface and uneven gloss. Since the wind direction of the external cooling fan 41 is not changed, a driving device for changing the direction becomes unnecessary. Further, as shown in FIG. 5, a plurality of external cooling fans 41 having a constant wind direction may be provided so that the conveyance direction of the recording material and the wind direction are not reversed. With such an orientation, the airflow from the external cooling fan 41 comes into contact with the rear end side of the recording material to be conveyed, so that both improvement in cooling efficiency and prevention of uneven gloss can be achieved. The wind speed of these external cooling fans 41 may be further variable, and the operating efficiency can be increased.

DESCRIPTION OF SYMBOLS 30 Gloss imparting belt 33 Halogen heater 36 Heating roller 37 Separation roller 40 Pressure roller 41 External cooling fan 42 Internal cooling fan 56 Non-contact sensor 300 Fixing device 301 Gloss imparting device P Recording material T Toner

JP 2004-325934 A JP 05-019642 A JP-A-10-198191

Claims (4)

An endless belt-like recording medium carrier that carries a recording medium on which fixing toner is placed on at least one side;
A roller pair composed of one of the stretching rollers that stretch the recording medium carrier and a pressure roller that is pressed against the stretching roller by sandwiching the recording medium carrier;
In the gloss imparting device, comprising at least one cooling device that is located outside the recording medium carrier on the downstream side in the recording medium conveyance direction from the roller pair and blows air to the recording medium carrier.
The wind direction from the cooling device is configured to be changeable,
The gloss applying device, wherein the cooling device changes a wind direction according to a position of the recording medium on the recording medium carrier.   The gloss applying apparatus according to claim 1, wherein the cooling device changes a wind speed according to a position of the recording medium on the recording medium carrier.   The gloss applying apparatus according to claim 1, wherein the cooling device changes at least one of a wind direction and a wind speed according to a type of the recording medium. An image forming apparatus having the gloss providing device according to any one of claims 1-3.

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