JP5173361B2 - Image forming system - Google Patents

Description

  The present invention relates to an image forming system using an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having the functions of these devices.

  In the image forming system, one of the requirements for the high quality of the formed image is the glossiness, and the smoothness of the output image is one of the factors that determine the quality of the glossiness. In order to obtain smoothness, a glossy special paper with a transparent thermoplastic resin layer formed as a toner receiving layer on a sheet of recording material or transfer material is used, and a toner image is embedded in the toner receiving layer to obtain a high glossiness. An apparatus for forming an image has been proposed (see, for example, Patent Documents 1 and 2). In these apparatuses, the toner image formed by embedding in the toner receiving layer is fixed by a fixing device and then sent to a downstream smoothing device to move the toner image while keeping the sheet in close contact with the belt having a high gloss surface. Heat and melt together with the receiving layer. In this way, in the process of conveying the sheet in close contact with the belt, the sheet is passed through a cooling device, the toner image is cooled, and then the sheet is separated from the belt and taken out. By passing through such a process, the surface of the toner image or sheet follows the glossy surface of the belt having a high glossy surface, so that a high glossy surface having smoothness can be obtained. The meaning of cooling through a cooling device in the process before peeling the sheet from the belt is to prevent the toner or resin layer from being offset (offset) on the fixing roller and preventing the surface of the sheet from becoming rough and uneven. Because.

Japanese Patent Laid-Open No. 04-216580 Japanese Patent Laid-Open No. 04-362679

  However, when trying to output a high quality image having high image quality and high glossiness in the apparatus of the above-mentioned patent document, the following problems occur.

  One is related to the material of the sheet. When using general coated paper, high-quality paper, PPC paper, etc., instead of glossy processing paper with a toner receiving layer formed of a thermoplastic resin layer that softens at the fixing temperature, uniform and appropriate high gloss over the entire image I cannot get the image. The reason is as follows.

  When the sheet on which the toner image is formed is passed through a fixing device for glossiness, the toner is melted by heating at the fixing nip portion, and the molten toner is pressed to be applied to the surface of the high gloss belt. In close contact. The sheet that has passed through the fixing nip portion needs to be conveyed in a close contact state without being peeled off from the belt until the cooling of the toner image is completed.

  When a toner image is formed on a general sheet such as the above-mentioned coated paper without a toner receiving layer, and heated and pressed through a fixing device to give gloss, the image portion on which the toner image is formed is softened by heating. As a result, the adhesiveness increases and the belt adheres closely. However, the sheet portion of the white background portion, which is a non-image portion where no toner image is formed, is not sticky and is not sufficiently fixed on the surface of the belt. In that case, if a heat curl is generated in which the sheet immediately after passing through the fixing nip portion is rounded by heating, the sheet may be conveyed in a posture as if it was peeled off from the belt. When the end portion of the sheet is peeled off from the belt, the peeling spreads to the image portion, and the image portion is eventually peeled off from the belt surface. The image portion of the sheet should not peel from the belt when the cooling of the toner image is not completed. The fact that the sheet is peeled off from the belt before cooling means that the sheet is peeled off from the belt at a high temperature.

  Due to such inconvenience, the toner image on the sheet does not follow the surface of the high gloss and smooth belt, the smooth surface is not transferred, and the toner image is solidified as it is. As a result, it is difficult to form a high-quality and high-gloss image when it is desired to use a sheet such as coated paper, high-quality paper, PPC paper, or plain paper instead of the gloss processing paper. This problem occurs particularly remarkably at the boundary between the image area and the non-image area (white background area) on the sheet or in the vicinity thereof.

  On the other hand, with respect to a structure in which a sheet is conveyed in close contact with an endless belt, a technique for charging the belt and attracting the sheet with an electrostatic force is well known. Such a sheet electrostatic attraction structure requires a power source for applying a voltage to be charged, a vise application member, a static elimination mechanism for peeling the sheet, and the like. Therefore, this is reflected in the cost of the image forming apparatus. Therefore, there is a strong demand for a low-cost fixing device that can avoid the use of a sheet electrostatic attraction structure as much as possible and that can handle a wide variety of sheets and surely adheres to a belt at the time of fixing, and an image forming apparatus including the fixing device.

  The object of the present invention is not limited to the use of glossy exclusive paper on which a toner receiving layer is formed, and even when using sheets such as coated paper, high-quality paper, PPC paper, and plain paper, it is highly glossy and has high quality. An image forming system capable of obtaining the above image is provided. In addition, an image forming system that can be reduced in cost is provided.

To achieve the above object, a typical image forming system according to the present invention includes an image forming means for forming a toner image on a sheet, a belt for heating the toner image formed on the sheet at a nip portion, and the belt. An image glossing means comprising a cooling means for cooling the sheet moving while being in close contact with the belt before separating from the belt, a cutting means for cutting the sheet, the image forming means, the image glossing means, and the cutting means have a, and control means for controlling the driving of said control means includes a margin area of the conveying direction leading end side of the sheet, only between the toner image formed on the basis of input image information, a strip-shaped toner band is formed by the image forming means, thereon is capable of executing the glossy image forming mode to execute the glossing process by the image glossing unit, conveying direction of the sheet by the cutting means Characterized in that the toner band after glossing the distal only be removed by cutting.

  According to the image forming system of the present invention, by selecting the glossy image forming mode, the sheet on which the toner image is formed is cooled by the cooling means before being separated from the belt after being heated at the nip portion, and the image glossing means Glossing treatment is applied. Thereby, a high-quality image having high image quality and high glossiness can be output.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of an image forming system according to the invention will be described in detail with reference to the drawings.

  FIG. 1 shows a color multifunction machine having a copying function using an intermediate transfer member and a printer function as a specific example of the image forming system of this embodiment. In this case, it has a main housing that houses the image forming means and the fixing unit, and a sub-housing that houses the smoothing device that is the image glossing means alone. The sub-housing is a so-called optional unit that can be freely attached to and detached from the main housing according to the purpose of use of the user. The main housing is a unit that can complete the formation of a toner image on a sheet that is a normal recording material such as plain paper. However, there is no inconvenience even in an image forming system in which the image forming unit, the fixing unit, and the smoothing device are housed together in a single housing without being distinguished from the main housing and the sub housing. In addition, it is possible to select a normal printing method in which a sheet after image formation is processed only through the fixing unit, or a printing method in which a high glossy material is output after being sent to a smoothing device.

(Image forming means)
The image forming means includes an image forming process device (not shown) that forms a visible toner image on a sheet such as plain paper or coated paper. The outline is that an image reading apparatus is arranged above the apparatus, and a document to be copied is placed to read image information. The image information of the document read by the image reading apparatus is subjected to image processing, and the exposure unit is controlled according to the image processed data. An operation unit is provided on the side of the image reading apparatus, and the user operates the operation unit to input various settings and instructions such as an image forming mode. An image forming system comprising various process devices related to image formation, a fixing device, a smoothing device and the like in a control device composed of a CPU (Central Processing Unit) based on information signals of selection and instructions by a user Integrate and control the whole.

  In the apparatus, there are four image forming stations Y, M, C, and K corresponding to toner image formation of four colors, for example, Y (yellow), M (magenta), C (cyan), and K (black). They are lined up almost horizontally. Each of the image forming stations Y, M, C, and K has substantially the same structure except that the color of the toner as the developer is different.

  In FIG. 1, a drum-shaped photosensitive drum 1 as an image carrier is rotatably supported at each of the image forming stations Y, M, C, and K. Around the photosensitive drum 1, process means such as a charging roller 2 as charging means, an exposure unit 3 as image exposing means, and a developing device 4 as developing means are arranged. Further, a primary transfer roller 6 as a primary transfer unit and a cleaner 5 as a cleaning unit are installed.

  Further, an intermediate transfer belt 71 as an intermediate transfer member is rotatably provided so as to be in contact with the photosensitive drum 1. The intermediate transfer belt 71 is stretched between each roller of a driven roller 72, a secondary transfer counter roller 73, and a driving roller 74 driven by a driving motor. A primary transfer roller 6 is disposed at a position facing the photosensitive drum 1 with the intermediate transfer belt 71 interposed therebetween. The driven roller 72 also serves as a tension roller and has a function of applying a required tension to the intermediate transfer belt 71. The secondary transfer facing roller 73 is disposed to face the secondary transfer roller 9 with the intermediate transfer belt 71 interposed therebetween. Further, a secondary transfer bias voltage is applied to the secondary transfer counter roller 73 from a high voltage power source during the secondary transfer.

  Further, a cassette for stacking and storing sheets is installed below the intermediate transfer belt 71, and a pickup roller for separating and transporting the sheets one by one is installed. The sheet fed by the pickup roller is conveyed toward the registration roller 8 through a plurality of conveyance roller pairs. The registration roller 8 has a function of controlling the sheet delivery timing so that the timing at which the toner image on the intermediate transfer belt 71 enters the secondary transfer portion matches the timing at which the sheet enters the secondary transfer portion. Is responsible.

  With the above configuration, the image forming unit performs image formation as follows.

  All process devices in the image forming means operate (rotate) at a process speed of 130 mm / sec. The exposure unit 3 has an exposure scanning speed corresponding to the rotation of the photosensitive drum 1 at the process speed.

  First, the surface of the photosensitive drum 1 rotating in the counterclockwise direction in FIG. 1 is uniformly charged by the charging roller 2, and laser light is irradiated from the exposure unit 3 in accordance with an image signal to form an electrostatic latent image. Is done. The electrostatic latent image is visualized by attaching a developer by the developing device 4. The toner image formed on the photosensitive drum 1 is primarily transferred to the intermediate transfer belt 71 by applying a primary transfer bias to the primary transfer roller 6.

  Further, when forming a toner image on the photosensitive drum 1, as a “toner band forming step” which is an initial step for performing image glossing, as will be described later with reference to FIGS. A “toner band 31” is formed. The toner band 31 is transferred onto the sheet simultaneously with the toner image. The size of the toner band 31 to be transferred is formed with a set width and a set length in a margin area on the leading end side in the sheet conveying direction. Such a toner band 31 is fixed in the fixing unit by conveying the sheet, and further provided for assisting the glossing process of the toner image in the smoothing device 20 which is the image glossing means that is the main part of the present embodiment. Is for. The margin area referred to here is an outer peripheral portion at the front end, rear end, and left and right ends on the sheet, and is an area provided so as not to record image information.

  The steps up to the above development are performed for each of the image forming stations Y, M, C, and K, and the toner images of the respective colors Y, M, C, and K are superimposed on each other on the intermediate transfer belt 71. Transcribed. That is, the yellow, magenta, cyan, and black toner images formed by the image forming stations Y, M, C, and K are transferred onto the intermediate transfer belt 71 to form a color image. Subsequently, a secondary transfer bias is applied to the secondary transfer counter roller 73, and the toner image on the intermediate transfer belt 71 is secondarily transferred collectively to the sheet fed to the secondary transfer unit. The sheet on which the color image has been transferred in this way is conveyed toward the fixing device 10 which is a fixing unit, and is subjected to a fixing process.

(Fixing part)
Next, as shown in FIG. 1, a fixing device 10 is disposed on the downstream side of the secondary transfer portion in the sheet conveyance direction.

  The fixing device 10 is composed of a fixing roller 11 and a roller pair including a pressure roller 1 as a mating member that presses against the fixing roller 11 to form a fixing nip portion. The applied pressure between the fixing roller 11 and the pressure roller 12 is a total pressure of 50 kg. The fixing roller 11 is configured as a laminate in which a rubber layer as an elastic layer and a fluororesin layer as a toner release layer are laminated on a hollow metal core made of metal such as aluminum (Al) or iron (Fe). A halogen heater as a heating source is installed inside the cored bar. As the heat source, for example, an IH method using electromagnetic induction heating can be used. Further, the fixing roller 11 is connected to a drive motor via a drive gear train, and rotates by rotational power output from the drive motor. The pressure roller 12 is a laminated body in which a rubber layer as an elastic layer and a fluororesin layer as a toner release layer are laminated on a hollow core metal like the fixing roller 11. A halogen heater is installed as a source. For this heating source, the IH system using the electromagnetic induction heating can be used. The pressure roller 12 is rotated together with the fixing roller 11.

  Further, near the surfaces of the fixing roller 11 and the pressure roller 12, a thermistor as a detecting means for detecting the respective temperatures is mounted. Further, a halogen heater is mounted inside each of the fixing roller 11 and the pressure roller 12, and energization on / off of the halogen heater is controlled by a control device based on a temperature detection signal output from the thermistor. . In this embodiment, the fixing temperature of the fixing roller 11 is set to 180 ° C., and the fixing temperature of the pressure roller 12 is set to 150 ° C., and the temperature is controlled by the control of the control device to maintain the fixing temperature.

  Accordingly, the fixing device 10 fixes the toner image and the toner band on the sheet conveyed from the secondary transfer portion by heating and pressing at the nip portion at the same time, and performs the fixing process.

  The temperature of the sheet fed from the fixing nip portion of the fixing device 10, that is, the “sheet peeling temperature” at which the sheet begins to peel from the roller surface is maintained at a high temperature of about 90 to 110 ° C., for example. That is, the fixing device 10 according to the present embodiment is a “high temperature peeling method” in which the sheet begins to separate from the fixing device 10 while maintaining a high temperature immediately after the sheet has passed through the fixing nip portion.

  The fixing device 10 has been described as a roller pair composed of a fixing roller 11 and a pressure roller 12. However, either the fixing side or the pressure side can be configured as a roller member and the other can be configured as an endless belt. As such, a belt can be used on at least one side.

(Smoothing device)
Next, as shown in FIGS. 1 and 2, a smoothing device 20 that is an image glossing unit is disposed as a main part of the present embodiment on the downstream side of the fixing device 10 along the sheet conveyance path.

-Selection of glossy image formation mode-
When a glossy image formation mode is selected to output a required high gloss image on a sheet by a user's judgment operation, an operation signal is output from the control device based on the gloss image formation mode instruction signal, and the smoothing device 20 is transmitted. In synchronization with the operation of the smoothing device 20 being turned on, the sheet exiting the fixing device 10 in a high temperature state is conveyed toward the smoothing device 20. The smoothing device 20 is configured as a cooling and peeling system that cools the conveyed sheet and smoothes the image surface of the sheet to increase the glossiness of the image, and executes the glossing process.

  Each part of the smoothing apparatus 20 is demonstrated using FIGS. 3-5 and FIGS. 6-8 together. The smoothing device 20 includes an endless belt 23 having a high gloss surface, a pressure roller 22 that forms a nip portion with the high gloss surface belt 23, and cooling devices 25 and 26 (FIG. 1) and the like are arranged. FIG. 3 shows a state in which the sheet P is conveyed on the belt 23 in the smoothing device 20 as viewed from the direction of arrow A in FIG. On the other hand, each figure after FIG. 6 shows the state seen from the arrow B direction of FIG.

  The belt 23 has a function of transferring its high glossy surface following the surface of the toner image by heating while closely contacting the image surface of the sheet P, and the glossiness (60 °) is in the range of 60 to 100. Is used. However, the surface glossiness of the belt 23 can be arbitrarily selected according to the glossiness of the image required for the color multifunction peripheral of this embodiment as an image forming apparatus.

  In addition, a thermosetting resin such as polyimide, a heat resistant resin, a metal, or the like can be used for the base material forming the main body of the belt 23. A silicon rubber layer having heat resistance is formed as an elastic layer on such a substrate. Fluorine rubber or the like can be used instead of silicon rubber. Further, a fluororesin layer is formed as a toner release layer on the silicon rubber layer.

  Further, if the thickness of the belt 23 is too thin, the strength of the belt itself and the pressure for embedding the toner in the toner receiving layer are insufficient, and if it is too thick, a large amount of heat is required to heat the belt. There is a risk that the toner will not be sufficiently embedded. Therefore, a belt having a thickness of 100 to 300 μm is used here.

  The belt 23 is stretched between the heating roller 21 and the tension roller 24 so as to rotate around, and the heating roller 21 functions as a driving roller that rotates the belt 23. The heating roller 21 is formed as a hollow roller in which a metal core having a good thermal conductivity and a rubber layer as an elastic layer are provided thereon. The metal core is formed of an aluminum hollow pipe having a diameter of 44 mm and a thickness of 5 mm, and the rubber layer is formed of silicon rubber having a JIS-A hardness of 50 degrees and a thickness of 300 μm. In addition, a halogen heater as a heating source is installed inside the heating roller 21. A so-called IH system using electromagnetic induction heating can be used as this heating source.

  Further, a thermistor as a detecting means for detecting the temperature of the belt 23 is installed in the vicinity of the outer surface of the belt 23 facing the heating roller 21. Based on the detection signal output from the thermistor, the control device variably controls the energization of the halogen heater, and the temperature of the belt 23 around the heating roller 21 is adjusted to maintain 130 ° C.

  Further, the tension roller 24 is installed in a separation portion where the sheet is peeled off from the belt 23 by the outer diameter curvature thereof. That is, the size of the tension roller 24 is set with a suitable roller diameter and curvature that can be peeled away from the belt 23 by the “waist strength” of the sheet itself.

  Further, a pressure roller 22 is rotatably installed at a position facing the heating roller 21 with the belt 23 interposed therebetween, and the pressure roller 22 is rotated by friction by the circumferential rotation of the belt 23. Yes.

  The pressure roller 22 is formed as a hollow roller provided with a metal core and a rubber layer as an elastic layer thereon. The rubber layer is formed of silicon rubber having a thickness of 3 mm. A heating source such as a halogen heater is also installed inside the pressure roller 22, and the sheet is heated together with the heating roller 21. As this heating source, it is possible to use another system such as an IH system using electromagnetic induction heating.

  The total pressure with which the pressure roller 22 cooperates with the heating roller 21 to sandwich the belt 23 is set to 50 kg (490 N) in this embodiment. The pressure roller 22 has a function of forming a nip portion with the belt 23, and the length of the nip portion along the sheet conveying direction is set to 5 mm.

  Further, a thermistor as a detecting means for detecting the temperature of the pressure roller 22 is installed in the vicinity of the outer surface of the pressure roller 22. Based on the detection signal output from the thermistor, the control device variably controls energization to the halogen heater, and adjusts the temperature of the pressure roller 22 to maintain 90 ° C. in this embodiment.

  The sheet P that is sandwiched and heated and pressed by the nip formed between the belt 23 and the pressure roller 22 is kept in close contact with the belt 23 to the cooling region of the cooling devices 25 and 26 that are cooling means. It is conveyed. A cooling fan is used as the cooling devices 25 and 26, and the cooling region of the belt 23 is cooled by the cooling fan. The cooling devices 25 and 26 include an inner duct and an outer duct installed on the inner surface side and the outer surface side of the cooling region of the belt 23. The cooling air generated by the cooling fans 25 and 26 is configured to pass through the inside and outside ducts. The cooling devices 25 and 26 have their cooling capacities set so that the toner is cooled to a temperature near the glass transition point before reaching the position where the sheet P peels from the belt 23.

  The cooling devices 25 and 26 are not limited to the above-described structure including a cooling fan, and may be configured to cool by bringing a heat pipe, a heat sink, or a Peltier element containing a coolant such as water into contact therewith. Further, a configuration in which the cooling devices 25 and 26 are installed only on one side of the belt 23 and cooling is performed from only one side of the belt 23 is possible.

  As can be seen, in the smoothing device 20 of this embodiment, the peeling temperature at which the sheet P begins to peel from the belt 23 is sufficiently lower than that of the fixing device 10. While the fixing device 10 is a “high temperature peeling method”, it is a “low temperature peeling method” in which the sheet P starts to be peeled off at a low temperature.

  Accordingly, the following glossing process is executed in the smoothing device 20 in the image forming system of the present embodiment.

  The sheet P that has been subjected to the fixing process by the fixing device 10 and is fed in a state of maintaining a high temperature of, for example, about 80 ° C. is conveyed toward the smoothing device 20 on the downstream side. The sheet P fed into the smoothing device 20 is heated and pressurized at the nip portion at the image surface. At this time, the toner image is heated to a temperature sufficiently higher than the glass transition temperature (Tg) of the toner, specifically about 110 ° C.

  Thereafter, the sheet P is conveyed to the cooling region while being in close contact with the belt 23, and is cooled to, for example, about 50 ° C. below the glass transition temperature (Tg) of the toner until the temperature is lowered to the set temperature by the cooling devices 25 and 26. By performing the cooling process, the toner image after cooling is made highly glossy following the highly glossy surface of the belt 23. Then, the sufficiently cooled sheet P starts to peel off at the separation part with its own rigidity and stiffness. As a result, it is possible to prevent the toner from being transferred to the belt 23 and causing unevenness on the image surface to become rough.

  The peeled sheet P can be output by cutting the blank area at the edge of the sheet by a cutter 27 (see FIG. 1), which is a cutting means, if necessary, and removing the blank area.

  The glossy processed sheet P by the above smoothing is discharged out of the apparatus, and image formation on the series of sheets P is completed.

  Here, a case where the required gloss cannot be obtained will be described.

  In the ideal state shown in FIG. 2, the sheet P that has passed through the nip portion by applying heat and pressure is transported in parallel with the belt 23, and the sheet P is transported on the belt 23 in a state of passing by the smoothing device 20. Is done. In this case, as shown in FIG. 5, the toner image 30 is cooled while being conveyed while being in close contact with the belt 23, and can be obtained by outputting an image whose surface is highly glossy.

However, as shown in FIGS. 4 and 7, when the end of the sheet P is peeled off from the belt 23 and is conveyed in a floating state, the end of the sheet P is curled so that the sheet P and the belt 23 May not always be parallel. Therefore, since the edge portion of the toner image 30 is not in close contact with the belt 23, the toner image 30 may be peeled off at a high temperature. Then, in the cross-sectional state of the output image, as shown in FIG. 9, the edge portion of the toner image 30 is not smooth, and the edge portion of the toner image 30 (IMG) indicated by the hatched portion in FIG. A toner region 50 (see FIG. 11) that does not become undesirably occurs.

  Although the occurrence of curl depends on the thickness of the sheet P and the amount of moisture, it has been confirmed by experiments by the present inventors that the region where the gloss failure occurs is a region approximately 1 mm to 3 mm from the edge portion of the toner image 30. Has been. Based on this, it was confirmed that the gloss failure does not occur at least in an area inside 5 mm from the edge portion of the toner image. 5 and 8 show the conveyance state of the sheet P when the toner band 31 is formed based on the confirmation.

  From the above confirmation, if the toner band 31 is formed with a width of 5 mm or more, even if the sheet P is curled and the end of the sheet is peeled off from the belt 23 and floats, The state of close contact with the belt 23 is maintained. That is, the state where the toner image 30 is in close contact with the belt 23 can be maintained. FIG. 11 shows a cross-sectional state of the output image at that time. The outer edge portion of the toner band 31 does not become smooth and the gloss failure shown by the hatched portion in FIG. 12 occurs, but the region of the toner image 30 does not show the gloss failure.

  When such an image glossing process is performed, the required high glossing process can be performed using not only a glossy processing paper having a toner receiving layer but also other ordinary plain paper, coated paper or PPC paper. Images can be output.

Hereinafter, consideration will be given to the effect of increasing gloss by several examples and reference examples in which toner bands are formed as follows.

Example 1
FIG. 13 shows a first embodiment relating to the size and position of the toner band formed simultaneously with the toner image in advance in the image forming section. In the case of Example 1, a color image is formed on a part of a sheet P of A4 size (297 × 210 mm). In the sheet P, the short side direction of A4 is set as the feed direction (transverse feed), and the front end side 2.5 mm and the left and right end sides 2.5 mm of the blank area are set as areas where no toner image is formed, and the feed direction is set inside thereof. A cyan (C) toner band 31 having a length of 5 mm and a width of 292 mm was formed. The color image was formed in the area inside the toner band 31.

≪Reference Example 1≫
FIG. 14 shows a case where a cyan toner band 31 having a length of 5 mm in the feeding direction and a width of 292 mm is formed inside the blank area on the rear end side in the conveyance direction of the sheet P in addition to the first embodiment. The color image in this case was formed in the area inside the toner band 31.

≪Reference Example 2≫
FIG. 15 shows a sheet in which a cyan toner band having a feed direction of 205 mm and a width of 5 mm is formed adjacent to the inside of the left and right margins of the sheet P in addition to the reference example 1 described above. The color image in this case was formed in the area inside the toner band 31.

≪Reference Example 3≫
FIG. 16 shows a toner band 31 having the same size as that of Reference Example 2 formed of a transparent colorless toner. This transparent toner is produced in the same manner using the same resin as the colored toner except that no color pigment is added.

  A color image was formed in the inner region of the transparent toner band through the above steps.

≪Comparative example 1≫
FIG. 17 shows a comparative example 1 in which a toner band is not formed and only a color image is formed.

≪Reference Example 4≫
FIG. 18 shows a case where a transparent toner is formed not only on the front end but also on the entire color image as Reference Example 4 .

The sheet P formed and output as in Example 1 , Reference Examples 1 to 4 and Comparative Example 1 is passed through the smoothing device 20 for glossing, and the glossiness at the edge portion of the image is visually observed. And evaluated. The evaluation results are shown in FIG. 19 as << Table 1 >>.

-Discussion-
In Comparative Example 1, poor gloss occurred at the edge portion around the color image. Further, in Example 1, a gloss failure due to high temperature separation occurred on the tip side of the cyan toner band, but no gloss failure occurred in the color image portion. In Reference Example 1 , it was possible to improve the gloss failure on the rear end side of the sheet. However, in both Example 1 and Reference Example 1 , curling may occur around the conveyance direction depending on the type of the sheet P and the direction of the sheet passing through, and the color image edge portions in the left and right end directions of the sheet P It was observed that poor gloss occurred due to high temperature peeling. In Reference Examples 2 and 3 , gloss failure occurred due to high temperature peeling at the outer edge of the toner band at both the trailing edge and the left and right edges of the sheet, but no gloss failure occurred in the color image portion. A high-gloss color image could be output. Further, in Reference Example 4 , in addition to eliminating the gloss failure at the image edge portion, it was possible to obtain a high gloss output from the high density area to the low density area in the color image area.

In addition, according to Reference Example 3 , since the toner band was formed of a transparent toner, a uniform glossy color image output that does not impair image quality was obtained. Even in Example 1 , Reference Example 1, and Reference Example 2 , the cutter 27 cuts and outputs the trailing edge of the sheet tip and the left and right edges by 7.5 mm, thereby obtaining a uniform glossy color image output without a margin area. It was. Further, the toner used for forming the toner band in Example 1 , Reference Example 1 and Reference Example 2 may be a color other than that of Example and Reference Example , and the same effect can be obtained by forming each side with a different color toner. can get.

In the above, several Examples 1 to Reference Example 4 according to the present embodiment have been described. However, the present invention is not limited to the results and effects of these Examples, and does not depart from the technical idea of the present invention. Other embodiments and examples, and application examples and modifications thereof are also possible.

  It is not limited to the gloss processing paper used in the electrophotographic image forming apparatus, and a printed matter on which a high gloss image is formed on plain paper can be output. It can be used as high-value-added, high-quality printed matter in fields such as brochures, flyers, pops, and displays.

1 is a diagram showing a preferred embodiment of an image forming apparatus according to the present invention. The figure which shows the smoothing apparatus which is the principal part of this embodiment. Sectional drawing of the fixing nip part of the same smoothing apparatus. FIG. 4 is a diagram illustrating a sheet conveyance state in the fixing nip portion. FIG. 4 is a diagram illustrating a sheet conveyance state in the fixing nip portion. The figure which shows the sheet conveyance state seen from the arrow B direction of FIG. The figure which shows the sheet conveyance state seen from the arrow B direction. The figure which shows the sheet conveyance state seen from the arrow B direction. Sectional drawing which shows an image edge part typically. The top view which shows typically the glossiness defect of an image edge part. Sectional drawing which shows the same gloss defect. FIG. 6 is a diagram illustrating a state where a toner image area does not become defective in gloss even when the same gloss failure occurs. The figure which shows Example 1 in the embodiment. The figure which shows the reference example 1 in the embodiment. The figure which shows the reference example 2 in the embodiment. The figure which shows the reference example 3 in the embodiment. The figure which shows a comparative example. The figure which shows the reference example 4. FIG. The figure which summarized glossiness evaluation as << Table 1 >>.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Primary charging device 3 Exposure means 4 Developing device 5 Cleaner 6 Primary transfer charging device 71 Intermediate transfer belt 72 Followed roller 73 Backup roller 74 Drive roller 8 Registration roller 9 Secondary transfer roller 10 Fixing device 11 Fixing roller 12 Addition Pressure roller 20 Smoothing device (image glossing means)
21 Heating roller 22 Pressure roller 23 Belt 24 Tension roller 25, 26 Cooling device (cooling means)
27 Cutter (cutting means)
P sheet 30 Toner image 31 Toner belt

Claims (1)

Image forming means for forming a toner image on a sheet;
An image glossing means comprising: a belt for heating the toner image formed on the sheet at the nip portion; and a cooling means for cooling the sheet that moves while being in close contact with the belt before being separated from the belt;
A cutting means for cutting the sheet;
Control means for controlling driving of the image forming means, the image glossing means, and the cutting means;
I have a,
The control means includes
A belt-like toner band is formed by the image forming means only between the margin area at the leading end side in the sheet conveyance direction and the toner image formed based on the input image information, and then,
A gloss image forming mode in which a glossing process is executed by the image glossing means ;
An image forming system, characterized in that the cutting means can cut and remove the toner band after the glossing process only on the front end side in the sheet conveying direction .