JP2016167035A - Dehumidifying device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce curl with a low power.SOLUTION: There is provided a dehumidifying device that dehumidifies the inside of an image forming apparatus including a fixing device that fixes toner images formed on recording media, the dehumidifying device comprising: accommodating means that accommodates recording media; heat generating means that generates heat during operation of the image forming apparatus; dehumidifying means that dehumidifies the inside of the image forming apparatus; and moving means that moves the dehumidifying means to the vicinity of the accommodating means or the vicinity of the heat generating means according to the operation state of the image forming apparatus.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a dehumidifying device and an image forming apparatus including the dehumidifying device.

  Conventionally, it is already known that a fixing unit in an electrophotographic image forming apparatus includes a fixing roller and a pressure roller. Then, when the sheet on which the toner image is transferred by the photosensitive member passes between the fixing roller and the pressure roller, the toner image transferred to the sheet is thermally fixed by the heater built in the fixing roller.

  By the way, it is known that curl occurs in the paper that has passed through the fixing unit. This curl occurs when a sheet having a high moisture content due to external environmental factors such as low temperature and high humidity is heat-fixed. The cause is that the degree of fiber shrinkage caused by the evaporation of moisture contained in the paper due to thermal fixing differs between the front and back surfaces of the paper due to the temperature difference between the fixing roller and the pressure roller.

  Since the occurrence of curling leads to a decrease in print quality, it is preferable to suppress the curling as much as possible. Therefore, a technique for reducing curl is already known by attaching a heater to a paper feed tray for storing paper, setting the heater to be turned on while the apparatus is not operating, and removing moisture from the paper. ing.

  As one technique for reducing the occurrence of curling, for example, Patent Document 1 discloses an image forming apparatus having a dehumidifying heater in a paper feed tray. This image forming apparatus employs a configuration that prevents a cost increase by using a temperature detection element that is used for temperature control other than the paper feed tray together with a detection element of a dehumidification control unit that performs power control of the dehumidification heater. ing.

  However, in the technique of controlling the dehumidifying heater based on the detected temperature in the apparatus as in Patent Document 1, the dehumidifying heater does not operate until a predetermined temperature is detected. In a default state such as during standby or standby, an operation to intentionally turn on the dehumidifying heater is required. Moreover, the situation where the electric power for ON operation is required also occurs. For this reason, the electric power used for curl reduction becomes high.

  The present invention has been made in view of such circumstances, and an object thereof is to reduce curl with low power.

  In order to achieve the above-described object, a dehumidifying device according to the present invention is a dehumidifying device that dehumidifies the inside of an image forming apparatus having a fixing device that fixes a toner image formed on a recording medium, and contains a recording medium. A heat generating means for generating heat during operation of the image forming apparatus, a dehumidifying means for dehumidifying the inside of the image forming apparatus, and the vicinity of the housing means or the heat generating means depending on the operating status of the image forming apparatus. And a moving means for moving the dehumidifying means in the vicinity.

  According to the present invention, curl reduction can be performed with low power.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a schematic block diagram of the process cartridge in embodiment of this invention. It is a schematic block diagram which shows the dehumidification apparatus in embodiment of this invention. It is a schematic block diagram which shows the modification of the dehumidification apparatus in embodiment of this invention.

  The dehumidifying device according to the embodiment of the present invention and the image forming apparatus having the dehumidifying device will be described below with reference to the drawings. However, the present invention is not limited to this embodiment as long as the gist of the present invention is not exceeded. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified thru | or abbreviate | omitted suitably. The image forming apparatus according to the present embodiment may include an electrophotographic copying machine, a laser printer, a facsimile, a multifunction peripheral such as an MFP, and the like.

  A schematic configuration of an image forming apparatus 100 having a dehumidifier according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the image forming apparatus 100 includes four process cartridges 6Y, 6M, 6M for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). C and K are provided.

  These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached. Taking a process cartridge 6M for generating an M toner image as an example, as shown in FIG. 2, a drum-shaped photosensitive member 1M, a drum cleaning device 2M, a charge eliminating device, a charging device 4M, a developing device 5M, and the like are provided. . The process cartridge 6M is detachable from the main body of the image forming apparatus 100, and consumable parts can be replaced at a time.

  The charging device 4M uniformly charges the surface of the photoreceptor 1M that rotates clockwise in the drawing by a predetermined driving unit. The surface of the uniformly charged photoreceptor 1M is exposed and scanned by the laser beam L and carries an electrostatic latent image for M. The M electrostatic latent image is developed into an M toner image by the developing device 5M using M toner. Then, intermediate transfer is performed on the intermediate transfer belt 8.

  The drum cleaning device 2M removes the toner remaining on the surface of the photoreceptor 1M after the intermediate transfer process. The static eliminator neutralizes residual charges on the photoreceptor 1M after cleaning. By this charge removal, the surface of the photoreceptor 1M is initialized and prepared for the next image formation. In the other process cartridges 6Y, 6C, and 6K, Y, C, and K toner images are similarly formed on the photoreceptors 1Y, 1C, and 1K, and are intermediately transferred onto the intermediate transfer belt 8.

  As shown in FIG. 1, an exposure device 7 is disposed below the process cartridges 6Y, M, C, and K in the drawing. The exposure device 7 serving as a latent image forming unit irradiates each of the photoconductors in the process cartridges 6Y, 6M, 6C, and 6K with a laser beam L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photoconductor with a laser beam (L) emitted from a light source through a plurality of optical lenses and mirrors while scanning with a polygon mirror rotated by a motor.

  On the lower side of the exposure apparatus 7 in the figure, paper supply means including a paper storage cassette 26, a paper supply roller 27 incorporated therein, a registration roller pair 28, and the like are arranged. The paper storage cassette 26 stores a plurality of sheets P, which are recording media, and a paper feed roller 27 is in contact with each uppermost sheet P.

  When the paper feeding roller 27 is rotated counterclockwise in the figure by a predetermined driving means, the uppermost paper P is fed toward the rollers of the registration roller pair 28.

  The registration roller pair 28 rotationally drives both rollers to sandwich the paper P, but temporarily stops rotating immediately after sandwiching. Then, the paper P is sent out toward a secondary transfer nip described later at an appropriate timing. In the sheet feeding unit having this configuration, the conveying unit is configured by a combination of the sheet feeding roller 27 and the registration roller pair 28 which is a timing roller pair. This transport means transports the paper P from a paper storage cassette 26 which is a storage means to a secondary transfer nip described later.

  Above the process cartridges 6Y, 6M, 6C, and 6K, an intermediate transfer unit 15 that moves the intermediate transfer belt 8 that is an intermediate transfer member endlessly while stretching is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 includes four primary transfer bias rollers 9Y, M, C, and K, a cleaning device 10, and the like. A secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14 and the like are also provided.

  The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched around these three rollers. The primary transfer bias rollers 9Y, 9M, 9C, and 9K hold the intermediate transfer belt 8 that moves endlessly between the photoreceptors 1Y, 1M, 1C, and 1K, thereby forming primary transfer nips. . In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (inner peripheral surface) of the intermediate transfer belt 8.

  All of the rollers except the primary transfer bias rollers 9Y, M, C, and K are electrically grounded. The intermediate transfer belt 8 sequentially passes through the primary transfer nips for Y, M, C, and K along with the endless movement thereof, and Y, M, and C on the photoreceptors 1Y, M, C, and K are sequentially transferred. , K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

  The secondary transfer backup roller 12 described above sandwiches the intermediate transfer belt 8 from the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the paper P at the secondary transfer nip. The intermediate transfer belt 8 that has passed through the secondary transfer nip is adhered to the transfer residual toner that has not been transferred to the paper P and is cleaned by the cleaning device 10.

  In the secondary transfer nip, the paper P is sandwiched between the intermediate transfer belt 8 whose surface moves in the forward direction and the secondary transfer roller 19 and is conveyed in a direction opposite to the registration roller pair 28 side. When the sheet P sent out from the secondary transfer nip passes between rollers of the fixing device 20, the four-color toner image transferred to the surface is fixed by heat and pressure. Thereafter, the paper P is discharged out of the apparatus through a pair of paper discharge rollers 29.

  A stack unit 30 is formed on the upper surface of the main body of the image forming apparatus 100, and the sheets P discharged to the outside by the discharge roller pair 29 are sequentially stacked on the stack unit 30.

  Next, the dehumidifying device in the present embodiment will be described with reference to FIG. In describing the dehumidifying apparatus in the present embodiment, a part of the configuration of the image forming apparatus 100 shown in FIG. 1 is used. Note that the dehumidifying apparatus in the present embodiment may include a part of the configuration of the image forming apparatus 100.

  FIG. 3 illustrates the photoreceptors 1Y, 1M, 1C, and 1K, the intermediate transfer belt 8, the secondary transfer roller 19, the fixing device 20, and paper storage as a storage unit among the components included in the image forming apparatus 100 according to the present exemplary embodiment. The cassette 26, the paper feed roller 27, and the registration roller pair 28 are extracted. For convenience of illustration, this drawing shows only the components necessary for the description, and there is no intention to exclude other components.

  Here, as an example of the heat generation means in the present invention, the fixing device 20 is the heat generation means H1, and the photoreceptors 1Y, M, C, and K are the heat generation means H2. As the heat generating means, in addition to the fixing device 20 and the photoreceptors 1Y, 1M, 1C, and 1K, all devices that generate heat when the apparatus is operated among the units included in the image forming apparatus 100 are applicable.

  In addition, the dehumidifying apparatus according to the present embodiment includes a sheet-shaped dehumidifying agent D as a dehumidifying unit, a dehumidifying agent storage cassette 50 as a dehumidifying agent storing unit that stores the dehumidifying agent D, and the dehumidifying agent D as a resist roller pair 28. A sheet roller 51 to be fed to the printer and a return roller 52 are provided. It is preferable that the dehumidifying agent storage cassette 50 is disposed in the vicinity of the paper storage cassette 26. In the present embodiment, the dehumidifying agent storage cassette 50 is disposed below the paper storage cassette 26. In this case, in order to enhance the dehumidifying effect, for example, the bottom surface of the paper storage cassette 26 may be configured in a mesh shape.

  Here, the dehumidifying agent D is in the form of a sheet, but this uses the conveyance path of the paper P, while the fixing device 20 as the heat generating means H1 and the photoreceptors 1Y, M, and H as the heat generating means H2. This is a configuration required for passing C and K. When a configuration other than this configuration is adopted, the dehumidifying agent D is not limited to a sheet shape. For example, the dehumidifying agent D may be a three-dimensional shape such as a thick solid. In this case, a dedicated transport path for transporting the dehumidifying agent D may be provided separately.

  The dehumidifying agent D can be used again as a dehumidifying agent by absorbing the surrounding moisture and dehumidifying it, and then applying heat to blow off the moisture. The dehumidifying agent D dehumidifies the inside of the image forming apparatus 100. Needless to say, the dehumidifying agent D can also dehumidify the paper P stored in the paper storage cassette 26. In this embodiment, the dehumidifying means is a “dehumidifying agent”, but a desiccant or a hygroscopic agent may be used instead. The dehumidifying agent may be a porous medium such as silica gel or zeolite, or any other known or later developed medium.

  Further, the dehumidifying apparatus in the present embodiment includes a moving unit 201, a timing control unit 202, and a temperature / humidity measuring unit 203. These means are realized by reading the program from a storage unit built in the image forming apparatus 100 and storing the means as a program and executing the program by the CPU.

  The sheet P fed toward the registration roller pair 28 by the sheet feeding roller 27 is defined as a sheet P ′, and the dehumidifying agent D conveyed toward the registration roller pair 28 by the sheet roller 51 is defined as a dehumidifying agent D ′. . The dehumidifying agent D that passes through the photoconductors 1Y, 1M, 1C, and 1K as the heat generating means H2 and returns to the dehumidifying agent storage cassette 50 is defined as a dehumidifying agent D ″.

  The moving unit 201 moves the dehumidifying agent D to the vicinity of the paper storage cassette 26 or to the vicinity of the heat generating units H1 and H2 according to the operation status of the image forming apparatus 100. That is, the moving unit 201 is a drive control unit that drives the sheet roller 51 to send the dehumidifying agent D to the conveyance path. The moving unit 201 also functions as a drive control unit that drives the return roller 52.

  Further, the moving unit 201 moves the dehumidifying agent D to the vicinity of the paper storage cassette 26 when the image forming apparatus 100 is not operating. In the movement of the dehumidifying agent D by the moving unit 201, when the image forming apparatus 100 is not in operation, it is necessary to dehumidify the paper P stored in the paper storage cassette 26. It can be left in the cassette 50.

  In addition, the movement of the dehumidifying agent D by the moving unit 201 is performed when the image forming apparatus 100 ends its operation after the dehumidifying agent D passes through the photoconductors 1Y, 1M, 1C, and 1K, which are the heat generating units H2. It includes driving the return roller 52 to return the dehumidifying agent D to the dehumidifying agent storage cassette 50.

  On the other hand, the moving unit 201 moves the dehumidifying agent D to the vicinity of the heat generating units H1 and H2 when the image forming apparatus 100 is operating. While the image forming apparatus 100 is in operation, the dehumidifying agent D is moved to the vicinity of the fixing device 20 that is the heat generating means H1 and the photoconductors 1Y, M, C, and K that are the heat generating means H2, and the heat generated from these is moved. By using it, it is possible to dehumidify the paper P stored in the paper storage cassette 26 when not in operation and remove the moisture from the dehumidifying agent D in a state where the dehumidifying effect is weakened, thereby restoring the dehumidifying effect.

  In the present embodiment, the sheet-like dehumidifying agent D is transported on the transport path of the paper P, and the rollers in the fixing device 20 that is the heat generating means H1 and the photoreceptors 1Y, M, C, and K that are the heat generating means H2. By being conveyed while being sandwiched between pairs, the dehumidifying effect can be restored by the heat generated from these.

  The timing control unit 202 controls the timing at which the dehumidifying agent D passes through the transport path of the paper P by the moving unit 201. The timing control unit 202 preferably sets the timing at which the dehumidifying agent D passes through the conveyance path of the paper P after the fixing process to the paper P by the fixing device 20. Thereby, it is possible to prevent a situation in which the user is put on standby by the operation for restoring the dehumidifying effect of the dehumidifying agent D.

  The temperature / humidity measuring unit 203 measures the temperature or humidity inside the image forming apparatus 100. The temperature / humidity measuring unit 203 may be a known sensor that measures temperature and humidity, and passes the measured temperature data and humidity data to the moving unit 201. The moving unit 201 changes the frequency of passing the dehumidifying agent D through the transport path of the paper P according to the temperature or humidity measured by the temperature / humidity measuring unit 203.

  Curling caused by printing occurs because the recording medium is left in a high temperature and high humidity environment and absorbs moisture. In the case of a high-temperature and high-humidity environment, the dehumidifying agent absorbs a large amount of water. Therefore, in this embodiment, it is preferable that the inside of the image forming apparatus 100 is frequently passed in order to reuse the dehumidifying agent D.

[Modification]
Next, a modification of the dehumidifying device in the present embodiment will be described with reference to FIG. In addition to the above-described configuration, the dehumidifying apparatus according to the present modified example takes out the hot air generated near the heat generating means H1 and H2 and generates hot air, and the hot air generated by the fan 301 is supplied to the paper storage cassette 26. Or the ventilation path 302 sent to the dehumidifying agent accommodation cassette 50 is provided, It is characterized by the above-mentioned. The fan 301 is driven and controlled by the drive control means 300.

  The fan 301 takes out hot air generated in the vicinity of the photoconductors 1Y, 1M, 1C, and 1K as the heat generating means H2 to generate hot air, which is sent to the paper storage cassette 26 through the air blowing path 302, thereby storing the paper. The paper P stored in the cassette 26 can be dehumidified. Further, by sending hot air to the dehumidifying agent storage cassette 50 through the air blowing path 302, it is possible to remove the moisture absorbed by the dehumidifying agent D stored in the dehumidifying agent storage cassette 50 and to restore the dehumidifying effect of the dehumidifying agent D. It becomes.

  As described above, according to the dehumidifying apparatus and the image forming apparatus having the dehumidifying apparatus according to the present embodiment, the dehumidifying agent is preferably used without using a device that consumes much power, such as a dehumidifying heater for dehumidifying the inside of the apparatus. In order to dehumidify the inside of the device and the paper, and to restore the dehumidifying effect of the dehumidifying agent, it is possible to remove the moisture absorbed by the dehumidifying agent using the heat generated in the device and reuse the dehumidifying agent. Thus, curling can be reduced with low power.

1Y, 1M, 1C, 1K Photoconductor 8 Intermediate transfer belt 19 Secondary transfer roller 20 Fixing device 26 Paper storage cassette 27 Paper feed roller 28 Registration roller pair H1, H2 Heat generating means 50 Dehumidifying agent storage cassette 51 Sheet roller 52 Return roller 201 Moving means 202 Timing control means 203 Temperature / humidity measuring means 300 Drive control means 301 Fan 302 Blower path

Japanese Patent Laid-Open No. 08-225169

Claims (10)

A dehumidifying device for dehumidifying the inside of an image forming apparatus having a fixing device for fixing a toner image formed on a recording medium,
Storage means for storing the recording medium;
Heat generating means for generating heat during operation of the image forming apparatus;
A dehumidifying means for dehumidifying the inside of the image forming apparatus;
A moving unit that moves the dehumidifying unit in the vicinity of the housing unit or in the vicinity of the heat generating unit according to an operation state of the image forming apparatus;
A dehumidifying device comprising:   The dehumidifying apparatus according to claim 1, wherein the moving unit moves the dehumidifying unit to the vicinity of the housing unit when the image forming apparatus is not operating.   The dehumidifying apparatus according to claim 1, wherein the moving unit moves the dehumidifying unit to the vicinity of the heat generating unit when the image forming apparatus is operating. A dehumidifying agent containing means for containing the dehumidifying means,
The dehumidifying device according to any one of claims 1 to 3, wherein the dehumidifying agent storage means is disposed in the vicinity of the storage means. The dehumidifying means is a sheet-like dehumidifying agent,
5. The transfer unit according to claim 1, wherein the moving unit allows the sheet-like dehumidifying agent to pass through a conveyance path of the recording medium when the image forming apparatus is operating. 6. Dehumidifier. Timing control means for controlling the timing of passing the sheet-like dehumidifying agent through the transport path of the recording medium by the moving means;
6. The dehumidifying device according to claim 5, wherein the timing control means sets the timing at which the sheet-like dehumidifying agent passes through the conveyance path after the fixing process to the recording medium by the fixing device. Comprising a temperature and humidity measuring means for measuring the temperature or humidity inside the image forming apparatus;
The dehumidifying apparatus according to claim 6, wherein the moving unit changes the frequency of passing the sheet-like dehumidifying agent through the conveyance path in accordance with the temperature or humidity measured by the temperature and humidity measuring unit. .   The dehumidifying device according to any one of claims 5 to 7, wherein the moving unit returns the sheet-shaped dehumidifying agent that has passed through the conveyance path to the dehumidifying agent containing unit. A fan that generates hot air by taking out hot air generated in the vicinity of the heat generating means;
A blowing path for sending hot air generated by the fan to the housing means or the dehumidifying agent housing means;
The dehumidifying device according to any one of claims 4 to 8, further comprising:   An image forming apparatus comprising the dehumidifying device according to claim 1.

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