JP2013203542A - Sheet feeder and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the amount of moisture in paper (humidity in a sheet feeder) at a constant amount or below while reducing a manufacturing cost and improving power-saving performance without using a control circuit such as a CPU and a sensor.SOLUTION: A sheet feeder includes a paper loading section, a paper feeding mechanism that feeds paper one by one, a drying section that performs drying by receiving power supply, a humidity change section in which members of different degrees of contraction and expansion due to humidity are combined and whose shape changes according to humidity, a first contact point provided in the humidity change section, and a switch section that includes a second contact point provided to contact the first contact point if humidity exceeds preset humidity, doesn't connect the drying section and a power supply if the first contact point is not in contact with the second contact point, and connects the drying section and the power supply to perform drying if the first contact point is in contact with the second contact point.

Description

  The present invention relates to a paper feeding device for drying paper in a paper feeding device. The present invention also relates to an image forming apparatus including a paper feeding device.

  In general, an image forming apparatus (for example, a printer, a copier, a multifunction peripheral, a FAX apparatus, etc.) includes a paper feeding device. The paper feeding device accommodates a plurality of sheets used for printing. When printing, the paper feeding device feeds the paper one by one. Here, if the amount of moisture contained in the sheet is large, the resistance value of the sheet decreases. When the resistance value of the paper is lowered, the density of the printed matter is lowered due to the reduction of the transfer efficiency of the toner image onto the paper, and the image quality is lowered. In addition, when the amount of moisture contained in the paper is large, the paper is easily curled and the paper is likely to be jammed. Further, if the amount of moisture contained in the sheet is large, the sheets may be attracted to each other, and the sheet may be easily fed (simultaneous conveyance of a plurality of sheets). As described above, problems may arise due to the large amount of water in the paper. Therefore, the paper in the paper feeder may be dehumidified.

  An example of a drying apparatus for drying such paper is disclosed in Patent Document 1. Specifically, Patent Document 1 discloses a heating and heat retaining unit (such as a heater of the paper feeding unit 61) that heats a predetermined part of the image forming unit to retain moisture to prevent dehumidification or condensation, and a heating and warming unit from a commercial power supply unit. Switching means for switching power supply to and interruption of power, environment detection means for detecting environmental information such as temperature or humidity, comparison means for comparing the detected environmental information with preset comparison information, and image formation In the mode in which image formation can be performed by the unit, the switching unit is made to cut off the power supply from the commercial power supply unit to the heat insulation unit, and in the energy saving mode, the switching unit is switched from the commercial power source unit to the switching unit based on the comparison result by the comparison unit An image forming apparatus provided with control means for controlling power supply to or from heat insulation means is described. This configuration makes it possible to energize the heating and heat retention means even when the energy saving mode or the energy saving control function is effective, and cuts off the power supply to the heating and heat retention means in the normal mode after turning on the power to reduce overall power consumption. (See Patent Document 1: Claim 4, paragraphs [0008], [0026], etc.).

JP 2003-084629 A

  First, the humidity inside and outside the sheet feeding device (image forming device) changes regardless of whether the image forming device is powered on and whether it is in the normal mode or the power saving mode. For this reason, from the viewpoint of image quality, jam prevention, double feed prevention, etc., the water content of the paper (humidity in the paper feeder) can be kept below a certain level regardless of the state of the image forming apparatus. In addition, there is a problem that a drying unit (for example, a heater) for drying the paper in the paper feeding device should be operated.

  Here, in any image forming apparatus or paper feeding apparatus, control of ON / OFF of driving of the drying unit (ON / OFF of power supply to the drying unit) is controlled using a control circuit such as a CPU, a microcomputer, a chip, or the like. Made. For example, one or a plurality of sensors that detect the temperature and humidity inside and outside the sheet feeding device and the image forming apparatus are provided. Then, the output of each sensor is input to the control circuit. Subsequently, the control circuit determines the necessity of dehumidification. If it is determined that it is necessary, the control circuit supplies power to the drying unit to dry the paper in the paper feeding device. In other words, power supply (drive) ON / OFF to the drying unit is generally performed using a control circuit.

  However, it is necessary to install a control circuit and a sensor and to wire signal lines to the control circuit. This causes a problem that the number of parts of the sheet feeding device and the image forming apparatus increases and the manufacturing cost increases.

  The image forming apparatus may be in a state where the main power is turned off at night or in a power saving state (power saving mode or sleep mode) in which the power consumption in the image forming apparatus is desired to be reduced as much as possible. In order to perform control using a control circuit such as a CPU in the main power OFF state or power saving state, power is supplied to the control circuit or sensor in the main power OFF state or power saving state, the control circuit is operated, and control is performed. The circuit needs to determine the need for dehumidification. However, when the control circuit is operated, a certain amount of power is consumed. In order to avoid unnecessary power supply to the drying unit, it is necessary to continue operating the control circuit or to start the control circuit periodically in order to check the humidity in the sheet feeding device. As a result, the power for operating the control circuit is consumed even though the power consumption of the image forming apparatus is desired to be suppressed. Accordingly, providing a control circuit to control the power supply to the drying unit also has a problem in terms of power saving.

  Here, in the image forming apparatus described in Patent Document 1, the power supply to the heating and heat retaining unit is basically stopped in the image forming mode. For this reason, there is a possibility that the sheet absorbs a large amount of water in a mode in which an image can be formed. Therefore, there is an insufficient aspect in terms of dehumidification performance. Even in the energy saving mode, the control means controls the power supply to the heating and warming means based on the comparison result by the comparison means. Accordingly, since the comparison unit and the control unit continue to operate even in the energy saving mode, the image forming apparatus described in Patent Document 1 has a problem in terms of power saving. Thus, the invention described in Patent Document 1 cannot solve the above problem.

  The present invention has been made in view of the above-described problems of the prior art, and eliminates the use of a control circuit such as a CPU or a sensor so as to reduce the manufacturing cost and improve the power saving performance. It is an object to keep (humidity in the paper feeding device) below a certain level.

  According to a first aspect of the present invention, there is provided a sheet feeding unit on which a plurality of sheets are loaded, a sheet feeding mechanism that feeds the sheets loaded on the sheet loading unit one by one, and a power supply. A humidity changing portion whose shape changes in accordance with humidity by combining members having different degrees of shrinkage and expansion depending on humidity, a first contact provided in the humidity changing portion, A second contact provided to contact the first contact when a predetermined humidity is exceeded, and the drying unit and the power source are not connected when the first contact and the second contact are not in contact; And a switch unit that connects the drying unit and a power source to perform drying when the one contact and the second contact are in contact with each other.

  According to this configuration, the switch unit is a combination of a member whose degree of contraction and expansion varies depending on the humidity, the humidity changing unit whose shape changes according to the humidity, the first contact provided in the humidity changing unit, and the humidity is predetermined. Including a second contact provided to contact the first contact when the humidity exceeds a predetermined humidity, and when the first contact and the second contact are not in contact, the drying unit and the power source are not connected, and the first contact and the second contact When the is in contact, the drying unit and power supply are connected to perform drying. Thus, when the humidity of the paper feeding device exceeds a predetermined humidity, power is automatically supplied to the drying unit, and the drying unit dries the paper feeding device and the paper. In addition, when the paper is dried by dehumidification by the drying unit and the humidity of the paper feeding device becomes equal to or lower than a predetermined humidity, the power supply to the drying unit is automatically stopped. Accordingly, the moisture content of the paper (humidity in the paper feeding device) can be kept constant regardless of the state of the image forming apparatus.

  In addition, in order to keep the humidity in the sheet feeding device below a certain level, no control circuit or sensor such as a CPU or microcomputer is used, so there is no need to provide a control circuit or a humidity sensor, thereby reducing the manufacturing cost of the sheet feeding device. be able to. In addition, even when the main power is off or in the power saving mode, power consumption due to driving of the control circuit and sensor does not occur as in the conventional case, so that a high power saving effect can be obtained.

  Here, the predetermined humidity is the humidity when the first contact and the second contact are in contact. For example, the predetermined humidity can be about 60 to 70% (when it is about 20 to 30 ° C., more specifically about 25 ° C.). The predetermined humidity can be set as appropriate by adjusting the positions of the first contact and the second contact in consideration of image quality, prevention of jamming, prevention of double feeding, and the like.

  According to a second aspect of the present invention, in the first aspect of the invention, as the humidity becomes higher than the predetermined humidity, the second contact is responsive to the force with which the first contact pushes the second contact. And a biasing member that moves from the reference position and biases the second contact in a direction to return to the reference position.

  According to this configuration, as the humidity becomes higher than the predetermined humidity, the second contact moves from the reference position according to the force with which the first contact pushes the second contact, and returns the second contact to the reference position. A biasing member that biases in the direction is included. Thereby, if the force by which the first contact pushes the second contact increases due to an increase in humidity, the second contact moves. Therefore, even if the force with which the first contact pushes the second contact increases with increasing humidity, the first contact and the second contact can be prevented from being damaged. Further, as the humidity decreases, the position of the second contact can be automatically returned to the reference position by the biasing member.

  According to a third aspect of the present invention, in the first or second aspect, the humidity changing portion is a member in which members having different degrees of contraction and expansion due to humidity are bonded together and wound in a spring shape. The contact is moved in the circumferential direction of the humidity changing portion according to the humidity change.

  According to this configuration, the humidity changing portion is formed by laminating a member in which the degree of contraction and expansion varies depending on the humidity, and the first contact is provided at one end of the humidity changing portion. Depending on the, it moves in the circumferential direction of the humidity changing part. Thereby, a switch part can be reduced in size.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the operation switch is provided between the power source and the drying unit, and switches whether or not to keep the power supply to the drying unit stopped. It was decided to include.

  According to this configuration, the operation switch is provided between the power source and the drying unit and for switching whether or not to supply power to the drying unit. When paper is not put in the paper feeding device (paper is not set), drying by the drying unit is useless, but power to the drying unit can be kept stopped by the operation switch. Therefore, wasteful power consumption can be eliminated according to the user's intention. Further, if the user determines that drying by the drying unit is not necessary, the power to the drying unit can be kept stopped by the operation switch. Therefore, the user can stop the paper drying function by his / her own intention in order to reduce power consumption.

  An image forming apparatus according to a fifth aspect includes the paper feeding device according to any one of the first to fourth aspects.

  According to this configuration, the image forming apparatus includes the above-described paper feeding device. As a result, it is possible to provide a high-function image forming apparatus in which the moisture content of the paper is kept below a certain level, the image quality is high, and the occurrence of jamming and double feeding is suppressed. In addition, it is possible to provide an image forming apparatus with reduced cost and high power saving performance.

  According to a sixth aspect of the present invention, in the fifth aspect of the invention, the image forming unit includes a toner image forming unit, and the image forming unit includes the drying unit and the switch unit.

  According to this configuration, the drying unit and the switch unit are provided in the image forming unit. As a result, the control circuit and sensor such as a CPU are not provided and the manufacturing cost is reduced and the power saving performance is improved, while the surface of the image carrier or the like has no water droplets (no condensation). Can keep.

  According to a seventh aspect of the invention, in the invention of the fifth or sixth aspect, the image includes a light source for reading a document, an optical member for guiding reflected light of the document, and an image sensor on which the reflected light of the document is incident. It has a reading unit, and the drying unit and the switch unit are provided inside the image reading unit.

  According to this configuration, the drying unit and the switch unit are provided inside the image reading unit. As a result, a control circuit such as a CPU or a sensor is not provided, and manufacturing costs are reduced and power saving performance is improved, while no water droplets are attached to the image sensor or optical member in the image reading unit (no condensation). State).

  As described above, according to the present invention, it is possible to reduce the manufacturing cost of the sheet feeding device and the image forming apparatus without providing a control circuit such as a CPU or a sensor. In addition, the power saving performance of the sheet feeding device and the image forming apparatus can be improved. In addition, the moisture content of the paper (humidity in the paper feeding device) can always be kept below a certain level.

1 is a schematic front sectional view of a multifunction machine. 2 is a block diagram illustrating an example of a hardware configuration of a multifunction peripheral. FIG. FIG. 6 is a circuit diagram illustrating an example of a configuration related to sheet drying of a sheet feeding device. It is a perspective view which shows an example of a switch part. It is explanatory drawing which shows an example of the bonding board contained in the humidity change part contained in a switch part. It is explanatory drawing which shows an example of the movement of the contact accompanying a humidity change. It is explanatory drawing for demonstrating drying except a paper feeder.

  Hereinafter, a multifunction peripheral 100 (corresponding to an image forming apparatus) including the sheet feeding device 1 according to the embodiment of the present invention will be described with reference to FIGS. However, each element such as configuration and arrangement described in each embodiment does not limit the scope of the invention and is merely an illustrative example.

(Schematic configuration of image forming apparatus)
First, an electrophotographic multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic front sectional view of the multifunction machine 100.

  An image reading unit 2 and a document conveying unit 3 are provided on the upper part of the multifunction peripheral 100 of the present embodiment. In addition, the sheet feeder 1, the conveyance path 4, the image forming unit 5, the fixing unit 6, and the like are provided in the MFP 100 main body.

  The document conveying section 3 conveys the documents one by one automatically and continuously toward the reading position (feed reading contact glass 21) of the image reading section 2. The document transport unit 3 has a fulcrum in the depth direction of the paper surface of FIG. 1 and can be opened and closed in the vertical direction of the paper surface. The document transport unit 3 presses the document placed on the placement reading contact glass 22 when the document is copied.

  The image reading unit 2 reads a document and generates image data. On the upper surface of the image reading unit 2, contact glass (two kinds of contact glass 21 for feed reading and contact glass 22 for placement reading) is provided.

  As shown in FIG. 1, a first moving frame 25 including a light source 23 (corresponding to an optical member) and a first mirror 241 (corresponding to an optical member) for irradiating a document with light in a housing of the image reading unit 2. (Corresponding to an optical member), a second moving frame 26 (corresponding to an optical member) including a second mirror 242 (corresponding to an optical member), a third mirror 243 (corresponding to an optical member), a lens 27 (corresponding to an optical member) Or an optical system member such as an image sensor 28 for reading the original for each line and generating image data. Further, in order to move each moving frame, a wire 29a, a winding drum 29b (rotated by a winding motor (not shown)) and the like are also provided in the image reading unit 2.

  The light emitted from the light source 23 strikes the original on each contact glass, and the reflected light is reflected on the first mirror 241 (first moving frame 25), the second mirror 242 (second moving frame 26), and the third mirror 243 (second The light is reflected by an optical member such as a moving frame 26) and guided to the lens 27. The lens 27 collects the reflected light and enters the image sensor 28.

  For example, the image sensor 28 is constituted by a CCD (Charge Coupled Device) in which photoelectric conversion elements are arranged in a line, and reads the original for each line in the main scanning direction based on the reflected light of the original. Reading is performed in units of lines in the main scanning direction (direction perpendicular to the document conveying direction), and reading in units of lines is continuously repeated in the sub-scanning direction (document conveying direction) to read one document.

  A plurality of wires 29a are attached to the first moving frame 25 and the second moving frame 26 (only one is shown in FIG. 1 for convenience). The other end of the wire 29a is connected to the take-up drum 29b, and the take-up drum 29b rotates forward and backward using a take-up motor (not shown) as a drive source, and the first moving frame 25 and the second moving frame 26 are in the horizontal direction. Move freely.

  First, in the case of reading a document transported by the document transport unit 3, the first moving frame 25 and the second moving frame 26 are moved to a lower position (reading position) of the feed reading contact glass 21 after the winding motor is driven. Fixed. Then, the light source 23 irradiates the passing document. On the other hand, when reading a document placed on the placement reading contact glass 22, the first moving frame 25 and the second moving frame 26 are moved from the home position to the right of FIG. 1 by the take-up drum 29b, the wire 29a, and the like. Each moving frame is moved horizontally in the direction, and the scanning operation is sequentially performed up to the document edge.

  The image reading unit 2 uses these optical system members to irradiate the original with light, A / D converts the output value of each pixel of the image sensor 28 that receives the reflected light of the original, and generates image data. For example, the multi-function device 100 can print based on the read image data (copy function). Note that an operation panel 101 can be provided on the front side of the image reading unit 2 to display print settings such as copying and the status of the multifunction peripheral 100 (see FIG. 2).

  The multifunction peripheral 100 according to the present embodiment includes a paper feeding device 1 that stores and supplies image forming paper. The paper feeding device 1 has various types (for example, plain paper, copy paper, recycled paper, etc.) and a plurality of sheets (for example, about 500 to 1000 sheets) of each size (for example, A4, A3, B4, B5, letter size, etc.). It includes a cassette 11 (corresponding to a paper placement section) that is loaded and accommodated. Then, the cassette 11 can be removed for paper supply or paper size change.

  The paper feeding device 1 is provided with a paper feeding roller 12 (corresponding to a paper feeding mechanism) that rotates when the paper is fed out. Further, a paper placement plate 13 on which paper is placed is provided in the cassette 11. Then, the end of the sheet placing plate 13 on the downstream side in the sheet conveyance direction is urged upward so that the uppermost sheet contacts (contacts) the sheet feeding roller 12. During printing, the paper feed roller 12 rotates and feeds paper one by one. Note that the number of sheet feeding devices 1 can be increased by stacking two or more in the vertical direction.

  A heater 14 (corresponding to a drying unit) is provided along the lower surface (or the upper surface) of the paper feeding device 1. For example, the heater 14 is a sheet (electric heating sheet) including a heating wire. When energized (by power supply), the heater 14 generates heat. Then, the inside of the paper feeding device 1 is warmed by the heat generated by the heater 14, the moisture (water) of the paper evaporates, and the paper is dried and dehumidified. As described above, by supplying power to the heater 14, the inside of the paper feeding device 1 and the paper can be dried. In this description, the heater 14 is exemplified as the drying unit, but the drying unit may be one that performs drying by blowing warm air or the like, and is not limited to the heating wire type heater 14.

  As will be described in detail later, a switch unit 15 for turning on / off the heater 14 depending on whether or not a predetermined humidity is exceeded is provided in the sheet feeding device 1. The switch unit 15 has a function as a humidity sensor, and keeps the humidity in the sheet feeding device 1 below a certain level.

  Next, the conveyance path 4 will be described. The transport path 4 is a path for transporting paper in the apparatus. The conveyance path 4 is provided with a registration roller pair 41 that sends out the toner image formation timing. In addition, a discharge tray 42 that receives the paper discharged from the discharge port and a discharge roller pair 43 that sends the paper to the discharge tray 42 are also provided.

  The image forming unit 5 forms an image (toner image) on a sheet fed from the sheet feeding device 1 based on the image data, and transfers the toner image onto the conveyed sheet. As the image data, document image data acquired by the image reading unit 2 and transmission image data from the computer 200 (see FIG. 2) connected to the multifunction peripheral 100 are used. The image forming unit 5 includes a photosensitive drum 51 supported so as to be rotationally driven in an arrow direction shown in FIG. 1, a charging device 52 disposed around the photosensitive drum 51, an exposure device 53, a developing device 54, a transfer roller 55, A cleaning device 56 and the like are provided.

  The toner image formation and transfer process will be described. The photosensitive drum 51 is rotationally driven in a predetermined direction. Then, the charging device 52 above the photosensitive drum 51 is charged to a predetermined potential. The exposure device 53 outputs laser light based on the image data, and scans and exposes the surface of the photosensitive drum 51 from the right side of the charging device 52 to form an electrostatic latent image corresponding to the image data.

  In FIG. 1, the developing device 54 on the right side of the photosensitive drum 51 supplies toner to the electrostatic latent image formed on the photosensitive drum 51 and develops it. The transfer roller 55 below the photosensitive drum 51 is pressed against the photosensitive drum 51 to form a nip. Then, the registration roller pair 41 is timed to cause the sheet to enter the nip. When the nip between the paper and the toner image enters, a predetermined voltage is applied to the transfer roller 55, and the toner image on the photosensitive drum 51 is transferred to the paper. The cleaning device 56 removes the toner remaining on the photosensitive drum 51 after the transfer.

  The fixing unit 6 fixes the toner image transferred to the paper. The fixing unit 6 of the present embodiment includes a heating roller 61 and a pressure roller 62 that incorporate a heating element. The heating roller 61 and the pressure roller 62 are pressed to form a nip. When the sheet passes through the nip, the toner is melted and heated, and the toner image is fixed on the sheet. The sheet after toner fixing is discharged to the discharge tray 42.

(Hardware configuration of MFP 100)
Next, an example of a hardware configuration of the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the multifunction peripheral 100.

  First, the main control unit 7 is provided in the main body of the multi-function device 100 as a part that controls the operation of the multi-function device 100. For example, the main control unit 7 is a substrate having a control element such as the CPU 71. The main control unit 7 controls the entire control of the multifunction peripheral 100. The main control unit 7 controls printing by performing ON / OFF of a part that performs overall control, a part that performs communication control, a part that performs image processing, a motor that rotates image forming and various rotating bodies, and the like. A plurality of types may be provided by dividing each function such as an engine control unit. In this description, a configuration in which these control units are combined is shown and described.

  The main control unit 7 has a storage unit 72. The storage unit 72 can store image data and the like in addition to programs and data for controlling the multifunction peripheral 100. For example, the storage unit 72 is a combination of volatile and non-volatile storage devices such as RAM, ROM, HDD, and flash ROM. The CPU 71 controls the multifunction peripheral 100 by executing arithmetic processing and transmitting and receiving control signals based on programs and data stored in the storage unit 72.

  The main control unit 7 is communicably connected to the document conveying unit 3, the image reading unit 2, the paper feeding device 1, the conveying path 4, the image forming unit 5, and the fixing unit 6, and controls each unit. The main control unit 7 is connected to the operation panel 101 so as to be communicable. As a result, the contents of settings and inputs made on the operation panel 101 are transmitted to the main control unit 7. The main control unit 7 gives an instruction to the image forming unit 5 or the like so that each unit operates according to the set content, and operates each unit included in the multifunction peripheral 100.

  Further, the main control unit 7 is connected to a communication unit 73 that is an interface for communicating with a computer 200 (for example, a personal computer) or a counterpart FAX apparatus 300 via a network, a cable, or a communication network. As a result, the MFP 100 receives image data from the computer-200 and prints it (printer function), accumulates the image data read by the image reading unit 2 in the storage unit 72, and transmits the image data to the computer-200. (Scanner function) and image data can be transmitted / received to / from an external FAX apparatus 300 (FAX function).

  In addition, a power supply unit 8 is provided in the multifunction peripheral 100. For example, the power supply unit 8 is connected to a commercial power supply and generates various voltages. In addition, a main switch 81 for turning on the main power supply for turning on / off the connection between the commercial power supply and the power supply unit 8 is provided.

  For example, the power supply unit 8 includes a plurality of power conversion circuits 82 including a rectifier circuit, a transformer, a converter, a smoothing circuit, and the like, and generates a plurality of types of voltages necessary for operating the multifunction peripheral 100. For example, the power supply unit 8 generates DC 24 V for driving the motor, DC 5 V for driving circuit elements in the main control unit 7, DC 3.3 V, and the like, and supplies them to each unit in the multifunction peripheral 100.

  Note that the multifunction peripheral 100 of the present embodiment has a normal mode and a power saving mode in which power consumption is reduced as compared with the normal mode, and the voltage and current amount generated in each mode are different. Therefore, a power control unit 83 that controls the operation of the power supply unit 8 (each power conversion circuit 82 in the power supply unit 8) is provided in accordance with each mode. When a predetermined power saving mode transition condition is satisfied, the multifunction peripheral 100 transitions to the power saving mode. For example, the elapse of the power saving mode transition time without using the multifunction peripheral 100 after a specific operation on the operation panel 101, job completion or activation completion is set as the power saving mode transition condition.

  Also, in the multi-function device 100, a monitoring unit 84 that monitors whether or not to return from the power saving mode to the normal mode (whether a return factor has occurred, for example, setting of paper, a document, operation of the operation panel 101, etc.). Is provided. In the power saving mode, the monitoring unit 84 is provided and the monitoring unit 84 determines whether or not to return to the normal mode during the power saving mode. In the power saving mode, the main control unit 7, the image reading unit 2, and the document conveying unit. 3, power supply to the image forming unit 5 and the fixing unit 6 can be stopped. On the other hand, even in the power saving mode, power is supplied to the monitoring unit 84 to drive it. The monitoring unit 84 mainly monitors the return from the power saving mode to the normal mode, and the circuit size is smaller than that of the main control unit 7, so that the power consumption is higher than that of driving the main control unit 7 in the power saving mode. Can be reduced.

(Drying paper in paper feeder 1)
Next, an example of a configuration related to paper drying in the paper feeding device 1 according to the embodiment will be described with reference to FIG. FIG. 3 is a circuit diagram illustrating an example of a configuration related to sheet drying of the sheet feeding device 1.

  When the paper absorbs moisture, the resistance value of the paper may decrease. When the moisture content of the paper is large, the amount of toner transferred to the paper is reduced (transfer efficiency is lowered). As a result, the density of the toner image decreases as a whole, the original cannot be reproduced properly, and the image quality may deteriorate.

  Further, the sheet is heated in the fixing unit 6. When the water content of the paper is large, the difference in the amount of water evaporation between the front surface side and the back surface side of the paper increases, and curling and wrinkles are likely to occur due to the difference in shrinkage rate. When the curl of the paper is strong, the paper is jammed and cheap in the conveyance path (jam is likely to occur).

  If the humidity in the paper feeding device 1 is high, moisture (water vapor) may enter the gap between the paper and the paper and the paper may be adsorbed. If the sheets are adsorbed, multiple feeding may occur in which a plurality of sheets are simultaneously fed and conveyed. When double feeding occurs, jamming occurs or post-processing for double feeding is required, such as printing a part of an image of one page on each of a plurality of sheets. In particular, the coated paper whose surface is glossy coated is likely to cause double feeding when the water content of the paper feeding device 1 increases.

  Therefore, in order to dry (dehumidify) the paper, the paper feeder 1 of the multifunction peripheral 100 according to this embodiment is provided with a heater 14. In the sheet feeding device 1, power is directly supplied to the heater 14 from an AC power source PW (commercial power source). As shown in FIG. 1, the heater 14 and the power supply unit 8 are connected in parallel to the AC power supply PW. Accordingly, if the multifunction device 100 is connected to the AC power source PW (commercial power) by a power cord or a power outlet, whether the main power source of the multifunction device 100 is turned on, whether in the normal mode or in the power saving mode. Regardless of whether the humidity in the sheet feeding device 1 exceeds a predetermined humidity, electric power is supplied to the heater 14.

  A switch unit 15 and an operation switch 16 are provided in the power supply path of the heater 14 from the AC power supply PW. The switch unit 15 is provided inside the sheet feeding device 1. The switch unit 15 closes to supply power to the heater 14 when the humidity in the sheet feeding device 1 exceeds a predetermined humidity, and opens to stop supplying power to the heater 14 when the humidity falls below the predetermined humidity. (Details will be described later).

  The operation switch 16 is a switch for operating whether or not the user supplies power to the heater 14 (for example, a rocker switch). For example, the operation switch 16 is provided so as to be exposed to the exterior portion of the front side of the sheet feeding device 1 so that it can be operated by the user. The operation switch 16 is kept in a closed state or an open state by a user operation.

  If the operation switch 16 is OFF (if it is in the open state), the power is not supplied to the heater 14 regardless of the humidity in the paper feeding device 1. On the other hand, if the operation switch 16 is ON (closed), when the humidity in the sheet feeding device 1 exceeds a predetermined humidity, power is supplied to the heater 14 and the sheet is dried. Made.

  For example, when the sheet is not required to be dried because the sheet is not set (not inserted) in the sheet feeding device 1 or the humidity of the installation environment of the multifunction peripheral 100 is less likely to be high, the user may switch the operation switch. 16 may be turned off. On the other hand, when it is considered that the paper needs to be dried (dehumidified), the user turns on the operation switch 16.

(Switch unit 15)
Next, the configuration of the switch unit 15 according to the embodiment will be described with reference to FIGS. FIG. 4 is a perspective view showing an example of the switch unit 15. FIG. 5 is an explanatory diagram illustrating an example of a bonded plate included in the humidity changing unit 150 of the switch unit 15. FIG. 6 is an explanatory view showing an example of the movement of the contact with the humidity change.

  The switch unit 15 is provided in the spring-like humidity changing unit 150 whose shape changes depending on the humidity, the first contact 151 that moves according to the humidity according to the deformation of the humidity changing unit 150, and the sheet feeding device 1. A second contact 152 is provided so as to come into contact with the first contact 151 when the internal humidity exceeds a predetermined humidity.

  First, the humidity changing unit 150 will be described with reference to FIGS. 5 and 6. As shown in FIG. 5 and FIG. 6, the humidity changing section 150 is obtained by winding a laminated plate 150 a obtained by bonding (combining) the first plate-like member 1501 and the second plate-like member 1502 in a spring shape (spring spring). ). For example, the first plate-like member 1501 and the second plate-like member 1502 are elongated rectangles of the same size, and one surface of the first plate-like member 1501 and one surface of the second plate-like member 1502 are arranged so that their sides overlap each other. They are pasted together and wound.

  The first plate-like member 1501 and the second plate-like member 1502 are different materials, and the shrinkage rate and the expansion rate (elongation rate) differ depending on the humidity. For example, one of the first plate-like member 1501 and the second plate-like member 1502 is a moisture-sensitive material (moisture-sensitive paper) whose shape changes depending on the degree of moisture absorption (the amount of water contained). Is a metal plate (for example, a brass plate) whose shape does not change according to humidity. In this description, the first plate member 1501 is a moisture sensitive material, and the second plate member 1502 is a metal plate.

  As shown in FIG. 6, the switch unit 15 incorporates a combination of a first plate member 1501 and a second plate member 1502 wound in a spring shape. In the present embodiment, a moisture-sensitive material (first plate-like member 1501) that expands as the amount of water contained is increased. For this reason, the greater the amount of water (water vapor amount) in the sheet feeding device 1, the more the spring of the humidity changing unit 150 is deformed.

  Here, the moisture contained in the moisture sensitive material increases as the relative humidity increases. For example, when the relative humidity increases with a temperature change that causes condensation, the amount of moisture absorption (the amount of water contained) of the first plate-like member 1501 of the humidity change unit 150 increases. Further, when the relative humidity decreases, the amount of moisture absorbed by the first plate-like member 1501 also decreases. Therefore, the shape of the humidity changing unit 150 changes according to the relative humidity (the difference in the amount of change due to temperature may occur).

  Then, as shown in FIGS. 4 and 6, a shaft member 153 is attached to the center point of the spring of the humidity changing unit 150. The shaft member 153 rotates in the axial direction in accordance with the contraction and expansion (change of the humidity changing unit 150) of the first plate member 1501. Further, in order to rotate the shaft member 153 and the contact plate 154, the end portion (outside end portion) opposite to the end portion (center side end portion) attached to the main shaft member 153 of the humidity changing portion 150 is fixed. Yes. A first power line PW1 is attached to the shaft member 153 and connected to the AC power source PW. A contact plate 154 extending in the radial direction of the spring is attached to the shaft member 153. A first contact 151 is provided at the end of the contact plate 154 in the outer direction of the spring of the humidity changing unit 150.

  As shown in FIG. 4, the humidity changing section 150 is sandwiched between two rectangular plates 155 and 156 (insulating plates such as resin and plastic) so as to sandwich the edge of the mainspring. In order to make it easier for the spring of the humidity changing section 150 to come into contact with the air in the machine, a part of the two rectangular plates 155 and 156 may be opened. Then, the shaft member 153 protrudes from the upper rectangular plate 155, and the contact plate 154 is attached to the protruding shaft member 153. The contact plate 154 (first contact 151) is separated by the humidity changing portion 150 (bonding plate 150a) and the rectangular plate 155, and the contact plate 154 and the humidity changing portion 150 are not in direct contact with each other.

  The first plate member 1501 expands (extends) as the humidity in the sheet feeding device 1 increases and the amount of water contained in the first plate member 1501 increases. Due to the expansion of the first plate-like member 1501, the humidity changing unit 150 is deformed in the direction in which the mainspring is wound, and the shaft member 153 rotates. In the example illustrated in FIG. 6, the shaft member 153, the contact plate 154, and the first contact 151 rotate in the clockwise direction when the switch unit 15 is viewed from above as the humidity in the sheet feeding device 1 increases. On the other hand, as the humidity in the sheet feeding device 1 decreases and the first plate member 1501 contracts, the humidity changing unit 150 is deformed in a direction in which the mainspring winding is weakened. In the example illustrated in FIG. 6, the shaft member 153, the contact plate 154, and the first contact 151 rotate counterclockwise as the humidity in the sheet feeding device 1 decreases.

  As shown in FIGS. 4 and 6, the second contact 152 is provided so as to come into contact with the first contact 151 when the humidity in the sheet feeding device 1 reaches a predetermined humidity. The second power line PW2 is attached to the second contact 152 and connected to the AC power supply PW. And when the 1st contact 151 and the 2nd contact 152 contact, the heater 14 will be in the state connected with AC power supply PW. Thereby, if the operation switch 16 is in the ON state, electric power is supplied to the heater 14.

  Here, the higher the humidity in the sheet feeding device 1 is, the stronger the force of winding the spring of the humidity changing unit 150 becomes, so the force with which the first contact 151 pushes the second contact 152 becomes stronger. Therefore, as shown in FIGS. 4 and 6, a guide groove 157 for guiding the movement of the second contact 152 is provided along the circumferential direction of the mainspring. The second contact 152 moves on the guide groove 157 according to the force pressed by the first contact 151. Here, the position where the first contact 151 and the second contact 152 are in contact with each other at a predetermined humidity is set as the reference position BP of the second contact 152. Then, as the humidity in the paper feeding device 1 increases from a predetermined humidity, the second contact 152 moves from the reference position BP along the direction in which the first contact 151 moves.

  The second contact 152 is urged in a direction to return to the reference position BP after moving along the guide groove 157. For example, a spring 158 (corresponding to a biasing member) that biases the second contact 152 toward the reference position BP is provided.

  Here, a predetermined humidity (humidity when the first contact 151 and the second contact 152 are in contact) can be set as appropriate. For example, the humidity at which drying by the heater 14 is started can be adjusted by adjusting the reference position BP of the second contact 152. In the sheet feeding device 1 of the present embodiment, a humidity of about 65% when the temperature is 20 to 25 ° C. is set as a predetermined humidity. A predetermined humidity may be set according to the characteristics of the paper to be accommodated and the image forming apparatus.

  As shown in FIG. 4, the position of the contact plate 154 when the humidity is equal to or lower than a predetermined humidity, and the position of the contact plate 154 when the humidity is predetermined (the first contact 151 and the second contact 152 are in contact with each other). A protrusion 159 (stopper) can be provided on the surface of the upper rectangular plate 155 between the two positions. If the protrusion 159 is provided, the protrusion 159 is intermittently switched between ON and OFF of the power supply to the heater 14 when the humidity in the sheet feeding device 1 is around a predetermined humidity. Can be prevented.

  The protrusion 159 is provided on the moving path of the contact plate 154. In other words, when the contact plate 154 moves, it contacts the protrusion 159. Further, when the force of the first contact 151 (contact plate 154) in the direction approaching the second contact 152 becomes stronger as the projection 159 is overcome (when the humidity in the paper feeding device 1 becomes higher), the contact plate 154 causes the projection 159 to move. The protrusion 159 can be provided at a position where it can get over. In addition, after the first contact 151 and the second contact 152 are in contact, the protrusion 159 is in contact with the back side of the first contact 151 (contact plate 154) so that the first contact 151 and the second contact 152 are in contact with each other. When the force of the first contact 151 (contact plate 154) in the direction away from the second contact 152 becomes stronger as the projection 159 is overcome (when the humidity in the paper feeding device 1 is lowered), the contact plate 154 causes the projection 159 to move. The protrusion 159 can be provided at a position where the first contact 151 and the second contact 152 are separated from each other. By providing the protrusion 159, a predetermined humidity can be set as a range.

  Thus, the power supply to the heater 14 can be automatically turned ON / OFF without using a control circuit such as the main control unit 7 depending on whether or not the humidity exceeds a predetermined humidity. Therefore, the humidity in the sheet feeding apparatus 1 can be kept below a certain level regardless of whether or not the main power of the multifunction device 100 is turned on and whether or not the multifunction device 100 is in the power saving mode. In addition, unlike the conventional case, since power is not supplied to the heater 14 by a control circuit such as a CPU or a microcomputer, the MFP 100 is temporarily turned off when the main power is not turned on or in the power saving mode. There is no need to supply power to a control circuit such as a CPU or a microcomputer so that the control circuit determines and controls whether or not to supply power to the heater 14.

(Drying other than paper feeder 1)
Next, an example in which the heater 14 and the switch unit 15 are provided in addition to the sheet feeding device 1 will be described with reference to FIG. FIG. 7 is an explanatory diagram for explaining drying in a device other than the paper feeder 1.

  When the temperature falls, such as in the early winter in the cold winter, condensation may occur on the surface of a rotating body such as the photosensitive drum 51 of the image forming unit 5, for example. If image formation is performed in a state where condensation has occurred, the image quality of the formed toner image may deteriorate, such as a decrease in the resistance value of the surface of the photosensitive drum 51 due to moisture, or development being hindered by water droplets.

  Therefore, in order to blow off water droplets and moisture adhering to the surface of each rotating body (photosensitive drum 51) in the image forming unit 5, a heater 57 and a switch unit 58 similar to those provided in the paper feeding device 1 are provided. 5 can be provided.

  For example, there is no particular limitation on the type and installation position of the heater 57 provided in the image forming unit 5. For example, the heater 57 is an electric heating sheet including a heating wire. And it is stored in the inside (for example, photosensitive drum 51) to be dried (dehumidified).

  Then, power is directly supplied from the AC power source PW (commercial power source) to the heater 57 provided in the image forming unit 5 of the MFP 100 of the present embodiment. As shown in FIG. 7, the heater 57, the power supply unit 8, and the heater 14 of the sheet feeding device 1 are connected in parallel to the AC power supply PW. Accordingly, if the multifunction device 100 is connected to the AC power source PW (commercial power) by a power cord or a power outlet, whether the main power source of the multifunction device 100 is turned on, whether in the normal mode or in the power saving mode. Regardless of whether the humidity of the image forming unit 5 exceeds a predetermined humidity, electric power is supplied to the heater 57.

  A switch unit 58 and an operation switch 59 similar to those provided in the sheet feeding device 1 are also provided for the heater 57 provided in the image forming unit 5. For example, the switch unit 58 is provided in the image forming unit 5. The switch unit 58 closes to supply power to the heater 57 when the humidity of the image forming unit 5 exceeds a predetermined humidity, and opens to stop supplying power to the heater 57 when the humidity is lower than the predetermined humidity. The switch unit 58 includes a humidity changing unit 150, a first contact 151, a second contact 152, and the like, similar to those provided in the sheet feeding device 1. Note that the details of the switch unit 58 can be applied to the contents described in the switch unit 151 of the sheet feeding device 1, and therefore will be omitted here.

  As with the sheet feeding device 1, an operation switch 59 can be provided to operate whether or not to supply power to the heater 57. For example, it is provided on the side surface of the multifunction peripheral 100 so that it can be operated by the user. The operation switch 59 is kept closed or opened by the user's operation.

  For example, a user who thinks that drying (dehumidification) of the photosensitive drum 51 of the image forming unit 5 is not necessary may turn the operation switch 59 to the OFF state. On the other hand, when it is considered that the photosensitive drum 51 needs to be dried, the user turns on the operation switch 59.

  Also, when the temperature falls, such as in the cold winter early morning, dew condensation may occur on the surface of the light source 23, each mirror, the lens 27, and the image sensor 28 in the image reading unit 2, for example. If a document is read in a state where condensation has occurred, the document may not be read properly due to diffused reflection of light due to moisture.

  Therefore, the heater 210 and the switch unit 211 similar to those provided in the paper feeding device 1 and the image forming unit 5 are provided in the image reading unit 2 in order to blow off water droplets and moisture adhering to the surface of each member in the image reading unit 2. Can be provided.

  And there is no restriction | limiting in the type of the heater 210 provided in the image reading part 2. FIG. For example, the heater 210 is an electric heating sheet including a heating wire. The heater 210 is provided inside the image reading unit 2.

  As shown in FIG. 7, the heater 210 provided in the image reading unit 2 is directly supplied with electric power from an AC power supply PW (commercial power supply). The heater 210, the power supply unit 8, the heater 14 of the paper feeding device 1, and the heater 57 of the image forming unit 5 are connected in parallel to the AC power source PW. Accordingly, if the multifunction device 100 is connected to the AC power source PW (commercial power) by a power cord or a power outlet, whether the main power source of the multifunction device 100 is turned on, whether in the normal mode or in the power saving mode. Regardless of whether the humidity of the image forming unit 5 exceeds a predetermined humidity, electric power is supplied to the heater 210.

  The same switch unit 211 and operation switch 212 as those provided in the paper feeding device 1 and the image forming unit 5 are also provided for the heater 210 provided in the image reading unit 2. For example, the switch unit 211 is provided inside the image reading unit 2. The switch unit 211 closes to supply power to the heater 210 when the humidity in the image reading unit 2 exceeds a predetermined humidity, and opens to stop supplying power to the heater 210 when the humidity falls below the predetermined humidity. . The switch unit 211 includes a humidity changing unit 150, a first contact 151, a second contact 152, and the like, similar to those provided in the paper feeding device 1 and the image forming unit 5. Note that details of the switch unit 211 can be applied to the contents described in the switch unit 151 of the sheet feeding device 1, and thus are omitted here.

  Similar to the sheet feeding device 1 and the image forming unit 5, an operation switch 212 can be provided to operate whether or not to supply power to the heater 210. For example, the operation switch 212 is provided on the side surface of the image reading unit 2 portion of the multifunction machine 100 so that the user can operate it. The operation switch 212 is kept in a closed state or an open state by a user operation.

  For example, a user who thinks that drying (dehumidification) inside the image reading unit 2 is unnecessary may turn the operation switch 212 OFF. On the other hand, when it is considered that the inside of the image reading unit 2 needs to be dried, the user turns on the operation switch 212.

  In this way, the sheet feeding device 1 according to the embodiment includes a sheet loading unit (cassette 11) on which a plurality of sheets are loaded, and a sheet feeding mechanism that sends out the sheets loaded on the sheet loading unit one by one. (Heat feed roller 12), a drying unit (heater 14) that performs drying by receiving power supply, and a humidity changing unit 150 that changes its shape according to humidity by combining members that have different degrees of contraction and expansion depending on humidity. A first contact 151 provided in the humidity changing unit 150 and a second contact 152 provided so as to come into contact with the first contact 151 when the humidity exceeds a predetermined humidity. When the two contacts 152 are not in contact, the drying unit is not connected to the power source, and when the first contact 151 and the second contact 152 are in contact, the drying unit is connected to the power source to perform drying. Including.

  Thus, when the humidity of the paper feeding device 1 exceeds a predetermined humidity, power is automatically supplied to the drying unit (heater 14), and the drying unit dries the paper feeding device 1 and the paper. Further, when the paper is dried by dehumidification by the drying unit and the humidity of the paper feeding device 1 becomes equal to or lower than a predetermined humidity, the power supply to the drying unit is automatically stopped. Therefore, the moisture content of the paper (humidity in the paper feeding device 1) can be kept constant regardless of the state of the image forming apparatus (for example, the multifunction peripheral 100). Further, in order to keep the humidity in the paper feeding device 1 below a certain level, no control circuit or sensor such as a CPU or microcomputer is used, so there is no need to provide a control circuit or control circuit, and the manufacturing cost of the paper feeding device 1 is reduced. Can be reduced. In addition, even when the main power is off or in the power saving mode, power consumption due to driving of the control circuit and sensor does not occur as in the conventional case, so that a high power saving effect can be obtained.

  Further, as the humidity becomes higher than the predetermined humidity, the second contact 152 moves from the reference position BP according to the force with which the first contact 151 pushes the second contact 152, and the second contact 152 is moved to the reference position BP. And a biasing member (spring 158) for biasing in the direction of returning to the position. Thereby, if the force with which the first contact 151 pushes the second contact 152 increases due to an increase in humidity, the second contact 152 moves. Therefore, even if the force with which the first contact 151 pushes the second contact 152 increases with an increase in humidity, the first contact 151 and the second contact 152 can be prevented from being damaged. Further, as the humidity decreases, the position of the second contact 152 can be automatically returned to the reference position BP by the biasing member.

  In addition, the humidity changing unit 150 is formed by laminating members having different degrees of contraction and expansion depending on the humidity, and the first contact 151 is arranged in the circumferential direction of the humidity changing unit 150 according to the humidity change. Moving. Thereby, the switch part 15 can be reduced in size.

  The sheet feeding device 1 includes an operation switch 16 provided between the power source and the drying unit (heater 14) for switching whether to keep the power supply to the drying unit stopped. When paper is not put in the paper feeding device 1 (paper is not set), drying by the drying unit is useless, but the power to the drying unit can be kept stopped by the operation switch 16. Therefore, wasteful power consumption can be eliminated according to the user's intention. If the user determines that drying by the drying unit is not necessary, the operation switch 16 can keep the power to the drying unit stopped. Therefore, the user can stop the paper drying function by his / her own intention in order to reduce power consumption.

  The image forming apparatus (for example, the multifunction peripheral 100) includes the paper feeding device 1 according to the embodiment. As a result, it is possible to provide a high-function image forming apparatus in which the moisture content of the paper is kept below a certain level, the image quality is high, and the occurrence of jamming and double feeding is suppressed. In addition, it is possible to provide an image forming apparatus with reduced cost and high power saving performance.

  The image forming apparatus (for example, the multifunction peripheral 100) includes an image forming unit 5 that forms a toner image, and the image forming unit 5 is provided with a drying unit (heater 14) and a switch unit 15. As a result, the control circuit and sensor such as a CPU are not provided and the manufacturing cost is reduced and the power saving performance is improved, while the surface of the image carrier or the like has no water droplets (no condensation). Can keep.

  The image forming apparatus (for example, the multifunction peripheral 100) includes an image reading unit 2 that includes a light source 23 for reading a document, an optical member that guides reflected light from the document, and an image sensor 28 that receives reflected light from the document. The image reading unit 2 is provided with a drying unit (heater 14) and a switch unit 15. As a result, there is no water drop on the image sensor 28 or the optical member in the image reading unit 2 while reducing the manufacturing cost and improving the power saving performance without providing a control circuit or sensor such as a CPU ( It can be maintained in a non-condensing state).

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used for a paper feeding device or an image forming apparatus having a heater.

1 Paper Feeder 11 Cassette (Paper Placement Section)
12 Paper feed roller (paper feed mechanism) 14 Heater (drying section)
DESCRIPTION OF SYMBOLS 15 Switch part 150 Humidity change part 151 1st contact 152 2nd contact 158 Spring (biasing member) 16 Operation switch 100 Multifunction machine (image forming apparatus) 2 Image reading part 23 Light source 241 1st mirror (optical member)
242 Second mirror (optical member) 243 Third mirror (optical member)
25 First moving frame (optical member) 26 Second moving frame (optical member)
27 Lens (optical member) 28 Image sensor 210 Heater 211 Switch unit 212 Operation switch 5 Image forming unit 57 Heater 58 Switch unit 59 Operation switch BP Reference position

Claims (7)

A paper placement section on which a plurality of paper is placed;
A paper feed mechanism that feeds the paper placed on the paper placement section one by one;
A drying section that performs drying by receiving power supply;
When a humidity changing part that changes its shape according to humidity by combining members whose degree of contraction and expansion varies depending on the humidity, a first contact provided in the humidity changing part, and when the humidity exceeds a predetermined humidity, the first Including a second contact provided so as to be in contact with one contact, and when the first contact and the second contact are not in contact, the drying unit and the power source are not connected, and the first contact and the second contact are in contact with each other A sheet feeding apparatus comprising: a drying unit and a switch unit for performing drying by connecting a power source when the unit is in operation. As the humidity becomes higher than the predetermined humidity, the second contact moves from the reference position according to the force with which the first contact pushes the second contact,
The sheet feeding device according to claim 1, further comprising a biasing member that biases the second contact in a direction to return the second contact to the reference position. The humidity changing part is a spirally wound member in which members having different degrees of contraction and expansion depending on humidity are bonded,
3. The sheet feeding device according to claim 1, wherein the first contact moves in a circumferential direction of the humidity changing portion according to a humidity change.   The operation switch for switching whether or not to keep the power supply to the drying unit in a state of stopping power supply is provided between a power source and the drying unit. Paper feeder.   An image forming apparatus comprising the paper feeding device according to claim 1. Including an image forming unit for forming a toner image;
The image forming apparatus according to claim 5, wherein the drying unit and the switch unit are provided in the image forming unit. An image reading unit including a light source for reading a document, an optical member that guides reflected light from the document, and an image sensor that receives reflected light from the document;
The image forming apparatus according to claim 5, wherein the drying unit and the switch unit are provided inside the image reading unit.

Images