JP4172510B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet by, for example, electrophotography.

  In an image forming apparatus such as a copying apparatus, a printer apparatus, and a facsimile apparatus, generally, a paper feed unit is provided with a plurality of paper feed trays, and the paper loaded in the paper feed tray contains moisture. If the toner image from the photosensitive drum is transferred to the paper, a transfer failure occurs, or the paper curls and a conveyance failure occurs.

  Therefore, in a conventional image forming apparatus, a heating element such as a dehumidifying heater is provided, and the inside of the housing is heated by the heating element, thereby dehumidifying the sheet and preventing the occurrence of transfer failure or sheet conveyance failure. ing.

For example, Patent Document 1 proposes an image forming apparatus that realizes optimization of dehumidification and reduction of power consumption by controlling a dehumidification heater according to the remaining amount of paper and the paper size.
JP-A-2005-104718

  2. Description of the Related Art Conventionally, there is an image forming apparatus having a function of continuing image formation by switching to paper feeding from another paper feeding tray when there is no paper in a paper feeding tray that is feeding paper during image formation.

  However, in the above-described prior art, there is no disclosure on how to perform tray heater control in such an image forming apparatus.

  For example, it is conceivable to continuously control the heaters of a plurality of trays and continue the image forming operation without unnecessary waiting time even when the paper feed tray is switched. However, there is a problem that power consumption increases. . In particular, in an image forming apparatus having a small power capacity, it is not possible to turn on a plurality of dehumidifying heaters at the same time. Therefore, it is necessary to perform control such as turning on only one designated tray heater. In this case, it is conceivable that the heater is switched after the tray being fed is switched to another tray without paper, but there is a problem that unnecessary waiting time occurs and productivity is lowered.

  Also, in the image forming apparatus, there are many types of paper used, and the characteristics of each paper are different. Depending on the paper, it is necessary to perform dehumidification in order to ensure feedability.

  However, in the above prior art, the energization control of the dehumidifying heater is performed based on the remaining amount of paper and the paper size paper, and the paper type is not taken into consideration, and the paper is appropriately selected according to the paper type. In order to improve the transfer failure and the paper transportability, it was necessary to improve the drying process.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus that secures productivity while suppressing wasteful power consumption.

The above object of the present invention is achieved by the following configurations.
1.
A first paper feed tray;
A second paper feed tray;
A paper feed tray selecting means for selecting a paper feed tray,
Paper remaining amount detecting means for detecting the remaining amount of paper set in the second paper feed tray;
First dehumidifying means for dehumidifying paper set in the first paper feed tray;
First humidity detection means for detecting the humidity inside the first paper feed tray;
When the paper feed tray selecting unit selects the second paper feed tray, the remaining amount of paper detected by the remaining paper amount detecting unit of the second paper feed tray being fed and the first humidity detecting unit Control means for controlling the first dehumidifying means based on the humidity detected by
An image forming apparatus comprising:
2.
The control means detects the control start condition of the first dehumidifying means, the remaining amount of paper detected by the remaining paper amount detecting means of the second paper feed tray being fed, and the first humidity detecting means. 2. The image forming apparatus according to 1 above, which is determined based on humidity.
3.
A second dehumidifying means for dehumidifying the paper set in the second paper feed tray;
A second humidity detecting means for detecting the humidity inside the second paper feed tray;
The control unit is configured to control the first dehumidification based on the remaining amount of paper detected by the remaining amount of paper detection unit, the humidity detected by the first humidity detection unit, and the humidity detected by the second humidity detection unit. 3. The image forming apparatus according to 1 or 2, wherein the image forming apparatus and the second dehumidifying means are controlled while being switched alternately.
4).
4. The image forming apparatus according to any one of claims 1 to 3, further comprising sheet information storage means for storing information relating to sheets set in each sheet feed tray.
5.
5. The image forming apparatus according to any one of claims 1 to 4, further comprising a selection unit that selects whether or not the dehumidifying unit is controlled by the control unit.

  According to the present invention, the dehumidifying means for the tray that is not the paper feed target can be controlled based on the remaining amount of the paper in the tray that is the paper feed target and the humidity of the tray that is not the paper feed target. This makes it possible to determine the control start timing with high accuracy, and to provide an image forming apparatus that secures productivity while suppressing wasteful power consumption.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the drawings. The present invention is applicable to both an image forming apparatus such as a printer that does not include an image reading unit such as a scanner, and an image forming apparatus such as a copying machine that includes an image reading unit such as a scanner. It is possible.

In this embodiment, an electrophotographic copying machine will be described as an example of an image forming apparatus.
(Mechanical configuration of image forming apparatus)
FIG. 1 is an external configuration diagram showing a mechanical configuration of an image forming apparatus 100 according to an embodiment of the present invention.

  The image forming apparatus 100 is an electrophotographic image forming apparatus that forms and outputs an image (toner image) corresponding to image data on a recording sheet, and feeds a desired sheet from a sheet feeding tray to an image forming unit. Generating a toner image from a paper feeding unit that transports the fed paper at a predetermined speed, an image writing unit that generates a laser beam according to image data, and a latent image according to the laser beam. And a printer engine including an image forming unit that transfers the image to a sheet.

  The image forming apparatus main body is provided with three stages (101a, 101b, 101c) of paper feeding trays, and a paper feeding unit 102 capable of setting a large amount of paper in one tray is connected to the right side of the image forming apparatus main body. The paper supply unit 102 has two stages (102a and 102b) of paper supply trays, and each of about 3000 sheets can be set at a time.

  Here, sheets of a predetermined size (A4, B4, A4R, etc.) and a predetermined paper type (plain paper, coated paper, etc.) are accumulated in each paper feed tray.

  In other words, the image forming apparatus 100 is compatible with various paper types, and is configured to operate under optimum conditions by changing image forming conditions depending on the paper.

  Among the papers, coated paper has a coated surface, so air permeability is poor, and moisture between papers is less likely to escape than other papers. For this reason, when the image forming apparatus is used in a high-humidity environment, the transportability is lowered, and a transport failure is likely to occur. In order to prevent this, dehumidification is performed by providing a heater for the purpose of dehumidification, thereby preventing poor conveyance.

  In the image forming apparatus 100, dehumidifying heaters (103 a, 103 b) are provided in the paper feed trays (102 a, 102 b) of the paper feed unit capable of setting a large amount of paper, and humidity detecting means (104 a, 104 b) that detects the humidity inside the tray. ) Is given.

Further, the image forming apparatus 100 is configured to switch to paper feeding from another paper feeding tray and continue image formation (tray switch) when there is no paper in the paper feeding tray being fed during image formation. Yes.
(Electrical configuration of control unit of image forming apparatus)
FIG. 2 is a block diagram illustrating an electrical configuration of a control unit of the image forming apparatus according to the embodiment of the present invention. The image forming apparatus main body is mainly composed of an operation unit 201, an overall control unit 202, and an engine control unit 203, and a drive unit (not shown) of each paper feed tray is connected to the engine control unit 203, and The control unit 203 performs feed control of the paper feed tray and heater control.

  The overall control unit 202 operates each device of the image forming apparatus 100 in a cooperative manner, and has a plurality of control programs and storage devices (not shown).

  An operation unit 201 is an operation input unit through which a user inputs an operation for setting the image forming apparatus. The heater control user setting unit 208 functions as a selection unit for the user to select whether or not to control the dehumidifying heater of the paper feed tray.

  The storage unit 214 includes a nonvolatile memory, and stores user data and system data that should be stored even after the power is turned off. The storage unit 214 functions as the paper information storage unit 204. The paper information storage unit 204 stores information such as adjustment of the front and back magnification of each of the plurality of paper feed trays, taking into account the paper size and type, the amount of paper, and the shrinkage of the paper. Has been.

  Further, regardless of the presence or absence of the dehumidifying heater, each paper feed tray has a paper remaining amount detecting means 205, and when the remaining state is changed, the engine control unit 203 and the overall control unit 202 are notified. In this embodiment, the remaining paper amount detection unit 205 is configured such that the paper is stacked and stored in the paper feed tray in a substantially vertical direction. For example, a distance sensor or a position sensor may be used. Alternatively, the remaining amount of paper may be detected from the pressure and mass applied to the paper feed tray when the paper is loaded, and a pressure sensor and a mass sensor may be used.

  A paper feed tray selection unit 206 selects a tray to be fed by referring to the paper information set in each paper feed tray stored in the paper information storage unit 204 by a job for performing an image forming operation ( And determines the paper feed tray to the engine control unit 203 via the overall control unit 202 together with an image forming operation instruction. As described above, the image forming apparatus 100 has a function of switching to paper feeding from another paper feeding tray and continuing image formation when there is no paper in the paper feeding tray that is feeding paper during image formation. ing. The paper feed tray selecting unit 206 selects (determines) the paper tray that is the switching destination (tray switch target) with reference to the paper information set in each paper feed tray stored in the paper information storage unit 204. Then, the engine control unit 203 is instructed through the overall control unit 202 about the paper tray to be switched to.

  The engine control unit 203 functions as a control unit. The paper feed unit 102 (102a, 102b) provided with a dehumidifying heater is provided with humidity detecting means 104 (104a, 104b) for detecting the humidity inside the tray in each tray. When the engine control unit 203 determines that dehumidification is necessary (when the relative humidity in the tray exceeds a predetermined threshold), the humidity detected by the humidity detection unit provided in the paper feed tray is The dehumidifying heater is controlled so as to achieve the internal target humidity, and dehumidification is performed by sending hot air into the paper feed tray by the fan.

  Further, the engine control unit 203 stores, in the storage unit 214, a threshold value of the remaining amount of paper in the paper feed tray that is being fed from which the dehumidification control of the switch destination paper tray is to be started, based on the humidity inside the switch destination tray. Is read from the read table, and it is determined whether or not the remaining amount of paper in the paper feed tray that is feeding has reached this threshold value. If it has been reached, the dehumidification of the paper feed tray at the switching destination is made via the dehumidifying heater control means 207. Control to start the heater control.

  The storage unit 214 stores the humidity threshold of the paper feed tray for determining whether the dehumidifying heater needs to be controlled, the target humidity when the dehumidifying heater is controlled, the humidity of the switching destination paper feeding tray, and the switching destination supply. A table that defines the relationship with the threshold of the remaining amount of paper in the paper feed tray that is currently feeding paper for which control of the dehumidifying heater of the paper tray is to be started is stored. Specifically, when the humidity inside the tray to be switched over exceeds a predetermined threshold, the threshold for the remaining amount of paper in the tray being fed increases as the humidity increases according to the humidity value. Is set. For example, a plurality of different threshold values are provided for the humidity inside the switching destination tray, and a threshold value for the remaining amount of paper in the tray being fed is determined corresponding to each division.

  In this example, the humidity threshold of the paper feed tray is set to 55% RH in terms of relative humidity, and the target humidity is set to 55% RH or less in terms of relative humidity. Further, the threshold value of the remaining amount of paper in the paper feed tray that is currently feeding should start control of the dehumidifying heater of the switching destination paper feed tray is set to 10 at the time of maximum setting according to the humidity of the paper tray of the switching destination. % To about 40%.

  As will be described in detail later, when the power capacity of the image forming apparatus is small and the dehumidifying heater 103a of the paper feed tray 102a and the dehumidifying heater 103b of the paper feed tray 102b cannot be turned on simultaneously (condition Y), they are alternately It is necessary to light up. Therefore, the heater of the paper tray to be switched is started to light earlier than the condition X. In addition to the humidity in the paper tray at the switching destination, considering this point, the paper remaining threshold of the paper tray that is currently being turned on is set to about 20% to 40% of the maximum setting time. ing.

  Further, when it is possible to turn on the dehumidifying heater 103a of the paper feed tray 102a and the dehumidifying heater 103b of the paper feed tray 102b at the same time (Condition X), the same humidity can be used because it will be in time even if lighting is started later than the condition Y. However, the remaining amount serving as a threshold may be small. In addition to the humidity in the paper tray at the switching destination, considering this point, set the paper remaining threshold of the paper tray during paper feeding, which is the lighting start time, to about 10% to 30% at the maximum setting time Has been.

  Further, the engine control unit 203 refers to the paper information stored in the paper information storage unit 204, and dehumidification is performed only when paper with poor air permeability (coated paper in this example) is set. I have to. Even when plain paper is used, it is preferable to perform dehumidification if it is determined from environmental humidity that there is a possibility of transfer failure or conveyance failure. In this way, the dehumidifying heater can be driven appropriately according to the type of paper, the paper can be dried, transfer defects and paper transportability can be improved, and wasteful power consumption can be suppressed. .

In the present embodiment, the example in which the blowing unit (fan) is provided as the dehumidifying unit has been described. However, the inside of the sheet feeding tray may be dehumidified by natural convection without providing the blowing unit.
(Operation of image forming apparatus)
Hereinafter, the principle of the operation of the image forming apparatus according to the present embodiment will be described with reference to the flowchart of FIG.

Here, it is assumed that coated paper is set in the paper feed trays 102a and 102b, and plain paper is set in the paper feed trays (101a, 101b, 101c) that do not require dehumidification.
All paper sizes are the same.

  When a paper feed instruction for coated paper is received by the image forming operation, the paper feed tray selecting unit 206 selects either one of the paper feed trays 102a and 102b (the tray A in FIG. 3 and the second one in the present embodiment). And the other paper feed tray (Tray B in FIG. 3, which corresponds to the first paper feed tray in this embodiment) is selected as a tray switch target tray. Shall. Heater control at this time and heater control during an operation in an idling state without a job or in a paper feed tray (101a, 101b, 101c) that does not require dehumidification will be described.

  Also, a second dehumidifying heater (corresponding to the second dehumidifying means in the present embodiment) for dehumidifying the paper set in the tray A which is the second paper feeding tray, and the first paper feeding tray. A first dehumidifying heater (corresponding to the first dehumidifying means in the present embodiment) that dehumidifies the paper set in the tray B is configured to be simultaneously driven (power supply).

  In a state where the power source of the image forming apparatus is turned on, a heater control routine shown in the flowchart of FIG. 3 is executed in parallel with a main routine (not shown) of image formation.

  First, in step S10, it is determined whether 100 msec time has elapsed by a timer means (not shown). If it has elapsed, the process proceeds to step S12.

  In step S12, it is determined whether there is an image formation start job. If the determination is negative, the process proceeds to step S16. If the determination is positive, the process proceeds to step S14.

  In step S14, it is determined whether or not the paper feed tray selection unit 206 has selected or the paper feed tray that has been selected and requires paper feed is a tray that requires heater control (paper feed tray A or B). If the determination is negative, the process proceeds to step S16. If the determination is affirmative, the process proceeds to step S22 and step S30.

  In step S16, it is determined whether or not to control the heaters for the paper feed trays A and B even when not in use. In accordance with the heater control condition setting screen displayed on the heater control user setting means 208, the user sets whether to perform heater control even when not in use. Based on this setting, it is determined whether or not to perform heater control even when not in use. If the determination is negative, the process proceeds to step S18. If the determination is positive, the process proceeds to step S20.

  In step S18, heater control of the paper feed trays A and B is not performed. That is, the heater is not driven and the process proceeds to step S10.

  In step S20, when the humidity inside the tray exceeds a predetermined threshold (55% RH), the engine control unit 203 causes the heater control unit 207 to achieve the target humidity in the tray (55% RH or less). Then, the driving of the heaters of the paper feed trays A and B is controlled, and the process proceeds to step S10.

  In step S22, when the humidity inside the tray A exceeds a predetermined threshold (55% RH), the engine control unit 203 controls the heater so as to reach the target humidity in the tray (55% RH or less). The driving of the heater of the paper feed tray A is controlled via 207, and the process proceeds to step S24.

  In step S24, it is determined whether the target humidity has been reached. If the determination is negative, the process proceeds to step S26, and if the determination is affirmative, the process proceeds to step S28.

  In step S26, paper feeding is prohibited until the target humidity is reached, and the process proceeds to S10.

  In step S28, the humidity is maintained in a state where the target humidity has been reached, the paper feeding is enabled, and the process proceeds to S10.

  In step S30, the paper feed tray B that is not the paper feed tray is selected as the tray switch target tray.

  In step S <b> 32, the engine control unit 203 performs a humidity check inside the paper feed tray B to determine whether heater control of the paper feed tray B is necessary. If the determination is negative, the process proceeds to step S34. If the determination is positive (if the humidity inside the paper feed tray B exceeds a predetermined threshold (55% RH)), the process proceeds to step S36. Transition.

  In step S34, the heater control of the paper feed tray B is not performed. That is, the heater is not driven and the process proceeds to step S10.

  In step S <b> 36, the engine control unit 203 checks the remaining amount of paper in the paper feed tray A, which is a paper feed tray, and checks the humidity inside the paper feed tray B. The engine control unit 203 refers to the storage unit 214 based on the humidity value inside the paper feed tray B, and sets the threshold value of the remaining amount of paper in the paper feed tray A where the heater control of the paper feed tray B is to be started. read.

  In step S38, the engine control unit 203 determines whether or not the remaining amount of paper in the paper feed tray A has reached the predetermined threshold value read in step S36. If the determination is negative, the process proceeds to step S34. If the determination is affirmative, the process proceeds to step S40.

  In step S40, the engine control unit 203 controls the driving of the heater of the paper feed tray B via the heater control unit 207 so that the tray target humidity (55% RH or less) is reached, and the process proceeds to step S10.

  As described above, when a paper feed instruction is received by an image forming operation, a paper feed tray with a dehumidifying heater that is not fed can be made unnecessary to control because the paper feed operation tray has been determined. Here, if the target is a tray switch (the switching destination tray for automatic tray switching when there is no paper in the paper feed tray), the tray switch is determined based on the remaining amount of paper in the tray being fed and the humidity of the target tray switch tray. When it is done, the time when the job can be continued without waiting for dehumidification is determined, and if the remaining amount of paper in the currently fed tray reaches the threshold, dehumidification of the tray that is the tray switch target If the control (drive) of the heater is started (step S40) and it is judged that the dehumidifying heater need not be controlled because the threshold value has not been reached, the control of the dehumidifying heater for the tray switch target tray is not yet performed ( Step S34) When the remaining amount of paper in the currently fed tray reaches the threshold value, the control of the dehumidifying heater is started.

  For example, the remaining amount of paper in the tray being fed exceeds a predetermined threshold, and the dehumidification control start timing of the switching destination tray is determined by the remaining amount of paper in the tray being fed and the humidity of the switching destination tray, If it is determined that dehumidification is necessary because the difference up to the target humidity that can be fed is large, dehumidification of the tray to be switched to is started, for example, when the remaining amount of paper in the tray being fed is 30%. On the other hand, when it is determined that the difference up to the target humidity that can be fed is small and dehumidification is possible in a short time, for example, when the remaining amount of paper in the tray being fed is 10%, the switching destination tray Start dehumidification.

  In this way, the heater control start timing of the switching destination tray is determined not only by the remaining amount of paper in the tray being fed, but also by the humidity state of the switching destination tray, so that the remaining amount of paper in the tray being fed is determined. If the humidity is high and it is determined that more dehumidification time is required, the dehumidification control is started earlier, and if it is determined that the humidity is low and a shorter dehumidification time is acceptable, the dehumidification control is started. Judgment based on the remaining amount of paper in the tray being fed and the humidity status of the other tray to be switched, such as delaying, enables high-precision heater control that ensures productivity while suppressing wasteful power consumption Become.

  When coated paper is set in the tray of the paper feed unit where the dehumidifying heater is installed, and it is not the target of the tray switch of the paper feed operation tray (when idling or operating with a paper feed tray that does not require dehumidification) The dehumidifying heater control is always performed so as to maintain a predetermined humidity, or for the purpose of energy saving, the dehumidifying heater is not operated and the control is performed so that the predetermined humidity is obtained when a paper feed instruction is received. . In the present embodiment, switching can be performed by a user who uses these controls (step S16).

  Also, productivity is the top priority (the dehumidifying heater is always ON when paper that requires dehumidification (coated paper in this example) is set), or depending on the method of use, there may be a wait for dehumidification. The user can switch the control according to the user needs, such as controlling the dehumidifying heater based on the remaining amount of paper in the tray being fed and the humidity of the tray that is the target of the tray switch. Can be provided.

  Next, a modified example of the image forming apparatus 100 according to the embodiment of the present invention will be described.

  In the above embodiment, the second dehumidifying heater that dehumidifies the paper set in the tray A as the second paper feed tray and the paper set in the tray B as the first paper feed tray. Although the case where the first dehumidifying heater to be dehumidified can be driven simultaneously has been shown, in the modification, the second dehumidifying heater and the first dehumidifying heater cannot be driven simultaneously, and the configuration of the apparatus itself Since this is the same as the above embodiment, the description thereof is omitted. In this example, a heater switch for switching the power supply between the first dehumidifying heater side and the second dehumidifying heater side is provided, and the engine control unit 203 controls the switching of the heater switch. The control start condition of the first dehumidifying heater is determined based on whether the remaining amount of paper detected by the remaining amount detection means of the second paper supply tray that is being fed is within the inside of the tray B that is the first paper supply tray. Assuming that a predetermined threshold value determined according to humidity has been reached, and assuming that the humidity inside the second sheet feeding tray during sheet feeding has reached the target humidity (55% RH or less), The control (driving) of the first dehumidifying heater is started and the control (driving) of the second dehumidifying heater of the second paper feeding tray that is currently feeding is temporarily stopped. In order to keep the humidity at a certain level, the dehumidification in the tray B as the switching destination is performed while switching the power supply to the two dehumidifying heaters (alternately).

  FIG. 4 is a flowchart showing a modification of the operation of the image forming apparatus according to the embodiment of the present invention.

Here, it is assumed that coated paper is set in the paper feed trays 102a and 102b, and plain paper is set in the paper feed trays (101a, 101b, 101c) that do not require dehumidification.
All paper sizes are the same.

  When a paper feed instruction for coated paper is received by the image forming operation, the paper feed tray selecting unit 206 selects either one of the paper feed trays 102a and 102b (the tray A in FIG. 3 and the second one in the present embodiment). And the other paper feed tray (Tray B in FIG. 3, which corresponds to the first paper feed tray in this embodiment) is selected as a tray switch target tray. Shall. Heater control at this time and heater control during an operation in an idling state without a job or in a paper feed tray (101a, 101b, 101c) that does not require dehumidification will be described.

  In a state where the power source of the image forming apparatus is turned on, a heater control routine shown in the flowchart of FIG. 4 is executed in parallel with the main routine (not shown) of image formation.

  First, in step S50, it is determined whether or not 100 msec has elapsed by a timer means (not shown). If it has elapsed, the process proceeds to step S52.

  In step S52, it is determined whether there is an image formation start job. If the determination is negative, the process proceeds to step S56, and if the determination is positive, the process proceeds to step S54.

  In step S54, it is determined whether the paper feed tray selection unit 206 has selected or whether the selected paper feed tray that is currently feeding is a tray that requires heater control (paper feed tray A or B). If the determination is negative, the process proceeds to step S56. If the determination is affirmative, the process proceeds to step S62 and step S70.

  In step S56, it is determined whether or not to control the heaters for the paper feed trays A and B even when not in use. In accordance with the heater control condition setting screen displayed on the heater control user setting means 208, the user sets whether to perform heater control even when not in use. Based on this setting, it is determined whether or not to perform heater control even when not in use. If the determination is negative, the process proceeds to step S58, and if the determination is positive, the process proceeds to step S60.

  In step S58, heater control of the paper feed trays A and B is not performed. That is, the heater is not driven and the process proceeds to step S50.

  In step S60, when the humidity inside the tray exceeds a predetermined threshold value (55% RH), the engine control unit 203 causes the heater control unit 207 to set the target humidity in the tray (55% RH or less). Then, the driving of the heaters of the paper feed trays A and B is controlled, and the process proceeds to step S50.

  In step S62, when the humidity inside the tray A exceeds a predetermined threshold (55% RH), the engine control unit 203 controls the heater so as to reach the tray target humidity (55% RH or less). The driving of the heater of the paper feed tray A is controlled via 207, and the process proceeds to step S64.

  In step S64, it is determined whether the target humidity has been reached. If the determination is negative, the process proceeds to step S66, and if the determination is affirmative, the process proceeds to step S68.

  In step S66, paper feeding is prohibited until the target humidity is reached, and the process proceeds to S50.

  In step S68, the humidity is maintained in a state where the target humidity has been reached, the paper can be fed, and the process proceeds to S50.

  In step S70, the paper feed tray B that is not the paper feed tray is selected as the tray switch target tray.

  In step S <b> 72, the engine control unit 203 performs a humidity check inside the paper feed tray B to determine whether heater control of the paper feed tray B is necessary. If the determination is negative, the process proceeds to step S74. If the determination is positive (if the humidity inside the paper feed tray B exceeds a predetermined threshold (55% RH)), the process proceeds to step S76. Transition.

  In step S74, the heater control of the paper feed tray B is not performed. That is, the heater is not driven and the process proceeds to step S50.

  In step S76, the engine control unit 203 performs a humidity check inside the paper feed tray A, which is a paper feed tray, a remaining paper amount check, and a humidity check inside the paper feed tray B. The engine control unit 203 refers to the storage unit 214 based on the humidity value inside the paper feed tray B, and sets the threshold value of the remaining amount of paper in the paper feed tray A where the heater control of the paper feed tray B is to be started. read.

  In step S78, the engine control unit 203 determines whether or not the remaining amount of paper in the paper feed tray A has reached the predetermined threshold value read in step S76. If the determination is negative, the process proceeds to step S74. If the determination is affirmative, the process proceeds to step S80.

  In step S80, the engine control unit 203 determines whether the heater of the paper feed tray B can be driven (lighted), that is, whether the humidity inside the paper feed tray A read in control step S76 has reached the target humidity. Whether it is determined. If the determination is negative, the process proceeds to step S74. If the determination is affirmative, the process proceeds to step S82.

  In step S82, the engine control unit 203 turns off the heater of the paper feed tray A, stops driving, and then feeds the paper feed tray B via the heater control means 207 so that the target humidity in the tray (55% RH or less) is reached. The heater is turned on to start driving, and thereafter the power supply to the two dehumidifying heaters is switched (alternately) so that the humidity in the tray A being fed is maintained at a certain level. The process proceeds to step S50 so that the dehumidification in the tray B is performed.

  As described above, in particular, in an image forming apparatus having a small power capacity, a plurality of dehumidifying heaters cannot be turned on at the same time, and it may be necessary to switch and use them as necessary. At this time, the remaining amount of paper in the tray being fed exceeds a predetermined threshold, and the dehumidification control start timing of the tray to be switched to is determined based on the remaining amount of paper in the tray being fed and the humidity of the other tray. However, if it is determined that there is a large difference up to the target humidity that can be fed and dehumidification is necessary, for example, there is a humidity in the tray that is feeding from a state where the remaining amount of paper in the tray that is feeding is 40%. While switching the power supply to the two dehumidifying heaters (alternately) so as to maintain a certain level, dehumidification of the switching destination tray is started.

  On the other hand, when it is determined that the difference up to the target humidity that can be fed is small and dehumidification is possible in a short time, for example, from the state where the remaining amount of paper in the tray being fed is 20%, the tray being fed While switching the power supply to the two dehumidifying heaters (alternately) so that the humidity inside is also maintained at a certain level, dehumidification of the switching destination tray is started.

  As described above, even in an image forming apparatus having a plurality of paper feed trays having dehumidifying means and using (driving) the dehumidifying means only at one location, the plurality of dehumidifying means are installed by looking at the humidity state of each paper feed tray. By performing control while switching, it is possible to provide an image forming apparatus that secures productivity while suppressing more wasted power consumption.

  Although various embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to that shown in the embodiments, and there are changes and additions within the scope not departing from the gist of the present invention. Are also included in the present invention. For example, the number and form of the above-described paper feed trays are not limited to the above embodiment, and a plurality of paper feed trays are provided, and at least one of the paper feed trays is provided with dehumidifying means and humidity inside the trays. The present invention can be applied to any image forming apparatus configured to include a humidity detecting means for detecting.

1 is an external configuration diagram illustrating a mechanical configuration of an image forming apparatus according to an exemplary embodiment of the present invention. FIG. 2 is a block diagram illustrating an electrical configuration of a control unit of the image forming apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating an example of an operation of the image forming apparatus according to the exemplary embodiment of the present invention. 10 is a flowchart showing a modification of the operation of the image forming apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 102 Paper feed unit 104 Paper feed tray humidity detection means 201 Operation part 202 Overall control part 203 Engine control part 204 Paper information storage means 205 Paper remaining quantity detection means

Claims (5)

A first paper feed tray;
A second paper feed tray;
A paper feed tray selecting means for selecting a paper feed tray,
Paper remaining amount detecting means for detecting the remaining amount of paper set in the second paper feed tray;
First dehumidifying means for dehumidifying paper set in the first paper feed tray;
First humidity detection means for detecting the humidity inside the first paper feed tray;
When the paper feed tray selecting unit selects the second paper feed tray, the remaining amount of paper detected by the remaining paper amount detecting unit of the second paper feed tray being fed and the first humidity detecting unit Control means for controlling the first dehumidifying means based on the humidity detected by
An image forming apparatus comprising: The control means detects the control start condition of the first dehumidifying means, the remaining amount of paper detected by the remaining paper amount detecting means of the second paper feed tray being fed, and the first humidity detecting means. The image forming apparatus according to claim 1, wherein the determination is based on humidity. A second dehumidifying means for dehumidifying the paper set in the second paper feed tray;
A second humidity detecting means for detecting the humidity inside the second paper feed tray;
The control unit is configured to control the first dehumidification based on the remaining amount of paper detected by the remaining amount of paper detection unit, the humidity detected by the first humidity detection unit, and the humidity detected by the second humidity detection unit. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus and the second dehumidifying means are controlled while being switched alternately. 4. The image forming apparatus according to claim 1, further comprising a sheet information storage unit configured to store information relating to a sheet set in each sheet feeding tray. 5. The image forming apparatus according to claim 1, further comprising a selection unit that selects whether or not the dehumidifying unit is controlled by the control unit.

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