JP4419994B2 - 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 to dehumidify the sheet, thereby 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 considered, 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;
A second dehumidifying means for dehumidifying the paper set in the second paper feed tray;
When the paper feed tray selecting unit selects the second paper feed tray, the first paper feed tray is selected based on the remaining amount of paper detected by the remaining paper amount detecting unit of the second paper feed tray that is feeding paper. Control means for controlling the dehumidifying means;
Paper feed switching means for automatically switching to paper feed from the first paper feed tray and continuing paper feed when there is no paper in the second paper feed tray being fed;
Equipped with a,
The control means sets the control start condition of the first dehumidifying means when the remaining amount of paper detected by the remaining paper amount detecting means of the second paper feed tray that is feeding has reached a predetermined threshold value. An image forming apparatus.
2.
2. The image forming apparatus according to claim 1, further comprising sheet information storage means for storing information relating to sheets set in each sheet feed tray .
3.
3. 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 .

  According to the present invention, a paper feed tray selecting unit that selects a tray to feed paper, a paper remaining amount detecting unit that detects a remaining amount of paper set in the second paper feed tray, and the first A first dehumidifying means for dehumidifying the paper set in the paper feed tray; and when the paper feed tray selecting means selects the second paper feed tray, the second paper feed tray that is feeding paper Control means for controlling the first dehumidifying means based on the remaining amount of paper detected by the remaining amount of paper detection means. Since dehumidifying means can be controlled, for example, when there is a large amount of paper remaining in a tray to be fed and there is no need for dehumidification in a tray that is not to be fed, power is not supplied to the dehumidifying heater that performs dehumidification Can be.

  That is, according to the present invention, it is possible to provide an image forming apparatus that secures productivity while suppressing wasteful power consumption according to the remaining amount of paper in a tray to be fed.

  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, an example in which a dehumidifying heater (103a, 103b) is provided in each paper feed tray (102a, 102b) of a paper feed unit capable of setting a large amount of paper 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 engine 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 is configured by a non-volatile memory and stores user data and system data that should be stored even after the power is turned off. The storage unit 214 stores a threshold for the remaining amount of paper for switching the paper feed tray and a table for changing the target temperature in the tray as shown in Table 1. In addition, the threshold value of the remaining amount of paper is set to about 20% at the maximum setting time.

  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 paper feed unit 102 provided with a dehumidifying heater is provided with a temperature detecting means for each tray, a means for detecting the outside air temperature commonly used for each tray, and a means for detecting the outside air humidity. When it is determined that dehumidification is necessary (when the outside air humidity (relative humidity) exceeds 55% RH), the temperature detected by the temperature detection means provided in the paper feed tray becomes the target temperature in the tray. The dehumidifying heater is controlled as described above, and dehumidification is performed by sending hot air into the paper feed tray by the fan.

  Specifically, the storage unit 214 stores a table for changing the target temperature in the tray according to the outside air humidity. For example, a table for changing the target temperature in the tray as shown in Table 1 is stored in advance in the storage unit 214, and the target temperature in the tray is changed according to the detected value of the outside air humidity.

  In the table shown in Table 1, a plurality of different threshold values and optimum target temperatures in the tray are determined corresponding to the respective threshold values. When the outside air humidity is 55% RH or less, heater control is unnecessary and the heater is not operated. When the outside air humidity is 56% RH or more and 60% RH or less, the target temperature in the tray is set to the outside air temperature + 6 ° C., and the heater is controlled. When the outside air humidity is 61% RH or more and 65% RH or less, the target temperature in the tray is set to the outside air temperature + 7 ° C., and the heater is controlled. When the outside air humidity is 66% RH or more and 70% RH or less, the target temperature in the tray is set to the outside air temperature + 8 ° C., and the heater is controlled. When the outside air humidity is 71% RH or more and 75% RH or less, the target temperature in the tray is set to the outside air temperature + 9 ° C., and the heater is controlled. When the outside air humidity is 76% RH or higher, the target temperature in the tray is set to the outside air temperature + 10 ° C., and the heater is controlled.

  As described above, in this embodiment, the moisture absorption of the paper is estimated from the outside air humidity, and the heating temperature of the heater is controlled according to the detection result of the outside air humidity, so the user manually adjusts the heater temperature. Such inconveniences and inaccuracies in temperature control can be eliminated.

  The engine control unit 203 functions as a control unit. The engine control unit 203 controls the driving of the heater based on the information of the paper feed tray selection unit 206 and the remaining amount of paper detected by the remaining amount of paper detection unit 205, and is stored in the storage unit 214 when driven. The table is read and the drive of the heater is controlled through the heater control means 207 so that the target temperature in the tray set according to the outside air humidity is reached.

  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 S33.

  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, the engine control unit 203 reads the table stored in the storage unit 214, and feeds the trays A and B via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. The heater is driven, and the process proceeds to step S10.

  In step S22, the engine control unit 203 reads the table stored in the storage unit 214, and is a tray to be fed via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. The driving of the heater of the paper feed tray A is controlled, and the process proceeds to step S24.

  In step S24, it is determined whether the target temperature 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 temperature is reached, and the process proceeds to S10.

  In step S28, the temperature is maintained in a state where the target temperature 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 remaining sheet check and an outside air humidity check on the sheet feed tray A that is a sheet feed tray.

  In step S <b> 34, the engine control unit 203 refers to the storage unit 214 and determines whether heater control of the paper feed tray B is necessary. If the determination is negative, the process proceeds to step S36. If the determination is positive, the remaining amount of paper in the paper supply tray A has reached a predetermined threshold (about 20% of the maximum setting), and the outside air If the humidity exceeds a predetermined threshold (55% RH), the process proceeds to step S38.

  In step S36, the engine control unit 203 reads the table stored in the storage unit 214, and uses the heater control unit 207 to heat the heater of the paper feed tray B so that the target temperature in the tray is set according to the outside air humidity. And the process proceeds to step S10.

  In step S38, 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.

  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, in the case of a tray switch target (a switching destination tray in automatic tray switching when there is no paper in the paper feed tray), heater control is performed when the outside air humidity exceeds a predetermined threshold. The control start timing is determined based on the remaining amount of paper in the paper tray being fed and the time when the job can be continued without waiting for dehumidification when the tray switch is performed. If the remaining amount of paper in the tray has reached the threshold value, the dehumidifying heater for the tray switch target tray is controlled (step S36), and it is determined that the threshold value has not been reached and the dehumidifying heater need not be controlled. The control of the dehumidifying heater for the tray switch target tray is not yet performed (step S38), and the control of the dehumidifying heater is started when the remaining amount of paper in the currently fed tray reaches the threshold value.

  As described above, the heater control start timing of the switching destination tray is determined based on the remaining amount of paper in the tray being fed, thereby enabling heater control that ensures productivity while suppressing wasteful power consumption.

  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 is always controlled 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, the dehumidifying heater is always controlled (although any tray can be fed immediately, but power consumption is high), or this control based on the remaining amount of paper being fed is performed (depending on the method of use, the paper feed There may be a case where a waiting time is generated before the start, but it is possible to make it possible to switch whether it can be suppressed as much as possible and power consumption can be reduced. In this way, since the user can select which of the usage method, productivity, and power consumption priority is given, an image forming apparatus that is easy to use can be provided for each user.

  Next, a first modification 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 is shown, the first modified example is a case where the second dehumidifying heater and the first dehumidifying heater cannot be driven simultaneously. Since the configuration itself is the same as that of 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 performs switching control of the heater switch. The control start condition of the first dehumidifying heater is a case where the remaining amount of paper detected by the remaining amount detecting means of the second paper feed tray that is feeding has reached a predetermined threshold, and the first dehumidifying heater The control (drive) of the second dehumidifying heater of the second paper feed tray that is feeding paper is stopped simultaneously with the start of heater control (drive).

  FIG. 4 is a flowchart showing a first 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 operation in an idling state without a job 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 S40, 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 S42.

  In step S42, it is determined whether there is an image formation start job. If the determination is negative, the process proceeds to step S46, and if the determination is positive, the process proceeds to step S44.

  In step S44, the paper feed tray A is selected as the paper feed tray by the paper feed tray selection means 206, and the paper feed tray B that is not the paper feed tray is selected as a tray switch target tray. It is determined whether the sheet is selected by the tray or sheet feeding tray selection unit 206, or whether the sheet is selected and being fed. If the determination is negative, the process proceeds to step S64. If the determination is affirmative, the process proceeds to step S52.

  In step S46, 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 the 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 S48. If the determination is affirmative, the process proceeds to step S50.

  In step S48, 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 S40.

  In step S50, the engine control unit 203 reads the table stored in the storage unit 214, and feeds the trays A and B via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. The heater is driven, and the process proceeds to step S40.

  In step S52, the engine control unit 203 reads the table stored in the storage unit 214, and is a tray to be fed via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. The driving of the heater of the paper feed tray A is controlled to determine whether or not the target temperature has been reached. If the determination is negative, the process proceeds to step S54. If the determination is affirmative, the process proceeds to step S56.

  In step S54, paper feeding is prohibited until the target temperature is reached, and the process proceeds to step S40.

  In step S56, the engine control unit 203 checks the remaining amount of paper in the paper feed tray A, which is a paper feed tray, and determines whether the remaining amount of paper has reached a predetermined threshold. If the determination is negative, the process proceeds to step S58. If the determination is affirmative (when the remaining amount of paper in the paper feed tray A reaches a predetermined threshold value), the process proceeds to step S60.

  In step S58, the temperature is maintained in a state where the target temperature has been reached, and the paper feed is ready, and the process proceeds to step S40.

  In step S60, the engine control unit 203 determines whether the heater ON (power supply) of another heater-equipped paper feed tray (paper feed tray B) is necessary. If the determination is negative, the process proceeds to step S58. If the determination is positive (the table stored in the storage unit 214 is read and the outside air humidity exceeds a predetermined threshold), the process proceeds to step S62. Transition.

  In step S62, the engine control unit 203 turns off the driving (power supply) of the heater of the paper feed tray A via the heater control means 207, and proceeds to step S40. At this time, the heater ON (power supply) of the other paper feed tray with heater (paper feed tray B) becomes possible.

  In step S <b> 64, the engine control unit 203 determines whether heater control for the paper feed tray B is necessary. If the determination is negative, the process proceeds to step S66. If the determination is affirmative (when the table stored in the storage unit 214 is read and the outside air humidity exceeds a predetermined threshold), the process proceeds to step S68. Transition.

  In step S66, the heater control of the paper feed tray B is not performed. That is, the heater is not driven (power supply), and the process proceeds to step S40.

  In step S68, the engine control unit 203 determines whether the heater of the paper feed tray B can be turned on (power supply). If the determination is negative, the process proceeds to step S66. If the determination is affirmative (the remaining amount of paper in the paper feed tray A has reached a predetermined threshold, the heater of the paper feed tray A is driven (power supply)). Is turned OFF), the process proceeds to step S70.

  In step S70, the engine control unit 203 reads the table stored in the storage unit 214, and uses the heater control unit 207 to heat the heater of the paper feed tray B so that the target temperature in the tray is set according to the outside air humidity. And the process proceeds to step S40.

  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, in the case of a tray switch target (a switching destination tray in automatic tray switching when there is no paper in the paper feed tray), heater control is performed when the outside air humidity exceeds a predetermined threshold. The control start timing is based on the assumption that the tray being fed has reached the target temperature. It is determined whether the remaining paper has been fed within the time until the threshold is exceeded, and if the remaining paper in the currently fed tray has reached that threshold, After turning off the tray heater in the paper, the tray dehumidifying heater is controlled (step S70), and if it is determined that the threshold value has not been reached and the tray heater being fed cannot be turned off, The control of the dehumidifying heater for the tray switch target tray is not yet performed (step S66), and the control of the dehumidifying heater is started when the remaining amount of paper in the currently fed tray reaches the threshold value.

  As described above, the heater control start timing of the switching destination tray is determined based on the remaining amount of paper in the tray being fed, so that the remaining amount of paper in the tray being fed is large and the tray being fed is out of paper. If it is determined that more time is required until the tray becomes empty, the heater of the tray being fed is not turned off, the heater control of the tray being switched to is not started, and the remaining amount of paper in the tray being fed is The amount of time until the tray being fed runs out of paper is less than or equal to the time until the humidity in the tray rises and exceeds the predetermined threshold after turning off the heater of the tray being fed At that time, by turning off the heater of the tray being fed and starting the heater control of the tray to be switched to, it becomes possible to perform heater control that ensures productivity while further reducing wasteful power consumption.

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

  In the above embodiment, both the paper feed trays 102a and 102b are paper feed trays with a dehumidifying heater. However, in the second modification, only the paper feed tray 102a is a paper feed tray with a heater. Except for this point, the configuration of the apparatus itself is the same as that of the above-described embodiment, and thus the description thereof is omitted.

  Here, the coated paper is set in a paper feed tray 102a (corresponding to the first paper feed tray in the present embodiment) having a dehumidifying heater (corresponding to the first dehumidifying means in the present embodiment), When a paper feed instruction for coated paper is received by the image forming operation, the paper feed tray selecting unit 206 selects 102a as the paper feed tray. Either one of the heater control at this time, an idling state without a job, or a paper feed tray without a heater (101a, 101b, 101c, 102b, which corresponds to the second paper feed tray in the present embodiment) Heater control that is selected as a paper feed tray by the paper feed tray selection unit 206 and is being fed will be described.

  In a state where the power supply of the image forming apparatus is turned on, a heater control routine shown in the flowchart of FIG. 5 is executed in parallel with a main routine (not shown) of image formation.

  FIG. 5 is a flowchart showing a second modification of the operation of the image forming apparatus according to the embodiment of the present invention.

  First, in step S80, 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 S82.

  Next, in step S82, it is determined whether there is a job for starting image formation. If the determination is negative, the process proceeds to step S84. If the determination is affirmative, the process proceeds to step S90.

  In step S84, it is determined whether or not to control the heater of the paper feed tray 102a even during idling. In accordance with the heater control condition setting screen displayed on the heater control user setting means 208, the user sets whether to perform the 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 S86. If the determination is affirmative, the process proceeds to step S88.

  In step S86, the heater control of the paper feed tray 102a is not performed. That is, the heater is not driven and the process proceeds to step S80.

  In step S88, the engine control unit 203 reads the table stored in the storage unit 214, and the heater of the paper feed tray 102a is set via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. And the process proceeds to step S80.

  In step S90, it is determined whether the paper feed tray selection unit 206 has selected, or whether the paper feed tray being fed is the paper feed tray 102a requiring heater control. If the determination is negative, the process proceeds to step S98, and if the determination is positive, the process proceeds to step S92.

  In step S92, the engine control unit 203 reads the table stored in the storage unit 214, and is a tray to be fed via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. The drive of the heater of the paper feed tray 102a is controlled to determine whether the target temperature has been reached. If the determination is negative, the process proceeds to step S94. If the determination is affirmative, the process proceeds to step S96.

  In step S94, paper feeding is prohibited until the target temperature is reached, and the process proceeds to step S80.

  In step S96, the temperature is maintained in a state where the target temperature has been reached, and the paper feed is ready, and the process proceeds to step S80.

  In step S98, the paper feed tray selection unit 206 runs out of paper while the paper feed tray without heater (one of 101a, 101b, 101c, 102b) selected as the paper feed tray is being fed. Is detected, it is determined whether or not there is a possibility of a tray switch to the paper feed tray 102a. If the determination is negative, the process proceeds to step S100. If the determination is affirmative, the process proceeds to step S102.

  In step S100, the heater control of the paper feed tray 102a is not performed. That is, the heater is not driven and the process proceeds to step S80.

  In step S102, the engine control unit 203 determines whether heater control of the paper feed tray 102a is necessary. If the determination is negative, the process proceeds to step S100. If the determination is positive (the table stored in the storage unit 214 is read and the outside air humidity exceeds a predetermined threshold), the process proceeds to step S104. Transition.

  In step S104, the engine control unit 203 determines whether or not the remaining amount of paper in the paper-feed tray without a heater that is feeding has reached a predetermined threshold value. If the determination is negative, the process proceeds to step S100, and if the determination is positive, the process proceeds to step S106.

  In step S106, the engine control unit 203 reads the table stored in the storage unit 214, and the heater of the paper feed tray 102a is set via the heater control unit 207 so that the target temperature in the tray is set according to the outside air humidity. And the process proceeds to step S80.

  As described above, when a paper feed instruction is received by a paper feed tray without a dehumidifying heater by image forming operation, control is not necessary for a paper feeding tray with a dehumidifying heater that has not been fed because the paper feeding operation tray has been determined. It is also possible to. Here, there is a possibility of becoming a tray switch target (a switching destination tray in automatic tray switching when there is no paper in the paper feed tray) based on paper information set in a paper feed tray without a dehumidifying heater during paper feeding. (Step S98). If there is a possibility, heater control is performed when the outside air humidity exceeds a predetermined threshold. The control start timing is determined based on the remaining amount of paper in the paper tray being fed and the time when the job can be continued without waiting for dehumidification when the tray switch is performed. If the remaining amount of paper in the tray has reached the threshold value, the dehumidifying heater of the tray that is the target of the tray switch is controlled (step S106), and it is determined that the threshold value has not been reached and the dehumidifying heater need not be controlled. The control of the dehumidifying heater for the tray switch target tray is not yet performed (step S100), and the control of the dehumidifying heater is started when the remaining amount of paper in the currently fed tray reaches the threshold value.

  As described above, the heater control start timing of the switching destination tray is determined based on the remaining amount of paper in the tray being fed, thereby enabling heater control that ensures productivity while suppressing wasteful 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-described embodiment, and include a plurality of paper feed trays, and at least one of the paper feed trays is provided with a dehumidifying means. The present invention can be applied to any image forming apparatus.

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. 6 is a flowchart illustrating a first modification of the operation of the image forming apparatus according to the embodiment of the present invention. 10 is a flowchart illustrating a second 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 201 Operation part 202 Overall control part 203 Engine control part 204 Paper information storage means 205 Paper remaining quantity detection means

Claims (3)

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;
A second dehumidifying means for dehumidifying the paper set in the second paper feed tray;
When the paper feed tray selecting unit selects the second paper feed tray, the first paper feed tray is selected based on the remaining amount of paper detected by the remaining paper amount detecting unit of the second paper feed tray that is feeding paper. Control means for controlling the dehumidifying means;
Paper feed switching means for automatically switching to paper feed from the first paper feed tray and continuing paper feed when there is no paper in the second paper feed tray being fed;
Equipped with a,
The control means sets the control start condition of the first dehumidifying means when the remaining amount of paper detected by the remaining paper amount detecting means of the second paper feed tray that is feeding has reached a predetermined threshold value. An image forming apparatus. 2. The image forming apparatus according to claim 1, further comprising sheet information storage means for storing information relating to sheets set in each sheet feed tray . 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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