JP2010132420A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress useless energy consumption in a dehumidifying means in an image forming device having the dehumidifying means. <P>SOLUTION: This image forming device has an image forming part for forming an image based on image data, a plurality of paper feeding trays for storing paper fed to the image forming part, the dehumidifying means for dehumidifying the paper stored in the paper feeding trays, and a control part for controlling respective operations of an image formation, paper feeding and dehumidification. The control part temporarily stops the operation of the dehumidifying means to the paper feeding trays when an interval up to the paper feeding in the paper feeding trays on and after the next order of arranging the dehumidifying means in image forming operation by a job exceeds a predetermined time or longer when paper feeding order of the paper from the paper feeding tray is fixed when image data of the job are fixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image based on image data and that can dehumidify a sheet stored in a paper feed tray.

  In an image forming apparatus such as a copying machine, a printer, or a multifunction peripheral, a toner image is formed on a photoreceptor provided in an image forming unit based on image data obtained by reading from a document reading device, and the toner An image is formed (also referred to as printing) by transferring an image onto a sheet fed from a sheet feeding tray and further fixing the image.

  Various types of paper are used as the paper on which image formation is performed, and the coated paper has a surface with high smoothness and poor air permeability because the surface is coated. ing. This coated paper is easy to increase the adhesion between the coated paper in a high humidity environment, and it is easy to increase the adhesion, and the top coated paper loaded in the paper feed tray is not burned in the machine. Paper may be fed and cause jams. In addition, when printing is performed by transporting paper in a high humidity state, there is a problem in that dew condensation occurs and causes malfunction. For this reason, an image forming apparatus in which a dehumidifying heater is provided in a paper feed tray has been proposed in order to reduce the humidity of paper such as coated paper (see Patent Document 1).

In the image forming apparatus disclosed in Patent Document 1, heating of the heater is started when paper is set on the operation unit without waiting for the start of image formation in the dehumidifying operation, and the paper is fed in a short time. Is possible. In this image forming apparatus, when the heater non-installation tray is selected after the job is finished, the heater of the heater installation tray is stopped.
JP-A-2005-96946

By the way, in the dehumidifying operation, even if heating of the heater is started by setting the paper in the operation unit as shown in Patent Document 1, it takes time for dehumidification to be sufficiently performed. However, there is a problem that the waiting time occurs and the productivity may decrease. For this reason, normally, the dehumidifying heater of the image forming apparatus is always controlled so that, for example, if the humidity is equal to or higher than a predetermined value, the energization is kept on, and when a job start instruction is given, output can be performed immediately. ing.
However, if the dehumidifying heater is left on, energization is continued even when paper feeding is not necessary for a long time, and there is a problem that power consumption is increased wastefully.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing energy consumed by a dehumidifying unit without impairing productivity.

  That is, among the present inventions, the first present invention includes an image forming unit that forms an image based on image data, a plurality of paper feed trays that store paper to be fed to the image forming unit, and the paper feed A dehumidifying means for dehumidifying the paper stored in the tray; and a control unit for controlling the image forming, paper feeding, and dehumidifying operations. The control unit determines the image data of the job and supplies the paper. When the paper feed order from the paper tray is fixed, the interval until the paper feed tray in the next or subsequent order in which the dehumidifying means is installed during the image forming operation by the job exceeds a predetermined time. At this time, the operation of the dehumidifying means for the paper feed tray is temporarily stopped.

According to the present invention, when the interval until the paper feed in the next and subsequent paper feed trays exceeds a predetermined time during image formation, the operation of the dehumidifying means is temporarily stopped to avoid wasteful energy consumption. To do. The dehumidifying means releases the stop in preparation for paper feeding in the paper feeding trays in the next and subsequent orders.
The dehumidifying means is not particularly limited as long as it can dehumidify the paper in the paper feed tray, and an appropriate one such as a dehumidifying heater can be selected.

  In the image forming apparatus according to the second aspect of the present invention, in the first aspect of the present invention, the control unit needs to perform a dehumidifying operation to stop the operation of the dehumidifying means in preparation for feeding the corresponding paper feed tray. It is characterized by releasing by time.

  According to the second aspect of the present invention, since the dehumidifying means is released by the time when the dehumidifying operation is required in the paper feeding tray for feeding paper, dehumidification is not performed at the timing of feeding paper in the paper feeding tray. It is possible to feed the paper immediately when it is properly performed.

  In the image forming apparatus according to the third aspect of the present invention, in the first or second aspect of the present invention, the control unit determines the interval until the paper feed tray is fed and the recovery time of the paper feed tray by the dehumidifying means. And determining whether or not to stop the operation of the dehumidifying means based on the comparison result.

  According to the third aspect of the present invention, it is possible to determine whether or not to stop the dehumidifying means in consideration of the recovery time when the dehumidifying means is temporarily stopped. It can be prevented from occurring.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, wherein the control unit uses the recovery time as the predetermined time.

  According to the fourth aspect of the present invention, the stoppage of the dehumidifying means can be easily determined by setting the recovery period to a predetermined time.

  In the image forming apparatus according to a fifth aspect of the present invention, in the fourth aspect of the present invention, the control unit sets the recovery time for the paper in the paper feed tray to be dehumidified after the dehumidifying means starts operating. It is characterized by the time required for dehumidification to

  According to the fifth aspect of the present invention, by determining the recovery time based on the time required for dehumidification, the paper is fed in a properly dehumidified state at the start of paper feeding in the paper feed tray.

  The image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to the fifth aspect, wherein the control unit determines the type of paper stored in the paper feed tray to be dehumidified when determining the recovery time. At least one of the basis weight or the temperature and humidity in the environment of the paper feed tray is used as a parameter value.

According to the sixth aspect of the present invention, by taking into consideration the paper type (plain paper, high-quality paper, coated paper, etc.), basis weight, temperature, humidity, etc., a highly accurate paper whose recovery time is realistic. It can be.
For example, coated paper has poor air permeability and requires time for dehumidification, and if the basis weight is large, it similarly requires time for dehumidification. The time required for dehumidification varies depending on the temperature and humidity (the lower the temperature, the higher the humidity, the longer the dehumidification time).

  According to a seventh aspect of the present invention, there is provided an image forming apparatus according to any one of the first to sixth aspects of the present invention, a humidity detecting means for detecting the humidity around the image forming apparatus or the humidity in the target paper feed tray, or an image. One or both of temperature detecting means for detecting the temperature around the forming apparatus or the temperature in the target paper feed tray is provided.

  According to the seventh aspect of the present invention, the humidity around the apparatus or in the paper feed tray is detected by the humidity detecting means, or the temperature around the apparatus or in the paper feed tray is detected by the temperature detecting means. The result can be used for the determination of the recovery time, the control of the dehumidifying means in a timely manner, and the stop. Either humidity or temperature may be measured, or both may be measured. Furthermore, the humidity and temperature may be detected both in the periphery of the apparatus and in the paper feed tray.

  The image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the seventh aspect, wherein the controller is configured to control the humidity around the image forming apparatus or the humidity in a target paper feed tray, or the temperature or target around the image forming apparatus. The recovery time is determined on the basis of one or both parameter values of the temperature in the paper feed tray.

  According to the eighth aspect of the present invention, the dehumidification recovery time can be accurately determined using the detection result.

  An image forming apparatus according to a ninth aspect of the present invention is characterized in that, in the sixth or eighth aspect of the present invention, the image forming apparatus includes a storage unit that stores data in which the parameter value is associated with the recovery time.

  According to the ninth aspect of the present invention, the above-described parameter values such as temperature and humidity are associated with the recovery time and stored in a non-volatile storage unit such as a flash memory or an HDD so that the control unit appropriately It can be read out and the recovery time can be immediately determined by the parameter value.

  The image forming apparatus of the tenth aspect of the present invention is the image forming apparatus according to any one of the first to ninth aspects of the present invention, wherein the control unit sets the sheet feeding order of the sheet feeding trays as an interval until the sheets are fed. In this case, a time obtained by multiplying the number of fed sheets necessary to reach the number of sheets fed by the sheet feeding time per sheet in the number of fed sheets is calculated.

  According to the tenth aspect of the present invention, it is possible to easily calculate the interval between the next and subsequent sheet feeding trays from the necessary number of sheets to be fed and the sheet feeding time per sheet.

  The image forming apparatus according to an eleventh aspect of the present invention is the image forming apparatus according to any one of the first to tenth aspects of the present invention, wherein the sheet feeding trays subsequent to the next order are not used in a job in which the sheet feeding order is determined. It is a tray, and the paper feed interval is a time required for the entire job.

  According to the eleventh aspect of the present invention, it is possible to determine whether or not to temporarily stop the dehumidifying means in consideration of the recovery time and the like before the end of the job even for a paper feed tray that is not scheduled to be used. . If the time required for job completion is longer than the recovery time or the like, it is possible to temporarily stop the dehumidifying means of the paper feed tray that is not scheduled to be used, thereby eliminating wasted energy. When the job is completed, the paper feed tray has been properly dehumidified and is ready to use.

  The image forming apparatus according to a twelfth aspect of the present invention is the image forming apparatus according to any one of the first to eleventh aspects of the invention, wherein the control unit is configured to control the paper feeding tray with respect to the paper feeding tray when an interval until the paper feeding is equal to or shorter than the predetermined time. It is characterized in that the operation of the dehumidifying means is continued.

  According to the twelfth aspect of the present invention, when the interval is equal to or shorter than the predetermined time, it is possible to prevent a decrease in productivity by setting the dehumidifying means in a dehumidifiable state without temporarily stopping the dehumidifying means.

  The image forming apparatus according to a thirteenth aspect of the present invention is the image forming apparatus according to any one of the first to twelfth aspects, wherein the dehumidifying means is a dehumidifying heater, and the dehumidifying heater is operated and stopped. It is characterized in that it is performed by turning on and off the energization.

  An image forming unit that forms an image based on image data, a plurality of paper feed trays that store paper to be fed to the image forming unit, and a dehumidifying unit that dehumidifies the paper stored in the paper feed tray A control unit that controls each of the image forming, sheet feeding, and dehumidifying operations, and the control unit determines the image data of the job and determines the sheet feeding order from the sheet feeding tray. In this case, the operation of the dehumidifying unit with respect to the sheet feeding tray is performed when the interval until the sheet feeding in the next and subsequent sheet feeding trays in which the dehumidifying unit is installed during the image forming operation by the job exceeds a predetermined time. Is temporarily stopped, so that energy consumption required for the dehumidifying means can be reduced without lowering productivity.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a central sectional view of the entire image forming apparatus and shows a mechanical configuration. The configuration will be described below.
The image forming apparatus 1 is provided with a scanner unit 130 and an automatic document feeder (ADF) 135 on the upper side thereof, and these constitute a document reading unit. In addition, a display unit 141 constituting a part of the operation unit 140 is provided on the upper side of the image forming apparatus 1 so that an operation input by the operator is possible.

In addition, a plurality of first to third paper feed trays are arranged on the lower side of the image forming apparatus 1, and the third paper feed tray is configured to be fed by air conveyance. Each paper feed tray is provided with temperature / humidity detectors 170 to 172 and first to third paper feed tray heater fan units. Further, a fourth large-capacity paper feed tray for air feeding and feeding is provided so as to be attached to the image forming apparatus 1. The fourth large-capacity paper feed tray is provided with a temperature / humidity detector 173 and a fourth paper feed tray heater fan unit. The first to fourth paper feed tray heater fan units are configured by combining a dehumidifying heater and a fan, and correspond to dehumidifying means of the present invention. The temperature / humidity detection units 170 to 173 detect the temperature and humidity in each paper feed tray, and also serve as the temperature detection unit and the humidity detection unit of the present invention.
In this embodiment, all the paper feed trays are described as having dehumidifying means, but a paper feed tray that does not have dehumidifying means may be included in part.

  A conveying path 158 extends from the first to third sheet feeding trays and the fourth large-capacity sheet feeding tray, and an image forming unit including an LD unit 152 and the like is disposed in the middle of the conveying path 158. . In the vicinity of the LD unit 152, a photoconductor, a charger, a developing unit, a fixing unit, and the like (not shown) are arranged to form an image forming unit. The image forming unit, the first to third sheet feeding trays, the fourth large capacity sheet feeding tray, the conveyance path 158, and the like constitute the printer unit 150. A post-processing device (FNS) 180 is installed on the downstream side of the image forming unit so that desired post-processing (stapling, punching, cutting, etc.) can be performed on the paper on which the image has been formed.

Next, a functional configuration of the image forming apparatus according to the present invention is shown in a circuit block diagram of FIG.
The image forming apparatus 1 includes an overall control unit 110, an automatic document feeder (ADF) 135, a scanner unit 130, an operation unit 140, a printer unit 150, and a post-processing device 180.

  The overall control unit 110 includes an image control CPU 111 that controls the entire image forming apparatus 1. The image control CPU 111 includes a program memory 112 that stores a program for operating the image control CPU 111, and a program operation time. A system memory (RAM) 113 and a non-volatile memory 114 that are used as temporary storage locations for the work area and data are connected. These memories constitute the storage unit of the present invention.

  The nonvolatile memory 114 stores initial print setting information of the image forming apparatus 1, machine setting information such as process control parameters, setting data of paper information (paper size, paper type, etc.) of each paper feed tray, and the like. Yes. The image control CPU 111 performs operations such as control of each part in accordance with a program stored in the program memory 112 while referring to data on the system memory 113. The image control CPU 111 can read non-volatile data in the non-volatile memory 114 and can write desired data into the non-volatile memory 114 as non-volatile data. The image control CPU 111 controls the operation of each unit of the image forming apparatus 1 in accordance with the machine setting information and the print setting information. The image processing control CPU 111 controls the entire image forming apparatus 1 and corresponds to a control unit of the present invention.

A DRAM control IC 115 is connected to the image control CPU 111, and an image memory 120 including a compression memory 121 is connected to the DRAM control IC 115.
A write processing unit 125 is connected to the DRAM control IC 115. The write processing unit 125 is connected to an LD unit (laser diode) 152 included in the image forming unit of the printer unit 150, and processes write data used for the operation of the LD unit 152. Further, the printer unit 150 includes a printer control unit 151 that controls the entire printer unit 150 (paper feeding, conveyance, image formation, paper discharge, post-processing, and the like). The printer control unit 151 includes the image control CPU 111 described above. It is connected to the.

  The printer control unit 151 controls the printer unit 150 by operating according to the control command of the image control CPU 111 while performing serial communication with the image control CPU 111. The printer control unit 151 is controllably connected to a paper feed mechanism, an air transport fan, tray heaters and tray heater fans of the first to fourth paper feed tray heater fan units, a transport mechanism, a temperature / humidity sensor, and the like.

The printer control unit 151 controls the load according to an instruction from the image control CPU 111, and performs paper conveyance, image formation, and the like. For example, when selecting the paper feed tray, the image control CPU 111 instructs the printer control unit 151 to select the paper feed tray.
In addition, the image control CPU 111 has an APS mode for automatically selecting a paper feed tray that satisfies the paper feed conditions (paper size, paper type, basis weight, etc.) at the time of paper feed. When the paper runs out, it has an ATS mode for automatically switching and selecting a paper feed tray that satisfies the paper feed conditions. Selection and switching of the paper feed tray in these modes is also performed through the printer control unit 151. .

  The image control CPU 111 can manage the priority order when selecting the paper feed tray, and the paper feed tray is selected according to the priority order when the APS and ATS modes are executed. The priorities are stored in the nonvolatile memory 114 and read by the image control CPU 111. The priority order can be changed by a setting change by the operator or an operation of the image control CPU 111. In the document pre-read mode, the paper feed tray can be selected in the APS mode.

The image control CPU 111 performs image formation by managing one or a plurality of JOBs. When a job is finalized, a plurality of paper feed trays may be used depending on the contents of the job (intersheet or the like) (including cases where a plurality of paper feed trays are used differently). Is determined. In the document read-ahead mode and the second and subsequent copies when outputting a plurality of copies in page units, the order of the paper feed trays is determined according to the determination of the image data.
When executing the job, the image control CPU 111 performs control to select a paper feed tray according to this paper feed order and to feed paper.

  Further, a post-processing device (FNS) 180 is connected to the printer controller 151, and the post-processing device (FNS) 180 is controlled via the printer controller 151.

  Next, the scanner unit 130 includes a CCD 131 that performs optical reading, and a scanner control unit 132 that controls the entire scanner unit 130. The scanner control unit 132 is connected to the image control CPU 111 so as to be capable of serial communication. The CCD 131 is connected to a reading processing unit 117 that processes image data read by the CCD 131. The reading processing unit 117 is connected to a DRAM control IC 115. The DRAM control IC 115 further receives image data. A compression / decompression IC 122 that performs compression processing and decompression processing is connected.

  The automatic document feeder (ADF) 135 includes an ADF control unit 136, which is connected to the image control CPU 111 and is controlled by the image control CPU 111.

The operation unit 140 includes a display unit 141 that serves as both a display screen and an operation screen and is configured by an LCD, and an operation unit control unit 142 that controls the entire operation unit. It is connected to the image control CPU 111 so that serial communication is possible. In the operation unit 140, under the control of the image control CPU 111, the display unit 141 causes machine setting input such as print settings and operation control conditions in the image forming apparatus 1, setting input related to output, display of setting contents, and desired information. Etc. can be displayed. Furthermore, it is possible to set paper information for each paper feed tray (size, paper type), output mode setting (with or without APS, ATS), paper feed conditions for tray selection, and the like.
In the operation unit 140, when a plurality of paper feed trays are used at the time of JOB setting, it is possible to input the setting of the order of the paper feed trays to be used. The setting contents are sent to the image control CPU 111 and managed by the image control CPU 111.

  FIG. 3 shows an operation screen 1400 on the display unit 140. On the operation screen 1400, printing conditions can be set and displayed. Further, when a paper setting button 1401 provided on the operation screen 1400 is pressed, a paper setting screen 1410 for each paper feed tray is displayed. In the paper setting screen 1410, paper information of paper size, paper type, basis weight, and color is displayed in the information column 1411 for each paper feed tray. After selecting a desired paper feed tray in the information column 1411, by pressing a size setting button 1412, a paper type setting button 1413, and the like displayed on the paper setting screen 1410 so as to be operable, the paper information of each paper feed tray is displayed. Can be changed. The display field 1411 of the paper setting screen 1410 displays whether or not a heater fan unit is installed in each paper feed tray. For the paper feed tray in which the heater fan unit is installed, the humidity adjustment of the heater fan unit is performed. Whether pre-drying is valid or invalid.

  Also, the image control CPU 111 is connected to an IO unit 116 so that data can be input / output to / from each unit in the apparatus. The temperature / humidity detection units 170 to 173 are connected to the IO unit 116. Yes. Thereby, the detection results of the temperature / humidity detection units 170 to 173 can be transmitted to the image control CPU 111.

In the image control CPU 111, the number of sheets that can be output per time is set in association with the paper type and the like together with the setting of the paper in each paper feed tray, and the data is stored in the nonvolatile memory 114 so as to be readable and writable.
Further, the image control CPU 111 manages the recovery time (drying return time) until the paper can be fed when the dehumidifying means is operated in each paper feed tray. The recovery time is set in advance in association with the detected temperature and the detected humidity, and the setting data is stored in a readable / writable manner in the nonvolatile memory 114 which is a part of the storage unit. The image control CPU 111 determines a recovery time by acquiring a parameter value such as a temperature associated with the recovery time by detection or the like.
Table 1 below is a table in which the detected humidity and the recovery time are associated with each other, and Table 2 is a table in which the detected temperature and the recovery time are associated with each other. The image control CPU 111 can immediately determine the recovery time by referring to the table in the table below based on the detected humidity and the detected temperature. Further, the recovery time associated with the parameter value can be changed via the operation unit 140, and the changed data is stored in the nonvolatile memory 114 and can be read by the image control CPU 111.
Furthermore, the dehumidification recovery time can be obtained by calculating the time required to reach a predetermined condition such as target humidity and target temperature based on parameter values such as detected humidity and detected temperature.

The image control CPU 111 manages the setting contents of the paper feed tray, the detection results of the temperature / humidity detection sensors 170 to 173, the recovery time, etc. Table 3 shows examples of the contents.
The first paper feed tray stores plain paper and does not require dehumidification, so the heater setting is invalidated and the return time is not displayed. As shown in Table 3, the image control CPU 111 determines the type of paper stored in each paper feed tray, humidity in the paper feed tray, temperature, return time (other than the first paper feed tray), and output per unit time. It manages the number of sheets possible.

Next, the basic operation of the image forming apparatus 1 will be described.
First, a procedure for storing image data in the image forming apparatus 1 will be described.
In the image forming apparatus 1, a case where the scanner unit 130 reads an image and generates image data will be described. The scanner unit 130 optically reads an image from a document by the CCD 131. At this time, the operation of the CCD 131 is controlled by the scanner control unit 132 that receives a command from the image control CPU 111. The reading of the document may be performed by an automatic document feeder (ADF) 135 or may be performed by placing the document on a platen glass.

  The image control CPU 111 operates according to a program, and issues a command to the scanner unit 130 based on an operation by the operation unit 140. The image read by the CCD 131 is subjected to data processing by the reading processing unit 117, and the processed image data is compressed by the compression / decompression IC 122 by a predetermined method and stored in the compression memory 121 via the DRAM control IC 115. The

  When the image forming apparatus 1 outputs an image, the image data stored in the compression memory 121 is sent to the compression / expansion IC 122 via the DRAM control IC 115 to decompress the data, and the decompressed data is sent via the DRAM control IC 115. The data is sent to the writing processing unit 125 to generate writing data, and the LD unit 152 performs writing on the photoconductor. Further, in the printer unit 150, each unit such as each paper feed tray and the conveyance path 155 is controlled by the printer control unit 151 that receives a command from the image control CPU 111. That is, a paper feed tray having the same paper information (size and paper type) as a job is selected from a plurality of paper feed trays to feed paper, and the printer unit 150 performs image formation, transfer to paper, and fixing. Then, transport to the post-processing device 180 by the transport path 155, post-processing by the post-processing device 180, and the like are sequentially performed to perform print output.

Note that when the job is executed, the operation of the dehumidifying means in each paper feed tray can be controlled in the document pre-reading mode or the like in which the image data is confirmed and the paper feed order of the paper feed trays is also determined.
For example, as shown in FIG. 4, when a job is executed, one sheet is first fed from the third sheet feeding tray, and then switched to sheet feeding from the first sheet feeding tray to feed N sheets. A description will be given of a job in which one sheet is fed from the third sheet feeding tray as an inter sheet and then returns to feeding from the first sheet feeding tray.
In the first paper feed tray that feeds normal paper, the heater of the fan heater unit is disabled, and the heater of the third paper feed tray that feeds coated paper or the like is enabled.

When starting to feed the first sheet from the third sheet feeding tray, after switching to the first sheet feeding tray, the sheet feeding interval A until feeding from the sheet feeding tray is calculated again. To do.
The sheet feeding interval T per sheet is PPM / 60 = 1 second for both the first sheet feeding tray and the third sheet feeding tray, and the number of sheets fed before switching to the third sheet feeding tray is (N + 1). Since there are sheets, the paper feed interval A = (N + 1) × T seconds = (N + 1) seconds.

On the other hand, as shown in Table 3, the recovery time B for the third paper feed tray is 1 minute = 60 seconds, so that N is 60 for the paper feed interval to exceed the recovery time. It is necessary to be.
Therefore, when the number of fed sheets in the first sheet feeding tray is 60 sheets or more,
Heater off time C = paper feed interval A−recovery time B> 0,
During the time indicated by the above equation, the heater of the third paper feed tray is temporarily stopped as shown in FIG.
If it is within this time, when the heater off time C has elapsed and the heater is turned on again, the third paper feed tray has returned to an appropriate dry state at the time of paper feed start, and immediately feeds paper. Can start. Therefore, the power consumption of the heater can be reduced without reducing the productivity.

  On the other hand, when the paper feed interval A is equal to or shorter than the recovery time B, as shown in FIG. 4B, when the heater is turned off, the time during which the heater is turned on until the paper feed start timing thereafter is equal to or shorter than the recovery time. become. In other words, the dry state cannot be restored by the start timing of feeding of the third sheet feeding tray, so that a waiting time occurs and sheet feeding is delayed. Therefore, under such conditions, the heater of the third paper feed tray is not turned off, and the power supply is turned on, waiting for the completion of feeding N sheets in the first paper feed tray, and then the third paper feed tray. Feed one sheet from the paper tray.

  In the above example, the paper feed interval is calculated only between two paper feed trays, but the paper feed interval may be calculated using three paper feed trays. For example, when feeding paper in the order of the first paper feed tray, the third paper feed tray, and the fourth paper feed tray, the third paper feed tray has a long paper feed interval. In the four paper feed trays, there is a form in which the recovery time is longer than the paper feed interval and the power is not turned off.

Next, a procedure for energization-off determination for the dehumidifying heater will be described based on the flowchart of FIG. The following procedure is executed by the image control CPU 111.
When executing the job, the control unit determines whether or not the image data and the sheet feeding order are confirmed (step s1). This job corresponds to the document pre-reading mode and the second and subsequent copies when a plurality of copies are output in units of pages. Such a job is output after all originals are read and stored in a memory or the like.

Here, when the document data or the paper feeding order is not fixed in the advance mode or the like (step s1, NO), if the heater for the paper feeding tray is valid, the control for the heater is turned on and will be described later. The process proceeds to step s9 (paper feeding) (step s12).
If the image data and the paper feed order have been confirmed (step s1, YES), it is determined whether or not there is a tray in which the heater is effective in the tray used in the job (step s2). If there is no tray in which the heater is effective, the process proceeds to step s9 (paper feeding).

If there is a heater that is effective in the tray used in the job (step s2, YES), as described above, the time (interval) until the next paper feed in the paper supply tray in which the heater is effective is calculated. (Step s3).
Next, the heater dehumidification recovery time in the corresponding tray is obtained by referring to the table (step s4).
The paper feed interval obtained above is compared with the recovery time to determine whether or not the paper feed interval exceeds the dehumidification recovery time (step s5). Here, if the paper feed interval does not exceed the dehumidification recovery time (step s5, NO), the power supply to the heater in the corresponding paper feed tray is not turned off and the control in the paper feed tray is kept on. (Step s7). Next, the process proceeds to a determination of whether or not the check has been completed for all the paper feed trays in which the heaters are valid (step s8).
If it is determined in step s5 that the paper feed interval exceeds the dehumidification recovery time (step s5, YES), the control to the heater of the corresponding paper feed tray is temporarily turned off (energization off). . Thereafter, the process proceeds to a determination as to whether or not the check has been completed for all the paper feed trays in which the heaters are valid (step s8).

In step s8, if the check of all trays in which the heater is valid is not completed (step s8, NO), the process returns to step s1, and the same determination is performed for the other trays. According to this procedure, determination can be performed over a plurality of jobs.
If it is determined in step s8 that all the trays in which the heaters are valid have been checked (step s8, YES), sheet feeding (step s9) and image formation (step s10) are started, and the set number of sheets is set. The above-described series of procedures is repeated until printing is completed (to step s11). When the set number of prints is completed, the procedure for determining whether to turn off the power to the dehumidifying heater is completed.
As described above, waste of energy consumption can be prevented by stopping the appropriate dehumidifying means of the paper feed tray without reducing productivity.

  As described above, the present invention has been described based on the above embodiment. However, the content of the present invention is not limited to the content of the above embodiment, and can be appropriately changed without departing from the scope of the present invention. It is.

1 is a diagram illustrating a central cross section of an entire image forming apparatus according to an embodiment of the present invention. Similarly, it is a circuit block diagram of the entire image forming apparatus. Similarly, a paper setting screen is shown. Similarly, it is a time chart showing the control of the dehumidifying means. Similarly, it is a flowchart which shows the control procedure of a dehumidification means.

Explanation of symbols

1 Image forming apparatus 101 Image processing CPU
102 Non-volatile memory 130 Scanner unit 140 Operation unit 150 Printer unit 170, 171, 172, 173 Temperature / humidity detection unit

Claims (13)

An image forming unit that forms an image based on image data, a plurality of paper feed trays that store paper to be fed to the image forming unit, and a dehumidifying unit that dehumidifies the paper stored in the paper feed tray A control unit for controlling the image forming, paper feeding and dehumidifying operations,
When the image data of the job is confirmed and the sheet feeding order from the sheet feeding tray is confirmed, the control unit starts from the next order in which the dehumidifying means is installed during the image forming operation by the job. An image forming apparatus characterized by temporarily stopping the operation of the dehumidifying means for the paper feed tray when the interval until the paper feed in the paper feed tray exceeds a predetermined time.   The image forming apparatus according to claim 1, wherein the control unit releases the operation stop of the dehumidifying unit by a time when the dehumidifying operation is required in preparation for paper feeding in the corresponding paper feeding tray.   Whether the control unit compares the interval until the paper feed tray is fed with the recovery time by the dehumidifying means for the paper feed tray and stops the operation of the dehumidifying means based on the comparison result. The image forming apparatus according to claim 1, wherein it is determined whether or not.   The image forming apparatus according to claim 3, wherein the control unit uses the recovery time as the predetermined time.   5. The control unit according to claim 4, wherein the recovery time is a time required for dehumidifying the paper in a paper feed tray to be dehumidified to a predetermined condition after the dehumidifying means starts operating. Image forming apparatus.   In determining the recovery time, the control unit sets at least one of a paper type and a basis weight of the paper stored in the paper feed tray to be dehumidified or a temperature and humidity in the environment of the paper feed tray as parameters. 6. The image forming apparatus according to claim 5, wherein the value is a value.   One or both of humidity detection means for detecting the humidity around the image forming apparatus or the humidity in the target paper feed tray or the temperature detection means for detecting the temperature around the image forming apparatus or the temperature in the target paper feed tray The image forming apparatus according to claim 1, further comprising:   The control unit is configured based on the parameter value of one or both of the humidity around the image forming apparatus or the humidity in the target paper feed tray, the temperature around the image forming apparatus or the temperature in the target paper feed tray. 8. The image forming apparatus according to claim 7, wherein a recovery time is determined.   The image forming apparatus according to claim 6, further comprising a storage unit that stores data in which the parameter value is associated with the recovery time.   The control unit multiplies the number of sheets fed until the sheet feeding tray reaches the sheet feeding order by the sheet feeding time per sheet in the sheet feeding number as the interval until the sheet feeding tray feeds. The image forming apparatus according to claim 1, wherein the image forming apparatus calculates a predetermined time.   The sheet feeding tray after the next order is a sheet feeding tray that is not used in a job in which the sheet feeding order is fixed, and the interval between sheet feeding is a time required for the entire job. The image forming apparatus according to any one of 1 to 10.   12. The control unit according to claim 1, wherein when the interval until the sheet feeding is equal to or shorter than the predetermined time, the operation of the dehumidifying unit with respect to the sheet feeding tray is continued. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the dehumidifying unit is a dehumidifying heater, and the operation of the dehumidifying heater and the stop of the operation are performed by turning on / off the energization of the dehumidifying heater.

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