JP2023028023A - Image forming device and control method of supply means used therefor - Google Patents

Abstract

To provide an image forming device efficiently suppressed in probability of occurrence of sheet jam and a control method of supply means used therefor.SOLUTION: An image forming device has storing means storing sheets, supply means supplying the sheets one by one from the storing means to a sheet transportation path, sheet detecting means arranged on the sheet transportation path and detecting passage of the sheets, and control means controlling the supply means. When sheet supply time from the start of the sheet supply by the supply means until detection of the sheet by the sheet detecting means is less than a prescribed reference value, the control means determines occurrence of multiple-sheet feeding, and allows the supply means to supply subsequent sheets, after holding until passage of prescribed extended stand-by time longer than prescribed ordinary stand-by time.SELECTED DRAWING: Figure 3

Description

The present invention relates to image forming apparatuses such as copiers, multifunction machines, printers, and facsimile machines.

2. Description of the Related Art As a technique for reducing the probability of occurrence of a sheet jam (sheet jam) on a sheet conveying path in an image forming apparatus, control for adjusting sheet intervals is known. For example, as in Patent Document 1, control to stop the transport roller and the paper feed roller when the paper interval is narrow, and as in Patent Document 2, the rotation timing of the pickup roller based on the delay time of paper transport. is known.

JP-A-2008-44757 JP 2013-49532 A

However, in the example disclosed in Patent Document 1, there is a problem that the processing efficiency may be lowered due to the stopping of the conveying roller and the paper feeding roller. Further, in the example disclosed in Patent Document 2, for example, when a plurality of sheets are pulled out in an overlapping state by the pickup roller, that is, a so-called sheet feeding occurs, the supply timing of the sheet that has already jumped out from the pickup roller is adjusted. There is a problem that it is difficult to adjust by controlling the pickup roller.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above conventional problems, and an image forming apparatus capable of efficiently suppressing the probability of occurrence of a sheet jam even when sheet feeding occurs. It is an object of the present invention to provide a control method for the supply means used in the apparatus.

In order to achieve the above object, the image forming apparatus described in the present application includes storage means for storing sheets, supply means for supplying the sheets one by one from the storage means to the sheet transport path, and and a control means for controlling the supply means, wherein the control means causes the supply means to start supplying the sheet. to the detection of the sheet by the sheet detection means is less than a predetermined reference value, it is determined that the sheet is accompanied by a predetermined extension longer than a predetermined normal standby time. After waiting until the standby time elapses, the supply means is caused to supply the subsequent sheet.

Further, the image forming apparatus further includes a registration roller arranged on the sheet conveying path, the supply unit has a supply roller that rotates by receiving a driving force, and the sheet detection unit rotates the registration roller. On the other hand, the pre-registration sensor is arranged on the upstream side of the sheet conveying path, and the sheet supply time is the time from the start of rotation of the supply roller to the detection of the sheet by the pre-registration sensor. After the start of rotation of the registration rollers, the control means may cause the supply means to supply the subsequent sheet after waiting until the extended standby time elapses.

Further, in the image forming apparatus, the control unit further includes a notification unit capable of informing a user of information, and waits until the extended waiting time elapses and then instructs the supply unit to supply subsequent sheets. The notification unit may notify the user of an alert when the supply delay to be executed is continuously executed a predetermined number of times.

Further, the image forming apparatus further includes size determination means for determining the size of the sheet, and the control means determines the normal standby time and the extended waiting time based on the size of the sheet determined by the size determination means. You can change the waiting time.

Further, the image forming apparatus further includes temperature and humidity measuring means for measuring the temperature and humidity around the housing means, and the control means measures the normal standby time and the The extended waiting time may be changed.

A method of controlling a supply means described in the present application is a method of controlling a supply means for supplying sheets one by one to a sheet conveying path, wherein after the supply means is caused to start supplying the sheets, the sheet is placed on the sheet conveying path. is less than a predetermined reference value, it is determined that sheet feeding has occurred, and a predetermined extended standby time longer than the predetermined normal standby time elapses After waiting, the supply means is caused to supply the subsequent sheet.

According to the present invention, the probability of occurrence of sheet jam can be efficiently suppressed.

1 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to Embodiment 1; FIG. 2 is a block diagram showing part of the control configuration of the image forming apparatus according to Embodiment 1; FIG. 4 is a flow chart showing part of a processing procedure by a control unit in Embodiment 1. FIG. 4 is a table showing a part of processing contents by a control unit in one example of Embodiment 1; FIG. 4 is a schematic diagram showing a state in which a plurality of sheets are stacked in a sheet cassette so that the burrs of each sheet face upward; FIG. 4 is a schematic diagram showing a state in which a plurality of sheets are stacked in a sheet cassette so that the burrs of each sheet face downward; 8 is a block diagram showing part of the control configuration of the image forming apparatus according to the second embodiment; FIG. FIG. 11 is a block diagram showing part of the control configuration of the image forming apparatus according to Embodiment 3; FIG. 12 is a diagram showing an example of a correction table according to Embodiment 3; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code|symbol is attached|subjected to the same component among each embodiment described below, and the description which overlaps with these components is abbreviate|omitted.

(Embodiment 1)
-Overall Configuration of Image Forming Apparatus-
First, the overall configuration of the image forming apparatus A according to the first embodiment will be described.

FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus A according to Embodiment 1. As shown in FIG. FIG. 2 is a block diagram showing part of the control configuration of the image forming apparatus A according to the first embodiment. In the drawings, the symbol X indicates the width direction (depth direction), the −X direction (minus X direction) is the front direction, and the +X direction (plus X direction) is the rear direction. Symbol Y indicates the left-right direction Y perpendicular to the width direction X, with the −Y direction (minus Y direction) being the left direction and the +Y direction (plus Y direction) being the right direction. The symbol Z indicates the vertical direction, with the −Z direction (minus Z direction) being the downward direction and the +Z direction (plus Z direction) being the upward direction. These settings are the same in the subsequent embodiments.

The image forming apparatus A is an electrophotographic image forming apparatus, and is an intermediate transfer type color multifunction machine capable of printing a full-color image. The image forming apparatus A includes an image reading section 1, an image forming section 2, an intermediate transfer member 3, a secondary transfer section 4, a fixing device 5, a sheet containing section 6, a group of sheet rollers 7, and a pre-registration section. It has a sensor 70 and a sheet discharge section 71 (see FIG. 1). The image forming apparatus A is provided with a sheet conveying path S through which sheets are conveyed. In this embodiment, the image forming apparatus A uses yellow (Y), magenta (M), cyan (C), and black (K) toners for printing.

The image reading unit 1 reads an image from a document, and is provided in the upper part of the image forming apparatus A. As shown in FIG. The image reading section 1 has a document reading device 10, a document table 11, and an automatic document processing device 12 (see FIG. 1).

The document reading device 10 irradiates a document with light and reads an image from the document based on the reflected light. The document reading device 10 includes, for example, a light source for irradiating a document with light, a lens, an image sensor, a mirror for guiding light reflected from the document to the lens, and the like. Image data is generated by photoelectrically converting the reflected light of the document incident on the image sensor through the lens.

The document table 11 is a portion on which a document is placed by a user, and is provided above the document reading device 10 . The document table 11 is made of transparent glass. The automatic document processor 12 automatically and continuously conveys the document inserted by the user to the document reader 10 , and is provided above the document table 11 . The image of the document is read by the document reading device 10 while the document is placed on the document table 11 or conveyed to the document reading device 10 by the automatic document processing device 12 .

The image forming section 2 forms a toner image based on image data, and includes an exposure device 20, a developing device 21, an image carrier 22, a charger 23, and a cleaning unit 24. (see Figure 1). The image data may be generated by the image reading section 1 or may be supplied from an external device.

The exposure device 20 forms an electrostatic latent image corresponding to each color on the image carrier 22 by exposing the surface of the image carrier 22 charged by the charger 23 to light according to each color. The exposure device 20 includes a light source for emitting a laser beam, a polygon mirror for scanning and reflecting the laser beam, and optical elements (for example, lenses and mirror etc.) and are built in.

The developing device 21 develops (visualizes) the electrostatic latent image formed on the surface of each image carrier 22 by toner of each color (Y, M, C, K) supplied from the toner cartridge T. It forms a toner image. When the developing device 21 causes the toner to fly onto the image carrier 22 , the toner is supplied to the electrostatic latent image formed on the surface of the image carrier 22 and a toner image is formed on the surface of the image carrier 22 . be.

The image carrier 22 has an electrostatic latent image formed on its surface, and is rotated in a predetermined direction by driving a main motor (not shown). A toner image visualized on the image carrier 22 is conveyed to the intermediate transfer member 3 by rotational driving of the image carrier 22 .

The charger 23 uniformly charges the surface of the image carrier 22 to a predetermined potential.

The cleaning unit 24 removes and collects toner remaining on the surface of the image carrier 22 after development and image transfer.

The intermediate transfer member 3 is arranged above the image carrier 22, and the toner image of each color formed on the surface of the image carrier 22 is once transferred. The intermediate transfer body 3 has an intermediate transfer belt 30, a drive roller 31, a driven roller 32, and a primary transfer roller 33 (see FIG. 1).

The intermediate transfer belt 30 is an endless belt that rotates in a predetermined direction, and is suspended between a drive roller 31 and a driven roller 32 . The outer surface of the intermediate transfer belt 30 is in contact with the image carrier 22 . The toner images of respective colors visualized on the image carrier 22 are successively superimposed and transferred onto the intermediate transfer belt 30 . The toner image transferred onto the intermediate transfer belt 30 is conveyed to the secondary transfer portion 4 by the rotation of the intermediate transfer belt 30 . The intermediate transfer belt 30 is made of, for example, a film having a thickness of approximately 100 μm to 150 μm.

The driving roller 31 is a roller driven to rotate in a predetermined direction by driving a belt motor (not shown), and is provided on the right end side of the intermediate transfer member 3 . The rotation of the drive roller 31 causes the intermediate transfer belt 30 to rotate.

The driven roller 32 is a roller rotatably provided along the intermediate transfer belt 30 . The driven roller 32 is rotated as the intermediate transfer belt 30 rotates.

The primary transfer rollers 33 are arranged in rows so as to correspond to the image carriers 22 via the intermediate transfer belt 30 . Hereinafter, transferring the toner images of each color formed on the image carrier 22 onto the intermediate transfer belt 30 will be referred to as “primary transfer”.

The secondary transfer section 4 transfers onto a sheet the toner image of each color that has been primarily transferred onto the intermediate transfer belt 30 . The secondary transfer portion 4 has a secondary transfer roller 40 provided at a transfer portion where the sheet and the intermediate transfer belt 30 face each other. Hereinafter, transferring the toner images of each color transferred onto the intermediate transfer belt 30 to the sheet is referred to as “secondary transfer”.

The fixing device 5 heats and melts the toner image that has been secondarily transferred onto the sheet to fix it onto the sheet, thereby fixing the toner image onto the sheet. is provided upstream of the

The sheet storage unit 6 is arranged in the lower part of the image forming apparatus A, and has a sheet cassette 60 that stores sheets used for image formation. In this embodiment, the sheet cassette 60 corresponds to the "accommodating means" described in the claims.

The sheet roller group 7 includes a pickup roller 7a, a supply roller 7b, a separation roller 7c, conveying rollers 7d to 7f, and a registration roller 7g.

The pickup roller 7 a pulls out the uppermost sheet of the sheet bundle of the sheet cassette 60 . The supply roller 7b feeds the sheet onto the sheet conveying path S. As shown in FIG. The separation roller 7c separates the pulled out sheets one by one in a state in which a plurality of sheets are stacked. The supply roller 7b is rotated by receiving a driving force from a supply motor 90 (see FIG. 2), and the pickup roller 7a and the separation roller 7c are rotated following the rotation of the supply roller 7b. In this embodiment, the pickup roller 7a, the supply roller 7b, and the separation roller 7c constitute the "supply means" described in the claims.

Conveying rollers 7d to 7f convey the sheet along the sheet conveying path S. As shown in FIG. The registration roller 7g temporarily stops the sheets conveyed from the sheet containing section 6 and aligns the leading edges of the sheets. The transport rollers 7d to 7f and the registration roller 7g are driven by a transport motor 91 (see FIG. 2) to rotate.

The pre-registration sensor 70 detects a sheet, and is arranged on the upstream side of the sheet conveying path S with respect to the registration roller 7g (see FIG. 1). In this embodiment, the pre-registration sensor 70 corresponds to the "sheet detection means" described in the claims.

The sheet discharge section 71 is provided in the upper portion of the image forming apparatus A, and loads and pulls the printed sheet face down.

In addition to the above configuration, the image forming apparatus A is provided with a control section 8 that executes control of each component described above in accordance with an input operation or the like by the user. The control unit 8 corresponds to the "control means" described in the claims. A configuration of the control unit 8 will be described later.

The image forming apparatus A as described above executes printing on a sheet as follows. First, the image forming section 2 forms a toner image based on image data generated by the image reading section 1 or supplied from an external device. This toner image is primarily transferred onto the intermediate transfer belt 30 of the intermediate transfer member 3 . During this time, the sheet is pulled out from the sheet cassette 60 by the pickup roller 7a, conveyed to the registration roller 7g by the conveyance roller 7d, and conveyed to the secondary transfer portion 4 by the registration roller 7g. Subsequently, the secondary transfer section 4 secondarily transfers the toner image that has been primarily transferred onto the intermediate transfer belt 30 onto a sheet. A fixing device 5 fixes the toner image that has been secondarily transferred onto the sheet. After that, the sheet is conveyed by the conveying roller 7d and discharged onto the sheet discharging section 71, thereby completing the printing on the sheet.

The sheet may be manually fed from the manual feed tray 61 to the sheet conveying path S.

- Control part -
By the way, when the sheets are pulled out from the sheet cassette 60 by the pickup roller 7a, a so-called "sheet feeding" may occur in which a plurality of sheets are pulled out in an overlapping state. Among the plurality of sheets that have been fed, the uppermost one sheet is sent to the sheet conveying path S by the separation roller 7c and the supply roller 7b, but the rest of the sheets are ejected from the pickup roller 7a. state. When such sheet feeding occurs, the interval between sheets becomes narrower than when sheet feeding does not occur, and the probability of occurrence of a sheet jam on the sheet conveying path S increases.

Therefore, in order to efficiently reduce the probability of occurrence of a sheet jam, the control unit 8 determines whether or not sheet feeding has occurred. After waiting until a predetermined extended standby time longer than the normal standby time elapses, the supply roller 7b is made to supply the subsequent sheet. The configuration and processing of the control unit 8 will be described in detail below.

<Configuration of control unit>
The control unit 8 has a processing unit 80, a storage unit 81, an input unit 82, and an output unit 83 (see FIG. 2), which are interconnected by bus lines (not shown). The pre-registration sensor 70 is communicatively connected to the input section 82 , and the supply motor 90 and the transport motor 91 are communicatively connected to the output section 83 .

The processing unit 80 includes a CPU (Central Processing Unit) and the like. The processing unit 80 has an entrainment determination unit 800 that determines whether sheet entrainment occurs (see FIG. 2).

In this embodiment, after the processing unit 80 rotates the supply roller 7b via the supply motor 90 and causes the supply roller 7b to start supplying the sheet, the pre-registration sensor 70 detects the sheet. Based on the "sheet supply time" until the sheet is fed, it is determined whether or not sheet feeding has occurred. When sheet entrainment occurs, the timing at which the pre-registration sensor 70 detects a sheet ejected from the pickup roller 7a tends to be earlier than when sheet entrainment does not occur. Therefore, if the sheet feeding time is equal to or greater than a supply time reference value 811 (to be described later), the accompanying feeding determination unit 800 determines that the sheet feeding has not occurred, and the sheet feeding time is less than the feeding time reference value 811. In this case, it is determined that sheet escort feeding has occurred.

The storage unit 81 includes nonvolatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory). A control program 810 and a supply time reference value 811 are stored in the storage unit 81 . A control program 810 is stored in the ROM of the storage unit 81 . The control program 810 stored in the ROM is read out under the control of the processing unit 80 and loaded onto the RAM, thereby executing the control program 810 . Note that the control program 810 is not limited to the above, and may be read from a recording medium such as an HDD, or may be downloaded from a network such as a LAN (Local Area Network).

A supply time reference value 811 is a value that serves as a reference for the sheet supply time, and is a value referred to by the accompanying feeding determination unit 800 . In this embodiment, the supply time reference value 811 is set as a fixed value.

<Processing mode>
In the present embodiment, the control unit 8 has a normal mode in which the supply roller 7b starts supplying subsequent sheets after waiting until a predetermined normal standby time elapses, and a predetermined extended standby time longer than the normal standby time. and a supply delay mode in which the supply roller 7b is caused to start supplying the subsequent sheet after waiting until the time elapses. The control unit 8 alternatively executes the normal mode or the supply delay mode for each predetermined number of sheets, for each sheet in this embodiment, based on whether or not the sheet is accompanied by feeding. Specifically, it is as follows.

When the accompanying feeding determination unit 800 of the processing unit 80 determines that the accompanying sheet feeding has not occurred, the processing unit 80 of the control unit 8 waits until a predetermined normal waiting time elapses, and then restarts the supply motor 90. A normal mode is executed in which the feed roller 7b is rotated through the feed roller 7b and the feed roller 7b starts feeding the subsequent sheet. On the other hand, when the accompanying feeding determining unit 800 determines that the sheet accompanying feeding has occurred, the processing unit 80 waits until a predetermined extended waiting time longer than the normal waiting time elapses, and then starts the supply motor 90 . A supply delay mode is executed in which the supply roller 7b is rotated via , and the supply roller 7b is caused to start supplying the subsequent sheet. As a result, the timing of starting the supply of subsequent sheets is delayed according to the occurrence of the sheet being fed together, and the interval between the sheets narrowed by the sheet being fed together is appropriately widened. can be effectively suppressed.

Further, in the present embodiment, the processing section 80 executes the supply delay mode after starting the rotation of the registration rollers 7g via the conveying motor 91 . As a result, after the preceding sheet is conveyed by the registration roller 7g, the supply roller 7b is caused to start supplying the succeeding sheet. You can definitely widen the gap.

<Processing procedure>
Next, a processing procedure of the processing mode by the control unit 8 will be described.

FIG. 3 is a flow chart showing part of the processing procedure by the control unit 8 according to the first embodiment. A series of processes shown in FIG. 3 are repeated according to the number of sheets to be processed. In the figure, the step of rotating the registration roller 7g is omitted for convenience of explanation.

First, in step S1, the processing section 80 of the control section 8 rotates the supply roller 7b via the supply motor 90 to start supplying the sheet to the supply roller 7b. Here, the processing unit 80 stores the supply start time at which the supply roller 7b starts supplying the sheet in the storage unit 81 as the sheet supply time.

Next, in step S<b>2 , the processing section 80 acquires from the pre-registration sensor 70 the sheet detection time at which the pre-registration sensor 70 detected the sheet.

Subsequently, in step S3, the processing unit 80 calculates the sheet supply time from the difference between the sheet detection time and the sheet supply time.

In step S<b>4 , the accompanying feeding determination unit 800 of the processing unit 80 determines whether or not the calculated sheet supply time is less than the supply time reference value 811 . If the sheet supply time is equal to or longer than the supply time reference value 811, the processing unit 80 proceeds to the normal mode in step S5, waits until the normal standby time elapses, and then starts supplying the subsequent sheet to the supply roller 7b. (step S1). On the other hand, if the sheet supply time is less than the supply time reference value 811, the processing unit 80 proceeds to the supply delay mode of step S6, waits until the extended standby time elapses, and then feeds the supply roller 7b with the subsequent sheet. is started to be supplied (step S1).

(Example of Embodiment 1)
Examples of the first embodiment will be described below.

FIG. 4 is a table showing a part of processing contents by the control unit 8 in one example of the first embodiment. In the figure, the arrows indicate the correspondence relationship between the sheet supply time and the waiting time of the processing unit 80 until the subsequent sheet supply starts.

In FIG. 4, the item "No." is a column showing sheet numbers, the item "sheet feeding time" is a column showing the sheet feeding time corresponding to each sheet, and the item "between sheets" is a column showing each sheet number. The column indicates the distance between the leading edge of the sheet and the trailing edge of the preceding sheet preceding each sheet. This is a column indicating time, and the item “CPM” is a column indicating CPM (Copies Per Minute) indicating the number of sheets processed per minute. In this embodiment, the supply time reference value 811 is set to 550 ms, the normal standby time is set to 858 ms, and the extended standby time is set to 919 ms.

As shown in FIG. In 2, since the sheet feeding time is equal to or longer than the supply time reference value 811, the accompanying feeding determination unit 800 of the processing unit 80 determines that sheet feeding has not occurred. Therefore, the processing section 80 executes the normal mode. After waiting until the normal waiting time elapses, the processing unit 80 feeds the supply roller 7b with the subsequent sheet, that is, the sheet No. 1. Start feeding 3. Next, sheet no. In 3, since the paper feed time is less than the supply time reference value 811, the accompanying feeding determination unit 800 determines that the accompanying sheet feeding has occurred. Therefore, the processing unit 80 executes the supply delay mode. After waiting until the extended waiting time elapses, the processing unit 80 feeds the supply roller 7b with the subsequent sheet, that is, sheet No. 1. Start feeding 4.

In this manner, by delaying the timing of starting the supply of subsequent sheets according to the occurrence of the sheet-to-feed, the interval between the sheets narrowed by the sheet-to-feed as shown in the item "sheet interval" can be adjusted appropriately. can be expanded. Further, since the normal mode or the supply delay mode is alternatively executed based on whether or not sheet feeding occurs for each predetermined number of sheets, the processing efficiency is improved as shown in the item "CPM". can be maintained.

It should be noted that the first embodiment described above is not limited to the control of sheet supply from the sheet cassette 60 of the sheet containing portion 6, and can be applied to the control of sheet supply from either the manual feed tray 61 or the automatic document processor 12. is.

Also, the supply time reference value 811 may be a variable value that fluctuates under predetermined conditions.

Further, the normal standby time and the extended standby time may be preset fixed values, or may be variable values that fluctuate under predetermined conditions.

(Embodiment 2)
Only the differences of the second embodiment from the first embodiment will be described below.

FIG. 5 is a schematic diagram showing a state in which a plurality of sheets are stacked in the sheet cassette 60 so that the burrs of each sheet face upward. FIG. 6 is a schematic diagram showing a state in which a plurality of sheets are stacked in the sheet cassette 60 so that the burrs of each sheet face downward.

By the way, when the supply delay mode is continuously executed a predetermined number of times, the following events can be assumed. Since the sheet is generally cut, it has burrs at the edges as shown in FIGS. As shown in FIG. 5, when a plurality of sheets are stacked in the sheet cassette 60 so that the burr of each sheet on the opposite side of the sheet pullout direction faces upward, the uppermost sheet is When the sheet is pulled out of the sheet cassette 60, the burrs of the sheet are less likely to interfere with the sheets in the lower layer, so that the sheets are less likely to be fed together. On the other hand, as shown in FIG. 6, when a plurality of sheets are stacked in the sheet cassette 60 so that the burr of each sheet on the side opposite to the sheet pull-out direction faces downward, one sheet of the uppermost layer When the sheet is pulled out of the sheet cassette 60, the burr of the sheet interferes with the sheet in the lower layer, and the sheet is likely to be fed together. When the supply delay mode is continuously executed a predetermined number of times, that is, when the accompanying sheet feeding determination unit 800 continuously determines that sheet accompanying feeding occurs a predetermined number of times consecutively, a plurality of sheets will be processed as shown in FIG. An event that is in a state as shown in can be assumed. Therefore, the control unit 8 according to the second embodiment has the following technical features in order to suppress the occurrence probability of sheet feeding.

FIG. 7 is a block diagram showing part of the control configuration of the image forming apparatus A according to the second embodiment.

In Embodiment 2, the control unit 8 further has a notification unit 84 capable of notifying the user of information (see FIG. 7). The processing unit 80 further has a counting unit 801 that counts the number of times the supply delay mode has been executed consecutively.

When the count value of the counting unit 801 is equal to or greater than a predetermined value, the processing unit 80 of the control unit 8 waits until the extended standby time elapses, and then causes the supply roller 7b to supply the succeeding sheet. When the mode is continuously executed a predetermined number of times, the notification unit 84 notifies the user of an alert. Specifically, the notification unit 84 notifies the user to turn the sheet surface upside down by outputting sound or displaying a character image or the like on a display unit (not shown). As a result, it is possible to suppress the frequency of sheet feeding.

(Embodiment 3)
Only the points of the third embodiment that differ from the first embodiment will be described below.

FIG. 8 is a block diagram showing part of the control configuration of the image forming apparatus A according to the third embodiment. FIG. 9 is a diagram showing an example of the correction table 812 according to the third embodiment.

In Embodiment 3, the image forming apparatus A further includes size determining means 9a for determining the sheet size, and temperature/humidity measuring means 9b for measuring the temperature and humidity around the sheet cassette 60, which corresponds to the containing means. (See Figure 8). For example, a photoelectric sensor such as a reflective optical sensor is used as the size discriminating means 9a. A temperature/humidity sensor is used for the temperature/humidity measuring means 9b, for example.

Further, in the third embodiment, the storage unit 81 of the control unit 8 stores a correction table 812, which is a calculation table referred to in correcting the normal standby time and the extended standby time (see FIGS. 8 and 9). .

The correction table 812 associates predetermined correction conditions and correction amounts corresponding to each correction condition with each other. The item "processing mode" of the correction table 812 is a column indicating the conditions of the processing mode of the control unit 8, the item "size" is a column indicating the conditions of the sheet size, and the item "temperature and humidity" is a column indicating the sheet cassette. 60 is a column indicating the conditions of temperature and humidity around 60, and the item "correction amount (ms)" is when each condition indicated by the item "processing mode", the item "size", and the item "temperature and humidity" is satisfied, FIG. 9 is a column showing correction amounts of normal standby time or extended standby time according to the processing mode (see FIG. 9). In the item "size", "LT" indicates letter size. In the item "temperature and humidity", "N" indicates that the temperature and humidity around the sheet cassette 60 is less than the predetermined threshold, and "H" indicates that the temperature and humidity around the sheet cassette 60 is less than the predetermined threshold. The case where it is above is shown.

The processing unit 80 refers to the correction table 812 and changes the normal standby time and the extended standby time based on the sheet size determined by the size determination unit 9a. The processing unit 80 also refers to the correction table 812 and changes the normal standby time and the extended standby time based on the measurement result of the temperature/humidity measuring means 9b. For example, when the sheet size is determined to be LT (letter size) by the size determination unit 9a and the temperature and humidity around the sheet cassette 60 measured by the temperature/humidity measurement unit 9b is equal to or greater than a predetermined threshold value. , when the processing unit 80 is executing the normal mode, the normal standby time is corrected by +α (ms) (see the third column from the top and the fourth column from the left in FIG. 9). Similarly, when the sheet size is determined to be other than LT (letter size) by the size determination means 9a and the temperature and humidity around the sheet cassette 60 measured by the temperature/humidity measurement means 9b is equal to or greater than a predetermined threshold value. When the processing unit 80 is executing the supply delay mode, the normal standby time is corrected by +β+δ (ms) (see the 9th column from the top and the 4th column from the left in FIG. 9).

As described above, the processing unit 80 changes the normal standby time and the extended standby time based on the sheet size, so that the sheet interval can be appropriately adjusted according to the sheet size.

Further, as described above, the processing unit 80 changes the normal standby time and the extended standby time based on the measurement result of the temperature/humidity measuring means 9b, that is, the temperature and humidity around the sheet cassette 60, thereby increasing the temperature and humidity. Even when sheets tend to stick to each other due to the rise and sheet feeding is likely to occur, the interval between sheets can be appropriately widened, so that the probability of occurrence of sheet jam can be efficiently suppressed.

The correction table 812 may be composed of separate correction tables that associate each of the sheet size condition and the temperature/humidity condition around the sheet cassette 60 with the correction amount.

The above-described embodiments and examples are illustrative in all respects and are not grounds for restrictive interpretation. Therefore, the technical scope of the present invention is not to be construed solely by the above-described embodiments and examples, but is defined based on the claims. In addition, all changes within the meaning and range of equivalents to the claims are included.

A Image forming apparatus 1 Image reading unit 2 Image forming unit 3 Intermediate transfer member 4 Secondary transfer unit 5 Fixing device 6 Sheet storage unit 7a Pickup roller 7b Supply roller 7c Separation roller 7g Registration roller 70 Pre-registration sensor 8 Control unit 8 Control unit 80 Processing unit 800 Accompanying determination unit 801 Counting unit 81 Storage unit 810 Control program 811 Supply time reference value 812 Correction table 82 Input unit 83 Output unit 84 Notification unit 9a Size determination means 9b Temperature/humidity measurement means 90 Supply motor 91 Conveying motor

Claims (6)

a containing means for containing the sheet;
supply means for supplying the sheets one by one from the storage means to the sheet conveying path;
a sheet detecting means arranged on the sheet conveying path for detecting passage of the sheet;
an image forming apparatus comprising: a control means for controlling the supply means,
The control means is
when the sheet supply time from when the supply unit starts supplying the sheet to when the sheet detection unit detects the sheet is less than a predetermined reference value,
It is characterized in that, after it is determined that sheet feeding has occurred and after waiting until a predetermined extended standby time longer than a predetermined normal standby time elapses, the supply means is caused to supply the succeeding sheet. Image forming device. The image forming apparatus according to claim 1,
further comprising a registration roller arranged on the sheet conveying path;
The supply means has a supply roller that rotates by receiving a driving force,
the sheet detecting means is a pre-registration sensor arranged upstream of the sheet conveying path with respect to the registration roller;
The sheet supply time is the time from when the supply roller starts to rotate until the pre-registration sensor detects the sheet,
The image forming apparatus according to claim 1, wherein after the registration rollers start rotating, the control unit waits until the extended standby time elapses, and then causes the supply unit to supply the succeeding sheet. The image forming apparatus according to claim 1 or claim 2,
The control means is
further having a reporting unit capable of reporting information to the user;
The notification unit notifies the user of an alert when a supply delay for causing the supply unit to supply subsequent sheets after waiting until the extended standby time elapses is continuously performed a predetermined number of times. An image forming apparatus characterized by: The image forming apparatus according to any one of claims 1 to 3,
further comprising size determination means for determining the size of the sheet,
The control means is
The image forming apparatus, wherein the normal standby time and the extended standby time are changed based on the size of the sheet determined by the size determination means. The image forming apparatus according to any one of claims 1 to 4,
Further comprising temperature and humidity measuring means for measuring the temperature and humidity around the housing means,
The control means is
An image forming apparatus, wherein the normal standby time and the extended standby time are changed based on the measurement result of the temperature/humidity measuring means. A method for controlling a supply means for supplying sheets one by one to a sheet conveying path, comprising:
when the time from when the supply unit starts supplying the sheet to when the sheet passes a predetermined position on the sheet conveying path is less than a predetermined reference value,
It is characterized in that, after it is determined that sheet feeding has occurred and after waiting until a predetermined extended standby time longer than a predetermined normal standby time elapses, the supply means is caused to supply the succeeding sheet. How to control the supply means.

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