Patent Application
20180147865
The present disclosure generally relates to an image forming apparatus and a feeding apparatus that determine whether or not a recording material is overloaded on an intermediate plate of a cassette.
Conventionally, some image forming apparatuses such as copiers or printers determine whether or not a recording material is overloaded on an intermediate plate of a cassette. When the recording material is overloaded, a great pressure more than necessary is applied from a feeding roller to the recording material, so that it is difficult for the recording material to be normally fed from the cassette, thus causing sheet jamming. Therefore, an image forming apparatus that determines whether or not a recording material is overloaded before feeding the recording material from a cassette, and when determining that the recording material is overloaded, notifies a user of the overloading, and thereby prevents occurrence of sheet jamming is proposed.
Japanese Patent Laid-Open No. 2013-35689 describes an image forming apparatus that has a first sensor detecting that a lift-up operation of an intermediate plate of a cassette starts and a second sensor detecting that a recording material has reached a feeding position by the lift-up operation. The image forming apparatus described in Japanese Patent Laid-Open No. 2013-35689 measures a time from when the first sensor detects the start of the lift-up operation to when the second sensor detects the recording material, and compares the lift-up time that is measured to a threshold time that is set in advance. When the lift-up time that is measured is shorter than the threshold time, the image forming apparatus determines that the recording material is overloaded.
In Japanese Patent Laid-Open No. 2013-35689, the threshold time to determine overloading is set to a fixed value on the basis of a lift-up time when the recording material with a maximum loading amount is loaded on the intermediate plate. However, even in image forming apparatuses having the same configuration, the lift-up time may vary between the apparatuses. This is because a degree of deformation of an elastic member, such as wire, that constitutes a lift-up mechanism varies between the apparatuses or a position at which a sensor for detecting that a recording material has reached a feeding position is installed varies between the apparatuses.
Thus, in the determination of overloading by Japanese Patent Laid-Open No. 2013-35689, although the recording material is actually overloaded, it may be erroneously determined that the recording material is not overloaded because of influence of the variation as described above. As a result, there is a case where it is difficult to prevent occurrence of sheet jamming. Control described in Japanese Patent Laid-Open No. 2013-35689 sufficiently satisfies accuracy for determination of overloading, which is desired at the time, but is required to achieve more enhancement of the accuracy.
According to aspects of the invention, whether or not a recording material is overloaded is accurately determined without influence of a variation factor between apparatuses.
An image forming apparatus according to aspects of the invention is an image forming apparatus that forms an image on a recording material, and includes: a housing unit that includes an intermediate plate on which a recording material is loaded and is attachable to or detachable from the image forming apparatus; a lift-up unit that lifts up the intermediate plate along a vertical direction with driving force supplied from a driving source; a first detection unit that detects that the recording material loaded on the intermediate plate which is lifted up by the lift-up unit has reached a feeding position; a second detection unit that detects presence of the recording material on the intermediate plate; a feeding unit that feeds the recording material which has reached the feeding position; a control unit that, when the housing unit is attached to the image forming apparatus, executes first lift-up control through which the intermediate plate is lifted up by the lift-up unit until the first detection unit detects that the recording material has reached the feeding position, and after the first lift-up control, executes second lift-up control through which when the first detection unit does not detect the recording material because the recording material has been fed by the feeding unit, the intermediate plate is lifted up by the lift-up unit until the first detection unit detects again that the recording material has reached the feeding position; a first acquisition unit that acquires a first driving amount serving as a driving amount of the driving source when the first lift-up control is executed until the first detection unit detects that the recording material has reached the feeding position; a storage unit that stores a threshold for determining overloading of the recording material on the intermediate plate; a determination unit that determines that the recording material is overloaded on the intermediate plate when the first driving amount acquired by the first acquisition unit is smaller than the threshold; a second acquisition unit that acquires a second driving amount obtained by adding the first driving amount to a cumulative driving amount of the driving source when the second lift-up control is executed until the second detection unit detects that there is no recording material on the intermediate plate; and a correction unit that obtains a differential amount by subtracting a predetermined driving amount from the second driving amount acquired by the second acquisition unit, and corrects, on a basis of the differential amount, the threshold stored in the storage unit or the first driving amount acquired by the first acquisition unit.
A feeding apparatus according to aspects of the invention is a feeding apparatus that feeds a recording material, and includes: a housing unit that includes an intermediate plate on which a recording material is loaded and is attachable to or detachable from the feeding apparatus; a lift-up unit that lifts up the intermediate plate along a vertical direction with driving force supplied from a driving source; a first detection unit that detects that the recording material loaded on the intermediate plate which is lifted up by the lift-up unit has reached a feeding position; a second detection unit that detects presence of the recording material on the intermediate plate; a feeding unit that feeds the recording material which has reached the feeding position; a control unit that, when the housing unit is attached to the feeding apparatus, executes first lift-up control through which the intermediate plate is lifted up by the lift-up unit until the first detection unit detects that the recording material has reached the feeding position, and after the first lift-up control, executes second lift-up control through which when the first detection unit does not detect the recording material because the recording material has been fed by the feeding unit, the intermediate plate is lifted up by the lift-up unit until the first detection unit detects again that the recording material has reached the feeding position; a first acquisition unit that acquires a first driving amount serving as a driving amount of the driving source when the first lift-up control is executed until the first detection unit detects that the recording material has reached the feeding position; a storage unit that stores a threshold for determining overloading of the recording material on the intermediate plate; a determination unit that determines that the recording material is overloaded on the intermediate plate when the first driving amount acquired by the first acquisition unit is smaller than the threshold; a second acquisition unit that acquires a second driving amount obtained by adding the first driving amount to a cumulative driving amount of the driving source when the second lift-up control is executed until the second detection unit detects that there is no recording material on the intermediate plate; and a correction unit that obtains a differential amount by subtracting a predetermined driving amount from the second driving amount acquired by the second acquisition unit, and corrects, on a basis of the differential amount, the threshold stored in the storage unit or the first driving amount acquired by the first acquisition unit.
Further features of aspects of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
When receiving a printing request from a video controller 250 illustrated in
In the feeding cassette 102 and the option feeding cassette 152, sheets S are loaded on intermediate plates 194 and 192 and housed with trailing end positions in conveyance directions regulated by trailing end regulators 126 and 176. When a sheet S is fed from the feeding cassette 102 or the option feeding cassette 152, a pickup roller 103 or 153 rotates. The sheet S fed by the pickup roller 103 or 153 is conveyed by a feeding roller 106 or 156 and conveyed to a top sensor 108 via a registration roller 107. A separation roller 105 or 155 forms a separation nip with the feeding roller 106 or 156 and separates a plurality of sheets S, which are fed in an overlapping manner by the pickup roller 103 or 153, into one sheet. Thereby, only the uppermost sheet S is conveyed to the registration roller 107. After a leading end of the sheet S is detected by the top sensor 108, the sheet S is conveyed to the image forming unit 120. Note that, which of the feeding cassette 102 and the option feeding cassette 152 is to feed the sheet S is decided on the basis of the printing request from the video controller 250.
The image forming unit 120 includes a photosensitive drum 109, a transfer roller 110, a charging roller 111, and a developing device 112. The photosensitive drum 109 is uniformly charged by the charging roller 111, and then is irradiated with laser light L output from the laser scanner 113, and has an electrostatic latent image formed on a surface thereof. When toner is supplied from the developing device 112, the electrostatic latent image formed in this manner is visualized as a toner image. With rotation of the photosensitive drum 109, the toner image formed on the photosensitive drum 109 is moved to a transfer nip, and the sheet S is also conveyed to the transfer nip in synchronization with the rotation of the photosensitive drum 109. At the transfer nip, a voltage of an opposite polarity to that of the toner image is applied to the transfer roller 110 and the toner image on the photosensitive drum 109 is transferred onto the sheet S. The sheet S onto which the toner image is transferred is conveyed to the fixing device 114 to be subjected to heat and pressure, and the toner image is fixed to the sheet S. The sheet to which the toner image is fixed is conveyed by triple rollers 116, an intermediate discharge roller 117, and a discharge roller 118, and discharged to a discharge tray 121. Thus, a sequence of print operations is finished.
Note that, when an image is formed on a back surface of the sheet S, after a trailing end of the sheet S passes through the triple rollers 116, the triple rollers 116, the intermediate discharge roller 117, and the discharge roller 118 rotate in a reverse direction and the sheet S is conveyed to a double-side conveyance path 125. Further, the sheet S is conveyed by a double-side conveyance roller 122 and conveyed again to the registration roller 107. A fixing discharge sensor 115 and a double-side conveyance sensor 123 are provided to detect whether the sheet S is normally conveyed. Note that, such a sequence of processing is controlled by an engine control unit 200 (illustrated in
The printer 101 is provided with a lifter motor 193 serving as a driving source for lifting up the intermediate plate 194 of the feeding cassette 102 and a lifter motor 190 serving as a driving source for lifting up the intermediate plate 192 of the option feeding cassette 152.
The printer 101 is provided with a sheet surface sensor 195 that detects a sheet surface of the sheet S loaded on the intermediate plate 194 of the feeding cassette 102 and a sheet presence sensor 104 that detects presence of the sheet S on the intermediate plate 194. The feeding cassette 102 is configured to be attachable to or detachable from the printer 101 to supply the sheet S, and the printer 101 is provided with a cassette detection sensor 198 that detects whether the feeding cassette 102 is attached to or detached from the printer 101.
The printer 101 is provided with a sheet surface sensor 196 that detects a sheet surface of the sheet S loaded on the intermediate plate 192 of the option feeding cassette 152 and a sheet presence sensor 154 that detects presence of the sheet S on the intermediate plate 192. The option feeding cassette 152 is configured to be attachable to or detachable from the printer 101 to supply the sheet S. The printer 101 is provided with a cassette detection sensor 199 that detects whether the option feeding cassette 152 is attached to or detached from the printer 101. Further, a wire 191 is provided between the intermediate plate 192 of the option feeding cassette 152 and the lifter motor 190, and it is configured so that the intermediate plate 192 is lifted up along a vertical direction when the wire 191 is wound around a wire reel 197. The wire reel 197 is detachably connected to the lifter motor 190 provided in the printer 101 by a coupling mechanism (not illustrated). When the option feeding cassette 152 is attached to the printer 101, the wire reel 197 is connected to the lifter motor 190 and rotates upon reception of driving force from the lifter motor 190.
Next, a control block diagram of the image forming apparatus in the present embodiment is illustrated in
The lift-up control unit 230 has a first control unit 231, a first measurement unit 232, a second control unit 233, and a second measurement unit 234. The overloading determination unit 210 has a determination unit 212, a correction unit 211, a calculation unit 214, and a storage unit 215. The engine control unit 200 is connected to each of the video controller 250, the lifter motors 190 and 193, the sheet surface sensors 195 and 196, the sheet presence sensors 104 and 154, and the cassette detection sensors 198 and 199.
The image formation control unit 220 controls the image forming unit 120 and the fixing device 114 while conveying the sheet S by driving a motor rotating a roller pair on a conveyance path, thereby forming the toner image on the sheet S.
Next, a function of the lift-up control unit 230 will be described. Though description will be given below for control of the option feeding cassette 152, it is also applicable to determination of overloading related to the feeding cassette 102 as described below.
The lift-up control unit 230 performs lift-up control related to the intermediate plate 192. The lift-up control is control for driving the lifter motor 190 and lifting up the intermediate plate 192 until the sheet surface of the sheet S is detected by the sheet surface sensor 196. When the sheet surface of the sheet S is detected by the sheet surface sensor 196, the uppermost sheet S among sheets S loaded on the intermediate plate 192 is lifted up to a feeding position. The sheet S lifted up to the feeding position is subjected to appropriate feeding pressure from the pickup roller 153 and is thus normally fed.
The option feeding cassette 152 is configured to be attachable to or detachable from the printer 101. When the option feeding cassette 152 is detached from the printer 101, the intermediate plate 192 is lowered. This is because when the option feeding cassette 152 is detached from the printer 101, connection between the lifter motor 190 provided in a main body and the wire reel 197 provided in the cassette is disconnected.
On the other hand, when the cassette detection sensor 199 detects that the option feeding cassette 152 is attached to the printer 101, the engine control unit 200 requests the first control unit 231 to start initial lift-up control (first lift-up control). In response to the request of the engine control unit 200, the first control unit 231 drives the lifter motor 190 and lifts up the intermediate plate 192. The driving of the lifter motor 190 by the first control unit 231 is continuously performed until the sheet surface sensor 196 detects the sheet surface of the uppermost sheet S or the intermediate plate 192. The case where the sheet surface sensor 196 detects the intermediate plate 192 refers to a case where no sheet S is loaded on the intermediate plate 192. After that, when the sheet surface sensor 196 detects the sheet surface of the sheet S, the first control unit 231 stops the lifter motor 190. In this manner, the first control unit 231 lifts up sheets S of the option feeding cassette 152 to the feeding position.
After the initial lift-up control, an image forming operation is executed and the sheets S are fed one by one from the option feeding cassette 152, and then, a level of the sheet surface is gradually reduced. As a result, the sheet surface sensor 196 is not able to detect the sheet surface of the sheet S. When the sheet surface sensor 196 is not able to detect the sheet surface of the sheet S, the engine control unit 200 requests the second control unit 233 to start additional lift-up control (second lift-up control). In response to the request of the engine control unit 200, the second control unit 233 drives the lifter motor 190 and lifts up the intermediate plate 192. Similarly to the case of the initial lift-up control, the driving of the lifter motor 190 by the second control unit 233 is continuously performed until the sheet surface sensor 196 detects the sheet surface. In this manner, the second control unit 233 lifts up sheets S of the option feeding cassette 152 to the feeding position again. Functions of the first measurement unit 232 and the second measurement unit 234 will be described later.
Next, a function of the overloading determination unit 210 will be described. A state where sheets S are overloaded on the intermediate plate 192 of the option feeding cassette 152 refers to a state where sheets S beyond a prescribed amount of the option feeding cassette 152 are loaded. When sheets S are overloaded, great feeding pressure more than necessary is applied to the sheets S from the pickup roller 153 and the sheets S are not able to be normally fed, so that sheet jamming may occur. Thus, the printer 101 of the present embodiment determines whether or not sheets S are overloaded before the sheets S are fed from the option feeding cassette 152, thus making it possible to prevent the occurrence of the sheet jamming.
First, a method for determining overloading in a related art will be described as a comparative example to the present embodiment. The first measurement unit 232 of the lift-up control unit 230 measures (acquires) a driving amount (first driving amount) of the lifter motor 190 in the initial lift-up control executed when the option feeding cassette 152 is attached to the printer 101. In this case, when a stepping motor is used as the lifter motor 190, a driving step number of the stepping motor is able to be obtained as the driving amount of the lifter motor 190. When the driving amount of the lifter motor 190 measured by the fist measurement unit 232 is smaller than a threshold that is stored in advance in the storage unit 215, the determination unit 212 of the overloading determination unit 210 determines that sheets S are overloaded. In the determination method as the comparative example, the threshold for determining overloading is set to a fixed value on the basis of a driving amount when sheets S with a maximum loading amount are loaded on the intermediate plate 192.
Here, the driving amount of the lifter motor 190 in the initial lift-up control varies between apparatuses due to influence of a variation factor between the apparatuses. Thus, when the threshold is uniformly set to the fixed value as in the comparative example, overloading is not able to be accurately determined in some cases. The variation factor between the apparatuses will be described in detail with reference to
Moreover, the lifting amount of the intermediate plate 192 until reaching the sheet surface sensor 196 that is installed at an ideal position obtained from a design drawing is denoted by h1 in
As described above, the driving amount of the lifter motor 190 until the uppermost sheet S reaches the position of the sheet surface sensor 196 after the intermediate plate 192 is lifted up varies between apparatuses. Thus, the overloading determination unit 210 of the present embodiment calculates a differential value between an actual measurement value and a reference value of the driving amount of the lifter motor 190 and corrects a threshold on the basis of a result of the calculation, thereby improving accuracy for determination of overloading.
A method for determining overloading according to the present embodiment will be described below. The determination method of the present embodiment is obtained by adding a step of correcting a threshold to the determination method of the comparative example.
In
The calculation unit 214 calculates a differential amount by subtracting a reference value from the driving amount (actual measurement value) of the lifter motor 190 measured by the second measurement unit 234. Here, the reference value is a driving amount of the lifter motor 190 until the intermediate plate 192 is detected by the sheet surface sensor 196 at the ideal position after the intermediate plate 192 positioned at the lowest position starts to be lifted up, corresponds to (a2−a1) in
The driving amount of the lifter motor 190 measured by the second measurement unit 234 corresponds to (a3−a0) in
The correction unit 211 corrects a threshold for determining overloading, which is stored in the storage unit 215, on the basis of the differential amount calculated by the calculation unit 214. In the present embodiment, a method for correcting the threshold by adding the differential amount to the threshold which has been already stored is used. After the threshold is corrected, the determination unit 212 performs the determination of overloading by the method described in the comparative example, that is, by comparing the driving amount of the lifter motor 190 measured by the first measurement unit 232 to the corrected threshold.
Next, cooperative processing of the lift-up control unit 230 and the overloading determination unit 210 will be described with reference to flowcharts of
When the option feeding cassette 152 is attached to the printer 101, the engine control unit 200 requests the first control unit 231 to start initial lift-up control (S400). As described above, the first control unit 231 executes the initial lift-up control in response to the request. Then, the engine control unit 200 notifies the first measurement unit 232 of start of the initial lift-up control (S401). After that, the engine control unit 200 waits for end of the initial lift-up control by the first control unit 231 (S402), and when the end of the initial lift-up control is notified from the first control unit 231, the engine control unit 200 notifies the first measurement unit 232 of the end of the initial lift-up control (S403).
When the start of the initial lift-up control is notified from the engine control unit 200, the first measurement unit 232 firstly acquires a current step number Step1 of the lifter motor 190 (S420). Next, the first measurement unit 232 waits until the end of the initial lift-up control is notified (S421). When the end of the initial lift-up control is notified from the engine control unit 200, the first measurement unit 232 acquires a current step number Step2 of the lifter motor 190 (S422). Then, the first measurement unit 232 uses Step1 and Step2 to calculate, as a first driving amount, a driving amount (aS1=Step2−Step1) of the lifter motor 190 during the initial lift-up control (S423). Note that, the driving amount aS1 of the lifter motor 190 illustrated in
When the initial lift-up control ends, the engine control unit 200 requests the determination unit 212 to determine overloading (S404). In response to the request, the determination unit 212 determines overloading. Note that, the determination processing of overloading by the determination unit 212 will be described later with reference to
After the determination of overloading by the determination unit 212 ends, the engine control unit 200 notifies the second measurement unit 234 of the end of the determination of overloading (S405). Upon the notification, the second measurement unit 234 starts measurement of a second driving amount. Then, the engine control unit 200 and the second measurement unit 234 measure the second driving amount in cooperation with each other.
When a printing instruction is given from the video controller 250, the engine control unit 200 checks that there is a sheet S in the option feeding cassette 152 by the sheet presence sensor 154 (S406) and performs feeding from the option feeding cassette 152 (S407). By repeating feeding in response to the printing instruction from the video controller 250, the sheet surface of the sheet S loaded on the intermediate plate 192 of the option feeding cassette 152 is gradually lowered. Thus, when the sheet surface sensor 196 is not able to detect the sheet S, the engine control unit 200 determines that a height of the sheet surface needs to be corrected and requests the second control unit 233 to start additional lift-up control (S408). The engine control unit 200 notifies the second measurement unit 234 of start of the additional lift-up control (S409). Then, the engine control unit 200 waits for end of the additional lift-up control by the second control unit 233 (S410), and when the end of the additional lift-up control is notified from the second control unit 233, the engine control unit 200 notifies the second measurement unit 234 of the end of the additional lift-up control (S411).
The engine control unit 200 repeatedly performs the feeding control and the additional lift-up control until the sheet S on the intermediate plate 192 of the option feeding cassette 152 is out (S406). The state where the sheet S of the option feeding cassette 152 is out is able to be detected by the sheet presence sensor 154. Note that, when the sheet S of the option feeding cassette 152 is out, the engine control unit 200 notifies, to the second measurement unit 234, that the sheet S is out (S412). After that, the engine control unit 200 requests the calculation unit 214 to calculate a differential amount (S413) and requests the correction unit 211 to correct a threshold (S414). Operations of the calculation unit 214 and the correction unit 211 will be described later with reference to
The second measurement unit 234 starts processing after the end of the determination of overloading is notified from the engine control unit 200. When the end of the determination of overloading is notified from the engine control unit 200, the second measurement unit 234 receives the driving amount aS1 of the lifter motor 190 during the initial lift-up control, which is measured by the first measurement unit 232, and substitutes the driving amount aS1 to the second driving amount (aS2=aS1) (S430). Next, the second measurement unit 234 acquires a current step number Step3 of the lifter motor 190. After that, the second measurement unit 234 waits for start of the additional lift-up control being notified from the engine control unit 200 (S432). When the start of the additional lift-up control is notified, the second measurement unit 234 waits until end of the additional lift-up control is notified from the engine control unit 200 (S433). When the end of the additional lift-up control is notified from the engine control unit 200, the second measurement unit 234 acquires a current step number Step4 of the lifter motor 190. Then, the second measurement unit 234 uses Step3 and Step4 to calculate a driving amount (Step4−Step3) of the lifter motor 190 during the additional lift-up control and adds the driving amount to the second driving amount (aS2=aS2+(Step4−Step3)) (S435).
Through such processing, a sum of the driving amount of the lifter motor 190 during the initial lift-up control and the driving amount of the lifter motor 190 during the additional lift-up control (for one time) serves as a new second driving amount. Note that, until it is notified from the engine control unit 200 that the sheet S is out (S436), the second measurement unit 234 repeatedly measures the driving amount of the lifter motor 190 during the additional lift-up control, adds the driving amount to the second driving amount, and sequentially updates the second driving amount. As a result, the second measurement unit 234 measures, as the second driving amount, a cumulative driving amount of the lifter motor 190 until the sheet S of the option feeding cassette 152 is out after the option feeding cassette 152 is attached to the printer 101. In this manner, the engine control unit 200, the first measurement unit 232, and the second measurement unit 234 measure the first driving amount and the second driving amount in cooperation with each other.
Next, an operation of the determination unit 212 will be described with reference to a flowchart of
Note that, in a case where the determination unit 212 determines that the sheets S are overloaded, the engine control unit 200 stops a feeding operation by the pickup roller 153 even when a printing instruction is received. This makes it possible to prevent occurrence of unnecessary sheet jamming. Further, the engine control unit 200 causes the operation panel 302 to display a message indicating the overloading, so that it is possible to notify a user of occurrence of the overloading.
Next, the operation of the calculation unit 214 will be described with reference to a flowchart of
Next, the operation of the correction unit 211 will be described with reference to a flowchart of
The new corrected threshold th is used for determination of overloading by the determination unit 212 at the time of next initial lift-up control (S404 of
Thus, according to the present embodiment, it is possible to accurately determine whether or not a recording material is overloaded without influence of a variation factor between apparatuses.
Note that, though the control for determining overloading has been described by taking the option feed cassette 152 as an example in Embodiment 1, there is no limitation thereto. The invention may be applied to control for determining overloading of the feeding cassette 102. In this case, the intermediate plate 194 of the feeding cassette 102 is different from the intermediate plate 192 of the option feeding cassette 152 and is not configured to be lifted up or lowered by the wire 191. As the configuration of the feeding cassette 102, for example, a configuration in which an arm member (not illustrated) is operated via a gear train connected to the lifter motor 193 so that the intermediate plate 194 is pushed up from below, or the like is considered. Thus, it is considered that there is no influence of a variation factor between apparatuses that is caused, for example, when a slack of the wire 191 is eliminated, and elongation of the wire 191 due to elasticity or backlash of the wire reel 197 is eliminated. However, as an error is generated in the installation position of the sheet surface sensor 195 in the feeding cassette 102 as well, overloading is able to be determined more accurately by applying aspects of the invention.
The method for accurately determining overloading at the time of next initial lift-up control by correcting a threshold with use of a differential amount that is previously calculated has been described in Embodiment 1. However, as spring characteristics and the like of the wire 191 change in accordance with an environment (temperature, humidity) where the printer 101 is used, when a use environment is different from that in a previous lift-up operation, the driving amount of the lifter motor 190 varies and accuracy for determination of overloading may be reduced.
Then, in the present embodiment, by assuming a variation due to a difference of the use environment of the printer 101, an average value of a plurality of differential amounts that are calculated in past is obtained, a threshold is corrected on the basis of the average value, and overloading is accurately determined. As description for a main part is similar to that of Embodiment 1, only a part different from that of Embodiment 1 will be described here. Note that, it is premised in the present embodiment that the option feeding cassette 152 is configured to lift up or lower the intermediate plate 192 by the wire 191.
Operations of the engine control unit 200, the first measurement unit 232, and the second measurement unit 234 in the present embodiment are similar to those of Embodiment 1 (
Next, an operation of the calculation unit 214 in the present embodiment will be described with reference to a flowchart of
Next, an operation of the correction unit 211 in the present embodiment will be described with reference to a flowchart of
Thus, according to the present embodiment, by calculating an average value of differential amounts, it is possible to reduce influence of a variation due to a use environment of an apparatus and accurately determine whether or not a recording material is overloaded.
Note that, though description has been given with use of simple average of differential amounts in Embodiment 2, there is no limitation thereto. For example, by adopting a method for calculating an average value of a plurality of differential amounts that are stored except for a maximum value and a minimum value, a variation of the differential amounts is also able to be further reduced. Though description has been given by assuming that the number of pieces of data of differential amounts stored in the storage unit 215 is five, there is no limitation thereto.
A differential amount calculated in Embodiment 1 varies in accordance with a height (loading amount) of a sheet bundle loaded on the intermediate plate 192 of the option feeding cassette 152. A relation therebetween will be described in detail with reference to
In
Thus, in the present embodiment, the correction unit 211 calculates the height of the sheet bundle from the number and thickness of sheets S that are fed, and corrects the differential amount in accordance with the calculated height of the sheet bundle. Through the correction based on the height of the sheet bundle, the differential amount not depending on the height of the loaded sheet bundle is calculated. As description for a main part is similar to that of Embodiment 1, only a part different from that of Embodiment 1 will be described here. Note that, it is premised in the present embodiment that the option feeding cassette 152 is configured to lift up or lower the intermediate plate 192 by the wire 191.
Operations of the engine control unit 200, the first measurement unit 232, and the second measurement unit 234 in the present embodiment are similar to those of Embodiment 1 (
Next, an operation of the calculation unit 214 in the present embodiment will be described with reference to a flowchart of
When the differential amount dS calculated at S601 corresponds to d2 in
height of loaded sheet bundle: p1=number of times of feeding×thickness of sheet S(for one sheet) (Equation 1)
Next, the calculation unit 214 calculates a differential amount correction value dS′ in accordance with (Equation 2) (S1202). The differential amount correction value dS′ corresponds to (d3−d2) in
differential amount correction value: dS′=α×(p2−p1) (Equation 2)
α: correction coefficient
p1: height of sheet bundle calculated by (Equation 1)
p2: height of sheet bundle corresponding to maximum loading amount
Note that, in (Equation 2), α is stored in the storage unit 215 in advance and is a value specific to an apparatus. In
Thus, according to the present embodiment, it is possible to calculate a differential amount in a situation where determination as overloading is to be performed regardless of the loading amount of sheets S, thus making it possible to accurately determine whether or not a recording material is overloaded.
Note that, in Embodiment 3, though the calculated differential amount is corrected in accordance with a linear equation obtained in advance as illustrated in
Though the differential amount is corrected in accordance with the height of loaded sheet bundle in Embodiment 3, there is no limitation thereto. As a total weight of the sheets S changes also in accordance with a size of the sheets S or a basis weight of the sheets S, it is possible to cause the video controller 250 to notify the size of the sheets S or the basis weight of the sheets S and correct the differential amount on the basis of such sheet type information (characteristic information) of the sheets S.
Though description has been given in Embodiment 3 by taking a configuration in which sheet type information is notified from the video controller 250 as an example, there is no limitation thereto. For example, it may be configured so that an optical sensor that radiates light to a sheet S and detects a light quantity of light transmitting the sheet S may be arranged in a conveyance path of the printer 101 so that a thickness of the sheet S is automatically detected.
It may be also configured so that a plurality of differential amounts corrected in accordance with the loading amount are used by combining Embodiments 2 and 3 to determine whether or not a recording material is overloaded.
Though control for calculating a driving amount in accordance with a step number by using a stepping motor as the lifter motor 190 has been described in Embodiments 1 to 3 above, there is no limitation thereto. A type of a motor is not limited as long as the motor has a configuration which allows measurement of a driving amount of the motor. For example, a configuration in which a motor itself does not have a unit configured to detect a rotation status of the motor, but an encoder is provided in a rotation shaft of the motor to enable measurement of a driving amount of the motor may be used.
Though control for correcting a threshold on the basis of a differential amount calculated by the correction unit 211 has been described in Embodiments 1 to 3 above, there is no limitation thereto. Determination of overloading may be performed with a method for subtracting a differential amount from a first driving amount and comparing the resultant to a fixed threshold without changing the threshold.
Though a configuration in which the engine control unit 200 is provided in the printer main body 300 has been described in Embodiments 1 to 3 above, there is no limitation thereto. The engine control unit 200 may be provided in the feeding option device 301. When the engine control unit 200 is provided in the feeding option device 301, the engine control unit 200 has, instead of the image formation control unit 220 described in
Though a laser beam printer is indicated as an example in Embodiments 1 to 3 above, the image forming apparatus to which aspects of the invention are applied is not limited thereto and a printer employing another printing system, such as an ink-jet printer, or a copier may be used.
While aspects of the present invention have been described with reference to exemplary embodiments, it is to be understood that aspects of the invention are not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2016-233346 filed Nov. 30, 2016, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-233346 | Nov 2016 | JP | national |
