JP7196466B2 - IMAGE FORMING APPARATUS AND IMAGE FORMING APPARATUS CONTROL METHOD - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an image forming apparatus, and more particularly to sheet transport control in an image forming apparatus.

2. Description of the Related Art Some types of image forming apparatuses, such as printers and multifunction peripherals, use toner for development. An image forming apparatus using these toners uses a photosensitive member to directly or indirectly transfer toner for development onto a sheet of paper, which is a transfer medium, and then transfers the toner onto the sheet of paper with a fixing roller. It is common to fix the toner.

In recent years, as image forming apparatuses have become quieter, faster, and compatible with a wider range of media, there has been a demand for high reliability of paper feeding from the paper feeding unit. In addition, in order to improve convenience, when paper feeding is interrupted, it is also required to accurately present the cause of paper feeding interruption to the user. That is, it is desirable to identify the cause of interruption of paper feeding by presenting the cause of paper outage, paper jam, etc. to the user, and to enable easy recovery to normal state.

For example, Japanese Unexamined Patent Application Publication No. 2002-60092 (Patent Document 1) discloses that "a sheet containing means for stacking and containing a plurality of sheets of paper, and the sheets are fed one by one from the sheet containing means based on a paper feed start signal. A paper feeding mechanism that feeds paper to the tip, a paper jam detecting means that detects whether or not the paper sent out from the paper containing means by the paper feeding mechanism has passed, and a topmost paper contained in the paper containing means. No paper detection means for detecting presence/absence of paper in the storage means by movement of a movably touching rocking member, display means for displaying required information, paper feeding mechanism, paper jam detection means, and no paper detection means. and a control means for determining whether there is a paper jam or no paper based on the detection information from each detection means, and for displaying the result of the determination on the display means. After judging that there is a paper jam based on the detection information from the paper jam detection means, suspends the display of the judgment result on the display means until a predetermined time elapses, and during that suspension, the detection from the no paper detection means is performed. When it is determined from the information that there is no paper, the display of the determination result is preferentially set to be executed" (paragraph [0009]).

JP-A-2002-60092

According to the technique disclosed in Japanese Patent Application Laid-Open No. 2002-200312, it is possible to prevent erroneous detection of a paper jam as a paper jam only in a configuration such as a paper feed cassette in which a paper-empty detection sensor can be arranged upstream to some extent from the paper feed mechanism. can be prevented.

However, in a configuration such as a manual feed tray, a sensor for detecting the length of the sheet placed on the manual feed tray in the transport direction (hereinafter referred to as an "FD (Feed Dimension) detection sensor") and a tray. It is necessary to install both a sensor that detects whether or not paper is loaded (hereinafter referred to as an "empty detection sensor"), and due to the configuration, the empty detection sensor must be placed near the paper feed mechanism. Therefore, in applications that require high-speed paper feeding with a short paper feed interval, the interval between the paper being transported and the following paper is very short, so the empty detection sensor cannot detect it in time, and the empty paper is considered a paper jam. False detection may occur. Therefore, there is a need for a technology for preventing erroneous detection of paper jams that can be applied to manual feed trays.

The present disclosure has been made in view of the above background, and an object in one aspect is to provide a technique for preventing erroneous detection of out-of-paper as a paper jam in a paper feeding mechanism such as a manual feed tray. to do.

An image forming apparatus according to a certain aspect includes a manual feed tray on which a plurality of sheets are placed, a paper transport section for transporting the paper from the manual feed tray, and a sheet placed on the manual feed tray provided in the manual feed tray. A paper length detection section for detecting the length in the conveying direction and a control section for controlling the image forming apparatus are provided. The controller delays the start of transport of the succeeding paper by a predetermined time when the detection result of the paper length detector changes while the paper transporter is transporting the paper.

In one aspect, the image forming apparatus further includes an empty detection unit that is arranged along the paper transport path and detects the presence or absence of paper set in the manual feed tray. Due to the delay in the start of transport of the succeeding paper, transport of the succeeding paper starts after the empty detection unit detects the presence or absence of the paper.

In one aspect, the image forming apparatus further includes a display section that displays information to the user. If the control unit judges that the paper in the manual feed tray has run out during the paper feeding operation based on the detection result of the paper length detection unit, it displays the paper out information on the display unit regardless of the detection result of the empty detection unit. do.

In one aspect, the image forming apparatus further includes a display section that displays information to the user. When the detection result of the paper length detection unit changes during the paper feeding operation and the empty detection unit detects paper exhaustion, the control unit displays paper exhaustion information on the display unit.

In one aspect, the image forming apparatus further includes a paper width detection section that detects the width of the paper in the transport direction. The control section determines the paper size based on the detection results of the paper length detection section and the paper width detection section.

In one aspect, the control section adjusts the predetermined time based on the detection results of the paper length detection section and the paper width detection section.

In one aspect, the image forming apparatus further includes an operation unit that receives input from a user. When the paper size is input by the operation unit, the control unit adjusts the predetermined time based on the input paper size regardless of the detection results of the paper length detection unit and the paper width detection unit. .

In one aspect, the paper length detection unit is arranged below the paper set in the manual feed tray.

In one aspect, the paper length detection unit includes a transmissive sensor and a light shielding part of the transmissive sensor.

According to another embodiment, a control method in an image forming apparatus is provided. This control method includes the steps of detecting paper placed in a transportable position on the manual feed tray, transporting the paper from the manual feed tray via rollers, and following the paper transported via the rollers. and when the length of the paper placed in the transportable position on the manual feed tray cannot be detected while the paper is being transported via the rollers, the paper following the rollers is and delaying the drive to convey for a predetermined time.

In one aspect, the control method further includes the step of restarting the driving of the rollers after the presence or absence of subsequent paper is detected by a delay.

In one aspect, the control method detects the presence or absence of subsequent paper when the length in the transport direction of the paper placed at a transportable position on the manual feed tray cannot be detected while the paper is being transported via the rollers. The step of displaying out-of-paper information regardless of the detection of is also included.

In one aspect, the control method makes it impossible to detect the length in the transport direction of the paper placed at a transportable position on the manual feed tray while the paper is being transported via the rollers, and the following paper runs out. The further step of displaying out-of-paper information when detected.

According to the present technology, it is possible to prevent erroneous detection of out of paper as a paper jam in a paper feeding mechanism such as a manual feed tray.

The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings.

1 is a configuration diagram showing a configuration example of image forming apparatus 100 according to the present embodiment; FIG. 1 is a configuration diagram showing a configuration example of manual feed tray 101 of image forming apparatus 100 according to the present embodiment. FIG. 2 is a configuration diagram showing one configuration example of FD detection sensor 201 of image forming apparatus 100 according to the present embodiment. FIG. FIG. 4 is a diagram showing the operation of sensors and rollers in each stage of paper transport; FIG. 5 is a diagram showing how a sheet is conveyed in stage A of FIG. 4; FIG. 5 is a diagram showing how a sheet is conveyed in stage B of FIG. 4; FIG. 5 is a diagram showing how a sheet is conveyed in stage C of FIG. 4; FIG. 5 is a diagram showing how a sheet is conveyed in stage D of FIG. 4; FIG. 5 is a diagram showing how a sheet is conveyed at stage E of FIG. 4; FIG. 5 is a diagram showing how a sheet is conveyed in stage F of FIG. 4; 4 is a flow chart showing transport delay control according to the present embodiment; 5 is a flow chart showing processing for preventing erroneous determination of paper out and paper jam according to the present embodiment.

Hereinafter, embodiments of the technical concept according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First embodiment]
<A. Apparatus Configuration of Image Forming Apparatus 100>
First, the configuration of image forming apparatus 100 according to the present embodiment will be described. As a typical example, an image forming apparatus 100, which is a color image forming apparatus implemented as a multi-function peripheral (MFP), will be described, but the technical idea according to the present embodiment is limited to the color image forming apparatus. The present invention can also be applied to a monochrome image forming apparatus.

FIG. 1 is a diagram showing a configuration example of an image forming apparatus 100 according to this embodiment. Referring to FIG. 1, image forming apparatus 100 includes manual feed tray 101, paper feed cassette 102, paper feed roller 103, registration roller 104, imaging unit 105, intermediate transfer belt 106, and transfer roller 107. , a fixing unit 108 , an output tray 109 , and a control unit 110 .

The imaging unit 105 includes a photoreceptor, charging section, exposure section, and development section. Imaging unit 105 includes a plurality of imaging units for generating toner images of cyan (C), magenta (M), yellow (Y), and black (K).

Image forming apparatus 100 according to the present embodiment employs, as an example, a configuration in which toner images generated by respective imaging units 105 are transferred to a transfer receiving member via intermediate transfer belt 106 . In FIG. 1, the toner image is once transferred to the intermediate transfer belt 106 and then transferred to the transfer receiving member. good too.

Paper is placed on either the manual feed tray 101 or the paper feed cassette 102 . A paper feed roller 103 conveys sheets placed on the manual feed tray 101 or the paper feed cassette 102 one by one to a paper conveying path. The registration roller 104 conveys the paper conveyed by the paper feed roller 103 further downstream. A transfer roller 107 transfers the transfer image on the intermediate transfer belt 106 onto the conveyed paper. A fixing unit 108 melts the toner transferred to the surface of the paper and fixes it to the paper. The sheet on which fixing processing has been completed is discharged to the discharge tray 109 . Control unit 110 controls the overall operation of image forming apparatus 100 .

<B. Configuration of Manual Feed Tray 101>
FIG. 2 is a diagram showing a configuration example of manual feed tray 101 of image forming apparatus 100 according to the present embodiment. Referring to FIG. 2, manual feed tray 101 includes an FD detection sensor 201, a paper width detection sensor 202, a push-up plate 203, an empty detection sensor 204, and a double feed prevention member 205. FIG.

The FD detection sensor 201 is arranged on the manual feed tray 101 so as to come under the paper, and includes a projecting portion configured to sink under the weight of the paper. The protruding portion sinks under the weight of the paper placed on the manual feed tray. A paper width detection sensor 202 detects the width of the sandwiched paper. The control unit 110 automatically determines standard paper sizes such as A4 and A3 from the detection results of the paper width detection sensor 202 and the FD detection sensor 201 . The FD detection sensor 201 also detects whether or not the paper is placed at an appropriate position.

The push-up plate 203 rotates about the fulcrum Z and pushes up the leading edge of the paper placed on the manual feed tray 101 to a position where it touches the paper feed roller 103 . An empty detection sensor 204 detects the presence or absence of paper on the manual feed tray 101 . The double feed prevention member 205 is for preventing a plurality of sheets from being conveyed by the paper feed roller at the same time.

<C. Configuration of FD detection sensor 201>
FIG. 3 is a diagram showing a configuration example of FD detection sensor 201 of image forming apparatus 100 according to the present embodiment. Referring to FIG. 3, FD detection sensor 201 includes transmissive sensor 301 and light blocking part 302 . Also, the FD detection sensor 201 is provided inside the manual feed tray 101 .

When no paper is placed on the manual feed tray 101 , the torsion coil spring lifts the projecting portion of the light shielding part 302 from the hole 303 to the upper side of the manual feed tray 101 . In this state, the light shielding part 302 blocks the light from the transmissive sensor 301, so the input to the FD detection sensor 201 is turned off.

On the other hand, when paper is placed on the manual feed tray 101, the weight of the paper sinks the projecting portion of the light shielding part 302. As shown in FIG. As a result, the portion of the light shielding part 302 blocking the light from the transmissive sensor 301 is lifted, so that the input to the FD detection sensor 201 is turned ON.

Note that the configuration of the FD detection sensor 201 is not limited to that shown in FIG. 3, and any sensor other than a transmissive sensor may be used as long as it can detect that a sheet has been placed. The input of the FD detection sensor 201 is turned ON when no paper is placed on the manual feed tray 101, and the input of the FD detection sensor 201 is turned OFF when paper is placed on the manual feed tray 101. You may do so.

<D. Paper Conveyance Control>
FIG. 4 is a diagram showing the operation of each sensor and each roller in each stage of paper conveyance. 5 to 10, the operation of each section of the image forming apparatus 100 in each conveying stage of FIG. 4 will be described. Note that the control unit 110 reads inputs from various sensors and controls the rotation of various rollers.

FIG. 5 is a diagram showing an arrangement example of the manual feed tray 101 and peripheral parts of the manual feed tray 101 of the image forming apparatus 100, and also shows a paper transport state at stage A in FIG. It is a figure which shows. The registration roller 104 conveys the paper conveyed by the paper feed roller 103 toward the transfer roller 107 . Paper 501 , paper 502 and paper 503 are positioned inside image forming apparatus 100 or on manual feed tray 101 .

The registration roller 104 is conveying the paper 501 at the position of the primary conveyance start 401 in stage A of FIG. Also, the leading edge of the paper 502 is positioned at the paper feed roller 103 . In this state, the control unit 110 determines that there is paper in the manual feed tray 101 based on the input from the empty detection sensor 204 . Further, the FD detection sensor 201 is pushed down by the weight of the paper, and the control unit 110 determines that there is a paper at a transportable position on the manual feed tray 101 based on the input of the FD detection sensor 201 .

The control unit 110 starts rotating the paper feed roller 103 to convey the paper 502 . After conveying the paper 502 until the leading edge of the paper 502 reaches the position of the registration roller 104 , the control unit 110 stops the rotation of the paper feed roller 103 .

FIG. 6 is a diagram showing how the paper is conveyed at stage B in FIG. At stage B in FIG. 4 , the control unit 110 finishes conveying the paper 501 by the registration rollers 104 before the leading edge of the paper 502 reaches the registration rollers 104 . Next, the control unit 110 stops the rotation of the registration rollers 104 and, shortly thereafter, stops the rotation of the paper feed rollers 103 . By doing this, even if the leading edge of the paper 502 reaches the position of the registration roller 104, the registration roller 104 does not immediately convey the paper 502, so that an appropriate gap is provided between the paper 501 and the paper 502. be done. In this embodiment, the appropriate interval is, for example, an interval that does not allow two sheets of paper to be transported simultaneously by one roller. The feeding roller 103 conveying the leading edge of the paper placed on the manual feed tray 101 to the position of the registration roller 104, as in stages A to B, is referred to as the primary conveyance in order to distinguish it from the secondary conveyance, which will be described later. called transport.

FIG. 7 is a diagram showing how the paper is conveyed at stage C in FIG. At the secondary transport start position 402 in stage C of FIG. By doing so, the leading edge of the paper 502 is conveyed further ahead of the position of the registration roller 104 . After the paper feed roller 103 finishes conveying the paper 502 , the control unit 110 stops the rotation of the paper feed roller 103 . Even after the paper feed roller 103 stops rotating, the control unit 110 continues to rotate the registration roller 104 to start the next primary transport. As in stage C, the registration rollers 104 conveying the leading edge of the paper ahead of the registration rollers 104 is called secondary conveyance.

FIG. 8 is a diagram showing how the paper is conveyed at stage D in FIG. At the position of the primary transport start 403 in stage D of FIG. As the paper 503 is conveyed, the protruding portion of the FD detection sensor 201 is lifted. When the projecting portion of the FD detection sensor 201 is lifted and the input of the FD detection sensor 201 is turned off, the control unit 110 determines based on the input of the FD detection sensor 201 that there is no paper in the transportable position of the manual feed tray 101. do. More precisely, the controller 110 determines that there is no paper following the paper 503 that is currently being conveyed, and that the paper 503 is the final paper.

FIG. 9 is a diagram showing how the paper is conveyed at stage E in FIG. At stage E in FIG. 4 , the control unit 110 finishes conveying the sheet 501 by the registration rollers 104 before the leading edge of the sheet 503 reaches the registration rollers 104 as in stage B. FIG. After that, the control unit 110 stops the rotation of the registration rollers 104 , and shortly thereafter stops the rotation of the paper feed rollers 103 .

FIG. 10 is a diagram showing how the paper is conveyed at stage F in FIG. The control unit 110 starts rotating both the paper feed roller 103 and the registration roller 104 at the position of the secondary conveyance start 404 in FIG. By doing so, the control unit 110 causes the paper feed roller 103 and the registration roller 104 to convey the leading edge of the paper 503 further ahead of the position of the registration roller 104 . After the paper feed roller 103 finishes conveying the paper 502 , the control unit 110 stops the rotation of the paper feed roller 103 . The controller 110 continues to rotate the registration rollers 104 to start the next primary transport.

Originally, the control unit 110 starts rotating the paper feed roller 103 at the position of the primary conveyance delay control 405 . However, if the control unit 110 determines that there is no paper based on the input from the empty detection sensor 204 before the position of the primary transport delay control 405, the control unit 110 causes the paper feed roller 103 to start rotating. transport processing is stopped immediately.

However, the interval between sheets to be conveyed may be very short, and detection by the empty detection sensor 204 may be delayed. In that case, the control unit 110 starts rotating the paper feed roller 103 without stopping the transport process. In this case, since the paper to be conveyed does not exist on the manual feed tray 101, the paper will not be conveyed to the position of the registration roller 104 even after a certain period of time has passed.

If the leading edge of the paper is not conveyed to the position of the registration roller 104 within a certain period of time after the rotation of the paper feed roller 103 has started, the controller 110 erroneously determines that a paper jam has occurred, and performs image formation. Information notifying that a paper jam has occurred is displayed on the liquid crystal monitor of the apparatus 100 or the like.

In order to prevent an erroneous determination due to the detection delay of the empty detection sensor 204, in the present embodiment, when the FD detection sensor 201 determines that there is no succeeding paper, the control unit 110 moves to the position shown in FIG. Like X, the start of rotation of the paper feed roller 103 is delayed for a certain period of time (for example, a period of time sufficient for the detection processing of the empty detection sensor 204 to be completed). By doing so, the empty detection sensor 204 can complete detection of the presence or absence of paper before the control unit 110 starts rotating the paper feed roller 103 . As a result, the control unit 110 can complete the paper depletion determination based on the input of the empty detection sensor 204 before the paper jam determination, thereby eliminating erroneous determination of the paper depletion as a paper jam. can be done. Note that the control unit 110 may change the delay time according to each paper size determined by the FD detection sensor 201 and the paper width detection sensor 202 . For paper whose size cannot be automatically determined by the FD detection sensor 201 and the paper width detection sensor 202, the control unit 110 determines the paper size and sets the delay time according to the operation of the user's operation button or touch panel. may

<E. Flowchart of Transport Delay Control>
FIG. 11 is a flowchart showing carrier delay control according to this embodiment. With reference to FIG. 11, an example of the flow of conveying delay control for preventing erroneous determination of out of paper and paper jam will be described.

In step S1105, when control unit 110 detects a paper feed start signal (YES in step S1105), control proceeds to step S1110. The paper feed start signal is generated, for example, by the user operating an operation button or touch panel of the image forming apparatus 100 . If the paper feed start signal is not detected (NO in step S1105), control unit 110 repeats step S1105 and continues to wait for the paper feed start signal. Alternatively, control unit 110 may terminate the process instead of waiting for the paper feed start signal.

In step S<b>1110 , control unit 110 determines whether paper is placed on manual feed tray 101 based on an input from empty detection sensor 204 . When control unit 110 determines that no paper is detected by empty detection sensor 204 and paper is placed on manual feed tray 101 (NO in step S1110), control proceeds to step S1115. If control unit 110 determines that empty detection sensor 204 detects no paper and that manual feed tray 101 has no paper (YES in step S1110), control proceeds to step S1140.

In step S1115, the control unit 110 starts rotating the paper feed roller 103 for primary transport control. When the leading edge of the transported paper reaches the position of the registration roller 104 , the control unit 110 stops the rotation of the paper feed roller 103 .

In step S<b>1120 , based on the input from the FD detection sensor 201 , the control unit 110 determines whether or not the sheet is at a conveyable position on the manual feed tray 101 . The determination may be made based on the input from the FD detection sensor 201 and the input from the empty detection sensor 204 . Note that control unit 110 may perform the process of step S1120 without waiting for the process of step S1115 to be completed. If the protrusion of the FD detection sensor 201 remains pressed down by the weight of the paper, the signal from the FD detection sensor 201 does not change, so the control unit 110 determines that the paper is at a transportable position. On the other hand, when the last sheet of paper is conveyed and the protrusion of the FD detection sensor 201 is raised, the signal of the FD detection sensor 201 changes. judge. When control unit 110 determines that the paper is at a transportable position on manual feed tray 101 (NO in step S1120), control proceeds to step S1130. When control unit 110 determines that the sheet is not at a conveyable position on manual feed tray 101 (YES in step S1120), control proceeds to step S1125.

In step S1130, the control unit 110 rotates the paper feed roller 103 and the registration roller 104 for secondary transport, and transports the paper transported in step S1115 toward the transfer roller 107. FIG.

In step S1125, the control unit 110 sets a delay for the start time of the primary transportation, such as setting a flag on the program, and then shifts the control to step S1130. In the present embodiment, the delay setting refers to the setting of delaying the start time of the primary transport from the original time. For example, the control unit 110 delays the start time of the next primary transportation by a time sufficient for the detection processing by the empty detection sensor 204 to be completed after the secondary transportation. In step S1135, the control unit 110 performs the primary transportation delay processing only when the delay setting of the primary transportation start time is performed. When the control unit 110 delays the primary transport, the start timing of the next primary transport is later than normal. The primary transfer is never started first.

The primary transport and secondary transport of the paper are completed by the processing from steps S1115 to S1135. Thereafter, control unit 110 repeats the process from step S1110 until the specified number of sheets have been conveyed.

In step S<b>1140 , control unit 110 determines whether or not the specified number of sheets have been conveyed based on the input from the operation buttons of image forming apparatus 100 . If control unit 110 determines that the process of transporting the designated number of sheets has been completed (YES in step S1140), the process ends. If control unit 110 determines that the conveying process for the specified number of sheets has not been completed (NO in step S1140), control proceeds to step S1145.

In step S<b>1145 , control unit 110 displays information indicating that the paper has run out on the liquid crystal screen of image forming apparatus 100 or the like. In step S1150, control unit 110 suspends the paper feeding operation. In step S1155, control unit 110 waits until paper is replenished. When the empty detection sensor 204 and the FD detection sensor 201 detect that a new sheet has been placed, the control unit 110 shifts the control to step S1105.

As described in detail above, image forming apparatus 100 according to the present embodiment prevents erroneous detection of out of paper as paper jam even in a paper feeding mechanism such as a manual feed tray, and provides correct information to the user. It can be displayed and the convenience can be improved.

[Second embodiment]
A second embodiment will be described below. The hardware configuration of image forming apparatus 100 according to the present embodiment is the same as that of image forming apparatus 100 according to the first embodiment. Therefore, description of the hardware configuration will not be repeated.

FIG. 12 is a flowchart showing processing for preventing erroneous determination of paper jam and out of paper according to the present embodiment. With reference to FIG. 12, the flow of processing for preventing erroneous determinations of out of paper and paper jam will be described. The same reference numerals are assigned to the same processes as those shown in the flowchart of FIG. Therefore, description of the same processing will not be repeated.

In step S1205, when control unit 110 detects that the input of FD detection sensor 201 has changed (YES in step S1205), control unit 110 shifts the control to step S1140. According to the present embodiment, when the input of the FD detection sensor 201 is changed, the control unit 110 performs the paper-out determination processing without setting the delay processing of the primary paper feeding, unlike the first embodiment. is different.

According to the present embodiment, control unit 110 determines that the paper has run out when the input of FD detection sensor 201 changes after primary paper feeding has started. The FD detection sensor 201 is arranged at a position that matches the length of the sheet in the transport direction according to the standard. Input value changes. Therefore, if the control unit 110 uses the FD detection sensor 201 instead of the empty detection sensor 204 and determines that the paper has run out when the input of the FD detection sensor 201 changes, paper jams can be easily detected. It is possible to prevent erroneous judgment of cutting.

However, this embodiment can be applied to standard-sized paper such as A4, and the first embodiment is used for postcard-sized paper and non-standard-sized paper. is preferable.

In another aspect, the first embodiment and the second embodiment are used in combination, and the process according to the second embodiment is performed only on sheets of a standard size such as A4. The processing according to the first embodiment may be applied to other sheets.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

100 image forming apparatus, 101 manual feed tray, 102 paper feed cassette, 103 paper feed roller, 104 registration roller, 105 imaging unit, 106 intermediate transfer belt, 107 transfer roller, 108 fixing section, 109 discharge tray, 110 control section, 201 FD Detection sensor 202 Paper width detection sensor 203 Lifting plate 204 Empty detection sensor 205 Double feed prevention member 301 Transmissive sensor 302 Light shielding part 303 Hole 402, 404 Start of secondary transport 405 Delay control of secondary transport , 501, 502, 503 paper.

Claims (13)

An image forming apparatus,
a manual feed tray on which a plurality of sheets are placed;
a paper transport unit for transporting paper from the manual feed tray;
a paper length detection unit provided on the manual feed tray for detecting the length of the paper placed on the manual feed tray in the conveying direction;
A control unit that controls the image forming apparatus,
The image forming apparatus according to claim 1, wherein, when the detection result of the sheet length detecting section changes while the sheet is being conveyed by the sheet conveying section, the control section delays the start of conveying the succeeding sheet by a predetermined time. further comprising an empty detection unit arranged in the paper transport unit and configured to detect the presence or absence of paper set in the manual feed tray;
2. The image forming apparatus according to claim 1, wherein the delay causes the subsequent sheet to start to be transported after the empty detection unit detects the presence of the sheet. further comprising a display for displaying information to the user,
When the control unit determines that the paper in the manual feed tray has run out during the paper feeding operation based on the detection result of the paper length detection unit, the paper is displayed on the display unit regardless of the detection result of the empty detection unit. 3. The image forming apparatus according to claim 2, wherein the information of the cut is displayed. further comprising a display for displaying information to the user,
3. The control unit displays information about the lack of paper on the display unit when the detection result of the paper length detection unit changes during the paper feeding operation and the empty detection unit detects the paper shortage. 2. The image forming apparatus according to 2 above. Further equipped with a paper width detection unit that detects the width of the paper in the transport direction,
5. The image forming apparatus according to claim 1, wherein said control section determines a paper size based on detection results of said paper length detection section and said paper width detection section. 6. The image forming apparatus according to claim 5, wherein said control unit adjusts said predetermined time based on detection results of said paper length detection unit and said paper width detection unit. further comprising an operation unit for receiving input from the user,
When a paper size is input by the operation unit, the control unit determines the predetermined paper size based on the input paper size regardless of the detection results of the paper length detection unit and the paper width detection unit. 7. The image forming apparatus according to claim 6, wherein the time is adjusted. The image forming apparatus according to any one of claims 1 to 7, wherein the paper length detection section is arranged below the paper set on the manual feed tray. The image forming apparatus according to any one of claims 1 to 8, wherein the paper length detection section includes a transmissive sensor and a light shielding part of the transmissive sensor. a step of detecting paper placed on a manual feed tray at a transportable position;
conveying paper from the manual feed tray via rollers;
detecting the presence or absence of a sheet following the sheet conveyed through the roller;
When it becomes impossible to detect the length in the transport direction of the paper placed on the manual feed tray at a transportable position while the paper is being transported via the rollers, the rollers are driven to transport the subsequent paper. delaying for a predetermined time;
A control method in an image forming apparatus. 11. The control method according to claim 10, further comprising the step of resuming driving of said rollers after detecting the presence or absence of a succeeding sheet. If the length of the sheet placed on the manual feed tray at a transportable position cannot be detected while the sheet is being transported via the rollers, the sheet runs out regardless of the presence or absence of subsequent sheets. 12. The control method according to claim 11, further comprising the step of displaying the information of . When the length of the sheet placed on the manual feed tray at a transportable position becomes undetectable in the transport direction while the sheet is being transported via the rollers, and when the following sheet runs out is detected, the sheet runs out. 12. The control method of claim 11, further comprising displaying information.

Images