Image forming apparatus

Abstract

The present invention provides an image forming apparatus that can reduce the occurrence of the image forming operation starting before the paper supply to the paper feed tray is complete. [Solution] The paper presence / absence detection unit 14 detects the presence or absence of paper P on the paper feed tray 11. A pair of side fences 13 restrict the position of the paper P loaded on the paper feed tray in the paper width direction and are movable in the paper width direction. The fence position detection unit 15 detects the position of each of the pair of side fences 13. After the paper presence / absence detection unit 14 detects that there is no paper P on the paper feed tray 11, the control unit 7 determines that the supply of paper P to the paper feed tray 11 is complete when the fence position detection unit 15 detects that the distance between the pair of side fences 13 has increased and then decreased.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] An image forming apparatus provided with a plurality of paper feeding means such as a plurality of front paper feeding trays, a paper feed table, and a high-capacity paper feed table is known.

[0003] In such an image forming apparatus provided with a plurality of paper feeding means, when the same paper is set on each paper feeding means and printing is performed for a large number of sheets, when the paper in one paper feeding means runs out, the paper supply is automatically switched to the supply from another paper feeding means, and limitless paper feeding is performed to supply paper to the paper feeding means where the paper has run out (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an image forming apparatus provided with a plurality of paper feeding means as described above, when printing is performed using a paper feed table that supplies paper manually, if the paper runs out, the paper supply source is switched to another paper feeding means, and the printing job may end while replenishing the paper to the above paper feed table.

[0006] The paper to be loaded on the paper feed table can be loaded in multiple batches, and the printing job may end while a part of the paper to be loaded on the paper feed table (for example, one bundle of paper) is loaded.

[0007] In such cases, if the next job is received while paper is being replenished in the paper tray, the image forming operation may start with paper being fed from the tray that is still being replenished, preventing the paper replenishment from being completed properly. In addition, users may rush to load the paper, causing it to fold or bend, leading to a decrease in productivity.

[0008] Furthermore, in cases where only one job needed to be printed on a different colored paper, the machine would initially load the standard colored paper, and the image formation process for the next job would begin before the different colored paper was loaded, resulting in the inability to print on the desired paper.

[0009] Therefore, there was a need for a technology that could reduce the occurrence of image forming operations starting before the paper feed tray has been fully refilled.

[0010] The present invention has been made in view of the above, and aims to provide an image forming apparatus that can reduce the occurrence of the image forming operation starting before the paper supply to the paper feed tray is complete. [Means for solving the problem]

[0011] To achieve the above objective, the image forming apparatus of the present invention is characterized by comprising: a paper presence / absence detection unit that detects the presence or absence of paper on a paper feed tray on which paper is stacked; a fence that restricts the position of the paper stacked on the paper feed tray and is movable in a direction that restricts the position of the paper; a fence position detection unit that detects the position of the fence; and a determination unit that, after the paper presence / absence detection unit has detected that there is no paper on the paper feed tray, the fence moves to the side opposite to the side on which paper is stacked on the paper feed tray, and then moves to the side on which paper is stacked on the paper feed tray and is positioned in a position corresponding to the paper size, and the fence position detection unit has detected that this has completed the supply of paper to the paper feed tray. [Effects of the Invention]

[0012] According to the image forming apparatus of the present invention, when paper is supplied to the paper feed tray, it is possible to reduce the occurrence of the image forming operation starting before the paper supply is complete. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the image forming apparatus according to the first embodiment. [Figure 2] This is a flowchart illustrating the operation of the image forming apparatus when paper is supplied to the paper feed tray in the first embodiment. [Figure 3] This diagram illustrates the change in the position of a pair of side fences when paper is being supplied to the paper tray. [Figure 4] This is a flowchart illustrating the operation of the image forming apparatus when paper is supplied to the paper feed tray in the second embodiment. [Figure 5] This is a diagram showing the confirmation screen. [Figure 6] This is a flowchart illustrating the operation of the image forming apparatus when paper is supplied to the paper feed tray in the third embodiment. [Figure 7] This diagram illustrates the change in the position of a pair of side fences when they are pushed apart by the paper loaded on the paper tray. [Figure 8] This is a flowchart illustrating the operation of the image forming apparatus when paper is supplied to the paper feed tray in the fourth embodiment. [Figure 9] This is a flowchart illustrating the operation of the image forming apparatus when paper is supplied to the paper feed tray in the fifth embodiment. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals.

[0015] The embodiments described below illustrate devices and the like for embodying the technical idea of this invention, and the technical idea of this invention does not specify the materials, shapes, structures, arrangements, etc. of each component part as those described below. The technical idea of this invention can be variously modified within the scope of the claims.

[0016] [First Embodiment] FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention. In the following description, the direction orthogonal to the plane of FIG. 1 is defined as the front-rear direction, and the front side of the plane of the drawing is defined as the front. Also, the up-down and left-right directions in the plane of FIG. 1 are defined as the up-down and left-right directions.

[0017] As shown in FIG. 1, an image forming apparatus 1 according to the first embodiment includes an external paper feeding unit 2, an internal paper feeding unit 3, an image forming unit 4, a paper discharging unit 5, an operation panel unit 6, a control unit (corresponding to a determination unit) 7, and a housing 8 that houses or holds each unit.

[0018] The external paper feeding unit 2 feeds paper P to the image forming unit 4. The external paper feeding unit 2 includes a paper feed tray 11, a paper feed roller 12, a pair of side fences (corresponding to fences) 13, a paper presence / absence detection unit 14, and a fence position detection unit 15.

[0019] The paper feed tray 11 is for stacking paper P. A part of the paper feed tray 11 is exposed and installed outside the housing 8. Paper P is stacked on the paper feed tray 11 in a center alignment. The center alignment is an alignment that makes the center position of paper P coincide with the center position of the paper feed tray 11 in the front-rear direction. The paper feed tray 11 is configured to be able to move up and down.

[0020] The paper feed roller 12 takes out the paper P stacked on the paper feed tray 11 and conveys it to the image forming unit 4.

[0021] A pair of side fences 13 restrict the position of the paper P loaded on the paper feed tray 11 in the front-to-back direction (paper width direction). The pair of side fences 13 are erected on the paper feed tray 11 spaced apart from each other in the front-to-back direction, which is the direction in which the side fences 13 restrict the position of the paper P. The pair of side fences 13 are spaced equally apart from each other from the center of the paper feed tray 11 in the front-to-back direction. The pair of side fences 13 are configured to move in conjunction with each other in the front-to-back direction, symmetrically across the center of the paper feed tray 11 in the front-to-back direction, by manual operation by the user. That is, when one side fence 13 moves away from the center of the paper feed tray 11, the other side fence 13 also moves away from the center of the paper feed tray 11, and when one side fence 13 approaches the center of the paper feed tray 11, the other side fence 13 also moves closer to the center of the paper feed tray 11.

[0022] The paper presence detection unit 14 detects the presence or absence of paper P on the paper feed tray 11. The paper presence detection unit 14 turns on when paper P is loaded on the paper feed tray 11 and turns off when paper P is not loaded on the paper feed tray 11.

[0023] The fence position detection unit 15 detects the position of each of the pair of side fences 13 in the front-rear direction.

[0024] The internal paper feeding unit 3 feeds paper P to the image forming unit 4. The internal paper feeding unit 3 comprises a plurality of (two in the example in Figure 1) internal paper trays 21 and an internal paper transport unit 22.

[0025] The internal paper feed tray 21 is where the paper P is loaded. The internal paper feed tray 21 is located inside the housing 8.

[0026] The internal paper feed transport unit 22 takes out the paper P loaded in the internal paper feed tray 21 and transports it to the image forming unit 4.

[0027] The image forming unit 4 transports the paper P fed by the external paper feeding unit 2 or the internal paper feeding unit 3, and forms an image on the paper P.

[0028] The paper output unit 5 outputs the paper P on which the image has been formed by the image forming unit 4.

[0029] The control panel unit 6 includes a display unit 26 consisting of a liquid crystal display panel or the like that displays various screens, and an input unit 27 having operation buttons and a touch panel or the like that accept user input operations.

[0030] The control unit 7 controls the operation of each part of the image forming apparatus 1. The control unit 7 is composed of a CPU, RAM, ROM, hard disk, etc.

[0031] When paper P is being supplied to the paper feed tray 11, the control unit 7 determines that the supply of paper P to the paper feed tray 11 is complete when the paper presence detection unit 14 detects that there is no paper P on the paper feed tray 11, the distance between a pair of side fences 13 widens, and then the distance between them narrows, as detected by the fence position detection unit 15.

[0032] Furthermore, when the distance between a pair of side fences 13 increases, it corresponds to each side fence 13 moving to the side opposite to the side on which the paper P is loaded on the paper feed tray 11. Conversely, when the distance between a pair of side fences 13 decreases, it corresponds to each side fence 13 moving to the side on which the paper P is loaded on the paper feed tray 11. Here, for the front side fence 13, the rear side is the side on which the paper P is loaded on the paper feed tray 11. Also, for the rear side fence 13, the front side is the side on which the paper P is loaded on the paper feed tray 11.

[0033] Next, the operation of the image forming apparatus 1 when paper P is supplied to the paper feed tray 11 will be explained with reference to the flowchart in Figure 2.

[0034] The flowchart in Figure 2 begins when the paper presence detection unit 14 is turned off due to a paper shortage in the paper feed tray 11.

[0035] In step S1 of Figure 2, the control unit 7 determines whether the paper presence detection unit 14 is turned on or not. If it determines that the paper presence detection unit 14 is not turned on (step S1: NO), the control unit 7 repeats step S1.

[0036] If the paper presence detection unit 14 is determined to be turned on (step S1: YES), in step S2, the control unit 7 determines that paper P has been loaded onto the paper feed tray 11.

[0037] Next, in step S3, the control unit 7 determines whether the distance between the pair of side fences 13 has increased since the paper presence detection unit 14 was turned off. Here, the control unit 7 can grasp the change in the distance between the pair of side fences 13 based on the position detection signal from the fence position detection unit 15. If it is determined that the distance between the pair of side fences 13 has not increased (step S3: NO), the control unit 7 repeats step S3.

[0038] If the control unit determines that the distance between the pair of side fences 13 has increased (step S3: YES), in step S4, the control unit 7 determines that paper P is being supplied to the paper feed tray 11.

[0039] Next, in step S5, the control unit 7 determines whether the distance between the pair of side fences 13 has increased and then decreased to position them according to the paper size. If it determines that the distance between the pair of side fences 13 has not decreased to position them according to the paper size (step S5: NO), the control unit 7 repeats step S5.

[0040] Here, the control unit 7 determines that the pair of side fences 13 are positioned according to a standard paper size when they are positioned according to that size. Furthermore, if the user specifies a paper size, the control unit 7 determines that the pair of side fences 13 are positioned according to that size when they are positioned according to that size.

[0041] If the control unit 7 determines that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size (step S5: YES), then in step S6, the control unit 7 determines that the supply of paper P to the paper feed tray 11 is complete. This completes the series of operations.

[0042] When the control unit 7 determines that the supply of paper P to the paper feed tray 11 has been completed in step S6 described above, it raises the paper feed tray 11 to a height position where paper can be fed in order to start the image forming operation.

[0043] When the paper tray 11 runs out of paper P, the paper tray 11 lowers. When the user replenishes the paper tray 11 with paper P, before loading the paper P onto the tray, the user can operate the system to widen the distance between the pair of side fences 13 so that the distance is greater than the width of the paper P being replenished, as shown in Figure 3. In addition, the user may also widen the distance between the pair of side fences 13 after the paper P has been loaded onto the paper tray 11. When the distance between the pair of side fences 13 is widened, it is determined in step S3 of the flowchart in Figure 2 that the distance between the pair of side fences 13 has widened (step S3: YES).

[0044] After this, once all the paper P to be supplied has been loaded onto the paper tray 11, the distance between the pair of side fences 13 is narrowed, as shown in Figure 3, and the pair of side fences 13 are positioned according to the paper size. At this point, in step S5 of the flowchart in Figure 2 described above, it is determined that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size (step S5: YES). Then, it is determined that the supply of paper P to the paper tray 11 is complete (step S6).

[0045] As explained above, in the image forming apparatus 1, the control unit 7 determines that the supply of paper P to the paper feed tray 11 is complete when the paper presence detection unit 14 detects that there is no paper P on the paper feed tray 11, the distance between the pair of side fences 13 widens, and then the distance between them narrows, as detected by the fence position detection unit 15.

[0046] This reduces the likelihood of misjudging the timing of when the paper P has been replenished to the paper tray 11. As a result, it reduces the likelihood of the image forming operation starting before the paper P has been replenished.

[0047] Furthermore, this reduces the need to raise the paper feed tray 11 to perform the image forming operation before the paper supply P is complete, thus reducing the amount of wasted paper due to creases or bends caused by users rushing to load the paper P. It also reduces the decrease in productivity caused by creases or bends in the paper P.

[0048] [Second Embodiment] Next, a second embodiment, which modifies part of the first embodiment described above, will be explained.

[0049] Figure 4 is a flowchart illustrating the operation of the image forming apparatus 1 when paper P is supplied to the paper feed tray 11 in the second embodiment.

[0050] The processes in steps S11 to S16 in Figure 4 are the same as the processes in steps S1 to S6 in Figure 2 described above.

[0051] In step S15, if it is determined that the distance between the pair of side fences 13 has narrowed and they are not positioned according to the paper size (step S15: NO), then in step S17, the control unit 7 determines whether a predetermined time has elapsed since the distance between the pair of side fences 13 widened and the pair of side fences 13 have not moved. If it is determined that the predetermined time has not elapsed (step S17: NO), the control unit 7 returns to step S15.

[0052] If the control unit determines that a predetermined time has elapsed (step S17: YES), it determines that the replenishment of paper P is not complete, and in step S18, it displays the confirmation screen 31 shown in Figure 5 on the display unit 26.

[0053] The confirmation screen 31 displays a message 32 to prompt the user to confirm whether or not the paper supply P has been replenished.

[0054] After displaying the confirmation screen 31 in step S18, the control unit 7 returns to step S15 in Figure 4. In step S15, if it is determined that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size (step S15: YES), then in step S16, the control unit 7 determines that the supply of paper P to the paper tray 11 is complete. This completes the series of operations.

[0055] As described above, in the second embodiment, if a predetermined time has elapsed since the distance between the pair of side fences 13 widened and the pair of side fences 13 have not moved, the control unit 7 displays a confirmation screen 31 on the display unit 26 to allow the user to confirm whether or not the paper P replenishment is complete. This reduces the likelihood that a user who has replenished the paper P may forget to narrow the pair of side fences 13 to a position corresponding to the paper size.

[0056] [Third Embodiment] Next, a third embodiment, which modifies part of the first embodiment described above, will be explained.

[0057] Figure 6 is a flowchart illustrating the operation of the image forming apparatus 1 when paper P is supplied to the paper feed tray 11 in the third embodiment.

[0058] The processes in steps S21 to S23 in Figure 6 are the same as the processes in steps S1 to S3 in Figure 2 described above.

[0059] If, in step S23, it is determined that the distance between the pair of side fences 13 has increased (step S23: YES), then in step S24, the control unit 7 determines whether the difference in the distance between the pair of side fences 13 before and after the increase in distance is less than a predetermined value.

[0060] If it is determined that the value is less than a predetermined value (step S24: YES), in step S25, the control unit 7 determines whether the number of times the distance between the pair of side fences 13 has increased has reached a predetermined number of times. If it is determined that the predetermined number of times has not been reached (step S25: NO), the control unit 7 returns to step S23.

[0061] If the control unit determines that a predetermined number of times has been reached (step S25: YES), and if it determines in step S24 that the difference in the distance between the pair of side fences 13 before and after the distance between them widens is greater than or equal to a predetermined value (step S24: NO), the control unit 7 proceeds to step S26.

[0062] The processing in steps S26 to S28 is the same as the processing in steps S4 to S6 in Figure 2 described above.

[0063] Here, when paper P is supplied to the paper feed tray 11, the distance between a pair of side fences 13 may be narrower than the width of the paper P being supplied when the paper P is loaded onto the paper feed tray 11. In this case, the supplied paper P pushes the pair of side fences 13 apart, causing the distance between the pair of side fences 13 to gradually widen, as shown in Figure 7.

[0064] In this case, each time the distance between a pair of side fences 13 widens slightly, it is determined in step S24 of the flowchart in Figure 6 above that the distance between the pair of side fences 13 has widened by less than a predetermined value (step S24: YES). Then, when the number of times the distance between a pair of side fences 13 has widened by less than a predetermined value reaches a predetermined number of times (step S25: YES), it is determined that paper P is being supplied to the paper feed tray 11 (step S26).

[0065] After this, it is determined that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size (Step S27: YES), and it is determined that the supply of paper P to the paper tray 11 is complete (Step S28).

[0066] As described above, in the third embodiment, the control unit 7 determines that paper P is being supplied to the paper feed tray 11 when the number of times the distance between the pair of side fences 13 has widened to less than a predetermined value reaches a predetermined number of times. This makes it possible to determine whether or not paper P is being supplied even when paper P is loaded onto the paper feed tray 11 while the distance between the pair of side fences 13 is narrower than the width of the paper, causing the pair of side fences 13 to spread apart due to the paper P.

[0067] [Fourth Embodiment] Next, a fourth embodiment, which modifies part of the first embodiment described above, will be explained.

[0068] In the fourth embodiment, the image forming apparatus 1 is equipped with a buzzer (not shown) that emits a completion notification sound to notify the user that the replenishment of paper P is complete.

[0069] Figure 8 is a flowchart illustrating the operation of the image forming apparatus 1 when paper P is supplied to the paper feed tray 11 in the fourth embodiment.

[0070] The processes in steps S31 to S35 in Figure 8 are the same as the processes in steps S1 to S5 in Figure 2 described above.

[0071] In step S35, if it is determined that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size (step S5: YES), in step S36, the control unit 7 controls the buzzer to emit a completion notification sound.

[0072] Next, in step S37, the control unit 7 determines whether a predetermined waiting time has elapsed since it determined that a pair of side fences 13 have been positioned according to the paper size. If it determines that the waiting time has not elapsed (step S37: NO), the control unit 7 repeats step S37.

[0073] If the control unit determines that the waiting time has elapsed (step S37: YES), in step S38, the control unit 7 determines that the replenishment of paper P to the paper feed tray 11 is complete. This completes the series of operations.

[0074] As described above, in the third embodiment, when the control unit 7 determines that the distance between the pair of side fences 13 has narrowed and they are positioned according to the paper size, it controls the buzzer to emit a completion notification sound. This allows the user to be notified that the paper supply has been completed by the completion notification sound, even if it is not possible to visually confirm that the supply of paper P has been completed.

[0075] Furthermore, the control unit 7 determines that the replenishment of paper P is complete once a predetermined waiting time has elapsed since it determined that a pair of side fences 13 have been positioned according to the paper size. As a result, the paper feed tray 11 will not be raised to start the image forming operation until the waiting time has elapsed after the paper P has actually been replenished. This prevents the paper feed tray 11 from rising if the replenishment of paper P is not completed correctly or if the distance between the pair of side fences 13 is not properly narrowed.

[0076] [Fifth Embodiment] Next, a fifth embodiment will be described, which is a modified version of the fourth embodiment described above.

[0077] In the fifth embodiment, the buzzer (not shown) emits a cancellation notification sound, which is different from the completion notification sound, in addition to the completion notification sound, to notify the user that the paper supply completion status to the paper tray 11 has been canceled.

[0078] Figure 9 is a flowchart illustrating the operation of the image forming apparatus 1 when paper P is supplied to the paper feed tray 11 in the fifth embodiment.

[0079] The processes in steps S41 to S46 in Figure 9 are the same as the processes in steps S31 to S36 in Figure 8 described above.

[0080] When the buzzer sounds a completion notification tone in step S46, in step S47 the control unit 7 determines that the replenishment of paper P to the paper feed tray 11 is complete.

[0081] Next, in step S48, the control unit 7 determines whether the distance between the pair of side fences 13 has increased after determining that the supply of paper P has been completed.

[0082] If the control unit determines that the distance between the pair of side fences 13 has not increased (step S48: NO), in step S49, the control unit 7 determines whether a predetermined time has elapsed since it determined that the replenishment of paper P was complete. If it determines that the predetermined time has not elapsed (step S49: NO), the control unit 7 returns to step S48.

[0083] If the control unit determines that the distance between the pair of side fences 13 has increased (step S48: YES), in step S50, the control unit 7 controls the buzzer to emit a cancellation notification sound. After this, the control unit 7 returns to step S44.

[0084] In step S49, if the control unit 7 determines that a predetermined time has elapsed (step S49: YES), the series of operations ends.

[0085] Here, if the user cancels the paper replenishment completion status after completing the paper replenishment P, they widen the distance between the pair of side fences 13. When this operation is performed, in step S48 of the flowchart in Figure 9 described above, it is determined that the distance between the pair of side fences 13 has widened (step S48: YES). Then, a cancellation notification sound is emitted (step S50).

[0086] As described above, in the fifth embodiment, if the control unit 7 determines that the distance between a pair of side fences 13 has increased between the time a predetermined period has elapsed since it determined that the replenishment of paper P was complete, it controls the buzzer to emit a cancellation notification sound. This allows the user to immediately confirm that the paper replenishment completion state has been canceled and to take appropriate action, such as aligning the paper P.

[0087] [Other embodiments] As described above, the present invention has been described by the first to fifth embodiments, but the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples and operational techniques will become apparent to those skilled in the art from this disclosure.

[0088] In the image forming apparatus 1 of the first to fifth embodiments described above, an end fence may be added, which is a fence that can move in the left-right direction and is erected on the paper feed tray 11, and which contacts the upstream end (left end) of the paper P to restrict the position of the paper P in the transport direction (left-right direction). In this case, after the presence or absence detection unit 14 detects that there is no paper P on the paper feed tray 11, the distance between the pair of side fences 13 widens and the end fence moves upstream (left side), and then the distance between the pair of side fences 13 narrows and the end fence moves downstream (right side). When it is detected that the pair of side fences 13 and the end fence are positioned according to the paper size, it can be determined that the supply of paper P to the paper feed tray 11 is complete.

[0089] Here, when the end fence moves upstream (to the left), it corresponds to the end fence moving to the side opposite to the side on which the paper P is loaded on the paper feed tray 11. Conversely, when the end fence moves downstream (to the right), it corresponds to the end fence moving to the side on which the paper P is loaded on the paper feed tray 11.

[0090] Alternatively, the pair of side fences 13 of the image forming apparatus 1 in the first to fifth embodiments may be omitted, and the above-described end fence may be provided instead. In this case, after the presence or absence detection unit 14 detects that there is no paper P on the paper feed tray 11, the end fence moves to the upstream side (left side), and then, when it is detected that the end fence has moved to the downstream side (right side) and positioned according to the paper size, it can be determined that the supply of paper P to the paper feed tray 11 is complete.

[0091] Thus, it goes without saying that the present invention includes various embodiments and the like that are not described herein. Therefore, the technical scope of the present invention is defined solely by the inventive features relating to the claims that are reasonable based on the above description.

[0092] [Note] This application discloses the following invention:

[0093] (Note 1) A paper presence / absence detection unit that detects the presence or absence of paper on the paper feed tray where the paper is stacked, A fence that restricts the position of paper stacked on the aforementioned paper feed tray, and which is movable in the direction that restricts the position of the paper, A fence position detection unit for detecting the position of the fence, After the paper presence detection unit detects that there is no paper on the paper feed tray, the fence moves to the side opposite to the side where paper is stacked on the paper feed tray, and then moves to the side where paper is stacked on the paper feed tray and is positioned according to the paper size, as detected by the fence position detection unit, the determination unit determines that the supply of paper to the paper feed tray is complete. An image forming apparatus characterized by comprising: [Explanation of Symbols]

[0094] 1. Image forming apparatus 2 External paper feed section 3 Internal paper feed section 4 Image forming unit 5. Paper output section 6. Control Panel 7 Control Unit 8 cabinets 11 Paper feed tray 12 Paper feed rollers 13 Side fence 14. Paper presence / absence detection unit 15 Fence position detection unit 21 Internal paper feed tray 22 Internal paper feed transport section 26 Display section 27 Input section 31 Confirmation screen 32 messages

Claims

[Claim 1] A paper presence / absence detection unit that detects the presence or absence of paper on the paper feed tray where the paper is stacked, A fence that restricts the position of paper stacked on the aforementioned paper feed tray, and which is movable in the direction that restricts the position of the paper, A fence position detection unit for detecting the position of the fence, After the paper presence detection unit detects that there is no paper on the paper feed tray, the fence moves to the side opposite to the side where paper is stacked on the paper feed tray, and then moves to the side where paper is stacked on the paper feed tray and is positioned according to the paper size, as detected by the fence position detection unit, the determination unit determines that the supply of paper to the paper feed tray is complete. An image forming apparatus characterized by comprising:

Images