Image forming apparatus

Abstract

To simplify a configuration to detect the presence or absence and the size of a medium compared to before.SOLUTION: An image forming apparatus (U) comprises: accommodation means (TR1) that accommodates a medium (S); output means (1) that outputs an electromagnetic wave toward the medium (S); receiving means (2) that receives the electromagnetic wave output from the output means (1) and reflected subsequently; and discrimination means (C1) that calculates the distance to the medium (S) on the basis of the electromagnetic wave received by the receiving means (2), to discriminate the size of the medium (S) and the presence or absence of the medium (S) in the accommodation means (TR1).SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] 2. Description of the Related Art With regard to a storage means for storing a medium on which an image is recorded in an image forming apparatus, the techniques described in Patent Documents 1 and 2 below are conventionally known.

[0003] Patent Document 1 describes a technology in which a detection means (3) detects the presence or absence of a sheet (P) in the vicinity of the rear end in the sheet supply direction inside a sheet stacking tray (1). In Patent Document 1, the detection means (3) is attached to an end guide (5) that determines the position of the rear end of the sheet (P). In other words, when the position of the end guide (5) moves according to the size of the sheet (P), the detection means (3) also moves integrally.

[0004] Patent Document 2 describes a configuration in which a paper presence / absence sensor (63) is installed at the rear end, in the paper travel direction, of a guide plate (61) of a paper feed unit. In Patent Document 2, the paper presence / absence sensor (63) monitors the presence or absence of paper from the start of the paper feed operation until a predetermined timeout period has elapsed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-327174 A ("0008"-"0011", Figure 1) [Patent Document 2] JP 2007-137653 A ("0047"-"0056", Figs. 6 and 8) Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has a technical object to simplify the configuration for detecting the presence and size of a medium compared to the conventional configuration. [Means for solving the problem]

[0007] In order to solve the above technical problem, the image forming apparatus according to the invention described in claim 1 comprises: A storage means for storing a medium; an output means for outputting an electromagnetic wave toward the medium; a receiving means for receiving the electromagnetic wave reflected after being output from the output means; a determining means for calculating a distance to the medium based on the electromagnetic waves received by the receiving means and determining a size of the medium and whether or not the medium is present in the storage means; The present invention is characterized by comprising:

[0008] The invention described in claim 2 is the image forming apparatus described in claim 1, a first reflecting means disposed in the accommodation means for reflecting the electromagnetic wave having passed through the accommodation space of the medium; The present invention is characterized by comprising:

[0009] The invention described in claim 3 is the image forming apparatus described in claim 2, the first reflecting means disposed corresponding to one end of the medium opposite to the other end of the medium closer to the receiving means; The present invention is characterized by comprising:

[0010] The invention described in claim 4 is the image forming apparatus described in claim 3, a support means for supporting a lower surface of the medium and for lifting the medium as the medium is fed; a first passing means provided on the supporting means and through which the electromagnetic wave can pass; the first reflecting means disposed at a position where the electromagnetic wave that has passed through the first passing means arrives; The present invention is characterized by comprising:

[0011] The invention described in claim 5 is the image forming apparatus described in claim 1, a guide means movably supported within the receiving means for guiding an edge of the medium; a second passage means provided in the guide means and through which the electromagnetic wave can pass; The present invention is characterized by comprising:

[0012] The invention described in claim 6 is the image forming apparatus described in claim 5, a second reflection means supported by the guiding means and movable between a second closing position where the second reflection means closes the second passing means and reflects the electromagnetic wave when the second reflection means comes into contact with the medium contained in the container means, and a second opening position where the second reflection means opens the second passing means and allows the electromagnetic wave to pass when the container means is empty of medium; The present invention is characterized by comprising:

[0013] The invention described in claim 7 is the image forming apparatus described in claim 1, a third passage means provided in the containing means and through which the electromagnetic wave can pass; The present invention is characterized by comprising:

[0014] The invention described in claim 8 is the image forming apparatus described in claim 7, the storage means being detachable from a main body of the image forming apparatus; a third reflection means movable between a third open position where the third passing means is opened to pass the electromagnetic wave when the storage means is attached to the main body of the image forming apparatus, and a third closing position where the third passing means is closed to reflect the electromagnetic wave when the storage means is detached from the main body of the image forming apparatus; The present invention is characterized by comprising: Effect of the Invention

[0015] According to the invention as recited in claim 1, the configuration for detecting the presence and size of a medium can be simplified compared to the conventional configuration. According to the invention as recited in claim 2, the presence or absence of a medium can be determined based on the electromagnetic wave reflected by the first reflecting means. According to the invention as recited in claim 3, the presence or absence of the medium can be determined based on the electromagnetic wave reflected by the first reflecting means arranged on the side farther from the receiving means, rather than the size of the medium. According to the invention as recited in claim 4, it is possible to determine the presence or absence of a medium when the support means has moved to a position for lifting the medium.

[0016] According to the invention recited in claim 5, the size of the medium can be determined based on the electromagnetic wave reflected at the position of the second passing means. According to the sixth aspect of the invention, the presence or absence of a medium can be determined more reliably based on the electromagnetic wave reflected by the second reflecting means, compared to a case in which the second reflecting means is not provided. According to the invention as recited in claim 7, the presence or absence of the container means can be determined based on the electromagnetic wave reflected at the position of the third passing means. According to the invention described in claim 8, the presence or absence of the storage means can be determined based on the electromagnetic waves reflected by the third reflecting means. Therefore, the size of the medium, the presence or absence of the medium, and the presence or absence of the storage means can be determined by one set of output means and receiving means. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram of an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing a state in which no recording sheets remain. [Diagram 3] FIG. 3 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing a state in which recording sheets are accommodated. [Figure 4] FIG. 4 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing the state in which the paper feed tray is pulled out. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Next, examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples. In order to make the following explanation easier to understand, in the drawings, the front-to-back direction (width direction of the medium) is defined as the X-axis direction, the left-to-right direction (direction of medium transport) is defined as the Y-axis direction, and the up-down direction is defined as the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, -Z are defined as the front, rear, right, left, upper, and lower, or the front side, rear side, right side, left side, upper side, and lower side, respectively. In addition, in the figures, a "·" inside a "○" means an arrow going from the back to the front of the page, and an "×" inside a "○" means an arrow going from the front to the back of the page. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding. EXAMPLES

[0019] FIG. 1 is an explanatory diagram of an image forming apparatus according to a first embodiment of the present invention. In Fig. 1, a printer U as an example of an image forming apparatus of the present invention has a device main body U1. A control board SC on which various control circuits and storage media are arranged is arranged at the bottom of the printer U. The control board SC is provided with a control unit C that performs various controls of the printer U, an image processing unit GS whose operation is controlled by the control unit C, a write drive circuit DL as an example of a drive circuit for a latent image forming device, and a power supply circuit E as an example of a power supply device. The power supply circuit E applies voltages to charging rollers CRy, CRm, CRc, CRk as an example of a charging means, developing rollers G1y, G1m, G1c, G1k as an example of a developer holding means, and primary transfer rollers T1y, T1m, T1c, T1k as an example of a transfer means.

[0020] The image processing unit GS converts printing information input from a personal computer PC or the like, which is an example of an image information transmitting device electrically connected to the device main body U1, into image information for forming latent images corresponding to images of the four colors of yellow, magenta, cyan, and black, i.e., Y, M, C, and K, and outputs the information to the write drive circuit DL at a preset time. When the original image is a single-color image, that is, a monochrome image, image information of only black color is input to the write drive circuit DL. The write drive circuit DL has drive circuits for each color Y, M, C, and K (not shown), and outputs signals corresponding to the input image information at preset times to LED heads LHy, LHm, LHc, and LHk, which are examples of latent image forming means arranged for each color.

[0021] In Fig. 1, above the control board SC, imaging devices UY, UM, UC, and UK are arranged as an example of an imaging means for forming images (toner images) of each color of yellow, magenta, cyan, and black. In Fig. 1, the imaging device UK for black, i.e., K color, has a photoconductor Pk as an example of an image holding means. Around the photoconductor Pk, there are arranged a charging roller CRk for charging the surface of the photoconductor Pk, an LED head LHk for forming an electrostatic latent image on the surface of the photoconductor Pk, a developing device Gk as an example of a developing means for developing the latent image on the surface of the photoconductor Pk, and a photoconductor cleaner CLk as an example of an image holding means for removing developer remaining on the surface of the photoconductor Pk. The other color imagers UY, UM, UC are configured similarly to the black imager UK.

[0022] The photoconductors Py, Pm, Pc, and Pk have their surfaces uniformly charged by charging rollers CRy to CRk in charging areas Q1y, Q1m, Q1c, and Q1k that face the charging rollers CRy to CRk, and then latent images are written by LED heads LHy to LHk in latent image forming areas Q2y, Q2m, Q2c, and Q2k. The written electrostatic latent images are developed into toner images in development areas Q3y, Q3m, Q3c, and Q3k that face developing devices Gy, Gm, Gc, and Gk. The developed toner images are transported to primary transfer areas Q4y, Q4m, Q4c, and Q4k that come into contact with an intermediate transfer belt B, which is an example of an intermediate transfer body. A primary transfer voltage of opposite polarity to the toner charging polarity is applied to primary transfer rollers T1y-T1k, which are examples of primary transfer means arranged on the back side of intermediate transfer belt B in the primary transfer areas Q4y-Q4k, at a preset time from a power supply circuit E controlled by control unit C.

[0023] The toner images on the photoconductors Py to Pk are primarily transferred onto the intermediate transfer belt B by the primary transfer rollers T1y to T1k. After the primary transfer, residual toner, discharge products, and other adhering matter on the surfaces of the photoconductors Py to Pk are cleaned by photoconductor cleaners CLy, CLm, CLc, and CLk. The cleaned surfaces of the photoconductors Py to Pk are recharged by charging rollers CRy to CRk. The charging rollers CRy to CRk are in contact with charging cleaners CCy, CCm, CCc, and CCk, which are an example of a cleaning means for a charging member. Therefore, the charging cleaners CCy to CCk remove residues and the like that are not completely removed by the photoconductor cleaners CLy to CLk and that are attached to the charging rollers CRy to CRk from the photoconductors Py to Pk.

[0024] 1, a belt module BM as an example of an intermediate transfer unit is disposed above the photoconductors Py to Pk. The belt module BM has an intermediate transfer belt B as an example of an image holding means and an example of an intermediate transfer means. The intermediate transfer belt B is rotatably supported by an intermediate transfer support system including a belt driving roll Rd as an example of a driving means, a backup roll T2a as an example of a driven means and an example of a secondary transfer opposing means, and the primary transfer rollers T1y to T1k disposed opposite the photoconductors Py to Pk. In front of the intermediate transfer belt B, a belt cleaner CLb is disposed as an example of a cleaning unit for the intermediate transfer body.

[0025] A secondary transfer roll T2b as an example of a secondary transfer means is disposed facing the surface of the intermediate transfer belt B in contact with the backup roll T2a. The backup roll T2a and the secondary transfer roll T2b constitute the secondary transfer device T2 of Example 1. The opposing area of ​​the secondary transfer roll T2b and the intermediate transfer belt B forms a secondary transfer area Q5. The single-color or multi-color toner images transferred in succession onto the intermediate transfer belt B by the primary transfer rollers T1y to T1k in the primary transfer areas Q4y to Q4k are transported to the secondary transfer area Q5. The primary transfer rollers T1y to T1k, the intermediate transfer belt B, the secondary transfer device T2, and the like constitute a transfer device T1+T2+B as an example of the transfer means of the first embodiment.

[0026] A paper feed tray TR1 as an example of a medium storage means is provided below the control board SC. A lift plate PL1 as an example of a support means is arranged on the paper feed tray TR1. Recording sheets S as an example of a medium can be stacked on the upper surface of the lift plate PL1. The front end of the lift plate PL1 is raised by a lift spring PL2 as an example of a first biasing means during printing, thereby raising the front end of the recording sheet S. A pickup roll Rp as an example of a take-out means is arranged above the front side of the lift plate PL1. The pickup roll Rp contacts the uppermost recording sheet S of the stack of stacked recording sheets S when the lift plate PL1 is moved to the raised position. A separation roll Rs as an example of a separation means is arranged in front of the pickup roll Rp. The separation roll Rs has a feed roll Rs1 as an example of a transport means and a retard roll Rs2 as an example of a separation means. The feed roll Rs1 arranged on the upper side transports the uppermost recording sheet S downstream. The retard roll Rs2 separates the recording sheet S fed overlapping the uppermost recording sheet S.

[0027] Therefore, the recording sheets S loaded on the paper feed tray TR1 are sent out by the pickup roll Rp and separated one by one by the separation roll Rs. The recording sheets S sent by the feed roll Rs1 are transported to a first paper feed path SH6, which is an example of a medium transport path, by a transport roll Ra, which is an example of a transport means. At the upper end of the first paper feed path SH6, a registration roll Rr, which is an example of a transport means and an example of a member for adjusting the paper feed timing, is disposed. The registration roll Rr sends out the recording sheets S toward the secondary transfer area Q5 in accordance with the timing at which the toner image on the intermediate transfer belt B reaches the secondary transfer area Q5.

[0028] The toner image on the intermediate transfer belt B is transferred onto the recording sheet S, which is fed through the medium transport path SH toward the secondary transfer area Q5, as it passes through the secondary transfer area Q5. After the toner image is transferred to the intermediate transfer belt B in the secondary transfer area Q5, the intermediate transfer belt B is cleaned by the belt cleaner CLb to remove residual toner and discharge products remaining on the surface of the intermediate transfer belt B. The recording sheet S onto which the toner image has been transferred is transported to a fixing area Q6 of a fixing device F as an example of a fixing means. The fixing device F has a heating roll Fh as an example of a heating means and a pressure roll Fp as an example of a pressure means. The fixing area Q6 is formed by an area where the heating roll Fh and the pressure roll Fp are in contact with each other at a preset pressure. The unfixed toner image on the surface of the recording sheet S is fixed by heat and pressure when passing through the fixing area Q6. The recording sheet S on which the image has been fixed is discharged from a discharge roller Rh, which is an example of a medium discharge means, onto a discharge tray TRh.

[0029] In front of the discharge roller Rh, an additional connection path SH1 for reversal is formed as an example of a transport path, branching off from the media transport path SH and extending forward, and a gate GT1 as an example of a switching means is disposed at the branch point between the additional connection path SH1 and the media transport path SH. In the printer U of the first embodiment, a reversing unit U5 is supported on the rear surface of the device body U1. Inside the reversing unit U5, a reversing path SH2 as an example of a second conveying path is formed. The upstream end of the reversing path SH2 is connected to the right end of the additional connection path SH1 of the device body U1. The downstream end of the reversing path SH2 merges with the first paper feed path SH6 on the upstream side of the registration roll Rr of the device body U1. Therefore, when double-sided printing is performed, the recording sheet S with an image recorded on one side is transported along the medium transport path SH, and when the trailing end in the transport direction passes through the gate GT1, the discharge roller Rh rotates in the reverse direction, and the recording sheet S is sent to the additional connection path SH1 and the reversing path SH2. The recording sheet S is then transported by a transport roll Ra, which is an example of a transport member arranged on the reversing path SH2, and is sent again to the registration roll Rr in an inverted state.

[0030] In the printer U of the first embodiment, a second paper feed path SH7 as an example of a transport path is formed in front of the paper feed tray TR1. The second paper feed path SH7 extends in the vertical direction. The upper end of the second paper feed path SH7 is connected to the lower end of the first paper feed path SH6. The second paper feed path SH7 is configured so that when an additional paper feed tray is installed below the paper feed tray TR1, the recording sheet S can pass through from below.

[0031] (Description of the paper feed tray) FIG. 2 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing a state in which no recording sheets remain. FIG. 3 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing a state in which recording sheets are accommodated. FIG. 4 is an explanatory diagram of a main part of the paper feed tray according to the first embodiment, showing the state in which the paper feed tray is pulled out. 2 to 4, the device body U1 of the printer U of the first embodiment supports an optical sensor SN1 as an example of a detection means. The optical sensor SN1 is disposed at the rear of the paper feed tray TR1. The optical sensor SN1 has a light emitting unit 1 as an example of an output means and a light receiving unit 2 as an example of a receiving means. The light emitting unit 1 and the light receiving unit 2 are disposed close to each other in the horizontal direction. The light emitting unit 1 outputs light as an example of an electromagnetic wave. The wavelength of the electromagnetic wave to be output can be appropriately changed depending on the material of the recording sheet S as the measurement object, the material of the shielding object described later, and the like, and the purpose of reflecting, transmitting, or shielding the electromagnetic wave. Therefore, light such as visible light, infrared light, or ultraviolet light, radio waves such as microwaves, radiation, etc. can be selected depending on the purpose. The light receiving unit 2 can receive and detect reflected light or scattered light output from the light emitting unit 1.

[0032] A first reflector 12 as an example of a first reflecting means is supported on the inner surface of the front wall 11 of the paper feed tray TR1 in the embodiment 1. The first reflector 12 is made of a material that reflects the light of the optical sensor SN1. The lift-up plate PL1 is formed with a plate opening 13 as an example of a first passage means. The plate opening 13 in the first embodiment is formed in accordance with the position, height and range through which the light from the optical sensor SN1 passes when the lift-up plate PL1 is in the most elevated state, i.e., when there is no recording sheet S.

[0033] An end guide 16, which is an example of a guide means, is disposed at the rear of the paper feed tray TR1. The end guide 16 positions the rear end of the recording sheet S stored in the paper feed tray TR1 in the transport direction. Therefore, the end guide 16 is supported within the paper feed tray TR1 so as to be movable in the front-rear direction, i.e., along the sheet transport direction. A guide opening 17 as an example of a second passage means is formed in the end guide 16 of the first embodiment. The guide opening 17 is formed corresponding to the height and range through which the light from the optical sensor SN1 passes.

[0034] A second reflector 18 as an example of a second reflecting means is supported on the end guide 16. The second reflector 18 is disposed on the front side of the end guide 16, that is, on the side where the recording sheet S is accommodated. The upper end of the second reflector 18 is rotatably supported on the end guide 16. The second reflector 18 of the first embodiment is configured to be rotatable between a second closing position (see the broken line in FIG. 2) where the guide opening 17 is closed and a second opening position (see the solid line in FIG. 2) where the guide opening 17 is opened. In addition, a guide spring 19 as an example of a second biasing means is attached between the second reflector 18 and the end guide 16. The guide spring 19 applies a force to move the second reflector 18 toward the second opening position when no external force is acting on the second reflector 18. The rear side of the second reflector 18 is made of a material that reflects the light of the optical sensor SN1. Therefore, when the recording sheets S are stored, the second reflector 18 moves to the second closed position, and when the recording sheets S are gone, the second reflector 18 moves to the second open position. When the second reflector 18 moves to the second closed position, the light from the optical sensor SN1 is reflected by the second reflector 18.

[0035] A tray opening 22 as an example of a third passage means is formed in the rear wall 21 of the paper feed tray TR1. The tray opening 22 is formed to correspond to the height and range through which the light from the optical sensor SN1 passes. In the apparatus main body U1, with the sheet feed tray TR1 attached, a third reflector 26 as an example of a third reflecting means is disposed between the rear wall 21 and the optical sensor SN1. The third reflector 26 has a reflector body 26a and a contact portion 26b. The third reflector 26 is supported rotatably around a rotation shaft 26c at the upper end. The rear side of the reflector body 26a is made of a material that reflects the light of the optical sensor SN1.

[0036] The third reflector 26 of the first embodiment is movable between a third closed position where the reflector body 26a enters the optical path of the light of the optical sensor SN1, and a third open position where the reflector body 26a leaves the optical path. In the third closed position, the tray opening 22 is blocked. Therefore, the light does not reach the tray opening 22 and is reflected by the reflector body 26a. In the third open position, the light can reach the tray opening 22. In the first embodiment, when the paper feed tray TR1 is attached, the contact portion 26b is pressed against the rear wall 21 of the paper feed tray TR1, and the third reflector 26 moves to the third open position. When the paper feed tray TR1 is removed forward, the contact portion 26b moves away from the rear wall 21, and the third reflector 26 moves to the third closed position by its own weight.

[0037] (Description of the control unit of the first embodiment) In FIG. 1, the control unit (controller) C, which is an example of a control means of the printer U, has an input / output interface I / O that inputs and outputs signals from and to the outside. The control unit C also has a ROM (read-only memory) in which programs and information for performing necessary processing are stored. The control unit C also has a RAM (random access memory) for temporarily storing necessary data. The control unit C also has a CPU (central processing unit) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit C in the first embodiment is composed of a small information processing device, a so-called microcomputer. Therefore, the control unit C can realize various functions by executing programs stored in the ROM or the like. The control unit C of the first embodiment receives signals from signal output elements such as the personal computer PC and the optical sensor SN1, and outputs signals to controlled elements such as the power supply circuit E and a motor (not shown) to control them.

[0038] The discrimination means C1 of the control unit C has a distance calculation means C1a, a presence / absence discrimination means C1b, an attachment / detachment discrimination means C1c, and a size discrimination means C1d as an example of a medium size discrimination means, and calculates the distance to the recording sheet S based on the detection result of the optical sensor SN1, and discriminates the size of the recording sheet S and the presence or absence of the recording sheet S in the paper feed tray TR1. The distance calculation means C1a calculates a calculated distance L1, which is the distance to the position where the light is reflected, based on the light received by the light receiving unit 2. The calculated distance L1 can be calculated based on the time it takes for the light emitted by the light emitter 1 to be received by the light receiving unit 2 and the speed of light. The method of calculating the calculated distance L1 is not limited to this, and the calculated distance L1 can be calculated by any calculation method, such as a phase shift of the light wave.

[0039] The presence / absence discriminating means C1b discriminates the presence or absence of the recording sheet S in the paper feed tray TR1 based on the first distance La from the optical sensor SN1 to the first reflector 12 and the calculated distance L1. That is, it discriminates whether the recording sheet S remains in the paper feed tray TR1 or not. When the recording sheet S does not remain, the third reflector 26 moves to the third open position, and the second reflector 18 moves to the second open position. Therefore, the light of the optical sensor SN1 passes through both the tray opening 22 and the guide opening 17. Then, when the lift plate PL1 is raised, the light reaches the first reflector 12 after passing through the plate opening 13. When the lift plate PL1 is lowered, the light passes above the lift plate PL1 and reaches the first reflector 12. Therefore, when there is no recording sheet S, the optical sensor SN1 detects the light reflected by the first reflector 12, and the calculated distance L1 becomes the first distance La.

[0040] If the recording sheet S remains, the second reflector 18 moves to the second closed position. Therefore, the light does not reach the first reflector 12. When the recording sheet S is reduced, the second reflector 18 may not be pressed by the rear end of the recording sheet S and may move to the second open position. Even in this case, if the lift plate PL1 moves to the raised position and the recording sheet S is present on the lift plate PL1, the plate opening 13 is blocked by the recording sheet S. Therefore, the light of the optical sensor SN1 does not reach the first reflector 12. Therefore, in either case, the calculated distance L1 is shorter than the first distance La. Therefore, the presence or absence of the recording sheet S can be determined based on the calculated distance L1 and the first distance La.

[0041] The attachment / detachment determination unit C1c determines whether the paper feed tray TR1 is attached to the device main body U1 based on the third distance Lc from the optical sensor SN1 to the third reflector 26 that has moved to the third closed position and the calculated distance L1. That is, it determines whether the paper feed tray TR1 is completely attached to the device main body U1, detached, or in an incompletely attached state. When the paper feed tray TR1 is not installed, the third reflector 26 moves to the third closed position. Therefore, the light of the optical sensor SN1 is reflected by the third reflector 26. Therefore, the calculated distance L1 of the optical sensor SN1 becomes the third distance Lc. When the paper feed tray TR1 is installed, the third reflector 26 moves to the third open position. Therefore, the light of the optical sensor SN1 passes through the tray opening 22. Therefore, the calculated distance L1 becomes longer than the third distance Lc. Therefore, it is possible to determine whether the paper feed tray TR1 is installed or removed based on the calculated distance L1 and the third distance Lc.

[0042] The size discrimination unit C1d discriminates the size of the recording sheet S based on the calculated distance L1. That is, if the calculated distance L1 is shorter than the first distance La and longer than the third distance Lc, it means that the light reflected by the second reflector 18 is detected. Therefore, it means that the calculated distance L1 based on the position of the end guide 16 where the second reflector 18 is supported, that is, the length (size) of the recording sheet S in the sheet conveying direction, is detected. Therefore, it is possible to detect the size of the recording sheet S by comparing the calculated distance L1 with the second distance Lb according to the paper standard such as A4 or B5.

[0043] It is preferable that the first distance La, the second distance Lb, and the third distance Lc are not limited to values ​​that exactly match the distances from the optical sensor SN1 to each reflector 12, 18, and 26, but are set to a numerical range (e.g., La±d1) that takes into account an error and margin d1. Furthermore, when light is irradiated to each of the reflectors 12, 18, 26 at a position intermediate between the open position and the closed position, the reflected light is not reflected toward the light receiving unit 2. Therefore, it is possible to process the calculated distance L1 as if it had not been calculated.

[0044] (Function of Example 1) In the printer U of Example 1 having the above configuration, the calculated distance L1 is used to detect the size and presence or absence of the recording sheet S with one optical sensor SN1. In a conventional configuration, a sensor for detecting the presence or absence of the recording sheet S and a sensor for detecting the size are installed separately, which poses a problem of an increased number of sensors. In contrast, in Example 1, it is possible to reduce the number of sensors compared to the conventional configuration. Therefore, it is possible to simplify the configuration for detecting the presence or absence and size of the recording sheet S compared to the conventional configuration. Furthermore, in a configuration in which the detection means (3) is installed in the end guide (5) as in Patent Document 1, it is necessary to arrange the wiring to the detection means (3) and to devise a way to prevent the wiring from getting pinched when the end guide (5) is moved according to the sheet size, which causes a problem of requiring a complex movable mechanism. In contrast, in Example 1, it is only necessary to form the openings 13, 17, and 22 in the lift plate PL1, the end guide 16, and the rear side wall 21, and no complex mechanism is required. Therefore, it is possible to simplify the configuration compared to the conventional configuration.

[0045] Furthermore, in the first embodiment, one optical sensor SN1 can detect the size and presence or absence of the recording sheet S, as well as the attachment or detachment of the paper feed tray TR1. Therefore, compared to the conventional configuration that required a sensor for detecting attachment or detachment, it is possible to further reduce the number of sensors. Therefore, it is possible to further simplify the configuration compared to the conventional configuration.

[0046] (Example of change) Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H06) of the present invention are illustrated below. (H01) In the above embodiment, a printer U was used as an example of an image forming device, but this is not limited to this and the image forming device may also be configured as, for example, a copier, a fax, or a multifunction device having multiple or all of these functions.

[0047] (H02) In the above embodiment, a configuration having four image forming devices UY to UK is illustrated, but the present invention is not limited to this and can be applied to a configuration having image forming devices of two colors, three colors, or five or more colors. (H03) In the above embodiment, the direction of irradiation of light from the optical sensor SN1 is illustrated as being along the transport direction of the recording sheet S, but is not limited thereto. It may also be in a direction intersecting the transport direction of the recording sheet S by 90 degrees. (H04) In the above embodiment, the optical sensor SN1 is preferably disposed in the device main body U1, but is not limited to this. It may also be disposed on the rear wall 21 or the front wall 11 of the paper feed tray TR1.

[0048] (H05) In the above embodiment, the second reflector 18 and the third reflector 26 are configured to rotate and move, but the present invention is not limited to this. For example, they may be configured to slide vertically. That is, the second reflector 18 may be configured to slide vertically due to the weight of the recording sheets S, and the third reflector 26 may be configured to slide vertically due to the weight of the paper feed tray TR1 when it is installed. (H06) In the above embodiment, it is also possible to configure the device to measure the size of the recording sheets S based on the reflected light from the recording sheets S that are stacked on the lift plate PL1 and blocking the guide opening 17, without providing the second reflecting plate 18. Note that, since the reflected light from the rear end of the recording sheets S tends to make the measurement unstable, it is desirable to provide the second reflecting plate 18. In this case, it is also possible to configure the device to detect the remaining amount of the stacked recording sheets S based on the amount of reflected light, etc.

[0049] (Additional Note) (((1))) A storage means for storing a medium; an output means for outputting an electromagnetic wave toward the medium; a receiving means for receiving the electromagnetic wave reflected after being output from the output means; a determining means for calculating a distance to the medium based on the electromagnetic waves received by the receiving means and determining a size of the medium and whether or not the medium is present in the storage means; An image forming apparatus comprising: (((2))) a first reflecting means disposed in the accommodation means for reflecting the electromagnetic wave having passed through the accommodation space of the medium; The image forming apparatus according to (((1))) is characterized by comprising: (((3))) the first reflecting means disposed corresponding to one end of the medium opposite to the other end of the medium closer to the receiving means; The image forming apparatus according to (((2))) is characterized by comprising: (((4))) a support means for supporting a lower surface of the medium and for lifting the medium as the medium is fed; a first passing means provided on the supporting means and through which the electromagnetic wave can pass; the first reflecting means disposed at a position where the electromagnetic wave that has passed through the first passing means arrives; The image forming apparatus according to (((3))) is characterized by comprising: (((5))) a guide means movably supported within the receiving means for guiding an edge of the medium; a second passage means provided in the guide means and through which the electromagnetic wave can pass; The image forming apparatus according to any one of ((1)) to ((4)) above, (((6))) a second reflection means supported by the guiding means and movable between a second closing position where the second reflection means closes the second passing means and reflects the electromagnetic wave when the second reflection means comes into contact with the medium contained in the container means, and a second opening position where the second reflection means opens the second passing means and allows the electromagnetic wave to pass when the container means is empty of medium; The image forming apparatus according to (((5))) is characterized by comprising: (((7))) a third passage means provided in the containing means and through which the electromagnetic wave can pass; The image forming apparatus according to any one of ((1))) to (((6))) further comprises: (((8))) the storage means being detachable from a main body of the image forming apparatus; a third reflection means movable between a third open position where the third passing means is opened to pass the electromagnetic wave when the storage means is attached to the main body of the image forming apparatus, and a third closing position where the third passing means is closed to reflect the electromagnetic wave when the storage means is detached from the main body of the image forming apparatus; The image forming apparatus according to (((7))) is characterized by comprising:

[0050] According to the image forming apparatus of (((1))), the configuration for detecting the presence and size of a medium can be simplified compared to the conventional configuration. According to the image forming apparatus of (((2))), the presence or absence of a medium can be determined based on the electromagnetic wave reflected by the first reflecting means. According to the image forming apparatus of (((3))), the presence or absence of the medium can be determined based on the electromagnetic waves reflected by the first reflecting means arranged farther from the receiving means, rather than the size of the medium. According to the image forming device of (((4))), it is possible to determine whether or not the medium is present when the support means has moved to a position for lifting the medium. According to the image forming apparatus of (((5))), the size of the medium can be determined based on the electromagnetic wave reflected at the position of the second passing means. According to the image forming apparatus of (((6))), the presence or absence of a medium can be determined more reliably based on the electromagnetic wave reflected by the second reflecting means, compared to an image forming apparatus not having the second reflecting means. According to the image forming apparatus of (((7))), the presence or absence of the container means can be determined based on the electromagnetic wave reflected at the position of the third passing means. According to the image forming apparatus of (((8))), the presence or absence of the storage means can be determined based on the electromagnetic waves reflected by the third reflecting means. Therefore, the size of the medium, the presence or absence of the medium, and the presence or absence of the storage means can be determined by one set of output means and receiving means. [Explanation of symbols]

[0051] 1...Output means, 2...Receiving means, 12...first reflecting means, 13...first passage means; 16... Guidance means, 17...second means of passage, 18...second reflecting means, 22...Third means of passage, 26...third reflecting means, C1...discrimination means, PL1...Support means, S...medium, TR1…Containment means, U: Image forming device, U1: Main body of the image forming apparatus.

Claims

1. A storage means for storing a medium; an output means for outputting an electromagnetic wave toward the medium; a receiving means for receiving the electromagnetic wave reflected after being output from the output means; a determining means for calculating a distance to the medium based on the electromagnetic waves received by the receiving means, and determining a size of the medium and whether or not the medium is present in the storage means; An image forming apparatus comprising:

2. a first reflecting means disposed in the accommodation means for reflecting the electromagnetic wave having passed through the accommodation space of the medium; 2. The image forming apparatus according to claim 1, further comprising:

3. the first reflecting means disposed corresponding to one end of the medium opposite to the other end of the medium closer to the receiving means; 3. The image forming apparatus according to claim 2, further comprising:

4. a support means for supporting a lower surface of the medium and for lifting the medium as the medium is fed; a first passing means provided on the supporting means and through which the electromagnetic wave can pass; the first reflecting means disposed at a position where the electromagnetic wave having passed through the first passing means reaches; 4. The image forming apparatus according to claim 3, further comprising:

5. a guide means movably supported within the receiving means for guiding an edge of the medium; a second passage means provided in the guide means and through which the electromagnetic wave can pass; 2. The image forming apparatus according to claim 1, further comprising:

6. a second reflection means supported by the guiding means and movable between a second closing position where the second reflection means closes the second passing means and reflects the electromagnetic wave when the second reflection means comes into contact with the medium contained in the container means, and a second opening position where the second reflection means opens the second passing means and allows the electromagnetic wave to pass when the container means is empty of medium; The image forming apparatus according to claim 5 , further comprising:

7. a third passage means provided in the containing means and through which the electromagnetic wave can pass; 2. The image forming apparatus according to claim 1, further comprising:

8. the storage means being detachable from a main body of the image forming apparatus; a third reflecting means movable between a third open position where the third passing means is opened to pass the electromagnetic wave when the storage means is attached to the main body of the image forming apparatus, and a third closed position where the third passing means is closed to reflect the electromagnetic wave when the storage means is detached from the main body of the image forming apparatus; The image forming apparatus according to claim 7, further comprising:

Images