JP4804318B2 - Paper feeding device and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet feeding device and an image forming apparatus configured to be able to stack a plurality of sizes of recording sheets. In particular, the present invention relates to a copying machine, a printer, a facsimile machine, an Internet facsimile machine, and a multi-function machine having any one of these functions for forming an image on recording paper.

  2. Description of the Related Art Image forming apparatuses such as copiers and printers having a paper feeding device configured to be able to stack a plurality of sizes of recording paper are known. Since the size of the recording paper placed on the paper feeding device is essential information for properly forming an image on the recording paper, various methods for detecting the size of the recording paper placed on the paper feeding device. Has been proposed.

For example, a copying machine including a line sensor that detects the width and length of a recording sheet is disclosed (see Patent Document 1). According to this copying machine, the width and length of the recording paper are accurately detected.
JP-A-2005-231887

  However, in order to detect the size of the recording paper, it is necessary to provide a line sensor for detecting the width and length of the recording paper, which increases the manufacturing cost.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device and an image forming apparatus capable of accurately detecting the size of a recording sheet with a simple configuration.

In order to achieve the above object, a paper feeding device according to claim 1 is a paper feeding device configured to be able to stack a plurality of sizes of recording papers and to place the recording papers in the width direction. A first movable member that abuts at least one end surface of the recording paper, a second movable member that abuts at least one end surface in the longitudinal direction of the loaded recording paper, and the first movable member and the second movable member, respectively. Then, the first indicating member and the second indicating member configured to move along one predetermined trajectory, and the positions of the first indicating member and the second indicating member on the first trajectory are detected. Position detection means, and size detection means for obtaining the size of the loaded recording paper from the detected positions of the first movable member and the second movable member , wherein the first indicating member and the second indicating member are , When the position is overlapped on the 1 orbit, the position The positions of the first indicating member and the second indicating member can be detected by detecting means, respectively. The position detecting means is configured to detect the first via a line sensor disposed along the first track. The positions of the first indicating member and the second indicating member are detected, and the first indicating member and the second indicating member are configured to be identifiable by the line sensor because their shapes are different from each other. It is characterized by having.

  The sheet feeding device according to claim 2 is the sheet feeding device according to claim 1, wherein the first instruction member and the second instruction member are arranged at the position according to the size of the recording paper that can be placed. It is characterized in that it is configured to move in a range exceeding 1/2 of the detectable range of the detection means.

The sheet feeding device according to claim 3 is the sheet feeding device according to claim 1 or 2 , wherein one of the first indicating member and the second indicating member is set to the first width by the line sensor. A member to be detected, the other having two members detected by the line sensor to the second width and the third width, the two members being separated by an interval detected by the line sensor to the fourth width. The first width is larger than the second width and the third width, and the fourth width is larger than the first width.

Sheet feeding apparatus according to claim 4 is the sheet feeding apparatus according to claim 3, wherein the second width and the third width, and wherein the at least one value.

According to a fifth aspect of the present invention, there is provided a paper feeding device configured to be capable of stacking and placing a plurality of sizes of recording papers, wherein the paper feeding device hits at least one end surface of the placed recording papers in the width direction. The first movable member in contact, the second movable member in contact with at least one end surface in the longitudinal direction of the recording paper loaded, and the first movable member and the second movable member are respectively defined in advance. A first indicator member and a second indicator member configured to move along one orbit, and position detecting means for detecting positions of the first and second indicator members on the one orbit. Size detecting means for obtaining the size of the recording paper placed from the positions of the first movable member and the second movable member, and the first indicating member and the second indicating member are arranged on the first track. When the overlapped position is reached, the position detecting means The positions of the first indicating member and the second indicating member can be detected, respectively, and the position detecting means is configured to detect the first indicating member and the second indicating member via a line sensor disposed along the first track. The position of the indicating member is detected, and the first indicating member and the second indicating member are configured to be identifiable by the line sensor because their transmittances are different from each other. It is said.

The sheet feeding device according to claim 6 is the sheet feeding device according to claim 5 , wherein the position detecting unit is closer to the line sensor than the first indicating member and the second indicating member. A light source disposed on the side of the line sensor and a reflecting mirror disposed on a side away from the line sensor with respect to the first indicating member and the second indicating member, and reflecting a light beam from the light source. The first indicating member and the second indicating member are disposed on the optical path from the light source to the reflecting mirror and on the optical path from the reflecting mirror to the line sensor. The two indicating members are characterized in that one transmittance is 50 to 60% and the other transmittance is 60 to 80%.

The sheet feeding device according to claim 7 is the sheet feeding device according to claim 5 or 6 , wherein one of the first indicating member and the second indicating member is set to a fifth width by the line sensor. It is a member to be detected, and the other is a member detected by the line sensor to a sixth width different from the fifth width.

The paper feeding device according to claim 8 is the paper feeding device according to any one of claims 5 to 7 , wherein the first indicating member and the second indicating member have different transmittances from each other. It is characterized by comprising a (Neutral Density) filter.

According to a ninth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to eighth aspects, an operating means for accepting an external operation, and a display means for displaying information so as to be visible from the outside. Printing means for forming an image on the recording paper supplied from the paper feeding device, and the size of the recording paper detected by the paper feeding device is displayed on the display means and received via the operation means. And a control means for setting the printing means based on the inputted operation input.

According to the paper feeding device of the first aspect, the first movable member that contacts at least one end surface in the width direction of the loaded recording paper and the at least one end surface in the longitudinal direction of the loaded recording paper. The positions of the first indicating member and the second indicating member configured to move along one predetermined trajectory are detected in conjunction with the abutting second movable member, and the detected first movable member and Since the size of the loaded recording paper can be obtained from the position of the second movable member, the size of the recording paper can be accurately detected with a simple configuration. That is, since the first indicating member and the second indicating member are configured to move along one trajectory, the first detector (for example, a line sensor) disposed along the one trajectory makes the first. This is because the positions of the indicating member and the second indicating member can be detected.

In addition, since the first indicating member and the second indicating member are configured to be able to detect the positions of the first indicating member and the second indicating member, respectively, when the first indicating member and the second indicating member are overlapped on one track, Even when the first indicating member and the second indicating member are located on the same track, the size of the recording sheet can be accurately detected. Furthermore, since the first indicating member and the second indicating member are different in shape from each other, the first indicating member and the second indicating member are configured to be identifiable by a line sensor arranged along one track. And even if it is a case where the 2nd instruction | indication member becomes the position which overlapped on the track | orbit of 1, it can detect the size of a recording paper correctly with a simple structure.

  According to the paper feeding device of the second aspect, the first indicating member and the second indicating member are in a range more than ½ of the detectable range of the position detecting unit according to the size of the recording paper that can be placed. Therefore, the size of the recording paper can be detected more accurately.

According to the paper feeding device according to claim 3, member (here referred to as first member) detected on one the first width by the line sensor of the first indicating member and the second indicating member is, the other Two members (herein referred to as second member and third member) detected by the line sensor to the second width and the third width are provided, and the two members are separated by an interval detected by the line sensor to the fourth width. In addition, since the first width is larger than the second width and the third width, and the fourth width is larger than the first width, the first indication member and the second indication Even when the members are overlapped on one orbit, the size of the recording paper can be accurately detected with a simple configuration.

  That is, since the first width is larger than the second width and the third width, at least one of the movable directions of the first member even when the first member overlaps the second member (or the third member). Since the end surface of the projection protrudes from the second member (or the third member), the position of the first member can be detected. In addition, since the fourth width is larger than the first width, even if the first member is located between the second member and the third member, at least one end surface in the movable direction of the first member is Since it is separated from the second member (or the third member), the position of the first member can be detected.

According to the paper feeding device of the fourth aspect , since the second width and the third width are the same value, it is possible to easily detect the size of the recording paper.

  That is, since the second width and the third width are the same value, the case where the first member overlaps the second member and the case where the first member overlaps the third member are determined by substantially the same determination method. (For details, see the section of the best mode for carrying out the invention).

According to the paper feeding device of the fifth aspect , the first indicating member and the second indicating member are identified by the line sensor arranged along one orbit because the transmittance is different from each other. Since it is configured to be possible, the size of the recording paper can be accurately detected with a simple configuration.

According to the paper feeding device of claim 6 , the first indicating member and the second indicating member are disposed on the optical path from the light source to the reflecting mirror and on the optical path from the reflecting mirror to the line sensor. Therefore, the light beam that has passed through the first indicator member (or second indicator member) is reflected by the reflecting mirror, and then passes again through the first indicator member (or second indicator member) to the line sensor. Received light. In addition, since the first indicating member and the second indicating member have one transmittance of 50 to 60% and the other transmittance of 60 to 80%, they can be easily identified by the line sensor. That is, the transmittance of the portion where the first indicating member and the second indicating member overlap is 9% (= (0.5 × 0.6) ² × 100) to 23% (= (0.6 × 0. 8) ² × 100), which is different from the square of the transmittance of the first indicating member and the second indicating member (25% to 36%, 36% to 64%), so that the first indicating member and the second indicating member Since it is possible to detect the overlapping portion, it can be easily identified by the line sensor.

According to the sheet feeding device of claim 7 , one of the first indicating member and the second indicating member is a member that is detected to the fifth width by the line sensor, and the other is the member that is detected by the line sensor. Since the member is detected at the sixth width different from the fifth width, it can be more easily identified by the line sensor. That is, since the width detected by the line sensor is different between the first indicating member and the second indicating member, the first indicating member and the second indicating member are identified based on the detection width and transmittance of the line sensor. Therefore, it can be more easily identified by the line sensor.

According to the paper feeding device of the eighth aspect , since the first indicating member and the second indicating member are formed of ND filters having different transmittances, the transmittances of the first indicating member and the second indicating member are accurately determined. It becomes possible to comprise.

According to the image forming apparatus of the ninth aspect , the size of the recording paper detected by the paper feeding device according to any one of the first to eighth aspects is displayed and the received operation input is displayed. Based on the setting of the printing unit for forming an image on the recording paper, the user can check the size of the displayed recording paper and set the printing unit for forming the image on the recording paper.

  Hereinafter, an example of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an example of a schematic configuration of an image forming apparatus according to the present invention. Here, the case where the image forming apparatus is a printer will be described. However, the image forming apparatus may be another image forming apparatus (for example, a facsimile, an internet facsimile, a copying machine, a multifunction machine, etc.) that forms an image on recording paper. Good. As shown in FIG. 1, the printer 1 includes a photosensitive unit 11, a laser beam scanning unit 12, a developing unit 13, a fixing unit 14, and a paper feeding unit 2. The printer 1 is communicably connected to a personal computer (not shown), and receives an instruction from the personal computer and forms an image on recording paper. The printer 1 includes a control unit 3 (see FIG. 2), a display unit, and an operation unit at appropriate positions.

  Here, the control unit controls the operation of the entire apparatus of the printer 1, and the display unit includes an LCD (Liquid Crystal Display) 4 (see FIG. 2) and the like, and is set based on an instruction from the control unit. Information, guidance information, message information, etc. are displayed so as to be visible to the user. The operation unit receives operation input from the user, generates operation input information corresponding to the received operation input, and outputs the operation input information to the control unit.

  The photosensitive unit 11 (corresponding to a part of the printing unit) includes a photosensitive drum. First, the surface of the photosensitive drum is charged almost uniformly by a charging roller, and then the electrostatic latent image is detected by the laser beam scanning unit 12. Is formed, and the developing unit 13 attaches toner to form a toner image. The laser beam scanning unit 12 (corresponding to a part of the printing unit) forms an electrostatic latent image on the surface of the photosensitive drum of the photosensitive unit 11 by a laser beam. The developing unit 13 (corresponding to a part of the printing unit) is for forming a toner image by attaching toner to the electrostatic latent image formed by the laser beam scanning unit 12. The fixing unit 14 (corresponding to a part of the printing unit) fixes the toner image formed on the recording paper by the developing unit 13.

  The paper feed unit 2 (corresponding to a paper feed device) is configured to be able to stack a plurality of sizes of recording paper and to supply the recording paper to the photosensitive unit 11. The paper feeding unit 2 includes a front end stopper 21, a rear end guide 22, a side guide 23, a line sensor 24, and an LED (Light Emitting Diode) 25.

  The front end stopper 21 is a plate-like member that is fixedly installed at one end (right end in the drawing) of the recording paper placement position in the paper feeding unit 2, and the user places the recording paper on the paper feeding unit 2. This is a stopper that serves as a reference for fixing the leading edge of the recording paper when the paper is placed.

  A rear end guide 22 (corresponding to a second movable member) is erected at one end (left end in the figure) of the recording paper placement position in the paper supply unit 2 and is configured to be movable in the left-right direction in the figure. This is a guide member that fixes the trailing edge of the recording paper when the user places the recording paper on the paper feeding unit 2.

  The side guides 23 (corresponding to the first movable member) are erected on both sides (the front side and the back side in the drawing) of the recording paper placement position in the paper feeding unit 2, and one side is in the opposite direction to the other side. A plate-like member configured to be movable in a direction (perpendicular to the paper surface in the figure), and a guide that fixes both ends of the recording paper in the width direction when the user places the recording paper on the paper feeding unit 2. is there.

  The line sensor 24 (corresponding to a part of the position detection means) is a detection bar (a length detection bar 224 and a width detection bar shown in FIGS. 3 and 4) that move in correspondence with the rear end guide 22 and the side guide 23. 236) is detected. The line sensor 24 is configured by arranging elements capable of detecting the amount of received light such as a CCD (Charge Coupled Devices) on a straight line, and outputs the amount of received light of each element to the control unit.

  An LED 25 (corresponding to a part of the light source and position detecting means) is a linear light source having substantially the same length as that of the line sensor 24 and is a reflection disposed on the lower surface of the recording paper placement position in the paper feeding unit 2. The light is projected toward the plate (see FIG. 4B).

  FIG. 2 is a configuration diagram illustrating an example of an electrical configuration for detecting the position of the detection bar. A signal from a CCD disposed in the line sensor 24 is input to an amplifier 244, A / D converted by an A / D converter 242, and then temporarily stored in a RAM (Random Access Memory) 243.

  The control unit 3 (corresponding to the size detection unit) includes a CPU (Central Processing Unit), a RAM, and a ROM (Read Only Memory). The control unit 33 includes an ASIC (= Application Specific Integrated Circuit). Control commands for the amplifier 244, the A / D converter 242, and the RAM 243 are output. The control circuit 33 controls the amplifier 244, the A / D converter 242 and the RAM 243 based on a control command from the CPU. Further, the CPU of the control unit 3 controls the light emission (light quantity, light emission timing, etc.) of the LED 25 via the transistor 252 and the current limiting resistor 251. Further, an EEPROM (Electronically Erasable and Programmable ROM) 32 is connected to the control unit 3. The EEPROM 32 stores in advance width information and the like of detection bars (width detection bar 236 and length detection bar 224), which will be described later, and also stores detection data from the line sensor 24. In addition, an LCD 4 is connected to the control unit 3, and various information such as the size of the recording paper is displayed so as to be visible from the outside.

  FIG. 3 is a configuration diagram illustrating an example of a mechanical configuration for detecting the position of the detection bar. 1A is a perspective view of the paper feed unit 2 shown in FIG. 1 from the top surface side, and FIG. 1B is a diagram showing the relationship between the recording paper size and the position of the detection bar. Further, here, one end of the recording paper (see the recording paper front end position PT shown in FIG. 3B) abuts on the front end stopper 21 and is placed at a position indicated by a broken line.

  A first rack 231 is erected on one side of the side guide 23 (here, the upper side). The first rack 231 is a large-diameter gear of a first reduction gear 232 that functions as a pinion of a rack-and-pinion mechanism. Meshed. The small diameter gear of the first reduction gear 232 that rotates integrally with the large diameter gear engages with the pulley 233, and the pulley 233 engages with the large diameter gear of the second reduction gear 234. The small-diameter gear of the second reduction gear 234 that rotates integrally with the large-diameter gear meshes with the second rack 235 that is the rack of the rack and pinion mechanism, and has a width at one end (here, the left end) of the second rack 235. A detection bar 236 (corresponding to the first indicating member) is provided upright.

  Next, the operation from the side guide 23 to the width detection bar 236 will be described. When the side guide 23 is moved to the narrow side (the upper side guide 23 is moved to the lower side), the first rack 231 is moved to the lower side integrally with the upper side guide 23, and the first rack 231 is moved. The large-diameter gear of the first reduction gear 232 meshed with is rotated counterclockwise. The small diameter gear of the first reduction gear 232 also rotates counterclockwise, and the pulley 233 engaged with the small diameter gear is also rotated counterclockwise. Then, the large-diameter gear of the second reduction gear 234 engaged with the pulley 233 is rotated counterclockwise. Furthermore, the small diameter gear of the second reduction gear 234 is also rotated counterclockwise, the second rack 235 meshing with the small diameter gear is moved rightward, and the width detection bar 236 standing on the second rack 235 is also provided. Moved to the right.

  A third rack 221 is erected on the rear end guide 22, and the third rack 221 meshes with a large-diameter gear of a third reduction gear 222 that functions as a pinion of a rack-and-pinion mechanism. The small-diameter gear of the third reduction gear 222 that rotates integrally with the large-diameter gear meshes with the fourth rack 223 that is a rack of the rack-and-pinion mechanism, and one end (here, the right end) of the fourth rack 223. Further, a length detection bar 224 (corresponding to a second indicating member) is provided upright.

  Next, the operation from the rear end guide 22 to the length detection bar 224 will be described. When the rear end guide 22 is moved to the short side (the rear end guide 22 is moved to the right side), the third rack 221 is moved to the right side integrally with the rear end guide 22 and is engaged with the third rack 221. The large-diameter gear of the three reduction gear 222 is rotated clockwise. Then, the small-diameter gear of the third reduction gear 222 also rotates clockwise, the fourth rack 223 engaged with the small-diameter gear is moved leftward, and the length detection bar 224 erected on the fourth rack 223 is also Moved to the left.

  Further, a fixed bar 241 that defines a reference position is disposed at a predetermined position (here, a position near the left end) of the line sensor 24. Here, the distance between the right end of the rear end guide 22 and the left end of the front end stopper 21 corresponds to the recording sheet width Y, and the distance between the lower end of the upper side guide 23 and the upper end of the lower side guide 23 is the recording sheet length X. It corresponds to. Then, corresponding to the recording paper width Y, a width detection amount δy that is an interval between the width detection bar 236 and the fixed bar 241 is determined. Similarly, the length detection amount δx that is the distance between the length detection bar 224 and the fixed bar 241 is determined in correspondence with the recording paper length X.

  Here, the ratio of the change amount of the width detection amount δy to the change amount of the recording paper width Y (reduction rate αy) is determined by the gear ratio of the small-diameter gear to the large-diameter gear in the first reduction gear 232 and the second reduction gear 234. The ratio of the change amount of the detected length δx to the change amount of the recording paper length X (deceleration rate αx) is determined by the gear ratio of the small gear to the large gear in the third reduction gear 222. That is, the desired reduction rate αy and reduction rate αx can be realized by appropriately setting the gear ratios of the first reduction gear 232, the second reduction gear 234, and the third reduction gear 222. The width detection bar 236 and the length detection bar 224 have a deceleration rate αy and a deceleration rate αx so as to move in a range exceeding 1/2 of the detectable range of the line sensor 24 according to the size of the recording paper that can be placed. Is set.

<First Embodiment>
FIG. 4 is a cross-sectional view illustrating an example of the AA cross section and the BB cross section according to the first embodiment of the paper feed unit 2 illustrated in FIG. 3. (A) is an AA cross section of the paper feed unit 2 shown in FIG. 3 (a), and (b) is a BB cross section of the paper feed unit 2 shown in FIG. 3 (a). A hole 27 is formed in a part of the recording paper tray of the paper supply unit 2. A line sensor 24 and an LED 25 are disposed below the hole 27, and a fixing bar 241 is disposed above the hole 27. A width detection bar 236, a length detection bar 224, and a reflecting mirror 26 (corresponding to a part of the position detection means) are provided. However, a width detection bar 236 and a length detection bar 224 are disposed between the reflecting mirror 26 and the hole 27. That is, when the light beam emitted from the LED 25 is blocked by the width detection bar 236 (or the length detection bar 224), the line sensor 24 does not receive the light, and the light beam emitted from the LED 25 has a width detection bar 236 and a length. When not blocked by the detection bar 224, the light passes through the hole 27, is reflected by the reflecting mirror 26, passes through the hole 27 again, and is received by the line sensor 24.

  FIG. 5 is an explanatory diagram for explaining a method of calculating the width detection amount δy and the length detection amount δx from the detection signal of the line sensor 24 according to the first embodiment. The process of calculating the width detection amount δy and the length detection amount δx from the detection signal of the line sensor 24 is performed by the control unit 3 (CPU) shown in FIG. (A) is a figure which shows the relationship between the position of the width | variety detection bar 236 and the length detection bar 224, and the detection signal (detection voltage VO) of the line sensor 24, (b) is the width | variety detection bar 236 and length. 5 is a configuration diagram illustrating an example of a configuration of a detection bar 224. FIG. As shown in (b), the width detection bar 236 is made of a member that is detected by the line sensor 24 to the first width YW, and the length detection bar 224 is made by the line sensor 24 with the second width XW1 and the third width XW3. The two members are integrally formed in a U-shape and are separated by an interval detected by the line sensor 24 to the fourth width XW2.

Here, the width detection bar 236 and the length detection bar 224 are configured so that the first width YW, the second width XW1, the third width XW3, and the fourth width XW2 satisfy the following expressions (1) to (3). Is formed. However, here, in order to easily obtain the recording paper width Y and the recording paper length X, the second width XW1 = the third width XW3.
First width YW> second width XW1 (1)
First width YW> third width XW3 (2)
First width YW <fourth width XW2 (3)

  Even when the width detection bar 236 and the length detection bar 224 overlap, as will be described in detail with reference to FIG. The width detection amount δy and the length detection amount δx can be accurately obtained.

  The detection signal (detection voltage VO) of the line sensor 24 is a signal as shown in (a) because the portions corresponding to the positions of the width detection bar 236 and the length detection bar 224 are shielded from light. Here, the threshold voltage Vth is set to a substantially central value between the detection voltage VO at the time of light shielding and the detection voltage at the time of light reception.

In (a), the elements of the line sensor 24 corresponding to the right end position of the fixed bar 241, the left end position of the width detection bar 236, and the left end position of the length detection bar 224 are respectively from the left end element of the line sensor 24. When the element number NZ, NY, NX is represented by the element number NZ, NY, NX, the width detection amount δy and the length detection amount δx can be obtained by the following equations (4) and (5).
Width detection amount δy = (NY−NZ) × ΔL (4)
Length detection amount δx = (NX−NZ) × ΔL (5)
Here, ΔL is the size of the pixels constituting the line sensor 24.

Therefore, the recording paper width Y and the recording paper length X are obtained by the following equations (6) and (7). That is, by obtaining the element numbers NZ, NY, and NX from the detection voltage of the line sensor 24, the recording paper width Y and the recording paper length X are obtained.
Recording paper width Y = (NY−NZ) × ΔL ÷ deceleration rate αy (6)
Recording paper length X = (NX−NZ) × ΔL ÷ Deceleration rate αx (7)

  FIG. 6 is a diagram for explaining an example of a method for obtaining the element numbers NZ, NY, and NX based on the positional relationship between the width detection bar 236 and the length detection bar 224. A case where the width detection bar 236 moves to the right side with respect to the length detection bar 224 will be described in the order of (a) to (g). Also, from (a) to (g), a change point detected by the line sensor 24 (a point changing from “ON” to “OFF”, or a point changing from “OFF” to “ON”), respectively. Here, the element numbers corresponding to “change points”) are assigned N1 to N8 in order from the left. In addition, the number of change points detected by the line sensor 24 is defined as a number C.

1. When the conditions of C = 8, XW1 = N6-N5, and YW = N4-N3 are satisfied, it can be determined that the positional relationship in FIG. 6A is satisfied, and NY and NX can be obtained by the following equations.
NX = N5
NY = N3

2. When the conditions of C = 6, XW3 (= XW1) = N6-N5, and XW2 = N5-N4 are satisfied, it can be determined that the positional relationship in FIG. 6B is satisfied, and NY and NX are obtained by the following equations. be able to.
NX = N4-XW1
NY = N3

3. When the conditions of C = 6, XW3 (= XW1) = N6-N5, and XW2 + XW1 = N5-N3 are satisfied, it can be determined that the positional relationship in FIG. 6C is satisfied, and NY and NX are obtained by the following equations. be able to.
NX = N3
NY = N4-YW

4). When the conditions of C = 8, XW1 = N4-N3, and YW = N6-N5 are satisfied, it can be determined that the positional relationship in FIG. 6D is satisfied, and therefore NY and NX can be obtained by the following equations.
NX = N3
NY = N5

5. When the conditions of C = 6, XW1 = N4-N3, XW2 + XW3 (= XW1) = N6-N4 are satisfied, it can be determined that the positional relationship of FIG. be able to.
NX = N3
NY = N5

6). When the conditions of C = 6, XW1 = N4-N3, and XW2 = N5-N4 are satisfied, it can be determined that the positional relationship in FIG. 6F is satisfied, and NY and NX can be obtained by the following equations.
NX = N3
NY = N6-YW

7). When the conditions of C = 8, XW1 = N4-N3, and YW = N8-N7 are satisfied, it can be determined that the positional relationship in FIG. 6G is satisfied, and thus NY and NX can be obtained by the following equations.
NX = N3
NY = N7

  In this way, the positional relationship between the width detection bar 236 and the length detection bar 224 is determined based on the element number corresponding to the change point detected by the line sensor 24 and the number of change points, and the element numbers NZ, Since NY and NX can be obtained, the recording paper width Y and the recording paper length X are obtained using the above-described equations (6) and (7).

  FIG. 7 is a chart showing an example of data detected by the line sensor 24 stored in the EEPROM 32 shown in FIG. The EEPROM 32 stores, for each change point, the pixel number Nγ (γ = 1 to 8) of the change point and the number of pixels Mγ (γ = 1 to 8) in which “ON” or “OFF” data continues. Is.

  In this manner, the side guide 23 that contacts at least one end surface in the width direction of the loaded recording paper and the rear end guide 22 that contacts at least one end surface in the longitudinal direction of the loaded recording paper are interlocked with each other. Then, the positions of the width detection bar 236 and the length detection bar 224 configured to move along one predetermined trajectory are detected, and the detected positions of the side guide 23 and the rear end guide 22 are loaded. Since the size of the placed recording paper is required, the size of the recording paper can be accurately detected with a simple configuration.

  Further, since the width detection bar 236 and the length detection bar 224 are configured to move in a range exceeding 1/2 of the detectable range of the line sensor 24 according to the size of the recording paper that can be placed, It is possible to accurately detect the size of the recording paper.

  Further, when the width detection bar 236 and the length detection bar 224 are overlapped on one track, the positions of the width detection bar 236 and the length detection bar 224 can be detected. Even when the width detection bar 236 and the length detection bar 224 are overlapped on one track, it is possible to accurately detect the size of the recording paper.

  In addition, the width detection bar 236 and the length detection bar 224 are configured to be identifiable by the line sensor 24 arranged along one orbit due to the difference in shape. Even when the detection bar 236 and the length detection bar 224 are overlapped on one track, the size of the recording paper can be accurately detected with a simple configuration.

  Further, one of the width detection bar 236 and the length detection bar 224 (here, the width detection bar 236) is a member (herein referred to as a first member) that is detected by the line sensor 24 to the first width YW, and the other (Here, the length detection bar 224) includes two members (herein referred to as a second member and a third member) that are detected by the line sensor 24 in the second width XW1 and the third width XW3. Are integrally formed at a distance detected by the line sensor 24 to the fourth width XW2, and the first width YW is larger than the second width XW1 and the third width XW3, and the fourth width Since XW2 is larger than the first width YW, even when the width detection bar 236 and the length detection bar 224 are overlapped on one track, the recording paper can be accurately and accurately configured. The size can be detected

  Further, since the second width XW1 and the third width XW3 are the same value, the size of the recording paper can be easily detected.

  In addition, since the size of the detected recording paper is displayed on the LCD 4 and the printing conditions for forming an image on the recording paper are set based on the received operation input, the user can display the displayed recording paper. By confirming the size of the paper, it is possible to set printing conditions for forming an image on the recording paper.

Second Embodiment
FIG. 8 is a cross-sectional view illustrating an example of an AA cross section and a BB cross section according to the second embodiment of the paper feed unit 2 illustrated in FIG. 3. (A) is an AA cross section of the paper feed unit 2 shown in FIG. 3 (a), and (b) is a BB cross section of the paper feed unit 2 shown in FIG. 3 (a). For the paper feeding unit 2 according to the first embodiment shown in FIG. 4, a width detection bar 236 a is provided instead of the width detection bar 236, and a length detection bar 224 a is provided instead of the length detection bar 224. It is different in that it is. The same components as those of the paper feeding unit 2 according to the first embodiment shown in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  The length detection bar 224a is composed of, for example, an ND (Neutral Density) filter having a transmittance of 55% (55% square is approximately 30%), and the width detection bar 236a is, for example, 71% (71% square). (About 50%) is composed of ND filters. That is, 30% of the light transmitted through the length detection bar 224a is received by the line sensor 24, and 50% of the light transmitted through the width detection bar 236a is received by the line sensor 24. The ND filter controls the amount of light that is transmitted by dispersing the light-absorbing substance in the optical glass. The width detection bar 236a is a member that is detected by the line sensor 24 to the fifth width YW, and the length detection bar 224a is a sixth width XW (sixth width XW) smaller than the fifth width YW by the line sensor 24. <5th width YW) It is comprised from the member detected.

  When the light beam emitted from the LED 25 is blocked by the width detection bar 236a (or the length detection bar 224a), the light beam transmitted through the width detection bar 236a (or the length detection bar 224a) passes through the hole 27 and is reflected. The light is reflected by the mirror 26, passes through the width detection bar 236a (or length detection bar 224a) again, passes through the hole 27, and is received by the line sensor 24. When the light beam emitted from the LED 25 is not blocked by the width detection bar 236a and the length detection bar 224a, the light passes through the hole 27, is reflected by the reflecting mirror 26, passes through the hole 27 again, and is again reflected by the line sensor 24. Received light.

  9 to 11 are explanatory diagrams for explaining a method of calculating the width detection amount δy and the length detection amount δx from the detection signal of the line sensor 24 according to the second embodiment. The process of calculating the width detection amount δy and the length detection amount δx from the detection signal of the line sensor 24 is performed by the control unit 3 (CPU) shown in FIG. 9 to 11, the positional relationship between the width detection bar 236a and the length detection bar 224a is shown on the upper side, and the detection signal (detection voltage VO) of the line sensor 24 is shown on the lower side. However, here, for convenience, the line sensor 24 detects the detection signal (detection voltage VO) of the line sensor 24 with respect to the amount of light received by the line sensor 24 when the light beam is not blocked by the width detection bar 236a and the length detection bar 224a. This is expressed as a ratio (%) of the amount of received light. Further, in the order of FIGS. 9A, 9B, 10A, 10B, and 11, the width detection bar 236a is located on the left side of the length detection bar 224a (the direction close to the fixed bar 241). Has moved to.

As described with reference to FIG. 5, in the same manner as the line sensor 24 according to the first embodiment, the right end position of the fixing bar 241, the left end position of the width detection bar 236 a, and the left end position of the length detection bar 224 a. When the element numbers NZ, NY, and NX indicate the element numbers of the corresponding line sensor 24 from the leftmost element of the line sensor 24, the width detection amount δy and the length detection amount δx. Is obtained by the following equations (8) and (9).
Width detection amount δy = (NY−NZ) × ΔL (8)
Length detection amount δx = (NX−NZ) × ΔL (9)
Here, ΔL is the size of the pixels constituting the line sensor 24.

Therefore, the recording paper width Y and the recording paper length X are obtained by the following equations (10) and (11). That is, by obtaining the element numbers NZ, NY, and NX from the detection voltage of the line sensor 24, the recording paper width Y and the recording paper length X are obtained.
Recording paper width Y = (NY−NZ) × ΔL ÷ Deceleration rate αy (10)
Recording paper length X = (NX−NZ) × ΔL ÷ Deceleration rate αx (11)

Here, a method for obtaining the element numbers NZ, NY, and NX will be described. First, it is determined which expression (12) to (16) below is satisfied by the detection voltage VO of each pixel detected by the line sensor 24. When the following expressions (12) to (16) are satisfied, the parameter VP values for obtaining the element numbers NZ, NY, and NX are set to 1, 2, 3, 4, and 5, respectively. .
VO <7.5 (= (0 + 15) / 2)
→ VP = 1 (12)
7.5 <VO <22.5 (= (15 + 30) / 2)
→ VP = 2 (13)
22.5 <VO <40 (= (30 + 50) / 2)
→ VP = 3 (14)
40 <VO <77.5 (= (50 + 100) / 2)
→ VP = 4 (15)
77.5 <VO
→ VP = 5 (16)

  As described above, the length detection bar 224a is composed of an ND filter having a transmittance of 55% (55% square is about 30%), and the width detection bar 236a has a transmittance of 71% (71%), for example. Therefore, the detection voltage VO of the pixel corresponding to the length detection bar 224a is 30%, and the detection voltage VO of the pixel corresponding to the width detection bar 236a is 50%. %. The detection voltage VO of the pixel corresponding to the portion where the length detection bar 224a and the width detection bar 236a overlap is 15% (= 0.3 × 0.5 × 100).

  That is, a pixel having a parameter VP value of “1” corresponds to the fixed bar 241, and a pixel having a parameter VP value of “2” is a portion where the length detection bar 224 a and the width detection bar 236 a overlap. Correspondingly, a pixel having a parameter VP value “3” corresponds to the length detection bar 224a, and a pixel having a parameter VP value “4” corresponds to the width detection bar 236a. A pixel having a parameter VP value “5” corresponds to a region where neither the length detection bar 224a nor the width detection bar 236a exists.

  The value of the parameter VP is checked in order from the leftmost pixel of the run sensor 24 shown in FIG. 8A, and the last pixel number having the parameter VP value of 1 is set as the element number NZ. Then, the pixel number of the pixel immediately after the value of the parameter VP is changed to 2, 3 and 4 (= the left end side of the run sensor 24 shown in FIG. 8A) (hereinafter referred to as the changed pixel number NV) is stored.

  When the value of the change pixel number NV at the left end (side adjacent to the fixed bar 241) is 2 (the left end of the width detection bar 236a between FIG. 10A and FIG. 10B, the length When the position of the detection bar 224a coincides with the left end), the change pixel number NV is set as the element number NY and the element number NX.

  When the value of the change pixel number NV at the left end (the side close to the fixed bar 241) is 3 (in the case of FIG. 10A, FIG. 10B, and FIG. 11A), this change pixel The number NV is an element number NX. Then, the change pixel number NV which is the change pixel number NV on the right side of the change pixel number NV and whose value changes to 2 or 4 is defined as an element number NY.

  When the value of the change pixel number NV at the left end (side adjacent to the fixed bar 241) is 4 (FIGS. 11B and 12), this change pixel number NV is set as the element number NY. Then, the change pixel number NV on the right side of the change pixel number NV and having the value changing to 2 or 3 is set as an element number NX.

  In this way, the width detection bar 236a and the length detection bar 224a are configured to be identifiable by the line sensor 24 arranged along one orbit due to the difference in transmittance. Therefore, the size of the recording paper can be accurately detected with a simple configuration.

Since the width detection bar 236a and the length detection bar 224a are disposed on the optical path from the LED 25 to the reflecting mirror 26 and on the optical path from the reflecting mirror 26 to the line sensor 24, the width detection bar The light beam that has passed through 236a (or the length detection bar 224a) is reflected by the reflecting mirror 26, and then again passes through the width detection bar 236a (or the length detection bar 224a) and is received by the line sensor 24. The width detection bar 236a and the length detection bar 224a have one transmittance of 50 to 60% (here, the transmittance of the length detection bar 224a is 55%), and the other transmittance is 60 to 80. % (Here, the transmittance of the width detection bar 236a is 71%), it can be easily identified by the line sensor 24. That is, the transmittance of the portion where the width detection bar 236a and the length detection bar 224a overlap each other is 15% (= 0.55 ² × 0.71 ² × 100), and the width detection bar 236a and the length detection bar 224a. Therefore, it is possible to detect a portion where the width detection bar 236a and the length detection bar 224a overlap with each other, so that the line sensor 24 can easily identify them. It can be done.

  Further, the width detection bar 236a is made of a member that is detected by the line sensor 24 to the fifth width YW, and the length detection bar 224 is a sixth width XW (sixth width XW) smaller than the fifth width YW by the line sensor 24. <5th width YW) Since it is comprised from the member detected, it can identify more easily by the line sensor 24. FIG. That is, since the width detected by the line sensor 24 is different between the width detection bar 236a and the length detection bar 224a, the width detection bar 236a and the length detection bar are based on the detection width and transmittance of the line sensor 24. Since 224a can be identified, it can be more easily identified by the line sensor 24.

The present invention can also be applied to the following forms.
(A) In the first embodiment, the width detection bar 236 and the length detection bar 224 are configured to be identifiable by the line sensor 24 arranged along one orbit by being different in shape. However, as shown in the second embodiment, the width detection bar 236a and the length detection bar 224a are configured to be identifiable by the line sensor 24 because their transmittances are different from each other. It may be in the form.

  (B) In the first and second embodiments, the line sensor 24 and the LED 25 are on the same side (lower side) of the width detection bar 236 (236a) and the length detection bar 224 (224a) with respect to the hole 27. Although the case where the line sensor 24 and the LED 25 are opposite to the hole 27 is described (transmission type). In this case, the reflecting mirror 26 is not required, the apparatus is simplified, and a detection error does not occur due to contamination of the reflecting mirror 26, so that the detection accuracy is further improved.

  In this case, the transmittance of the width detection bar 236a and the length detection bar 224a is preferably 20 to 40% (for example, 30%) on one side and 40 to 60% (for example, 50%) on the other side. . That is, the transmittance of the portion where the width detection bar 236a and the length detection bar 224a overlap is 15% (= 0.30 × 0.50 × 100), and the transmission of the width detection bar 236a and the length detection bar 224a. Since it is different from the rate (30%, 50%), it is possible to detect a portion where the width detection bar 236a and the length detection bar 224a overlap with each other, so that the line sensor 24 can easily identify them. is there.

  (C) In the first embodiment, the width detection bar 236 is made of a member that is detected by the line sensor 24 to the first width YW, and the length detection bar 224 is detected by the line sensor 24 by the second width XW1 and the third width. Although two members detected by XW3 are provided and the two members are separated by an interval detected by the line sensor 24 to the fourth width XW2, they are integrally formed in a U-shape. Conversely, the width detection bar 236 may include two members.

  (D) Although the case where the second width XW1 and the third width XW3 have the same value has been described in the first embodiment, the second width XW1 and the third width XW3 may be different. In this case, the two members formed on the length detection bar 224 can be more accurately discriminated.

  (E) In the second embodiment, the case where the width detection bar 236a and the length detection bar 224a are composed of members that are detected to have different widths by the line sensor 24 has been described. However, the width detection bar 236a and the length are described. The form in which the detection bar 224a is comprised from the member detected by the line sensor 24 by substantially the same width | variety may be sufficient.

  (F) In the second embodiment, the case where the positions of the width detection bar 236a and the length detection bar 224a are obtained from the value of the detection voltage VO (= transmittance) has been described. However, the width detection bar 236a and the length detection bar 224a are described. May be obtained based on the value of the detection voltage VO (= transmittance) and the number of pixels having the same value of the detection voltage VO (= width of the width detection bar 236a and the length detection bar 224a). In this case, the positions of the width detection bar 236a and the length detection bar 224a can be obtained more accurately.

FIG. 1 is a configuration diagram illustrating an example of a schematic configuration of an image forming apparatus according to the present invention. These are the block diagrams which show an example of the electric structure for detecting the position of a detection bar. These are block diagrams which show an example of the mechanical structure for detecting the position of a detection bar. These are sectional views showing an example of the AA section and the BB section of the sheet feeding unit shown in FIG. 3 (first embodiment). These are explanatory drawings for explaining a method of calculating a width detection amount δy and a length detection amount δx from the detection signal of the line sensor (first embodiment). These are the figures for demonstrating an example of the method of calculating | requiring element number NZ, NY, NX by the positional relationship of a width detection bar and a length detection bar (1st Embodiment). These are the charts which show an example of the detection data by the line sensor stored in EEPROM shown in FIG. 2 (1st Embodiment). These are sectional views showing an example of an AA section and a BB section of the sheet feeding unit 2 shown in FIG. 3 (second embodiment). These are 1st explanatory drawings for demonstrating the method to calculate width | variety detection amount (delta) y and length detection amount (delta) x from the detection signal of a line sensor (2nd Embodiment). These are 2nd explanatory drawings for demonstrating the method to calculate width | variety detection amount (delta) y and length detection amount (delta) x from the detection signal of a line sensor (2nd Embodiment). These are 3rd explanatory drawings for demonstrating the method to calculate width | variety detection amount (delta) y and length detection amount (delta) x from the detection signal of a line sensor (2nd Embodiment).

Explanation of symbols

1 Printer (image forming device)
2 Paper feeding unit (paper feeding device)
21 Front end stopper 22 Rear end guide (second movable member)
23 Side guide (first movable member)
24 line sensor (part of position detection means)
25 LED (part of position detection means)
26 Reflector (part of position detection means)
27 hole 224 length detection bar (second indicating member)
224a Length detection bar (second indicating member)
236 Width detection bar (first indicating member)
236a Width detection bar (first indicating member)
241 fixed bar

Claims (9)

A paper feeding device configured to be able to stack a plurality of size recording papers,
A first movable member that comes into contact with at least one end face in the width direction of the loaded recording paper;
A second movable member that comes into contact with at least one end surface of the placed recording paper in the longitudinal direction;
A first indicating member and a second indicating member configured to move along one predetermined trajectory in conjunction with the first movable member and the second movable member;
Position detecting means for detecting positions of the first indicating member and the second indicating member on the one orbit;
A size detecting means for obtaining the size of the loaded recording paper from the detected positions of the first movable member and the second movable member;
Equipped with a,
When the first indicating member and the second indicating member are overlapped on the first track, the positions of the first indicating member and the second indicating member can be detected by the position detecting unit. Configured,
The position detecting means detects the positions of the first indicating member and the second indicating member via a line sensor arranged along the one orbit,
The sheet feeding device, wherein the first indicating member and the second indicating member are configured so as to be distinguishable by the line sensor because their shapes are different from each other.   The first indicating member and the second indicating member are configured to move in a range exceeding 1/2 of the detectable range of the position detecting unit according to the size of the recording paper that can be placed. The paper feeding device according to claim 1. One of the first indicator member and the second indicator member is a member that is detected by the line sensor to the first width, and the other is two members that are detected by the line sensor to the second width and the third width. The two members are integrally formed with a distance of a distance detected by the line sensor to be detected by the line sensor,
3. The first width according to claim 1, wherein the first width is larger than the second width and the third width, and the fourth width is larger than the first width. Paper feeder. The sheet feeding device according to claim 3, wherein the second width and the third width have the same value. A paper feeding device configured to be able to stack a plurality of size recording papers,
A first movable member that comes into contact with at least one end face in the width direction of the loaded recording paper;
A second movable member that comes into contact with at least one end surface of the placed recording paper in the longitudinal direction;
A first indicating member and a second indicating member configured to move along one predetermined trajectory in conjunction with the first movable member and the second movable member;
Position detecting means for detecting positions of the first indicating member and the second indicating member on the one orbit;
A size detecting means for obtaining the size of the loaded recording paper from the detected positions of the first movable member and the second movable member;
With
When the first indicating member and the second indicating member are overlapped on the first track, the positions of the first indicating member and the second indicating member can be detected by the position detecting unit. Configured,
The position detecting means detects the positions of the first indicating member and the second indicating member via a line sensor arranged along the one orbit,
The sheet feeding device, wherein the first indicating member and the second indicating member are configured to be identifiable by the line sensor when their transmittances are different from each other. The position detecting means includes
A light source disposed on the side close to the line sensor with respect to the first indicating member and the second indicating member;
A reflecting mirror disposed on a side away from the line sensor with respect to the first indicating member and the second indicating member, and reflecting a light beam from the light source;
With
The first indicating member and the second indicating member are disposed on an optical path from the light source to the reflecting mirror, and are disposed on an optical path from the reflecting mirror to the line sensor,
6. The sheet feeding device according to claim 5, wherein one of the first indicating member and the second indicating member has a transmittance of 50 to 60%, and the other has a transmittance of 60 to 80%. One of the first indicating member and the second indicating member is a member that is detected by the line sensor to the fifth width, and the other is a member that is detected by the line sensor to have a sixth width that is different from the fifth width. The paper feeding device according to claim 5, wherein the paper feeding device is a paper feeding device. The sheet feeding device according to any one of claims 5 to 7, wherein the first indicating member and the second indicating member are ND (Neutral Density) filters having different transmittances. A paper feeding device according to any one of claims 1 to 8,
An operation means for accepting an external operation;
A display means for displaying information so as to be visible from the outside;
Printing means for forming an image on the recording paper supplied from the paper feeding device;
Control means for displaying the size of the recording paper detected by the paper feeding device on the display means and setting the printing means based on an operation input received via the operation means;
An image forming apparatus comprising:

Images