Image reading device, and image forming apparatus

Abstract

To provide a document reading device that can be accelerated, can be reduced in a size, and can also ensure quality of a read image.SOLUTION: Control means can execute a first resolution mode for reading an image of a sheet at a first resolution (no in S2), and a second resolution mode for reading the image of the sheet at a second resolution higher than the first resolution (yes in S2). The control means can execute a high speed mode for setting a conveyance speed to a first conveyance speed in the first resolution mode, and a low speed mode for setting the conveyance speed to a second conveyance speed lower than the first conveyance speed in the second resolution mode. In executing the low speed mode, the control means can execute a first low speed mode for setting a first driving speed to driving means (S5) when the sheet has a first thickness (no in S3), and a second low speed mode for setting a second driving speed faster than the first driving speed to the driving means (S6) when the sheet has a second thickness larger than the first thickness.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image reading device that conveys a sheet, and an image forming apparatus. [Background technology]

[0002] For example, printers, copiers, facsimile machines, automatic document feeders (ADFs), and the like are equipped with mechanisms for transporting sheets. When a sheet is transported, the transport resistance (load torque) varies depending on the thickness (basis weight) and size of the sheet. For this reason, a device has been disclosed that sets the current value supplied to a drive motor that drives rollers that transport the sheet according to sheet information (paper information) (see Patent Document 1). The device in Patent Document 1 appropriately selects the current value of the drive motor according to the thickness and size of the sheet, thereby reducing heat generation and power consumption when the sheet is transported. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-182882 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when thick paper is transported, the transport resistance is greater than that of paper types such as plain paper, etc. Therefore, when the document is thick paper, there is a problem in that the amount of slippage between each roller pair increases when the image on the document is read.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image reading device and an image forming device that can handle thick paper. [Means for solving the problem]

[0006] This image reading device comprises a sheet stacking means on which sheets are loaded, a plurality of transport rollers that transport the sheets loaded on the sheet stacking means, an image reading means that reads the image of the sheet transported by the plurality of transport rollers through a transparent member, a guide member that is arranged opposite the transparent member and guides the sheet transported by the plurality of transport rollers, a motor that drives a first roller and a second roller among the plurality of transport rollers that are arranged on either side of the guide member in the sheet transport direction, a setting means that sets a first resolution and a second resolution higher than the first resolution as the resolution at which the image reading means reads the image of the sheet, and a control means that can execute a normal mode and a cardboard mode that transports a sheet that is thicker than the sheet transported in the normal mode, and is characterized in that when the second resolution is set as the resolution at which the image reading means reads the image of the sheet, the rotational speed of the motor in the cardboard mode is faster than the rotational speed of the motor in the normal mode.

[0007] The present image forming apparatus is characterized by comprising the image reading device described above, and an image forming section that forms the image read by the image reading means on another sheet. [Effects of the Invention]

[0008] According to the present invention, thick paper can be used. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1A is a schematic diagram showing an overall configuration of a printer according to a first embodiment, and FIG. 1B is a schematic diagram showing an image forming engine. [Figure 2] FIG. 2 is a block diagram showing a control unit according to the first embodiment, and sensors and various motors connected thereto. [Figure 3] 5 is a flowchart showing drive speed mode setting control according to the first embodiment. [Figure 4] 5 is a graph showing the relationship between the intensity of vibration received by a vibration receiving element of the document thickness detection sensor and a threshold value in the first embodiment. [Figure 5] FIG. 10 is a schematic diagram showing the structure of a document thickness detection sensor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment [Overall configuration] First, a first embodiment of the present invention will be described. A printer 100 as an image forming apparatus according to the first embodiment is an electrophotographic laser beam printer. As shown in FIG. 1(a), the printer 100 includes a printer main body 70 and a document reading device 10 attached to the top of the printer main body 70. In the following, the term "sheet" refers to plain paper as well as special paper such as cardboard and coated paper, recording materials in special shapes such as envelopes and index paper, and plastic films and cloths for overhead projectors, and documents are also an example of sheets.

[0011] The printer main body 70 has an image forming engine 60 therein as an image forming section. As shown in FIG. 1(b), the image forming engine 60 includes an image forming unit PU as an electrophotographic image forming means and a fixing device 7. When a command to start an image forming operation is issued, the photosensitive drum 1, which is a photosensitive member, rotates, and the drum surface is uniformly charged by the charging device 2. Then, the exposure device 3 modulates and outputs laser light based on image data transmitted from the image reading devices 30 and 31 as image reading means or an external computer, and scans the surface of the photosensitive drum 1 to form an electrostatic latent image. This electrostatic latent image is visualized (developed) into a toner image by the toner supplied from the developing device 4.

[0012] In parallel with this image forming operation, a feeding operation is performed to feed sheets loaded on a cassette or manual feed tray (not shown) toward the image forming engine 60. The fed sheets are transported in accordance with the progress of the image forming operation by the image forming unit PU. The toner image carried on the photosensitive drum 1 is then transferred onto the sheet by the transfer roller 5. Any toner remaining on the photosensitive drum 1 after the toner image has been transferred is collected by a cleaning device 6. The sheet onto which the unfixed toner image has been transferred is passed to a fixing device 7, where it is sandwiched between a pair of rollers and heated and pressurized. The sheet on which the toner has melted and adhered to the sheet and the image has been fixed is discharged by a discharge means such as a pair of discharge rollers.

[0013] [Image reader] Next, the document reading device 10 will be described in detail. As shown in FIG. 1(a), the document reading device 10 includes an ADF (automatic document feeder) 20 that feeds documents D loaded on a document tray 121 and discharges them onto a discharge tray 122, and a reading unit 40 that reads the documents transported by the ADF 20. That is, the ADF 20 constitutes a sheet transport device that transports sheets as documents to the reading unit 40. The reading unit 40 constitutes an image reading section that has an image reading device 30 that reads an image on the front surface of the document D. The document tray 121 constitutes sheet stacking means, and the discharge tray 122 constitutes discharge stacking means. The ADF 20 is rotatably supported by a hinge relative to the reading unit 40 so that a document table glass 203 can be opened. The document D, which is an example of a sheet, may be blank paper or may have an image formed on one or both sides.

[0014] The ADF 20 includes, as a conveying means, a pickup roller 101 as a feed roller, a separation drive roller 102 and a separation driven roller 103 that form a separation roller pair, and a registration roller pair 104. Furthermore, the ADF 20 includes, as a conveying means, conveying roller pairs 105, 106, and 108 and a discharge roller pair 109. The ADF 20 also includes an image reading device 31. The ADF 20 also includes a document presence / absence detection sensor Sn1, a document width detection sensor Sn2, and a document length / shortness detection sensor Sn3. The ADF 20 also includes a document detection sensor Sn4, a document detection sensor Sn5, a document detection sensor Sn6, a document detection sensor Sn7, a document detection sensor Sn8, and an ultrasonic sensor Sn10.

[0015] Of these sensors, reflective or transmissive optical sensors can be used for the sensors other than the document width detection sensor Sn2 and the ultrasonic sensor Sn10. Furthermore, the document width detection sensor Sn2 can be an optical sensor such as a photointerrupter that detects the position of a light-shielding plate provided on the regulating plate 123. Details of the ultrasonic sensor Sn10 will be described later. As shown in FIG. 2, the signals of these sensors are output to the control unit 80, and are determined by the control unit 80 to function as follows:

[0016] The document presence / absence detection sensor Sn1 detects the presence or absence of a document D on the document tray 121. The document width detection sensor Sn2 detects the width of the document D by detecting the position of a regulating plate 123 that regulates the width of the document D on the document tray 121. The document length detection sensor Sn3 detects whether the length of the document D on the document tray 121 is equal to or greater than a predetermined length, thereby detecting whether the document length is equal to or greater than a predetermined length. The document detection sensors Sn4 to Sn8 detect the leading and trailing ends of the document D. The ultrasonic sensor Sn10, which serves as a detection means, emits ultrasonic waves from an oscillation element toward the document D and receives the ultrasonic waves that pass through the document D with a receiving element. As shown in FIG. 4, the ultrasonic waves received by the receiving element vary depending on the transmittance of the document D, and therefore, whether the document D is a cardboard sheet or other sheet can be determined by whether the value converted into a voltage V exceeds a threshold.

[0017] On the other hand, the reading unit 40 includes a platen glass 201 , a jump table 202 , a document glass 203 , and an image reading device 30 .

[0018] The document reading device 10 reads image information from the document D in a flow reading mode in which the document image is scanned while the document D loaded on the document tray 121 is fed by the ADF 20, and in a fixed reading mode in which the document placed on the document glass 203 is scanned. The flow reading mode is selected when the document presence / absence detection sensor Sn1 detects the document D loaded on the document tray 121, or when the user explicitly instructs it via the operation panel of the printer main body 70 or the like.

[0019] When the skimming mode is executed, the pickup roller 101 descends and abuts against the topmost document D on the document tray 121. The document D is then fed by the pickup roller 101 and separated one by one at a separation nip formed as a separation means by the separation drive roller 102 and the separation driven roller 103. A torque limiter is disposed in the rotation support structure of the separation driven roller 103, so that the separation driven roller 103 rotates together with the separation drive roller 102 when one document is fed, and does not rotate when two or more documents are fed. This allows the documents to be separated one by one. Note that a drive force may be input to the separation driven roller 103 in the direction opposite to the sheet feeding direction.

[0020] The leading and trailing edges of the document D that has passed through the separation nip are detected by document detection sensor Sn4, and serve as a reference for the timing of raising and lowering the pickup roller 101 and the timing of starting and stopping its drive. Also, the leading and trailing edges of the document D are detected by document detection sensor Sn5, and serve as a reference for the timing of starting and stopping the drive of the registration roller pair 104. The pickup roller 101 and separation drive roller 102 are connected to and driven by the same drive source, feeding / separation motor M1 (see FIG. 2).

[0021] The leading edge of the transported document D hits the registration roller pair 104, which is in a stopped state, and skew of the document D is corrected. The document D, whose skew has been corrected, is transported by the registration roller pair 104, and is transported by transport roller pairs 105, 106, and 108 toward the platen glass 201 and the image reading device 31. A platen guide 107 is disposed opposite the platen glass 201, and the platen guide 107 guides the document D passing through the platen glass 201 so that it does not lift off the platen glass 201. The transport roller pairs 105, 106, and 108 are connected to and driven by a transport motor M2 (see FIG. 2), and the registration roller pair 104 is connected to and driven by a registration motor M3 (see FIG. 2).

[0022] The leading and trailing edges of the document D that has passed through the pair of registration rollers 104 are detected by document detection sensor Sn6, and serve as a reference for the start and stop timing of the drive of pairs of transport rollers 105, 106, and 108. Furthermore, the leading and trailing edges of the document D that has passed through pair of transport rollers 106 are detected by document detection sensor Sn7, and serve as a reference for the start and end of the reading operation of image reading device 30. Furthermore, the leading and trailing edges of the document D that has passed through pair of transport rollers 108 are detected by document detection sensor Sn8, and serve as a reference for the start and end of the reading operation of image reading device 31.

[0023] An image on the front side of the original D is read by the image reading device 30 through the platen glass 201, and an image on the back side of the original D is read by the image reading device 31. Image information photoelectrically converted by light receiving elements of line sensors (not shown) of these image reading devices 30 and 31 is transferred to the control unit 80 (see FIG. 2). Then, the original D that has passed through the platen glass 201 is guided by the jump platform 202 to the pair of conveying rollers 108, passes through the image reading device 31, and is discharged onto the discharge tray 122 by the pair of discharge rollers 109. The pair of discharge rollers 109 is connected to and driven by a discharge motor M4 (see FIG. 2).

[0024] On the other hand, the fixed reading mode is selected when the device detects an original D placed on the platen glass 203 or when the user explicitly instructs this via an operation panel or the like of the printer main body 70. In this case, the original D on the platen glass 203 does not move, and the image reading device 30 moves along the platen glass 203 to scan the original D. Similarly, image information photoelectrically converted by a light receiving element of a line sensor (not shown) of the image reading device 30 is transferred to the control unit 80 (see FIG. 2).

[0025] [Control Unit] Next, the configuration of the control unit 80, which serves as a control means for the printer 100 and the ADF 20, will be described with reference to FIG. 2. As shown in FIG. 2, the control unit 80 includes a CPU 81, a RAM 82, a ROM 83, etc. The control unit 80 is also connected to the aforementioned document presence / absence detection sensor Sn1, document width detection sensor Sn2, document length detection sensor Sn3, document detection sensors Sn4 to Sn8, and ultrasonic sensor Sn10, which serves as a document thickness detection sensor, and receives signals from these sensors. The control unit 80 is also connected to a feeding / separating motor M1, a conveying motor M2, a registration motor M3, and a discharge motor M4, which serve as driving means or driving motors, and the document conveying speed of each roller pair is set by setting the driving speeds of these motors.

[0026] [Mode setting control] Next, the mode setting control when setting the drive speed of each drive motor such as the above-mentioned feeding / separating motor M1, conveying motor M2, registration motor M3, and discharge motor M4 will be described using FIG. 3 with reference to FIG. 1(a).

[0027] In this embodiment, to reduce the space required for the ADF 20, the document tray 121 and the discharge tray 122 are arranged so as to overlap each other in the vertical direction. Therefore, the transport path 110 for transporting the document D is U-shaped when viewed from the width direction perpendicular to the document transport direction (sheet transport direction) so as to invert the document D. That is, the transport path 110 has a curved shape 111. The smaller the arc diameter of the curved shape 111, the more compact the ADF 20 can be. However, the greater the rigidity of the document D (the force that attempts to return the document to its original shape when bent), the greater the transport resistance. The rigidity of the document D is approximately proportional to the thickness of the document D. In other words, if the document D is cardboard, the transport resistance is greater than for other paper types (such as plain paper). If the document D is cardboard, the transport resistance increases and the amount of slippage in each roller pair also increases. Therefore, even if each drive motor is driven at the same speed, the transport speed slows by several percent. If the transport speed of the document D is slowed down, the image read by the image reading devices 30 and 31 will be extended in the sub-scanning direction accordingly. Therefore, it is possible to slow down the image reading speed by the image reading devices 30 and 31 accordingly, but this would require detailed control of the scanning speed, which would make the control complex.

[0028] On the other hand, in order to improve productivity, when reading monochrome images or low-resolution images, it is conceivable to transport the original D at high speed. However, when the transport speed of the original D is increased, transport resistance increases according to the speed, and the performance of each drive motor cannot keep up, and in particular, with thick paper originals D, the transport speed drops at the curved shape 111, and there is a risk of the next original D catching up and causing a jam (paper jam).

[0029] Therefore, in this embodiment, the mode setting control described below is executed to enable the ADF 20 to be made compact, and to increase the speed and improve productivity while maintaining the quality of the scanned image. In this embodiment, the designed conveying speed of the original D is either a high speed or a slower speed. The reading speeds of the image reading devices 30 and 31 are also either a high speed corresponding to the conveying speed or a slower speed. The read processing modes in this embodiment include a color mode in which the image of the original D is read in color and a monochrome mode in which the image of the original D is read in black and white. Furthermore, the read processing modes in this embodiment include a high-resolution mode, e.g., 600 dpi or higher, and a low-resolution mode, e.g., less than 600 dpi.

[0030] When the control unit 80 starts the mode setting control, it first determines whether the setting of the image reading process commanded by the operation unit (operation panel) (not shown) of the printer 100 or an external computer is the color mode (S1). That is, it determines whether the setting of the image reading process commanded is the monochrome mode in which the image of the document D is read in black and white by the image reading devices 30, 31, or the color mode in which the image is read in color. If it is not the color mode (no in S1), that is, if it is the monochrome mode, it proceeds to step S4.

[0031] On the other hand, if the mode is color (yes in S1), the resolution in the image reading process settings instructed by the operation unit (operation panel) (not shown) of printer 100 or an external computer is determined (S2). That is, if the instructed resolution is a low resolution (first resolution) such as less than 600 dpi (no in S2), the process proceeds to step S4 as the low resolution mode (first resolution mode). On the other hand, if the instructed resolution is a high resolution (second resolution) that is higher than the low resolution, such as 600 dpi or more (yes in S2), the process proceeds to step S3 as the high resolution (second resolution mode).

[0032] In step S3, the control unit 80 determines whether the document D is thick paper (second thickness) or other than thick paper (first thickness) based on the detection result of the ultrasonic sensor Sn10. That is, if the document D is thick paper, the paper type mode is determined to be thick paper mode (yes in S3), and if the document D is other than thick paper, the paper type mode is determined to be normal mode (no in S3). If the normal mode is determined, the mode is color mode and high resolution mode, so the control unit 80 sets the transport speed and reading speed of the document D to a first low-speed mode (second transport speed) (S5). When the first low-speed mode is set, the control unit 80 sets the first drive speed for each drive motor (feed / separation motor M1, transport motor M2, registration motor M3, and discharge motor M4). Therefore, each roller (pickup roller 101, separation drive roller 102, registration roller pair 104, conveying roller pairs 105, 106, 108, and discharge roller pair 109) is rotated at a low first drive speed, and the conveying speed of the document D is set to a low speed. This ensures the quality of the read image while reading a color and high-resolution image.

[0033] If step S3 determines that the mode is the thick paper mode, the mode is color and high-resolution, and the control unit 80 then sets the transport speed and reading speed of the document D to a second low-speed mode (S6), which slows down the transport speed and reading speed of the document D. When the second low-speed mode is set, the control unit 80 sets the drive motors (feed / separation motor M1, transport motor M2, registration motor M3, and discharge motor M4) to a second drive speed, which is faster than the first drive speed, for the second low-speed mode. Therefore, the rollers (pickup roller 101, separation drive roller 102, registration roller pair 104, transport roller pairs 105, 106, and 108, and discharge roller pair 109) are rotated at a second drive speed that is slower and faster than the first low-speed mode. This second drive speed takes into account the amount of slippage of the thick paper on each rotor. In other words, the transport speed of the document D is set to be the same as the transport speed in the first low-speed mode when, for example, plain paper is being transported. This makes it possible to prevent the read image from being stretched even if the document D is made of thick paper, and ensure the quality of the read image.

[0034] As described above, when the process proceeds to step S3, it has been determined through steps S1 and S2 that the low-speed mode will be executed if the color mode and the high-resolution mode are selected. When the low-speed mode is executed, one of the first low-speed mode as the normal mode and the second low-speed mode as the cardboard mode is executed depending on the thickness of the document D.

[0035] On the other hand, when the process proceeds to step S4, similarly to step S3, it is determined whether the document D is cardboard or other than cardboard based on the detection result of the ultrasonic sensor Sn10. That is, if the document D is cardboard, it is determined to be cardboard mode (yes in S4), and if the document D is other than cardboard, it is determined to be normal mode (no in S4). If it is determined to be normal mode, it is set to high-speed mode, which sets the transport speed and reading speed of the document D to high speed (first transport speed) (S7). When set to high-speed mode, the control unit 80 sets each drive motor to a high drive speed as the high-speed mode. Therefore, each roller is driven to rotate at high speed, and the transport speed of the document D is set to high speed, which is faster than the above-mentioned low speed. This makes it possible to increase the number of sheets processed per unit time when reading monochrome, low-resolution images on plain paper, etc., and improve productivity.

[0036] Furthermore, if step S4 determines that the mode is thick paper mode, then although this is either monochrome mode or low-resolution mode, the process proceeds to step S6 described above, where the second low-speed mode is set, in which the transport speed and reading speed of the original D are slowed. Therefore, each roller is driven to rotate at a low speed and the second drive speed. This allows for the original D to be read at a high speed if the original D is thick paper, which could cause a jam, particularly at the curved shape 111. However, since the image is read at a low speed, this type of jam can be prevented. Furthermore, by driving each drive motor at the second drive speed, which takes into account the amount of slippage of the thick paper, it is possible to prevent the read image from being stretched, even if the reading speed remains low, and the quality of the read image can be ensured.

[0037] For the sake of convenience, the description has been given assuming that three drive speeds, namely, a first drive speed, a second drive speed, and a high drive speed, are set for each of the feeding / separating motor M1, the conveying motor M2, the registration motor M3, and the discharge motor M4. However, when setting the drive speed for each of these drive motors, rather than setting the same drive speed among the three drive speeds, different drive speeds are set for each depending on the friction coefficient and outer diameter of each roller so that the document D is conveyed at the same speed. In other words, in the case of the thick paper mode, when setting the second drive speed for each of the multiple drive motors, different drive speeds are set for each so that the document D is conveyed at the same speed by each roller.

[0038] As described above, in the first embodiment, even when the document D is thick paper, the conveying speed can be made the same as when the document D is not thick paper, thereby simplifying various controls.

[0039] <Second embodiment> Next, a second embodiment, which is a partial modification of the first embodiment, will be described with reference to FIG. 5. In the first embodiment, an ultrasonic sensor Sn10 is disposed downstream of the pair of registration rollers 104 in the document transport direction to detect the thickness of the document D. In the second embodiment, instead of the ultrasonic sensor Sn10, an optical sensor Sn11 is provided on the pair of registration rollers 104 as a detection means to detect the thickness of the document D. That is, the optical sensor Sn11 has a structure in which light is blocked when the amount of movement of one of the roller shafts of the pair of registration rollers 104 exceeds a predetermined amount, and when the amount of movement exceeds the predetermined amount, the document D can be detected as thick paper. The other configurations, operations, and effects are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0040] <Possibilities for other embodiments> In the first and second embodiments described above, the high-speed mode or the low-speed mode is determined based on both the color mode and the high-resolution mode. However, the high-speed mode or the low-speed mode may be determined based only on the color mode, or the high-resolution mode or the low-speed mode may be determined based only on the high-resolution mode.

[0041] In the first and second embodiments, the thickness of the sheet is determined as two types, cardboard and non-cardboard, and the drive speed of the drive motor in the low-speed mode is set to two types accordingly. However, the present invention is not limited to this, and three or more types of thickness may be determined and the drive speed of the drive motor may be set accordingly.

[0042] In the first and second embodiments, the image reading process is described as being set to either a color mode or a monochrome mode. However, the present invention is not limited to this. For example, a low color gradation or a grayscale may be treated as either a color mode or a monochrome mode. Furthermore, a low color gradation or a grayscale may be set as an intermediate mode, allowing a medium-speed mode between the low-speed mode and the high-speed mode to be set.

[0043] In the first and second embodiments, a high-resolution mode of 600 dpi or more and a low-resolution mode of less than 600 dpi are set in the image reading process. However, this is not limiting, and for example, 400 dpi may be set as the medium resolution mode, so that a medium-speed mode between the low-speed mode and the high-speed mode can be set. Note that these numerical values ​​for resolution, such as 600 dpi, are merely examples, and any value may be used.

[0044] In the first and second embodiments, the ADF 20 is described as having four motors: the feeding / separating motor M1, the conveying motor M2, the registration motor M3, and the discharge motor M4. However, this is not limiting, and the number of motors may be reduced to three or less by providing a driving force transmission switching mechanism such as a clutch and sharing the motors. Conversely, the number of motors may be increased to five or more, for example, by providing a motor for each conveying roller.

[0045] In the first embodiment, the ultrasonic sensor Sn10 is used to detect the thickness of the original D, and in the second embodiment, the optical sensor Sn11 provided on the registration roller pair 104 is used to detect the thickness of the original D. However, the present invention is not limited to these, and the thickness of the original D (sheet) may be detected (determined) in any manner. For example, when the type of sheet is set on the operation panel of the printer main body 70 or by an external computer, the thickness of the sheet may be detected based on the type information. [Explanation of symbols]

[0046] 10... Document reading device: 30, 31... Image reading means (image reading device): 60... Image forming unit (image forming engine): 80... Control means (control unit): 100... Image forming device (printer): 101... Conveying means, feeding roller: 102, 103... Conveying means, separation roller pair: 104... Conveying means, registration roller pair: 105, 106, 108... Conveying means, conveying roller pair: 109... Conveying means, discharge roller pair: 110... Conveying path: 111... Curved shape: 121... Sheet stacking means (document tray): 122... Discharge stacking means (discharge tray): D... Sheet (document): M1... Driving means, driving motor (feeding and separation motor): M2... Driving means, driving motor (conveying motor): M3... Driving means, driving motor (registration motor): M4... Driving means, driving motor (discharge motor): Sn10... Detection means (ultrasonic sensor): Sn11... Detection means (optical sensor)

Claims

1. a sheet stacking means for stacking sheets; a plurality of conveying rollers for conveying the sheets stacked on the sheet stacking means; an image reading unit that reads an image on the sheet conveyed by the plurality of conveying rollers through a transparent member; a guide member disposed opposite the transparent member and configured to guide the sheet conveyed by the plurality of conveying rollers; a motor that drives a first roller and a second roller among the plurality of conveying rollers, the first roller and the second roller being disposed on either side of the guide member in a sheet conveying direction; a setting unit for setting a first resolution and a second resolution higher than the first resolution as resolutions at which the image reading unit reads an image on a sheet; a control means for controlling a normal mode and a cardboard mode for conveying a sheet that is thicker than the sheet conveyed in the normal mode; when the second resolution is set as the resolution at which the image reading means reads an image on a sheet, the rotation speed of the motor in the cardboard mode is faster than the rotation speed of the motor in the normal mode; An image reading device characterized by:

2. a discharge stacking means for stacking sheets whose images have been read by the image reading means; a conveying path for conveying sheets from the sheet stacking means to the discharge stacking means, the sheet stacking means and the discharge stacking means are arranged at positions where they overlap in the vertical direction, the conveying path has a curved shape when viewed from a direction perpendicular to the sheet conveying direction so as to turn over the sheet.

2. The image reading device according to claim 1, wherein:

3. A detection means for detecting the thickness of the sheet is provided.

3. The image reading device according to claim 1, wherein the image reading device is a scanning device.

4. the setting means is capable of setting the normal mode and the cardboard mode as modes to be executed by the control means; 3. The image reading device according to claim 1, wherein the image reading device is a scanning device.

5. the first roller is disposed adjacent to the guide member on the upstream side in the conveying direction, the second roller is disposed adjacent to the guide member on the downstream side in the conveying direction; 5. The image reading device according to claim 1, wherein the image reading device is a scanning device.

6. a sheet conveying speed when an image is read at the first resolution in the normal mode is faster than a sheet conveying speed when an image is read at the second resolution in the normal mode and a sheet conveying speed when an image is read at the first and second resolutions in the cardboard mode; 6. The image reading device according to claim 1, wherein the image reading device is a scanning device.

7. a sheet stacking means for stacking sheets; a plurality of conveying rollers for conveying the sheets stacked on the sheet stacking means; an image reading unit that reads an image on the sheet conveyed by the plurality of conveying rollers through a transparent member; a guide member disposed opposite the transparent member and configured to guide the sheet conveyed by the plurality of conveying rollers; a motor that drives a first roller and a second roller among the plurality of conveying rollers, the first roller and the second roller being disposed on either side of the guide member in a sheet conveying direction; a setting means for setting a first resolution and a second resolution higher than the first resolution as the resolution at which the image reading means reads the image on the sheet, and for setting whether the image reading means reads the image on the sheet in color or monochrome; a control means for controlling a normal mode and a cardboard mode for conveying a sheet that is thicker than the sheet conveyed in the normal mode; when the second resolution is set as a resolution at which the image reading means reads the image on the sheet, and when the image reading means reads the image on the sheet in color, the rotation speed of the motor in the cardboard mode is faster than the rotation speed of the motor in the normal mode; An image reading device characterized by:

8. An image reading device according to any one of claims 1 to 7; an image forming unit that forms the image read by the image reading means on another sheet, An image forming apparatus characterized by:

Images