Image forming apparatus

Abstract

To provide an image forming apparatus that improves the accuracy of reading an image with a simple configuration.SOLUTION: A printer body 104, which is image forming means for forming an image on a recording material, has an environmental sensor Sn4 which is detection means for detecting environmental information including at least either one of temperature or humidity, and an image forming condition is set on the basis of the environmental information detected by the detection means. An image reading device 101, which has conveying means for conveying a document and driving sources for driving the conveying means and is reading means for reading image information from a document conveyed by the conveying means, further has a reader control unit 400 which is control means for controlling a supply motor and a conveying motor which are the driving sources and is connected to the printer body. The control means controls the driving speed of the conveying means driven by the driving sources on the basis of the environmental information detected by the detection means in the printer body.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material. [Background technology]

[0002] Patent Document 1 describes an original reading device that corrects the drive frequency of a pulse motor that drives a feed roller based on the detection result of a temperature sensor located near the feed roller that conveys the original. Patent Document 2 describes an original feeding and reading device that corrects the rotation speed of a stepping motor that drives a paper discharge roller based on the detection result of a contact temperature detection sensor that contacts the outer surface of the paper discharge roller that discharges the original. Patent Document 3 describes an image reading device that corrects the reading cycle of a CCD based on environmental conditions acquired by a temperature sensor and a humidity sensor located near the feed roller that conveys the original. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-236565 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-269601 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-270822 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configurations of the above documents, in order to control the motor drive speed or reading cycle in accordance with environmental conditions, it is necessary to place a sensor near the conveying roller in the document conveying device, and adding a sensor leads to an increase in the number of parts and an increase in costs.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus that can improve the accuracy of reading an image with a simple configuration. [Means for solving the problem]

[0006] One aspect of the present invention is an image forming apparatus comprising: an image forming means for forming an image on a recording material; a detection means for detecting environmental information including at least one of temperature and humidity, wherein the apparatus main body is configured to set image formation conditions based on the environmental information detected by the detection means; a transport means for transporting a document; a drive source for driving the transport means; a reading means for reading image information from the document transported by the transport means; and a control means for controlling the drive source, and an image reading device connected to the apparatus main body, wherein the control means controls the drive speed of the transport means driven by the drive source based on the environmental information detected by the detection means of the apparatus main body.

[0007] Another aspect of the present invention is an image forming apparatus comprising: an image forming means for forming an image on a recording material; a detection means for detecting environmental information including at least one of temperature and humidity, wherein the apparatus main body is configured to set image formation conditions based on the environmental information detected by the detection means; a transport means for transporting a document; a reading means for reading image information line by line from the document transported by the transport means; and a control means for controlling the reading means, and an image reading device connected to the apparatus main body, wherein the control means controls the reading cycle when the reading means reads image information based on the environmental information detected by the detection means of the apparatus main body. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus that can improve the accuracy of reading an image with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of an image reading apparatus according to a first embodiment. [Figure 3] 1 is a schematic diagram of an image reading apparatus according to a first embodiment. [Figure 4] FIG. 1 is an explanatory diagram of an image reading apparatus according to a first embodiment. [Figure 5] FIG. 2 is a block diagram showing a control system of the image forming apparatus according to the first embodiment. [Figure 6] 4 is a flowchart showing a control method for the image reading apparatus according to the first embodiment. [Figure 7] 4A and 4B are correction tables (a, b) for the motor driving speed in the first embodiment. [Figure 8] 10A to 10C are flowcharts showing a control method for an image reading device according to a modified example. [Figure 9] 10A and 10B are flowcharts showing a control method of an image reading device according to a modified example. [Figure 10] 10 is a flowchart showing a control method of an image reading apparatus according to a second embodiment. [Figure 11] 10 is a flowchart showing a control method of an image reading apparatus according to a third embodiment. [Figure 12] 10A and 10B are flowcharts showing a control method of an image reading device according to a modified example. [Figure 13] 11 is a correction table for the motor driving speed in the third embodiment. [Figure 14] 10 is a flowchart showing a control method of an image reading apparatus according to a fourth embodiment. [Figure 15] FIG. 10 is a schematic diagram of an image reading device according to a modified example. [Figure 16] FIG. 10 is a block diagram showing a control system of an image forming apparatus according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] First Embodiment First, an image forming apparatus 100 according to the first embodiment will be described with reference to Fig. 1. The image forming apparatus 100 according to the embodiment is an electrophotographic copying machine (or multifunction machine) equipped with an image reading device 101. This image forming apparatus 100 is merely one example of an image forming apparatus to which the technology according to the present disclosure can be applied, and the "image forming apparatus" may be, for example, a large commercial printing machine or an inkjet device.

[0012] 1, image forming apparatus 100 includes a printer main body 104 as the image forming apparatus main body, and an image reading device 101 arranged above printer main body 104. Image forming apparatus 100 can read image information from an original document using image forming apparatus 100, and form an image on a recording material based on the read image information. As the recording material (recording medium) and original document, a variety of sheet materials of different sizes and materials can be used, including paper such as plain paper and cardboard, surface-treated sheet materials such as coated paper, specially shaped sheet materials such as envelopes and index paper, plastic film, cloth, etc.

[0013] (printer body) An image forming unit 120, which is an electrophotographic engine, is disposed inside the printer main body 104 as an image forming means for forming an image on a recording material P. The image forming unit 120 includes four process units 111, 112, 113, and 114 (image forming stations), and laser scanners 107, 108, 109, and 110 as exposure means. The image forming unit 120 also includes an intermediate transfer belt 115, a secondary transfer roller 116, and a fixing device 118.

[0014] Each of the process units 111 to 114 includes a photosensitive drum 11 as an image carrier, a charging unit 12, a developing unit 13, and a cleaning unit. The charging unit 12 is, for example, a charging roller that contacts the surface of the photosensitive drum 11. The developing unit 13 includes a developer container that contains toner as a developer, and a developing roller (developer carrier) that carries the toner and supplies it to the photosensitive drum 11. An intermediate transfer belt 115 as an intermediate transfer body is stretched over multiple rollers. The four process units 111 to 114 are arranged side by side along the intermediate transfer belt 115. A primary transfer roller 14 is arranged on the inner periphery of the intermediate transfer belt 115, facing each photosensitive drum 11 with the intermediate transfer belt 115 in between. A transfer unit (secondary transfer unit) where a toner image is transferred is formed as a nip between a secondary transfer roller 116 and the intermediate transfer belt 115.

[0015] The fixing device 118 has a fixing roller 118a, a pressure roller 118b (pressure member) pressed against the fixing roller 118a, and a fixing heater 21 (FIG. 5) for heating the fixing roller 118a. The fixing device 118 is a thermal fixing unit that heats and pressurizes the image on the recording material P while sandwiching and conveying the recording material P in a fixing nip formed between the fixing roller 118a and the pressure roller 118b. The fixing device 118 is provided with a temperature detection element such as a thermistor for detecting the temperature of the fixing roller 118a or the fixing heater 21. During image formation, the main body control unit 20 (FIG. 5) controls the power supply to the fixing heater 21 based on the detection result of the temperature detection element so that the fixing roller 118a reaches a predetermined target temperature (fixing temperature) suitable for fixing the image.

[0016] The fixing roller 118a is an example of a fixing member (heating member), and may be a cylindrical film or an endless belt member stretched over multiple rollers. The fixing heater 21 is a heat source for heating the fixing member (heating member). The fixing heater 21 may be, for example, a halogen lamp that emits radiant heat, a heater substrate with a heating resistor pattern printed on a ceramic substrate, or a coil unit that heats a conductive layer in the heating member using the principle of induction heating.

[0017] An overview of the image forming operation, which is a series of operations by which the image forming apparatus 100 forms an image on the recording material P, will be described. For example, when a user presses a copy execution button with an original document set in the image reading device 101, the control unit of the image forming apparatus 100 starts an image reading operation by the printer main body 104 and an image forming operation by the printer main body 104. The control unit forms an image on the recording material P based on image information acquired by causing the image reading device 101 to execute the image reading operation. The configuration of the image reading device 101 and the image reading operation will be described later.

[0018] During image formation, the photosensitive drums 11 and intermediate transfer belt 115 of each process unit 111-114 are rotated. The charging unit 12 uniformly charges the surface of the photosensitive drum 11 by applying a charging voltage from a charging voltage application circuit of a high-voltage power supply 22 (FIG. 5) mounted in the printer main body 104. The laser scanners 107-110 are driven based on image data obtained by breaking down image information into yellow, magenta, cyan, and black components, and irradiate the photosensitive drum 11 with light. This exposes the photosensitive drum 11, and an electrostatic latent image is formed on the surface of the photosensitive drum 11.

[0019] The developing unit develops the electrostatic latent image using toner as a developer. Specifically, a developing voltage is applied to the developing roller from a developing voltage application circuit of a high-voltage power supply 22, and toner is transferred from the developing roller to the photosensitive drum 11 in accordance with the potential distribution on the surface of the photosensitive drum 11. This develops the electrostatic latent image on the photosensitive drum 11 into a toner image. As a result, single-color toner images of yellow, magenta, cyan, and black are formed on the four photosensitive drums 11. These single-color toner images are primarily transferred onto the intermediate transfer belt 115 so that they overlap each other by the primary transfer roller 14, to which a primary transfer voltage is applied from a primary transfer voltage application circuit of the high-voltage power supply 22. As a result, a full-color toner image (hereinafter simply referred to as a toner image) is formed on the intermediate transfer belt 115.

[0020] In parallel with the formation of the toner image, the feeding roller 106 feeds the recording material P one sheet at a time from the feeding cassette 105 toward the secondary transfer portion. A secondary transfer voltage is applied to the secondary transfer roller 116 from the secondary transfer voltage application circuit of the high-voltage power supply 22, whereby the toner image is secondarily transferred from the intermediate transfer belt 115 to the recording material P at the secondary transfer portion. After passing through the secondary transfer portion, the recording material P is sent to the fixing device 118, where the toner image is heated and pressed. This fixes the toner image to the recording material P. After passing through the fixing device 118, the recording material P is discharged outside the printer main body 104 and stacked on a discharge tray 119.

[0021] (Image reader) Next, the image reading device 101 will be described mainly with reference to Figures 2 to 4. Figure 2 is a perspective view of the image reading device 101. Figure 3 is a schematic diagram showing a cross section of the image reading device 101. Figure 4 is a schematic diagram showing the image reading device 101 with the ADF 102 open.

[0022] The image reading device 101 has a reader 103 and an automatic document feeder (hereinafter referred to as ADF) 102 (FIG. 1). The reader 103 is attached to the top of a printer body 104. As shown in FIG. 4, the ADF 102 is supported by the reader 103 via a hinge 317 and is provided so as to be openable and closable relative to the reader 103. The ADF 102 is an example of a sheet transport device that transports sheets (documents).

[0023] 2 and 3, the reader 103 has a first reading unit 306, a flow reading glass 312, and a document table glass 316. The ADF 102 also has a document tray 200, a discharge tray 202, a second reading unit 307, and a flow reading glass 313. The ADF 102 also has a pickup roller 300, a separation roller pair 301, a pull-out roller pair 302, a first read roller pair 303, a second read roller pair 304, and a discharge roller pair 305. All of these transport rollers (300 to 305) are examples of transport means that transport the document D1.

[0024] The first reading unit 306 and the second reading unit 307 are examples of reading means for reading image information from a conveyed document. In this embodiment, the first reading unit 306 is a CCD-type image sensor unit, and the second reading unit 307 is a CIS-type image sensor unit. The first reading unit 306 includes a sensor board 309 on which light-receiving elements are arranged in a line in the sheet width direction, a light source 310 that irradiates light onto the document D1, and a plurality of mirrors 308 that constitute a reduction optical system that forms an optical image of the document D1 on the light-receiving surface of the sensor board. The second reading unit 307 includes a CMOS sensor board on which light-receiving elements are arranged in a line in the sheet width direction, a light source that irradiates light onto the document D1, and a 1x1 optical system that forms an optical image of the document D1 on the light-receiving surface of the sensor board.

[0025] The first reading unit 306 and the second reading unit 307 serving as reading means in this embodiment are both line sensors that acquire line images of the original D1 at a predetermined reading cycle. The line image is an image of one line in which pixels are arranged in the sheet width direction, which is the main scanning direction. The reader control unit 400 (FIG. 5) of the image reading device 101 acquires image information as two-dimensional image data by connecting the line images acquired by the first reading unit 306 and the second reading unit 307 in the sub-scanning direction (original transport direction).

[0026] The pickup roller 300 is a pickup member that picks up the document D1 from the document tray 200, which serves as a loading section on which the document D1 is placed. The separation roller pair 301 includes a feed roller and a separation roller. The feed roller is a feeding member that feeds the document D1 that has been loaded from the document tray 200. The separation roller comes into contact with the feed roller to form a separation nip.

[0027] The separation roller is an example of a separating member that separates sheets by applying frictional force to the sheets. The separation roller may be a roller member supported via a torque limiter on a shaft member fixed to the frame of the ADF 102. The separation roller may also be a retard-drive roller that receives a driving force via a torque limiter in a direction (clockwise in FIG. 3) opposite to the movement direction (document feed direction) of the document D1 in the separation nip. Instead of the separation roller, a pad-shaped elastic member (rubber pad) that contacts the feed roller may be used as the separating member.

[0028] The image reading device 101 is capable of performing an image reading operation (flow-reading operation) in which the first reading unit 306 and the second reading unit 307 read image information on the original D1 while the ADF 102 transports the original D1 one sheet at a time. When the image reading operation is started, the pickup roller 300 rotates while in contact with the topmost original D1 on the original tray 200, and feeds the original D1 from the original tray 200. The separation roller pair 301 applies frictional force to the original D1 in the separation nip in the direction opposite to the original feeding direction, while the feed roller transports the original D1. When multiple originals D1 enter the separation nip, the separation roller prevents the originals D1 other than the one in contact with the feed roller from passing through the separation nip. As a result, the originals D1 pass through the separation nip in a single separated state.

[0029] Original document D1 that has passed through the separation nip is transported in this order by a pair of pull-out rollers 302, a first pair of read rollers 303, and a second pair of read rollers 304. During this process, a first reading unit 306 optically scans the first side (front side) of original document D1 through a flow-reading glass 312 and converts it into an electronic signal. A second reading unit 307 optically scans the second side (back side) of original document D1 through a flow-reading glass 313 and converts it into an electronic signal. This obtains image information as electronic image data. Original document D1, from which the image information has been read, is discharged from the transport path within ADF 102 by a pair of discharge rollers 305 and stacked on discharge tray 202.

[0030] The image reading device 101 can also read image information from a stationary original placed on the reader 103. In this case, as shown in Fig. 4, the user opens the ADF 102 and places an original D2 on the platen glass 316 of the reader 103, and then closes the ADF 102 to instruct execution of reading. Then, the first reading unit 306 optically scans the original D2 while moving in the sub-scanning direction to obtain image information.

[0031] (ADF document detection mechanism) Furthermore, the ADF 102 has a detection unit (size detection unit) that detects the size of the original document. The size detection unit in this embodiment is composed of an original document presence sensor Sn1, an original document width sensor Sn2, and an original document length sensor Sn3. The original document presence sensor Sn1, the original document width sensor Sn2, and the original document length sensor Sn3 are examples of a size acquisition unit that acquires information about the size of the original document D1. The size acquisition unit may be an operation panel that allows the user to input the original document size.

[0032] The document presence sensor Sn1 and the document length sensor Sn3 are sensors that detect the presence or absence of a document D1 at a predetermined position on the document tray 200. The document presence sensor Sn1 is disposed near the downstream end position of the document tray 200 in the document feed direction. The document length sensor Sn3 is disposed at a predetermined distance upstream of the document presence sensor Sn1 in the document feed direction. Each of the document presence sensor Sn1 and the document length sensor Sn3 can be a reflective or transmissive optical sensor.

[0033] The document width sensor Sn2 is a sensor that detects the width of the document in the document width direction perpendicular to the document feed direction (document transport direction). As the document width sensor Sn2, an optical sensor such as a photointerrupter that detects the position of a light-shielding plate provided on a side regulating plate 201 provided in the document tray 200 can be used. The side regulating plates 201 are a pair of regulating members that move in conjunction with each other in the document width direction and regulate both side edges of the document (FIG. 2).

[0034] As shown in Fig. 5, signals from these sensors (Sn1 to Sn3) are output to the reader control unit 400. Fig. 5 is a block diagram showing a control system of the image forming apparatus 100 according to this embodiment.

[0035] The reader control unit 400 determines whether or not there is a document D1 on the document tray 200 based on the detection result of the document presence / absence sensor Sn1. The reader control unit 400 also determines the length of the document D1 on the document tray 200 in the document width direction (hereinafter simply referred to as the document width) based on the detection result of the document width sensor Sn2. The reader control unit 400 also determines whether or not the length of the document D1 on the document tray 200 in the document feed direction (hereinafter simply referred to as the document length) is equal to or greater than a predetermined length based on the detection result of the document length sensor Sn3.

[0036] 5, the pickup roller 300 and the separation roller pair 301 are both connected to and driven by a feed motor M1. The pull-out roller pair 302, the first read roller pair 303, the second read roller pair 304, and the discharge roller pair 305 are connected to and driven by a conveyance motor M2. The feed motor M1 and the conveyance motor M2 are all examples of drive sources that drive the conveyance means.

[0037] (Image forming device control system) The control system of the image forming apparatus 100 will be described with reference to Fig. 5. As shown in Fig. 5, the printer main body 104 has a main body control unit 20, and the image reading device 101 has a reader control unit 400. The main body control unit 20 and the reader control unit 400 are connected so as to be able to communicate with each other.

[0038] The main body control unit 20 and the reader control unit 400 work together to function as a control system that controls the operation of the image forming apparatus 100. The main body control unit 20 controls the operation of the printer main body 104 and also supervises the operation of the entire image forming apparatus 100 including the image reading device 101. The reader control unit 400 is a control means that controls the operation of the image reading device 101 based on instructions from the main body control unit 20.

[0039] The reader control unit 400 has a CPU 401, RAM 402, ROM 403, etc. The reader control unit 400 is also connected to the above-mentioned document presence sensor Sn1, document width sensor Sn2, and document length sensor Sn3, and receives signals from each sensor. The reader control unit 400 is also connected to a feed motor M1 and a transport motor M2, which are drive sources, and a first reading unit 306 and a second reading unit 307, which serve as reading means, and controls these units. The reader control unit 400 also receives environmental information detected by an environmental sensor Sn4 of the printer main body 104 via the main body control unit 20.

[0040] The ROM 403 stores programs and data for controlling the image reading device 101. The CPU 401 reads out the programs from the ROM 403 and executes them while using the RAM 402 as a work area. The CPU 401 controls the operations of the drive sources (M1, M2) and reading means (306, 307) based on the detection results of the sensors (Sn1 to Sn4), thereby being able to execute each step in each flowchart described below.

[0041] In this embodiment, the reader control unit 400 sets the drive speed of the feed motor M1 and the transport motor M2 to drive the transport rollers (300-305) in accordance with the set value (target value, objective value) of the document transport speed. The reader control unit 400 also sets the reading cycle of the first reading unit 306 and the second reading unit 307 in accordance with the set value of the document transport speed. The set value of the document transport speed is set in advance according to the execution conditions of the image reading operation, such as the size of the document, the resolution at the time of reading, whether color reading or monochrome reading is performed, and whether double-sided reading or single-sided reading is performed.

[0042] In this embodiment, the reader control unit 400 acquires the detection result of the environmental sensor Sn4 of the printer main body 104 as information indicating the environmental conditions of the image reading device 101 (hereinafter referred to as environmental information). In this embodiment, the "environmental conditions" include at least temperature and humidity conditions. As will be described in detail later, the reader control unit 400 controls the motor drive speed and / or reading cycle based on the environmental information acquired from the environmental sensor Sn4 of the printer main body 104.

[0043] 5, the printer main body 104 is provided with a main body control unit 20, an environment sensor Sn4, a fixing heater 21, a high-voltage power supply 22, an anti-condensation heater 23, and a cooling fan 24. The main body control unit 20 is connected to the environment sensor Sn4 and receives signals from the environment sensor Sn4. The main body control unit 20 also controls the operation of each load provided in the printer main body 104, such as the fixing heater 21, the high-voltage power supply 22, the anti-condensation heater 23, and the cooling fan 24. The fixing heater 21 and the high-voltage power supply 22 have been described above, so a description thereof will be omitted.

[0044] The main body control unit 20 includes a CPU, RAM, ROM, etc. The ROM stores programs and data for controlling the image forming apparatus 100. The CPU reads the programs from the ROM and executes the programs while using the RAM as a work area. For example, the CPU of the main body control unit 20 drives the image forming unit 120 and the conveying members of the printer main body 104 in accordance with the programs, thereby performing the image forming operation described above.

[0045] The environmental sensor Sn4 is a detection unit (environment detection unit) that detects at least one of the temperature (environmental temperature) and humidity (environmental humidity) of the environment in which the image forming apparatus 100 is installed. Hereinafter, information on the environmental temperature detected by the environmental sensor Sn4 will be referred to as temperature information, information on the environmental humidity detected by the environmental sensor Sn4 will be referred to as humidity information, and the temperature information and humidity information will be collectively referred to as environmental information. The environmental sensor Sn4 of this embodiment detects both temperature information and humidity information. Furthermore, although relative humidity is used as an index of humidity in this embodiment, the index of humidity acquired using the environmental sensor Sn4 may be absolute humidity.

[0046] Furthermore, the environmental sensor Sn4 may be an internal sensor arranged to detect the temperature and humidity inside the housing of the printer main body 104, or an external sensor arranged to detect the temperature and humidity outside the housing of the printer main body 104. Both an internal sensor and an external sensor may be arranged as the environmental sensor Sn4. The external sensor is arranged, for example, near an opening (air intake) of the housing that takes in outside air from outside the housing by using negative pressure generated by the cooling fan 24. On the other hand, the internal sensor is arranged inside the housing and away from the air intake (particularly near components that are easily affected by fluctuations in temperature and humidity).

[0047] The anti-condensation heater 23 is a heater for warming the inside of the printer main body 104 to prevent condensation in the printer main body 104. Condensation in the printer main body 104 is likely to occur when there is a large difference between the temperature outside the printer main body 104 (ambient temperature) and the temperature inside the printer main body 104. A large difference between the ambient temperature and the temperature inside the printer main body 104 occurs, for example, when the components of the printer main body 104 wake up cold overnight and the room temperature rises suddenly when the office air conditioning starts up. Condensation can cause image defects or problems with the conveyance of the recording material P depending on the location of the condensation. For example, if condensation occurs on the conveyance guide that guides the recording material P, the recording material P may come into contact with water droplets and become wet as it passes through the conveyance guide, which can cause image defects or wrinkles in the recording material P during subsequent image formation. Furthermore, condensation on the surface of the photosensitive drum 11 can interfere with processes such as charging and exposure in the electrophotographic process, resulting in image defects.

[0048] The cooling fan 24 is a fan for cooling the inside of the printer main body 104. The cooling fan 24 takes in outside air through an air intake provided in the housing of the printer main body 104 and generates an airflow for cooling the components inside the printer main body 104. The objects to be cooled include heat sources inside the printer main body 104 (e.g., the fixing device 118 and the high-voltage power supply 22) and components whose image quality is affected by a rise in temperature (e.g., the photosensitive drum 11 and the developing unit 13).

[0049] (Setting image formation conditions according to environmental information) Based on the environmental information detected by the environmental sensor Sn4, the main body control unit 20 sets image formation conditions in the printer main body 104. The image formation conditions are parameters and function settings that are set to form an appropriate image through image formation operations.

[0050] In this embodiment, the image forming conditions set by the main body control unit 20 based on environmental information include at least the fixing temperature value, various high voltage values ​​in the electrophotographic process, ON / OFF of the anti-condensation heater 23, and the driving state of the cooling fan 24. In other words, in this embodiment, the target temperature of the fixing device 118 is set based on information detected by the environmental sensor Sn4 (detection unit). Also, in this embodiment, at least one voltage value of the charging voltage, the image voltage, and the transfer voltage is set based on information detected by the environmental sensor Sn4 (detection unit). Also, in this embodiment, the driving state of the cooling fan 24 (fan) is set based on information detected by the environmental sensor Sn4 (detection unit). Also, in this embodiment, whether heating by the anti-condensation heater 23 (heater) is performed is set based on information detected by the environmental sensor Sn4 (detection unit).

[0051] In addition, since the image forming unit 120 of this embodiment is an intermediate transfer type electrophotographic mechanism, the "transfer voltage" includes a primary transfer voltage and a secondary transfer voltage, and the voltage value of at least one of these may be set based on environmental information. When a direct transfer type electrophotographic mechanism is used as the image forming unit 120, the voltage value of the transfer voltage applied to a transfer unit for transferring an image from the photosensitive drum 11 (image carrier) to the recording material P may be set based on environmental information.

[0052] Specifically, the main body control unit 20 of this embodiment changes the value of the fixing temperature based on the temperature information detected by the environmental sensor Sn4 so that the fixing temperature becomes higher as the environmental temperature decreases. This is because when the environmental temperature is low, the temperature of the recording material P is low, and therefore, in order to obtain good fixing performance, it is necessary to increase the amount of heat that the fixing roller 118a applies to the recording material P compared to when the environmental temperature is high.

[0053] The main body controller 20 also adjusts various high voltages (e.g., charging voltage, developing voltage, primary transfer voltage, and secondary transfer voltage) used in the electrophotographic process based on temperature and humidity information detected by the environmental sensor Sn4. The charge retention performance of the photosensitive drum 11 and the charging performance of the charging unit 12 change depending on the environmental temperature and humidity. Therefore, the main body controller 20 adjusts the charging voltage in accordance with the temperature and humidity information so that the surface potential of the photosensitive drum 11 after charging by the charging unit 12 reaches a predetermined potential regardless of the environmental conditions. Furthermore, the charging performance of the toner and the resistance value of the primary transfer unit change depending on the environmental temperature and humidity. Therefore, the main body controller 20 adjusts the developing voltage and primary transfer voltage in accordance with the temperature and humidity information so that good developability and transferability during primary transfer can be achieved regardless of the environmental conditions. Furthermore, the resistance value of the recording material P is higher in a low-temperature, low-humidity environment than in a high-temperature, high-humidity environment. Therefore, the main body control unit 20 increases the secondary transfer voltage (increases the absolute value) in a low-temperature, low-humidity environment compared to a high-temperature, high-humidity environment, for example, so that good transferability during secondary transfer can be obtained regardless of the environmental conditions.

[0054] Furthermore, based on the temperature information detected by the environmental sensor Sn4, the main body control unit 20 operates (ON) the anti-condensation heater 23 when the difference between the outside air temperature and the temperature inside the printer is equal to or greater than a threshold, and stops (OFF) the anti-condensation heater 23 when the difference between the outside air temperature and the temperature inside the printer is less than the threshold. As a result, in a state where there is a large difference between the outside air temperature and the temperature inside the printer, which makes it easy for condensation to occur, the inside of the printer main body 104 is warmed by the heat from the anti-condensation heater 23, thereby suppressing the occurrence of condensation.

[0055] Furthermore, the main body control unit 20 operates the cooling fan when the internal temperature is equal to or higher than a predetermined temperature based on temperature information (particularly the internal temperature) detected by the environmental sensor Sn4, or controls the driving of the cooling fan 24 so that the airflow of the cooling fan 24 increases as the internal temperature increases. By cooling the inside of the printer main body 104 with the cooling fan 24 when the internal temperature is high, it is possible to suppress, for example, deterioration of image quality caused by a change in the sensitivity of the photosensitive layer due to a rise in the temperature of the photosensitive drum 11, or deterioration of toner caused by a rise in the temperature of the developing unit 13.

[0056] Although the main body controller 20 of this embodiment sets the above conditions based on environmental information, any one or more of the above conditions may be set based on environmental conditions. For example, the main body controller 20 may be configured to control only the fixing temperature of the fixing heater 21 as an image formation condition set based on environmental information acquired by the environmental sensor Sn4. Furthermore, the main body controller 20 may set image formation conditions other than the above conditions based on environmental conditions.

[0057] (Adjustment according to environmental conditions in image reading devices) Mode control for setting a set value of the document transport speed according to the document size and control for correcting the motor drive speed based on environmental information will be described.

[0058] In the following description, the motor drive speed refers to the rotation speed of the feed motor M1 and the transport motor M2 when the ADF 102 transports the document D1. The speed at which the document D1, receiving the transport force from the transport rollers (300-305), moves along the transport path 315 is referred to as the "transport speed." The relationship between the motor drive speed and the transport speed is roughly as follows: The angular velocity of the transport roller is determined by the motor drive speed and the reduction ratio of the drive transmission mechanism that transmits rotation from the motor to the transport roller. The circumferential speed of the transport roller is determined by the angular velocity of the transport roller and the outer diameter of the transport roller. When the transport roller does not slip relative to the document D1, the circumferential speed of the transport roller matches the transport speed of the document D1. In reality, slight slippage may occur between the transport roller and the document D1, so the circumferential speed of the transport roller does not necessarily match the transport speed of the document D1.

[0059] In the following description, the drive speeds of the two motors (M1, M2) are collectively referred to as the motor drive speed, but the rotation speeds of the two motors may be the same or different. In other words, in the following description, the motor drive speed of the feed motor M1 and the motor drive speed of the carry motor M2 may be controlled independently of each other.

[0060] In this embodiment, the document tray 200 and discharge tray 202 of the ADF 102 are arranged so as to overlap when viewed in the vertical direction (FIG. 3). Therefore, a transport path 315 along which the document D1 is transported from the document tray 200 to the discharge tray 202 within the main body of the ADF 102 is curved in a substantially U-shape when viewed in the document width direction perpendicular to the document transport direction. In other words, the document D1 is fed from the document tray 200 toward one side in the horizontal direction (the left side in FIG. 3) and discharged to the discharge tray 202 toward the other side in the horizontal direction (the right side in FIG. 3).

[0061] The original D1 is conveyed in a curved state along the curved conveying path 315. For this reason, the conveying resistance when conveying the original D1 varies depending on the type of original D1. For example, the size of the original D1 affects the area of ​​contact with the conveying path 315 and the manner of contact, which results in a change in conveying resistance; the larger the original size, the greater the conveying resistance. Meanwhile, at least a portion of the conveying rollers (300 to 305) are made up of multiple roller bodies (rollers) lined up in the original width direction, and therefore the larger the original size, the greater the number of roller bodies that simultaneously clamp the original D1, and the greater the conveying force applied to the original D1.

[0062] The amount of slippage of the original D1 relative to the transport rollers varies depending on the transport resistance that the original D1 receives from the transport path 315 and the transport force that the transport rollers (300-305) apply to the original D1. Therefore, even if the feed motor M1 and the transport motor M2 are rotated at a predetermined rotation speed, the transport speed at which the original D1 is actually transported may vary by several percent depending on conditions such as the original size. In other words, even if the motor drive speed is constant, the actual transport speed of the original D1 may vary by several percent.

[0063] Incidentally, each of the first reading unit 306 and the second reading unit 307 reads an image (line image) of the original D1 line by line based on receiving a horizontal synchronization signal from the reader control unit 400. The horizontal synchronization signal is a signal that instructs the reading means on the timing to acquire the line image. The interval and frequency of the horizontal synchronization signal correspond to the reading cycle and reading frequency at which the reader control unit 400 instructs the reading means to read the image. The reading cycle is set based on a preset setting value (target value) of the conveying speed so that the aspect ratio of the read image (a two-dimensional image in which the line images acquired by the first reading unit 306 and the second reading unit are arranged in the sub-scanning direction) matches the aspect ratio of the actual original D1.

[0064] Therefore, when the transport speed of the original document D1 fluctuates, the distance that the original document D1 moves while the first reading unit 306 and the second reading unit 307 acquire line images one line at a time differs, resulting in a difference in the spacing of the line images based on the transport speed setting value. As a result, the read image is stretched or shrunk in the sub-scanning direction (original document transport direction). Specifically, if the actual transport speed is slower than the setting value, the read image is stretched or shrunk in the sub-scanning direction with the original document D1 as the reference. If the actual transport speed is faster than the setting value, the read image is shrunk in the sub-scanning direction with the original document D1 as the reference. In this way, if the transport speed of the original document D1 deviates from the setting value due to factors such as the original document size, the reading accuracy may decrease.

[0065] Therefore, the motor drive speed or the reading cycle of the reading units (306, 307) corresponding to the set value of the conveyance speed of the original D1 is changed depending on the original size. In other words, measures are taken to set the motor drive speed corresponding to a specific set value of the conveyance speed to different values ​​depending on the basis weight and / or size of the original D1. Also, measures are taken to set the reading cycle of the reading units (306, 307) corresponding to a specific set value of the conveyance speed to different values ​​depending on the basis weight and / or size of the original D1. This makes it possible to prevent a decrease in reading accuracy due to fluctuations in the conveyance speed of the original D1 caused by differences in original size.

[0066] However, even if the above measures are taken, the reading accuracy may be reduced depending on the environment in which the image reading device 101 is used.

[0067] Specifically, the rigidity and surface properties (coefficient of friction with the transport rollers) of the original D1 change depending on the temperature and humidity conditions. For example, in a low-humidity environment (approximately 10% RH), moisture is removed from the original D1, increasing its rigidity, increasing transport resistance, and decreasing the friction between the transport rollers and the original D1. Therefore, in a low-humidity environment, the amount of slippage of each transport roller increases compared to a comfortable humidity environment (approximately 50-60% RH), slowing the transport speed of the original D1, which may result in the scanned image being stretched in the sub-scanning direction. Furthermore, in a high-humidity environment (approximately 80% RH), the rigidity decreases, decreasing transport resistance, and increasing the friction between the transport rollers and the original D1. Therefore, in a high-humidity environment, the amount of slippage of each transport roller decreases compared to a comfortable humidity environment (approximately 50-60% RH), increasing the transport speed of the original D1, which may result in the scanned image being shrunk in the sub-scanning direction.

[0068] Thus, even if measures are taken to change the motor drive speed or the reading cycle of the reading units (306, 307) according to the basis weight and size of the document D1, the reading accuracy may be reduced depending on the environmental conditions.

[0069] The factors that cause the conveyance speed to fluctuate due to environmental conditions mentioned above include (1) humidity-related changes in the stiffness of the document D1 and (2) humidity-related changes in the frictional force between the document and the conveyance rollers. However, another factor, (3) temperature-related changes in the outer diameter of the conveyance rollers, also has an impact. In this embodiment, each of the conveyance rollers (300-305) uses a roller whose outer periphery is made of silicone rubber. In this case, it has been confirmed that a 10°C change in temperature causes a 0.10-0.15% change in the outer diameter of the roller. When the outer diameter of the conveyance roller changes, the circumferential speed of the conveyance roller changes even if the angular velocity of the conveyance roller is constant, resulting in a fluctuation in the conveyance speed of the document D1. In other words, the higher the temperature of the environment in which the image reading device 101 is used, the faster the actual conveyance speed of the document D1 tends to be.

[0070] The above factors (1) to (3) can occur independently, but when they occur together, they can synergistically increase the fluctuation range of the transport speed of the document D1, thereby increasing the degree of variation in reading accuracy. As a result, depending on the environmental conditions, reading accuracy may decrease.

[0071] (Adjusting motor drive speed according to environmental conditions) Therefore, in this embodiment, in order to increase the accuracy of the read image as much as possible regardless of differences in environmental conditions, control is performed to correct the motor drive speed based on environmental information detected by the environmental sensor Sn4 of the printer main body 104. Below, a control method for the image reading device 101 in this embodiment will be described with reference to the flowchart in FIG.

[0072] The reader control unit 400 first detects the presence or absence of the document D1 on the document tray 200 using the document presence sensor Sn1. When the user sets the document D1 and the document presence sensor Sn1 detects that the document is present, the reader control unit 400 determines the size of the document D1 based on the detection results of the document width sensor Sn2 and the document length sensor Sn3 (S1). In this embodiment, if the document D1 is small in size (for example, A5 or smaller), the small size mode (S2b to S8b) is executed, and if the document D1 is not small in size, the normal mode (S2a to S8a) is executed.

[0073] In the normal mode, the reader control unit 400 sets the set value of the conveying speed to a first conveying speed (S2a). In the small size mode, the reader control unit 400 sets the set value of the conveying speed to a second conveying speed that is faster than the first conveying speed (S2b). The reader control unit 400 also sets motor drive speeds V1 and V2 corresponding to the conveying speeds. The motor drive speed corresponding to the first conveying speed is V1, and the motor drive speed corresponding to the second conveying speed is V2.

[0074] Motor drive speeds V1 and V2 are the motor drive speeds when no correction based on environmental information is performed. In other words, motor drive speeds V1 and V2 are preset so that the transport speed of document D1 matches the transport speed setting values ​​set in S2a and S2b under standard environmental conditions. Because the control of normal mode and small size mode is basically the same except for the differences in motor drive speeds V1 and V2 and their correction values, they will be described together below.

[0075] When a user inputs an instruction (JOB) to execute an image reading operation (S3a, S3b), the reader control unit 400 acquires environmental information (temperature information and humidity information) that is the detection result of the environmental sensor Sn4 of the printer main body 104 (S4a, S4b).

[0076] The main body control unit 20 updates the value of the environmental information based on the detection result of the environmental sensor Sn4 and stores it in RAM, for example, when the main power of the image forming apparatus 100 is turned on, when the image forming apparatus 100 returns from a sleep state, or when an image forming job is completed. In addition, the main body control unit 20 transmits the latest value of the environmental information to the reader control unit 400 in response to a request from the reader control unit 400.

[0077] The reader control unit 400 corrects the motor drive speeds V1 and V2 based on the acquired temperature information (S5a, S5b). Specifically, the values ​​of the motor drive speeds V1 and V2 are increased or decreased by adding a correction value based on the correction table in FIG. 7(a) to the motor drive speeds V1 and V2 set in S2a and S2b. Note that the "correction value" is expressed as a percentage value, where the value before correction is 100%, and the amount added or subtracted by correction.

[0078] In this embodiment, a standard temperature environment is set to 19°C to 27°C. When the environmental temperature is higher than this temperature range, the motor drive speeds V1 and V2 are corrected to be smaller. When the environmental temperature is lower than this temperature range, the motor drive speeds V1 and V2 are corrected to be larger. That is, the motor drive speed when the temperature detected by the detection means (environmental sensor Sn4) is a first temperature is set to the first speed, and the motor drive speed when the temperature detected by the detection means is a second temperature higher than the first temperature is set to the second speed. In this case, the reader control unit 400 corrects the motor drive speed so that the second speed is slower than the first speed. The first temperature is, for example, 20°C, and the second temperature is, for example, 30°C. This reduces the effect of changes in the outer diameter of the conveying roller due to temperature fluctuations.

[0079] Furthermore, the reader control unit 400 corrects the motor drive speeds V1 and V2 based on the acquired humidity information (S6a and S6b). Specifically, the motor drive speeds V1 and V2 are increased or decreased by adding a correction value based on the correction table of FIG. 7(b) to the motor drive speeds V1 and V2 corrected in S5a and S5b.

[0080] In this embodiment, a standard humidity range is 40 to 70% RH. When the environmental humidity is higher than this humidity range, the motor drive speeds V1 and V2 are corrected to be smaller. When the environmental humidity is lower than this humidity range, the motor drive speeds V1 and V2 are corrected to be larger. That is, the motor drive speed when the humidity detected by the detection means (environmental sensor Sn4) is a first humidity is defined as the first speed, and the motor drive speed when the humidity detected by the detection means is a second humidity higher than the first humidity is defined as the second speed. In this case, the reader control unit 400 corrects the motor drive speed so that the second speed is slower than the first speed. The first humidity is, for example, 10% RH, and the second humidity is, for example, 50% RH. This reduces the effects of fluctuations in stiffness of the document D1 and fluctuations in friction between the document and the transport roller due to high and low humidity.

[0081] 7(a) and 7(b) is stored in, for example, the ROM 403 of the reader control unit 400, and the CPU 401 accesses and references the ROM 403. Instead of using a correction table, the ROM 403 may store coefficients of a function representing the corrected motor drive speeds V1 and V2, with the motor drive speeds V1 and V2 before correction and the temperature information value as variables. In this case, the CPU 401 uses the coefficients to calculate the corrected motor drive speeds V1 and V2. Similarly, the ROM 403 may store coefficients of a function representing the corrected motor drive speeds V1 and V2 with the motor drive speeds V1 and V2 before correction and the humidity information value as variables, and the CPU 401 uses the coefficients to calculate the corrected motor drive speeds V1 and V2. In other words, regardless of the specific processing content of the reader control unit 400, the reader control unit 400 may be configured to control the motor drive speed based on environmental information, resulting in a result similar to that of the correction in this embodiment.

[0082] The reader control unit 400 rotates the motors (M1, M2) at rotational speeds corresponding to the corrected motor drive speeds V1, V2. As a result, the transport rollers (300-305) are driven to rotate at the corrected motor drive speeds V1, V2. The original D1 is then transported at a transport speed close to the first transport speed or the second transport speed, which are the set values ​​(target values) of the transport speed, and the image information is read by the reading units (306, 307). As a result, it is possible to suppress expansion / contraction of the read image in the sub-scanning direction due to differences in environmental conditions, thereby improving reading accuracy. When transport of all the originals D1 placed on the original tray 200 is completed, the reader control unit 400 ends the image reading operation (S8a, S8b).

[0083] As described above, according to this embodiment, an object is to provide an image forming apparatus that can improve image reading accuracy with a simple configuration by utilizing the detection results of the environment sensor Sn4 of the printer main body 104.

[0084] Furthermore, according to the above flow, the reader control unit 400 sets a set value for the transport speed of the original D1 based on information acquired by the size acquisition means (Sn1 to Sn3). The reader control unit 400 also corrects the motor drive speeds V1 and V2, which are preset corresponding to the set value for the transport speed, based on environmental information detected by the detection means (environmental sensor Sn4), and transports the original D1 based on the corrected motor drive speeds V1 and V2. According to this flow, it is possible to improve reading accuracy even when the fluctuation range of the transport speed of the original D1 due to changes in environmental conditions differs depending on the original size.

[0085] (Variation) The correction table of Fig. 7(a) is determined in advance based on the results of a preliminary evaluation of the amount of change in the outer diameter of the conveying rollers (300-305) used in this embodiment in response to fluctuations in environmental temperature. The correction table of Fig. 7(b) is determined in advance based on the results of a preliminary evaluation of the humidity-dependent fluctuation in stiffness of a standard document D1 and the humidity-dependent fluctuation in frictional force between the document and the conveying rollers. Therefore, the correction values ​​of Figs. 7(a) and 7(b) are merely examples, and should be changed as appropriate depending on the specific configuration of the conveying rollers.

[0086] 7(a) and 7(b) may be prepared in multiple types depending on the size and material of the original D1. For example, the correction value in the normal mode may be different from the correction value in the small size mode. As mentioned above, the influence of the environmental temperature and humidity on the conveying speed may vary depending on the original size and material. Therefore, by using different correction tables depending on the original size or material, more appropriate correction can be performed for originals D1 of various materials.

[0087] In this embodiment, a correction table based on temperature conditions and a correction table based on humidity conditions are prepared separately, and the respective correction values ​​are added together, but a correction table based on a combination of temperature and humidity conditions may also be prepared. For example, it is possible to set a correction value for the motor drive speed of +0.4% when both the temperature is 15 degrees or less and the humidity is 10% or less.

[0088] In this embodiment, the motor drive speed is corrected based on three pieces of information: the size of the original D1, and the temperature and humidity information as environmental information. However, these pieces of information may be used in various combinations. In other words, depending on the specific configuration of the image reading device 101, only part of the above three pieces of information may be used, taking into consideration the actual degree of influence of factors that may affect the transport speed of the original D1.

[0089] FIGS. 8(a) to 8(c) and FIGS. 9(a) and 9(b) are flowcharts showing modified examples in which different combinations of information are used to determine the motor drive speed.

[0090] In the example of FIG. 8(a), the conveying speed is not set based on the document size, but the motor driving speed is corrected based on temperature information. In this example, the reader control unit 400 uses a preset conveying speed and the corresponding motor driving speed V1 regardless of the document size. When a job is input (S11), the reader control unit 400 acquires environmental information (temperature information) detected by the environmental sensor Sn4 of the printer main body 104 (S12) and corrects the motor driving speed V1 based on the temperature information (S13). Then, the reader control unit 400 rotates each motor (M1, M2) at a rotation speed corresponding to the corrected motor driving speed V1 and starts conveying the document D1 (S14). When the conveying of all documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S15). This example makes it possible to realize a configuration that can improve reading accuracy regardless of humidity conditions with simple control.

[0091] In the example of FIG. 8(b), the conveying speed is not set based on the document size, but the motor driving speed is corrected based on humidity information. In this example, the reader control unit 400 uses a preset conveying speed and the corresponding motor driving speed V1 regardless of the document size. When a job is input (S21), the reader control unit 400 acquires environmental information (humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S22) and corrects the motor driving speed V1 based on the humidity information (S23). Then, the reader control unit 400 rotates each motor (M1, M2) at a rotation speed corresponding to the corrected motor driving speed V1 to start conveying the document D1 (S24). When the conveying of all documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S25). This example makes it possible to realize a configuration that can improve reading accuracy regardless of humidity conditions with simple control.

[0092] In the example of FIG. 8(c), the conveying speed is not set based on the document size, but the motor driving speed is corrected based on temperature information and humidity information. In this example, the reader control unit 400 uses a preset conveying speed and the corresponding motor driving speed V1 regardless of the document size. When a job is input (S31), the reader control unit 400 acquires environmental information (temperature information and humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S32). The reader control unit 400 corrects the motor driving speed V1 based on the temperature information (S33), and further corrects the motor driving speed V1 based on the humidity information (S34). Then, the reader control unit 400 rotates each motor (M1, M2) at a rotation speed corresponding to the corrected motor driving speed V1, and starts conveying the document D1 (S35). When the conveying of all documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S36). According to this example, a configuration that can improve reading accuracy regardless of temperature and humidity conditions can be realized with simple control.

[0093] In the example of FIG. 9A, the conveyance speed is set based on the document size, and the motor drive speed is corrected based on temperature information. In this example, the reader control unit 400 determines the size of the document D1, as in the first embodiment (S41), and sets the conveyance speed of the document D1 to the first conveyance speed or the second conveyance speed based on the determination result (S42a, S42b). When a job is input (S43a, S43b), the reader control unit 400 acquires environmental information (temperature information) detected by the environmental sensor Sn4 of the printer main body 104 (S44a, S44b). The reader control unit 400 corrects the motor drive speeds V1 and V2 based on the temperature information (S45a, S45b). Then, the reader control unit 400 rotates the motors (M1, M2) at rotational speeds corresponding to the corrected motor drive speeds V1 and V2, and starts conveying the document D1 (S46a, S46b). When the conveyance of all the documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S47a, S47b). According to this example, a configuration that can improve reading accuracy regardless of the document size and temperature conditions can be realized with simple control.

[0094] In the example of FIG. 9(b), the conveyance speed is set based on the document size, and the motor drive speed is corrected based on humidity information. In this example, the reader control unit 400 determines the size of the document D1, as in the first embodiment (S51), and sets the conveyance speed of the document D1 to the first conveyance speed or the second conveyance speed based on the determination result (S52a, S52b). When a job is input (S52a, S53b), the reader control unit 400 acquires environmental information (humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S54a, S54b). The reader control unit 400 corrects the motor drive speeds V1 and V2 based on the humidity information (S55a, S55b). Then, the reader control unit 400 rotates the motors (M1, M2) at rotational speeds corresponding to the corrected motor drive speeds V1 and V2, and starts conveying the document D1 (S56a, S56b). When the conveyance of all the documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S57a, S57b). According to this example, a configuration that can improve reading accuracy regardless of the document size and humidity conditions can be realized with simple control.

[0095] Second Embodiment Next, a second embodiment, which is a partial modification of the first embodiment, will be described with reference to Fig. 10. In the first embodiment, the motor drive speed was corrected based on environmental information, but in this embodiment, the reading cycle when the reading units (306, 307) read image information line by line is corrected based on environmental information. Below, elements with the same reference symbols as in the first embodiment have basically the same configurations and functions as those described in the first embodiment unless otherwise specified, and differences from the first embodiment will be mainly described.

[0096] 10, in this embodiment, the reader control unit 400 corrects the reading cycle of the reading units (306, 307) based on temperature information and humidity information. That is, the reader control unit 400 corrects the interval at which a horizontal synchronization signal that instructs the first reading unit 306 and the second reading unit 307 on the timing of acquiring a line image, based on the temperature information and humidity information.

[0097] In this embodiment, similar to the first embodiment, the reader control unit 400 determines the size of the original D1 (S61) and sets the set value of the conveyance speed of the original D1 to a first conveyance speed or a second conveyance speed depending on the determination result (S62a, S62b). When a job is input (S63a, S63b), the reader control unit 400 acquires environmental information (temperature information and humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S64a, S64b). Then, the reader control unit 400 corrects the motor drive speed based on the temperature information (S65a, S65b), and further corrects the motor drive speed based on the humidity information (S66a, S66b). Then, the reader control unit 400 rotates each motor (M1, M2) at a rotation speed corresponding to the corrected motor drive speed, and starts conveying the original D1 (S67a, S67b). When the conveyance of all the documents D1 placed on the document tray 200 is completed, the reader control section 400 ends the image reading operation (S68a, S68b).

[0098] As described above, if the reading cycle is constant, the actual conveyance speed of the original D1 may vary depending on the environmental conditions, which may cause the read image to expand or contract in the sub-scanning direction. According to this embodiment, even if the conveyance speed of the original D1 varies depending on the environmental conditions, the reading cycle is changed accordingly. As a result, the reading units (306, 307) can acquire line images at intervals that are closer to constant in the sub-scanning direction, regardless of differences in environmental conditions. For example, if the conveyance resistance is large and the actual conveyance speed of the original D1 is slower than the set value, extending the reading cycle compared to standard environmental conditions can prevent the read image from expanding in the sub-scanning direction.

[0099] As described above, according to this embodiment, an object is to provide an image forming apparatus that can improve the image reading accuracy with a simple configuration by utilizing the detection result of the environment sensor Sn4 of the printer main body 104.

[0100] In this embodiment, the correction value for the reading cycle based on the temperature information and humidity information can be determined using substantially the same table as in the first embodiment, by considering the correction table shown in Figures 7(a) and (b) to represent the reading speed (the number of line images acquired per unit time). However, when correcting the numerical value of the reading cycle (the ON interval of the horizontal synchronization signal), the value obtained by inverting the sign of the correction value [%] in Figures 7(a) and (b) is used, because the reading cycle and the reading speed are inversely proportional to each other.

[0101] For example, if the temperature information is 35°C or higher, the reading cycle can be shortened by 0.2% based on the temperature information (the reading speed can be increased by 0.2% compared to the standard environment). In other words, the reading cycle when the temperature detected by the detection means (environmental sensor Sn4) is the first temperature is defined as the first cycle, and the reading cycle when the temperature detected by the detection means is the second temperature, which is higher than the first temperature, is defined as the second cycle. In this case, the reader control unit 400 corrects the reading cycle so that the second cycle is shorter than the first cycle. The first temperature is, for example, 20°C, and the second temperature is, for example, 38°C. This reduces the effect of changes in the outer diameter of the conveying roller due to temperature fluctuations. is omitted.

[0102] Furthermore, for example, if the humidity information is 70% RH or higher, the reading cycle can be shortened by 0.2% based on the humidity information (the reading speed can be increased by 0.1% compared to the standard environment). In other words, the reading cycle when the humidity detected by the detection means (environmental sensor Sn4) is a first humidity is defined as the first cycle, and the reading cycle when the humidity detected by the detection means is a second humidity higher than the first humidity is defined as the second cycle. In this case, the reader control unit 400 corrects the reading cycle so that the second cycle is shorter than the first cycle. The first humidity is, for example, 50% RH, and the second humidity is, for example, 80% RH. This reduces the effects of fluctuations in stiffness of the document D1 and fluctuations in friction between the document and the transport roller due to high and low humidity.

[0103] (Variation) In this embodiment, the case where the reading cycle of the first reading unit 306 and the reading cycle of the second reading unit 307 are corrected using the same correction value has been described. However, this is not limiting, and for the same reason as in the third embodiment below, the reading cycle of the first reading unit 306 and the reading cycle of the second reading unit 307 may be corrected using different correction values. That is, a slight difference may be created in the reading cycle between the two reading units so as to absorb the difference between the transport speed of the original D1 at the reading position of the first reading unit 306 and the transport speed of the original D1 at the reading position of the second reading unit 307. This improves the reading accuracy when reading images from both sides of the original D1.

[0104] Third Embodiment Next, a third embodiment that combines the first and second embodiments will be described with reference to Fig. 11. In this embodiment, both the motor drive speed correction described in the first embodiment and the reading cycle correction described in the second embodiment are performed. Below, elements that are given the same reference symbols as the first and second embodiments have basically the same configurations and functions as those described in the first and second embodiments unless otherwise specified, and differences from the first and second embodiments will be mainly described.

[0105] In this embodiment, as in the first embodiment, the reader control unit 400 determines the size of the original D1 (S71) and sets the set value of the transport speed of the original D1 to the first transport speed or the second transport speed depending on the determination result (S72a, S72b). When a job is input (S73a, S73b), the reader control unit 400 acquires environmental information (temperature information and humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S74a, S74b). Then, the reader control unit 400 corrects the motor drive speed based on the temperature information and corrects the reading cycle of the second reading unit 307 based on the temperature information (S75a, S75b). Furthermore, the reader control unit 400 corrects the motor drive speed based on the humidity information and corrects the reading cycle of the second reading unit 307 based on the humidity information (S76a, S76b). Then, the reader control unit 400 rotates each motor (M1, M2) at a rotation speed corresponding to the corrected motor drive speed, and starts transporting the document D1 (S77a, S77b). When the transport of all documents D1 placed on the document tray 200 is completed, the reader control unit 400 ends the image reading operation (S78a, S78b).

[0106] In this embodiment, as per the above flow, correction of the reading cycle is performed in addition to correction of the motor drive speed only on one of the two reading units (the second reading unit 307). The advantages of this configuration will be described.

[0107] By correcting the motor drive speed based on temperature information and humidity information, it is possible to reduce fluctuations in the transport speed of the original D1 due to environmental conditions and suppress expansion and contraction of the read image in the sub-scanning direction, as described in the first embodiment. However, depending on the shape of the transport path 315, etc., there may be a slight difference between the transport speed of the original D1 at the reading position of the first reading unit 306 (hereinafter referred to as the first reading position) and the transport speed of the original D1 at the reading position of the second reading unit 307 (hereinafter referred to as the second reading position).

[0108] For example, in the ADF 102 of this embodiment, the first reading unit 306 is disposed immediately after the U-shaped curved portion of the conveying path 315, while the second reading unit 307 is disposed at a position away from the curved portion. Therefore, the conveying resistance experienced by the document D1 around the first reading unit 306 is likely to be greater than the conveying resistance experienced by the document D1 around the second reading unit 307.

[0109] 7(a) and 7(b) so that the conveying speed of the document D1 at the first reading position coincides with the set value, the conveying speed at the second reading position may deviate slightly from the set value. As a result, the read image acquired by the second reading unit 307 may expand or contract slightly in the sub-scanning direction.

[0110] Therefore, in this embodiment, slight differences in conveying speed due to differences in reading position are absorbed by correcting the reading cycle in addition to correcting the motor drive speed only for the second reading unit 307. For example, in this embodiment, the correction value of the motor drive speed according to the temperature information and the correction value of the reading cycle of the second reading unit 307 according to the temperature information are determined using the correction table shown in Fig. 13. Also, in this embodiment, the reading cycle of the first reading unit 306 is constant.

[0111] In this embodiment, whether the motor drive speed is increased or decreased by correcting the motor drive speed, the transport speed of the document D1 at the second reading position tends to be slightly slower than the transport speed of the document D1 at the first reading position. Therefore, in the correction table of Fig. 13, a correction value is set to lengthen the reading cycle (slow the reading speed) of the second reading unit 307 whether the value of the temperature information is higher or lower than the standard temperature range (19°C to 27°C). However, the correction value of Fig. 13 is merely an example, and should be changed as appropriate depending on the specific configuration of the ADF 102.

[0112] As described above, according to this embodiment, an object is to provide an image forming apparatus that can improve the image reading accuracy with a simple configuration by utilizing the detection result of the environment sensor Sn4 of the printer main body 104.

[0113] Furthermore, according to this embodiment, the reading cycle is corrected in conjunction with the correction of the motor drive speed for only one of the two reading units. In other words, the reader control unit 400 changes only one of the reading cycles of the first reading unit and the second reading unit so as to absorb the difference between the document transport speed at the first reading position and the document transport speed at the second reading position when the transport rollers (300-305) are driven at the drive speed corrected based on the environmental information detected by the environmental sensor Sn4 (detection means). This allows the difference in transport speed to be absorbed by the correction of the reading cycle, even if the transport speeds at the reading positions of the two reading units are slightly different. This improves the reading accuracy when reading images from both sides of the document D1.

[0114] (Variation) In the third embodiment, an example has been described in which the reading cycle of only the second reading unit 307 is corrected based on environmental information. However, as shown in FIG. 12(a), the reading cycle of only the first reading unit 306 may be corrected based on environmental information. In this example, the motor drive speed is corrected using a correction table that has been adjusted in advance so that the conveyance speed of the original D1 at the second reading position matches a set value (S75a', S75b', S76a', S76b'). Furthermore, the reading cycle of only the first reading unit 306 is corrected so as to absorb the difference in the conveyance speed of the original D1 between the first reading position and the second reading position. This provides the same advantages as the third embodiment.

[0115] Furthermore, as shown in FIG. 12(b), the reading periods of both the first reading unit 306 and the second reading unit 307 may be corrected based on environmental information (S75a′, S75b′, S76a′, S76b′). In this case, the correction value for the reading period of the first reading unit 306 and the correction value for the reading period of the second reading unit 307 are set to different values ​​so as to absorb the difference in the conveyance speed of the document D1 at the first reading position and the second reading position. In other words, the reader control unit 400 sets the reading period of the first reading unit and the reading period of the second reading unit to different values ​​so as to absorb the difference between the conveyance speed of the document at the first reading position and the conveyance speed of the document at the second reading position when the conveyance rollers (300 to 305) are driven at a drive speed corrected based on the environmental information detected by the environmental sensor Sn4 (detection means). This provides the same advantages as the third embodiment.

[0116] Fourth Embodiment Next, a fourth embodiment will be described with reference to Figures 14 to 16. In this embodiment, the set value of the conveying speed is determined taking into consideration not only the document size but also the basis weight of the document D1, and the motor drive speed and reading cycle are corrected based on environmental information. Below, elements with the same reference symbols as the first, second, and third embodiments have basically the same configurations and functions as those described in the first, second, and third embodiments unless otherwise specified, and differences from the first, second, and third embodiments will be mainly described.

[0117] The ADF 102 of this embodiment has a basis weight of 37 g / m 2 Thin paper from 209 g / m 2 It is possible to convey original D1 of various thicknesses, even thicker paper than 100 mm. On the other hand, the basis weight (thickness) is correlated with the rigidity of original D1, and the higher the rigidity of original D1 (the force that tries to return the original to its original shape when bent), the greater the resistance to conveyance when passing through conveyance path 315. For this reason, it is preferable to change the set value of the conveyance speed not only according to the original size but also according to the basis weight of original D1.

[0118] 14 is a flowchart showing a control method for the image reading device 101 in this embodiment. In this embodiment, the reader control unit 400 determines the size of the original D1 (S81), as in the first embodiment, and sets the set value of the conveying speed of the original D1 to the first conveying speed or the second conveying speed according to the determination result (S82a, S82b). Furthermore, the reader control unit 400 determines the basis weight of the original D1 (S83a, S83b), and sets the set value of the conveying speed of the original D1 to any one of the third to sixth conveying speeds according to the determination result (S84a to S84d). In other words, in this embodiment, the set value of the conveying speed is determined based on the size and basis weight (thickness) of the original D1.

[0119] The basis weight of the document D1 is input by the user via an operation panel provided on the image forming apparatus 100. In this case, the operation panel functions as a thickness acquisition unit that acquires information about the thickness of the document D1. In this embodiment, the basis weight is 209 g / m 2 The above cases are considered to be in cardboard mode, with a basis weight of 209 g / m 2 The normal mode is when the conveying speed is less than 1 / 4 the normal mode. In the thick paper mode, the set value of the conveying speed of the original D1 is set lower than in the normal mode to stably convey the thick original D1. In other words, the fourth conveying speed is slower than the third conveying speed, and the sixth conveying speed is slower than the fifth conveying speed. Furthermore, the third conveying speed may be the same as the first conveying speed, and the fifth conveying speed may be the same as the second conveying speed.

[0120] When a job is input (S85a to S85d), the reader control unit 400 acquires environmental information (temperature information and humidity information) detected by the environmental sensor Sn4 of the printer main body 104 (S86a to S86d). The reader control unit 400 then corrects the motor drive speed based on the temperature information (S87a to S87d), and further corrects the motor drive speed based on the humidity information (S88a to S88d). The reader control unit 400 then rotates the motors (M1, M2) at a rotation speed corresponding to the corrected motor drive speed, and begins transporting the document D1 (S89a to S89d). When transport of all documents D1 placed on the document tray 200 has been completed, the reader control unit 400 ends the image reading operation (S90a to S90d).

[0121] As described above, according to this embodiment, an object is to provide an image forming apparatus that can improve the image reading accuracy with a simple configuration by utilizing the detection result of the environment sensor Sn4 of the printer main body 104.

[0122] Furthermore, according to this embodiment, the set value of the conveying speed is changed depending on the thickness (basis weight) of the original D1. That is, according to the above flow, the reader control unit 400 sets the set value of the conveying speed of the original D1 based on information acquired by the thickness acquisition unit (operation panel). Furthermore, the reader control unit 400 corrects the motor drive speeds V3 to V6, which are preset corresponding to the set values ​​of the conveying speed, based on environmental information detected by the detection unit (environmental sensor Sn4), and conveys the original D1 based on the corrected motor drive speed. According to this flow, reading accuracy can be improved even when the fluctuation range of the conveying speed of the original D1 due to changes in environmental conditions varies depending on the thickness of the original D1. That is, for originals D1 made of various materials, the motor drive speed can be more appropriately corrected taking into account differences in the influence of environmental conditions due to differences in materials, thereby further improving image reading accuracy.

[0123] (Variation) In this embodiment, the position value for determining the cardboard mode is 209 g / m 2 However, the threshold value may be changed depending on the specific configuration of the ADF 102. Also, the set value of the conveying speed may be changed between three or more levels depending on the basis weight.

[0124] In addition, in this embodiment, a configuration is exemplified in which the setting value of the conveying speed is determined taking into account both the size and thickness (basis weight) of the original D1, but the setting value of the conveying speed may also be determined taking into account only the thickness (basis weight) of the original D1.

[0125] Alternatively, instead of having the user input the basis weight via the operation panel, original thickness sensors Sn5 and Sn6 for detecting the thickness of the original D1 may be provided in the ADF 102, as shown in FIGS. 15 and 16. The original thickness sensors Sn5 and Sn6 are another example of a thickness acquisition unit. The original thickness sensors Sn5 and Sn6 are, for example, ultrasonic sensors that have a transmitter that emits ultrasonic waves toward the transport path and a receiver that receives the ultrasonic waves that have passed through the original D1, and detect the thickness of the original D1 based on the attenuation rate of the ultrasonic waves. In this case, the reader control unit 400 can automatically determine the thickness of the original D1 based on the detection results of the original thickness sensors Sn5 and Sn6 after the start of transport of the original D1. In this case, the reader control unit 400 may start transport of the original D1 at the first transport speed or the second transport speed, and correct the motor drive speed after determining the thickness of the original D1.

[0126] (Other variations) The technical elements described in the above-described embodiments and their modifications can be arbitrarily combined and applied to a single device, as long as they are not essentially contradictory. For example, the set value of the conveying speed may be determined according to the thickness of the document D1 as in the fourth embodiment, and the reading cycle may be corrected based on environmental information as in the second embodiment. Furthermore, in addition to correcting the motor drive speed (S87a to S87d, S88a to S88d) based on environmental information as in the fourth embodiment, the reading cycle of only the second reading unit 307 may be corrected as in the third embodiment.

[0127] Furthermore, in each of the above-described embodiments, an example has been described in which the reader control unit 400 mounted on the image reading device 101 corrects the motor drive speed and / or the reading cycle based on the environmental information detected by the environmental sensor Sn4. However, the present invention is not limited to this. For example, the main body control unit 20 mounted on the printer main body 104 may calculate a correction value for the motor drive speed and / or the reading cycle based on the environmental information detected by the environmental sensor Sn4 and transmit the calculated correction value to the reader control unit 400. In this case, the reader control unit 400 that corrects the motor drive speed and / or the reading cycle based on the correction value received from the main body control unit 20 is also an example of a correction unit.

[0128] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0129] 101...image reading device / 104...device main body (printer main body) / 120...image forming means (image forming unit) / 300, 301, 302, 303, 304, 305...conveying means (pickup roller, separation roller pair, pull-out roller pair, first read roller pair, second read roller pair, discharge roller pair) / 306, 307...reading means (first reading unit, second reading unit) / M1, M2...driving source (feed motor, conveying motor) / Sn4...detecting means (environment sensor)

Claims

1. An image forming apparatus, an apparatus main body including an image forming unit that forms an image on a recording material and a detection unit that detects environmental information including at least one of temperature and humidity, and configured so that image forming conditions are set based on the environmental information detected by the detection unit; an image reading device connected to the device body, the image reading device having: a conveying means for conveying a document; a drive source for driving the conveying means; a reading means for reading image information from the document conveyed by the conveying means; and a control means for controlling the drive source; Equipped with the control means controls the driving speed of the transport means driven by the drive source based on the environmental information detected by the detection means of the device body. An image forming apparatus characterized by:

2. the detecting means detects the humidity of the environment; the control means controls the drive speed based on the environmental information related to humidity.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the control means sets the drive speed to a first speed when the humidity detected by the detection means is a first humidity, and sets the drive speed to a second speed slower than the first speed when the humidity detected by the detection means is a second humidity higher than the first humidity.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

4. the detecting means detects the temperature of the environment; the control means controls the driving speed based on the environmental information related to temperature.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the control means sets the drive speed to a first speed when the temperature detected by the detection means is a first temperature, and sets the drive speed to a second speed slower than the first speed when the temperature detected by the detection means is a second temperature higher than the first temperature.

5. The image forming apparatus according to claim 4.

6. the image reading device has a size acquisition means for acquiring information about the size of a document; the control means determines the drive speed based on both the information about the document size acquired by the size acquisition means and the environmental information detected by the detection means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. the image reading device has a thickness acquisition means for acquiring information about the thickness of a document; the control means determines the drive speed based on both the information on the thickness of the document acquired by the thickness acquisition means and the environmental information detected by the detection means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. the reading means includes a first reading unit that reads image information line by line from a first side of the document at a first reading position, and a second reading unit that reads image information line by line from a second side of the document at a second reading position that is different from the first reading position in a document transport direction, the control means changes only one of the reading period of the first reading unit and the reading period of the second reading unit so as to absorb a difference between a document transport speed at the first reading position and a document transport speed at the second reading position when the transport means is driven at a drive speed determined based on the environmental information detected by the detection means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. the reading means includes a first reading unit that reads image information line by line from a first side of the document at a first reading position, and a second reading unit that reads image information line by line from a second side of the document at a second reading position that is different from the first reading position in a document transport direction, the control means sets the reading cycle of the first reading unit and the reading cycle of the second reading unit to different values ​​so as to absorb a difference between the document transport speed at the first reading position and the document transport speed at the second reading position when the transport means is driven at a drive speed determined based on the environmental information detected by the detection means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

10. the drive source is a motor, The drive speed is the rotation speed of the motor.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

11. An image forming apparatus, an apparatus main body including an image forming unit that forms an image on a recording material and a detection unit that detects environmental information including at least one of temperature and humidity, and configured so that image forming conditions are set based on the environmental information detected by the detection unit; an image reading device connected to the device body, the image reading device comprising: a conveying means for conveying an original; a reading means for reading image information line by line from the original conveyed by the conveying means; and a control means for controlling the reading means; Equipped with the control means controls a reading cycle when the reading means reads image information based on the environmental information detected by the detection means of the device body. An image forming apparatus characterized by:

12. the detecting means detects the humidity of the environment; the control means controls the reading cycle based on the environmental information related to humidity.

12. The image forming apparatus according to claim 11.

13. the control means sets the reading period of the reading means to a first period when the humidity detected by the detection means is a first humidity, and sets the reading period of the reading means to a second period shorter than the first period when the humidity detected by the detection means is a second humidity higher than the first humidity.

13. The image forming apparatus according to claim 12.

14. the detecting means detects the temperature of the environment; the control means controls the reading cycle based on the environmental information related to temperature.

12. The image forming apparatus according to claim 11.

15. the control means sets the reading period of the reading means to a first period when the temperature detected by the detection means is a first temperature, and sets the reading period of the reading means to a second period shorter than the first period when the temperature detected by the detection means is a second temperature higher than the first temperature.

15. The image forming apparatus according to claim 14.

16. the reading means includes a first reading unit that reads image information line by line from a first side of the document at a first reading position, and a second reading unit that reads image information line by line from a second side of the document at a second reading position that is different from the first reading position in a document transport direction, the control unit sets the reading cycle of the first reading unit and the reading cycle of the second reading unit to different values ​​so as to absorb a difference between the document transport speed at the first reading position and the document transport speed at the second reading position.

12. The image forming apparatus according to claim 11.

17. the image forming means has a fixing device that heats the image formed on the recording material to fix it to the recording material, a target temperature of the fixing device is set based on the environmental information detected by the detection means; 17. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

18. the image forming means includes an image carrier, a charging unit that charges the surface of the image carrier by applying a charging voltage, a developer carrier that supplies toner to the image carrier by applying a developing voltage, and a transfer unit that transfers an image from the image carrier to a recording material by applying a transfer voltage; at least one of the charging voltage, the developing voltage, and the transfer voltage is set based on the environmental information detected by the detection unit; 17. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

19. the device body further includes a fan for cooling the inside of the device body, The driving state of the fan is set based on the environmental information detected by the detection means.

17. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

20. the device body has a heater that heats at least a part of the device body to suppress condensation in the device body; whether or not heating by the heater is performed is set based on the environmental information detected by the detection means.

17. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images