JP2010271386A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, surely performing image formation according to the kind of paper. <P>SOLUTION: In a digital multi-functional machine, the kind of inputted paper is compared with the determined kind of paper to determine whether they are the same (S14). When the kind of inputted paper and the determined kind of paper are the same (YES in the step S14), fixing control is made according to the kind of the input paper (S15). When the kind of input paper and the determined kind of paper are not the same (NO in the step S14), image formation conditions are altered according to the determined kind of paper. Then the fixing control is performed (S16). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that outputs a formed image onto a sheet.

  In a conventional image forming apparatus, an image developed by a developing device is transferred to a sheet fed from a sheet feeding cassette, and then the developed image is fixed on the sheet by a fixing roller and discharged. Such an image forming apparatus is disclosed in Japanese Patent Laid-Open No. 7-234604 (Patent Document 1).

  In the image forming apparatus disclosed in Patent Document 1, an independent drive system is provided for the fixing unit and the transfer unit, and a loop amount formed by the sheet is detected at the front portion of the fixing unit entrance. Then, the speed of the driving unit of the fixing unit is adjusted based on the detected loop amount. By doing so, the speed of the driving means in the fixing means is controlled to reduce the occurrence of image pitch defects.

JP-A-7-234604

  The conventional image forming apparatus represented by Patent Document 1 is configured to be capable of image formation on a plurality of types of paper. In the image forming apparatus, in order to form an appropriate image according to the type of paper, it is necessary to change image forming conditions, for example, temperature conditions by fixing and various correction values, according to the type of paper. Conventionally, the image forming conditions are changed according to the type of paper input by the user through the operation panel or the like.

  However, if the user makes a mistake in inputting the paper type or if there is no input of the paper type, it is not possible to form an appropriate image according to the paper type. In particular, when different types of paper are mixed, the above-described user input errors frequently occur.

  An object of the present invention is to provide an image forming apparatus capable of reliably performing image formation according to the type of paper.

  An image forming apparatus according to the present invention includes: an image forming unit that forms an image on a predetermined image forming condition and outputs the image to a sheet; a deflection detection unit that detects a deflection amount of the sheet; and a sheet detected by the deflection detection unit. A determination unit that determines the type of paper based on the amount of deflection, and a control unit that controls to change predetermined image forming conditions according to the type of paper determined by the determination unit.

  Preferably, an input means for inputting the paper type is provided, and the control means is operated when the paper type input by the input means is different from the paper type determined by the determination means.

  More preferably, the deflection detection means includes a loop sensor that irradiates the sheet with light and detects the amount of deflection of the sheet by the reflected light.

  More preferably, the image forming unit includes a transfer unit that transfers an image formed with toner onto a sheet, and a fixing unit that fixes the toner onto the sheet transferred by the transfer unit, and the deflection detection unit includes the transfer unit and the fixing unit. Between the two parts.

  Further, the predetermined image forming conditions may include a fixing temperature condition in the fixing unit, and the control unit may be configured to change the fixing temperature condition according to the type of paper.

  More preferably, in the case of forming an image on a plurality of sheets, the determination unit operates the deflection detection unit for each sheet to determine for each sheet, and the control unit determines a predetermined image forming condition for each sheet. Control to change.

  According to such a configuration, the amount of deflection of the output paper is detected, the type of the paper is determined based on the detected amount of deflection of the paper, and the image forming condition is changed according to the determined type of paper. Yes. As a result, even when there is a mistake in inputting the paper type by the user or when there is no input information on the paper type, an image can be formed under an appropriate image forming condition according to the paper type. Therefore, it is possible to reliably perform image formation according to the type of paper.

1 is a block diagram showing an overall configuration of a digital multifunction peripheral according to an embodiment of the present invention. It is a figure which shows an example of an operation part. FIG. 2 is a schematic cross-sectional view showing a part of a paper transport unit and a main part of a loop sensor included in a digital multi-function peripheral according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the control part in the case of forming an image. It is a graph which shows the relationship between a measurement distance and a sensor output voltage.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a digital multifunction peripheral 10 when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. Referring to FIG. 1, a digital multifunction device 10 includes a CPU, a control unit 11 that controls the entire digital multifunction device 10, a DRAM 12 for writing and reading image data and the like, and a digital multifunction device 10. An operation unit 13 that serves as an interface with a user in the digital multi-function peripheral 10, a document feeder 14 that automatically conveys a document to a predetermined document reading position, and a document feeder 14 An image reading unit 15 that reads an image of the document conveyed by the image reading unit 15 at a predetermined reading position, an image forming unit 16 that forms an image from the document read by the image reading unit 15, and image data And the like, a FAX communication unit 18 connected to the public line 20, and a network for connecting to the network 21. And a click IF (interface) unit 19.

  Here, as the image forming unit 16 included in the digital multifunction peripheral 10, the photosensitive member 24 that forms an electrostatic latent image from the image read by the image reading unit 15, and the electrostatic latent image formed on the photosensitive member 24. A developer 25 for supplying a developer such as toner onto the image forming unit 25 forms a visible image, a transfer unit 26 for transferring an image formed with toner on the photosensitive member 24 to a sheet, and a sheet on which the toner is transferred by the transfer unit 26 On the other hand, the image forming apparatus includes a fixing unit 27 that fixes toner onto a sheet by a fixing roller (not shown).

  The digital multi-function peripheral 10 also includes a paper feeding unit 28 that feeds paper to be output. The paper feed unit 28 is provided with a plurality of paper feed cassettes 29 for storing a plurality of paper sheets according to the type, size, direction difference, etc. of the paper. The user stores each sheet in each sheet feeding cassette 29 according to the type of sheet. The digital multi-function peripheral 10 also includes a discharge tray (not shown) that discharges paper outside the digital multi-function peripheral 10.

  The digital multi-function peripheral 10 can form an image by changing the image forming conditions in the image forming unit 16 according to the types of a plurality of sheets. The digital multi-function peripheral 10 can form images on plain paper, postcards, reprints, OHP (Over Head Projector) sheets, and other types of paper. The image forming conditions here include, for example, a fixing temperature in the fixing unit 27, a transfer voltage and a bias voltage in the transfer unit 26, and a sheet conveyance speed between the units included in the image forming unit 16.

  The control unit 11 compresses and writes the original data output from the image reading unit 15 in the DRAM 12, reads the data written in the DRAM 12, decompresses and encodes the data, and outputs it by the image forming unit 16.

  The digital multi-function peripheral 10 operates as a copier by forming an image in the image forming section 16 via the DRAM 12 using the document read by the image reading section 15. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 through the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and also by the image reading unit 15. The image data of the read original is transmitted to the public line 20 through the FAX communication unit 18 to operate as a facsimile machine.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  Next, details of the operation unit 13 will be described. FIG. 2 is a diagram illustrating an example of the operation unit 13. 1 and 2, the operation unit 13 includes a start key 31 for instructing the digital multifunction peripheral 10 to start processing, a stop key 32 for supporting the digital multifunction peripheral 10 to stop processing, and the number of images formed. A numeric keypad 33 for setting numerical values such as, a clear key 34 for initializing set image forming conditions, and a display screen 23 for displaying predetermined information relating to image formation.

  The display screen 23 displays predetermined information related to image formation by a control signal from the control unit 11. The display screen 23 is a touch panel format. That is, the user can set image forming conditions and the like by pressing a touch key displayed on the display screen 23.

  The display screen 23 in FIG. 2 displays a screen that allows the user to input the type of paper. Specifically, a character display 35 “Please input the type of paper” and a touch key 36 a for specifying “plain paper” as the type of paper that can be formed in the digital multi-function peripheral 10. A touch key 36b for designating “postcard”, a touch key 36c for designating “paper change”, a touch key 36d for designating “OHP sheet”, and a touch key 36e for designating “other” are displayed. The user selects and touches one of the touch keys 36a to 36e according to the type of paper to be used. In this way, the paper type is input. If the paper type is other than “plain paper”, “postcard”, “replacement”, or “OHP sheet”, touch the “other” touch key 36e to display additional paper types. Or, input the paper type manually.

  Here, the digital multi-function peripheral 10 includes a paper transport unit 41 that transports paper from the paper feed cassette 29 to the discharge tray in the digital multi-function peripheral 10, and a loop sensor 51 as a flexure detection unit that detects the flexure amount of the paper. . FIG. 3 is a schematic cross-sectional view showing a part of the paper transport unit 41 and a main part of the loop sensor 51.

  Referring to FIGS. 1 and 3, the paper transport unit 41 forms a paper transport path 42 for transporting paper and a part of the paper transport path 42 and guides the transported paper from the lower side of the paper. A conveyance guide unit 43, a part of the sheet conveyance path 42, an upper conveyance guide unit 44 that guides a sheet to be conveyed from the upper side of the sheet, and a plurality of conveyance rollers (not shown) are included. That is, the paper P is transported between the lower transport guide portion 43 and the upper transport guide portion 44 in the paper transport path 42. In the case shown in FIG. 3, the upstream side of the sheet conveyance path 42 on which the sheet P is conveyed is the right side of the sheet, and the downstream side is the left side of the sheet. That is, the paper P is conveyed from the right side to the left side of the paper. In addition, a transfer unit 26 is disposed on the right side of the paper surface shown in FIG. 3, and a fixing unit 27 is disposed on the left side of the paper surface. That is, the loop sensor 51 is provided between the transfer unit 26 and the fixing unit 27. In addition, the conveyance roller is provided in the paper surface right side and paper surface left side of FIG. 3, respectively, and conveyance of the paper P is performed by rotation of a conveyance roller.

  The loop sensor 51 is provided on a loop amount detection unit 52 that detects a loop amount of the paper P, that is, a deflection amount of the paper P, and a light emitting element that irradiates the paper P with light. 53, downstream of the light emitting element 53 and above the loop amount detection unit 52, and a light receiving element 54 for receiving light reflected by the paper P, and a light emitting element when the paper P is not conveyed And a reflection portion 55 that reflects the light emitted by the light source 53. The loop sensor 51 is provided in the paper transport path 42. Among the loop sensors 51, the loop amount detection unit 52, the light emitting element 53, and the light receiving element 54 are attached to the lower conveyance guide unit 43, and the reflection unit 55 is embedded in the upper conveyance guide unit 44. The upper surface of the light emitting element 53 and the upper surface of the light receiving element 54 are configured to be the same surface in the vertical direction.

  Next, a method for detecting the loop amount by the loop sensor 51 will be described. First, the sheet P is slightly bent so that the upper side is convex between the conveyance roller disposed on the upstream side of the sheet conveyance path 42 and the conveyance roller disposed on the downstream side of the sheet conveyance path 42. State. Then, the paper P is irradiated with light from the light emitting position 56 in the light emitting element 53. Here, the light is reflected at the reflection position 57 of the paper P, specifically, the paper P. The reflected light is received at the light receiving position 58 of the light receiving element 54. Using the information on the light emitting position 56, the light receiving position 58, and the reflection position 57, the position of the paper P is calculated by three-point surveying.

Here, the position of the sheet P is the position in the vertical direction between the lower side conveyance guide portion 43 and the upper side conveyance guide portion 44, and the sheet P exists from the position of the upper surface of the light emitting element 53 and the light receiving element 54. the distance _{L 1} to the reflecting position 57 to say. In FIG. 3, when an angle formed by a line 59 including the light emission position 56 extending in the horizontal direction and a line 60 connecting the light emission position 56 and the reflection position 57 is θ, if the angle θ is large, the position of the paper P Is determined to be far away. That is, it is determined that the distance from the upper surface of the light emitting element 53 to the position of the bent sheet P is long. Note that the angle formed between the line 61 connecting the light receiving position 58 and the reflection position 57 and the line 59 is also θ.

  Thereafter, the type of the paper P is determined from the amount of deflection of the paper P. For this determination, first, a deflection amount corresponding to the type of each sheet is calculated in advance and stored in the hard disk 17 as a database. Then, based on the stored database value, the type of paper corresponding to the amount of deflection detected by the loop amount detection method described above is determined.

When the paper P is not conveyed, the light from the light emitting element 53 is reflected at the reflection position 62 in the reflection unit 55. This distance is a distance L ₂ between the upper surface of the light emitting element 53 and the reflection position 62, and this is a reference when there is no paper P. The light reflection on the paper P is indicated by a dotted line, and the light reflection on the reflection portion 55 is indicated by a one-dot chain line. The determination of the specific type of paper P will be described later.

  Next, the operation of the control unit 11 when an image is formed using the digital multifunction peripheral 10 according to an embodiment of the present invention will be described. FIG. 4 is a flowchart showing the operation of the control unit 11 in this case.

  Referring to FIGS. 1 to 4, first, an image forming request is accepted in operation unit 13 (in FIG. 4, step S <b> 11, hereinafter, steps are omitted). Here, in image formation, the user inputs conditions such as the number of sheets to be output and also inputs the type of sheets to be output. Specifically, the paper type is input on the display screen 23 of the operation unit 13 as shown in FIG. Here, the operation unit 13 operates as input means for inputting the type of paper. Then, the control unit 11 extracts the input paper type (S12).

  Thereafter, when the paper type is input and the start key 31 is pressed, image formation is started. Here, the control unit 11 determines the type of paper (S13). The determination of the paper type is performed by the loop sensor 51 shown in FIG. Here, the control unit 11 operates as a determination unit that determines the type of paper.

  Next, it is compared whether or not the input paper type is the same as the determined paper type (S14). If the input paper type and the determined paper type are the same (YES in S14), fixing control is performed according to the input paper type (S15). That is, the fixing temperature, the conveyance speed, and the like in the fixing unit 27 are set according to the type of the input paper.

  On the other hand, if the input paper type and the determined paper type are not the same (YES in S14), that is, if the input paper type and the determined paper type are different, it is determined. The image forming conditions are changed according to the type of paper. Then, fixing control is performed (S16). That is, the fixing temperature, the conveyance speed, and the like in the fixing unit 27 are set according to the determined paper type.

  With this configuration, even when there is an input error of the paper type by the user, an image can be formed under an appropriate image forming condition according to the paper type. That is, it is possible to perform image formation by determining whether or not there is an input error in the type of input paper. Therefore, it is possible to reliably perform image formation according to the type of paper. In this case, it is possible to cope with the case where the user does not input the paper type. That is, when the user does not input the paper type, the image forming conditions are changed according to the determined paper type.

  Here, the amount of deflection according to the type of paper will be described. FIG. 5 is a graph relating to changes in the amount of deflection when the types of paper are different. In FIG. 5, the vertical axis indicates the sensor output (V) in the loop amount detection unit 52, and the horizontal axis indicates the measurement distance (cm). In FIG. 5, a solid line indicates a case where the paper type is a postcard, and a dotted line indicates a case where the paper type is an OHP sheet. The values of the graph shown in FIG. The measurement distance corresponds to the distance L in FIG.

  The difference in loop amount will be described with reference to FIG. 5 and Table 1. When the paper type is postcard, when the measurement distance is 2.0 cm, it is 3.27 V, when it is 3.0 cm, when it is 2.74 V, when it is 4.0 cm, when it is 2.11 V, 5.0 cm Is 1.67V. On the other hand, when the paper type is an OHP sheet, it is 2.37 V when 2.0 cm, 2.06 V when 3.0 cm, 1.47 V and 5.0 cm when 4.0 cm. In this case, it is 1.12V. As described above, the values of the postcard and the OHP sheet are greatly different, and the type of paper is determined based on the difference in the sensor output voltage value. For example, when it is determined that the paper type is an OHP sheet, the fixing temperature is lowered as compared with the case of the postcard.

  As described above, according to the digital multi-function peripheral 10 having such a configuration, it is possible to reliably perform image formation according to the type of paper.

  In the above embodiment, the amount of paper deflection is detected using the loop sensor. However, the present invention is not limited to this, and other deflection detection mechanisms such as a PI (Photo Interrupter) sensor The amount of paper deflection may be detected based on the difference in transmission amount, and the type of paper may be determined from the detected amount of deflection.

  In the above-described embodiment, the loop sensor is provided between the transfer unit and the fixing unit. However, the present invention is not limited to this, and the loop sensor is transferred from another location in the paper transport path, for example, a paper feed cassette. It is good also as providing between the parts. By doing so, it is possible to reflect the image forming conditions in the transfer portion, specifically, for example, transfer voltage, bias voltage, and the like. Therefore, image formation can be performed more appropriately according to the type of paper.

  In the above embodiment, the user is allowed to input the paper type on the display screen of the operation unit. However, the present invention is not limited to this, and the user is not allowed to input the paper type, and the amount of flexure of the paper is determined. The image formation may be performed by changing the image formation conditions according to the type of paper determined based on the basis. That is, it may be configured to always perform image formation based on the type of paper determined by the determination unit.

  Further, in the above-described embodiment, the determination unit operates the deflection detection unit for each sheet and determines for each sheet when forming an image on a plurality of sheets, and the control unit determines for each sheet. Control may be performed to change predetermined image forming conditions. By doing so, even when a plurality of types of paper are set, it is possible to cope more appropriately.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 20 Public line, 21 Network , 22 PC, 23 Display screen, 24 Photoconductor, 25 Developer, 26 Transfer section, 27 Fixing section, 28 Paper feed section, 29 Paper feed cassette, 31 Start key, 32 Stop key, 33 Numeric keypad, 34 Clear key, 35 Character display, 36a, 36b, 36c, 36d, 36e Touch key, 41 Paper transport section, 42 Paper transport path, 43 Lower transport guide section, 44 Upper transport guide section, 51 Loop sensor, 52 Loop amount detection section, 53 Light emitting element, 54 Light receiving element, 55 Reflecting part, 56, 57, 58, 62 rank , 59, 60, and 61-wire.

Claims (6)

Image forming means for forming an image on a predetermined image forming condition and outputting it to paper;
Deflection detection means for detecting the amount of deflection of the paper;
Determination means for determining the type of paper based on the amount of paper deflection detected by the deflection detection means;
An image forming apparatus comprising: a control unit that controls to change the predetermined image forming condition according to the type of paper determined by the determining unit. An input means for inputting the type of paper is provided.
The image forming apparatus according to claim 1, wherein the control unit is operated when a paper type input by the input unit is different from a paper type determined by the determination unit. 3. The image forming apparatus according to claim 1, wherein the deflection detection unit includes a loop sensor that irradiates light to the bent sheet and detects a deflection amount of the sheet by the reflected light. The image forming unit includes a transfer unit that transfers an image formed with toner onto a sheet, and a fixing unit that fixes the toner onto the sheet transferred by the transfer unit.
The image forming apparatus according to claim 1, wherein the deflection detection unit is provided between the transfer unit and the fixing unit. The predetermined image forming conditions include a fixing temperature condition in the fixing unit,
The image forming apparatus according to claim 4, wherein the control unit changes the fixing temperature condition according to a type of paper. In the case where an image is formed on a plurality of sheets, the determination unit determines for each sheet by operating the deflection detection unit for each sheet,
The image forming apparatus according to claim 1, wherein the control unit performs control to change the predetermined image forming condition for each sheet.

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