JP2018016467A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation apparatus which can correctly detect the temperature of a discharged sheet with a compact configuration.SOLUTION: A compound machine 11 includes fixation rollers 29a, 29b, a discharge tray 19, an actuator 36 and a thermistor 41. The discharge tray 19 is provided on the downstream side in the conveyance direction of a sheet 21 with respect to the fixation rollers 29a, 29b and on the outside of the compound machine 11, and laminates the sheet 21 discharged to the outside of the compound machine 11 thereon after fixation of a toner image to the sheet 21. The actuator 36 is movable in the conveyance direction of the sheet 21, is brought into contact with the sheet 21 when the sheet is discharged to the discharge tray 19 and detects that the sheet 21 is discharged to the discharge tray 19. The thermistor 41 is provided on the outside of the compound machine 11 being the position in contact with the sheet 21 discharged to the discharge tray 19, and detects the temperature of the sheet 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus typified by a multifunction peripheral, light is applied to a photoconductor based on image data to form an electrostatic latent image on the photoconductor. Thereafter, charged toner is supplied onto the formed electrostatic latent image to form a visible image, which is then transferred and fixed on paper, and output to the outside of the apparatus.

  In the image forming apparatus, sheets output to the outside of the apparatus are discharged onto a discharge tray and stacked. Here, when the discharged sheets are stacked, the temperature of the discharged sheets is not sufficiently lowered and becomes excessively hot. As a result, the toner once fixed on the paper may melt, and the discharged paper may stick to each other. This tendency is particularly strong when using low-temperature fixing toner in recent times. Therefore, it is necessary to manage the temperature of the discharged paper and to cool the discharged paper as necessary. Techniques relating to cooling of discharged paper are disclosed in Japanese Patent Application Laid-Open No. 2007-76867 (Patent Document 1) and Japanese Utility Model Laid-Open No. 1-88948 (Patent Document 2).

  The sheet stacking device disclosed in Patent Document 1 includes a sheet stacking unit that stacks heat-treated sheets. The sheet stacking apparatus includes a temperature detection unit that detects the temperature of the sheet, a cooling unit that cools the sheet, and a control unit that operates the cooling unit to cool the sheet when the temperature exceeds a predetermined value. It is a feature.

  Further, the transfer paper blocking prevention device disclosed in Patent Document 2 is a copying machine in which a fixing device with a heat roller is arranged in a transport path for transporting a transfer paper after the transfer process to a paper discharge tray. A thermistor provided downstream of the fixing device on the conveyance path, a counter roller disposed opposite to the thermistor so that the transfer paper can be brought into close contact with the thermistor, a cooling fan disposed downstream of the thermistor, It has a temperature control means for inputting the output of the thermistor and controlling the driving of the cooling fan based on this input.

JP 2007-76867 A Japanese Utility Model Publication No. 1-88948

  According to the technique disclosed in Patent Document 1, the temperature of the paper is detected in a non-contact manner. However, in such a configuration, since the distance between the sensor and the paper changes, the temperature cannot be accurately detected. Further, in the technique disclosed in Patent Document 2, since the thermistor is provided in the device, the size of the device may increase. That is, in order to reduce the influence of the fixing device that generates a high temperature in the copying machine, it is necessary to provide a thermistor at a position away from the fixing device. As a result, the size of the copying machine increases.

  An object of the present invention is to provide an image forming apparatus capable of accurately detecting the temperature of discharged paper with a compact configuration.

  The image forming apparatus according to the present invention forms an image on a sheet. The image forming apparatus includes a developing device, a transfer unit, a fixing roller, a discharge tray, a paper detection unit, and a temperature detection unit. The developing device forms a toner image which is a visible image with toner. The transfer unit transfers the toner image formed by the developing device to a sheet. The fixing roller is provided in the image forming apparatus on the downstream side in the sheet conveyance direction with respect to the transfer unit, and the toner image is transferred to the sheet while conveying the sheet on which the toner image has been transferred by the transfer unit to the downstream side. Let it settle. The discharge tray is provided on the downstream side of the sheet conveyance direction with respect to the fixing roller and outside the image forming apparatus, and after the toner image is fixed to the sheet, the sheet discharged outside the image forming apparatus is stacked thereon. To do. The paper detection unit contacts the paper when the paper is discharged to the discharge tray, and detects that the paper has been discharged to the discharge tray. The temperature detection unit is provided outside the image forming apparatus at a position where the sheet is discharged to the discharge tray and detects the temperature of the sheet.

  According to such an image forming apparatus, since the temperature detection unit is provided outside the image forming apparatus, it is not necessary to unnecessarily increase the size of the image forming apparatus, and the image forming apparatus has a compact configuration. be able to. In addition, since the temperature detection unit is provided at a position in contact with the paper and outside the image forming apparatus, the temperature of the paper can be accurately detected. Therefore, the image forming apparatus having such a configuration can accurately detect the temperature of the discharged paper with a compact configuration.

1 is a schematic diagram illustrating an appearance of a multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the multifunction peripheral. FIG. 5 is a diagram illustrating a configuration in the vicinity of a discharge tray provided in a multifunction machine according to an embodiment of the present invention, and illustrates a case where the amount of paper discharged on the discharge tray is small. FIG. 4 is a diagram illustrating a configuration in the vicinity of a discharge tray provided in a multifunction machine according to an embodiment of the present invention, and illustrates a case where the amount of paper discharged on the discharge tray is large. 6 is a flowchart illustrating a flow of processing when managing the temperature of discharged paper. It is a figure which shows the structure of the vicinity of the discharge tray with which the multifunctional device which concerns on other embodiment of this invention is equipped. FIG. 6 is a block diagram illustrating a configuration of a multifunction machine in the case illustrated in FIG. 5. 6 is a graph showing the relationship between the paper temperature and the continuous printing time.

Embodiments of the present invention will be described below. FIG. 1 is a diagram illustrating a multifunction machine 11 when an image forming apparatus according to an embodiment of the present invention is applied to a multifunction machine. 2 and 3 are diagrams showing a configuration in the vicinity of a later-described discharge tray 19 provided in the multifunction machine 11. FIG. 2 shows a case where the amount of paper 21 discharged on the discharge tray 19 is small, and FIG. 3 shows a case where the amount of paper 21 discharged on the discharge tray 19 is large. Note that the transport direction of the sheet 21 conveyed on the conveying path is indicated by the direction of the bold arrow D _1. In FIG. 1, the configuration of a cooling fan 33 and the like to be described later is not shown, and the configuration in the vicinity of the discharge tray 19 is schematically illustrated.

  1 to 3, the multifunction machine 11 has a plurality of functions such as a copying function, a printer function, and a facsimile function regarding image processing. The multifunction machine 11 includes a control unit 12, an operation unit 13, an image reading unit 14, an image forming unit 15, an ADF 16, a manual feed tray 17, three paper feed cassettes 18 a, 18 b and 18 c, and a discharge tray 19. With. Note that the multifunction machine 11 may be configured to include a hard disk (not shown) that stores various data.

  A control unit 12 including a CPU controls the entire multifunction machine 11. In FIG. 1, the control unit 12 is schematically indicated by a two-dot chain line. The operation unit 13 including a touch panel displays information from the multi-function peripheral 11 side and allows the user to input image forming conditions such as the number of copies to be printed and gradation, and power on / off. The image reading unit 14 reads an image of an original document set on an ADF (Auto Document Feeder) 16 serving as an original conveying device or a mounting table. Based on the image data read by the image reading unit 14 and the image data transmitted to the multi-function peripheral 11 via a network (not shown), the image forming unit 15 includes a manual feed tray 17 and a plurality of paper feed cassettes 18a, An image is formed on the sheet 21 that has been set and transported on the sheets 18b and 18c. The sheet 21 on which an image is formed by the image forming unit 15 is discharged to the discharge tray 19.

  The discharge tray 19 is provided outside the multifunction machine 11. That is, the discharge tray 19 is provided in the multifunction machine 11 so as to be exposed not in the housing but in an open space. The discharge tray 19 is provided on the downstream side in the transport direction of the paper 21 with respect to fixing rollers 29a and 29b described later. The discharge tray 19 discharges the paper 21 onto the paper 21 after the toner image is fixed on the paper 21 by the fixing rollers 29a and 29b. When a plurality of sheets 21 are discharged, the sheets 21 are stacked one by one on the discharge tray 19.

  Next, the configuration of the image forming unit 15 provided in the multifunction machine 11 will be described in more detail. The image forming unit 15 includes an LSU (Laser Scanner Unit) 22, a transfer belt 23 as an intermediate transfer member, and a secondary transfer roller 24 as a transfer unit. About LSU22, it has shown roughly with the dashed-dotted line. Note that the multifunction machine 11 includes a so-called four-tandem image forming unit 15.

  The image forming unit 15 corresponds to four colors of yellow, magenta, cyan, and black, and includes four photosensitive units 26a, 26b, 26c, and 26d including the photosensitive members 27a, 27b, 27c, and 27d, and four developing units. Development units 28a, 28b, 28c, and 28d. In FIG. 1, the photoreceptor units 26a to 26d and the developing units 28a to 28d are schematically shown by broken lines.

  The LSU 22 exposes the four photosensitive members 27a to 27d based on the image data read by the image reading unit 14 and the received image data. An electrostatic latent image is formed on the photoconductors 27a to 27d based on the exposed light of each color component. By supplying toner of each color from the developing units 28a to 28d to the electrostatic latent images formed on the photoreceptors 27a to 27d, toner images are formed on the photoreceptors 27a to 27d, respectively. The toner images formed on the photoconductors 27a to 27d are primarily transferred onto the transfer belt 23, respectively. The toner image primarily transferred onto the transfer belt 23 is secondarily transferred to the paper 21 by the secondary transfer roller 24, fixed to the paper 21 by the pair of fixing rollers 29 a and 29 b, and discharged to the discharge tray 19. .

  Here, the configuration of the fixing rollers 29a and 29b will be described in detail. The fixing rollers 29 a and 29 b are provided in the multifunction machine 11. The fixing rollers 29 a and 29 b are provided on the downstream side in the transport direction of the paper 21 with respect to the secondary transfer roller 24. The fixing rollers 29 a and 29 b are heated to a temperature at which fixing can be performed so that the toner image is fixed to the paper 21 when the paper 21 is conveyed. Of the pair of fixing rollers 29a and 29b, the fixing roller 29a that contacts the paper 21 on the side where the toner image is transferred is also referred to as a heating roller in which a heater is provided. On the other hand, the fixing roller 29b that contacts the paper 21 on the side where the toner image is not transferred is also referred to as a pressure roller made of a rubber-like member. The fixing rollers 29 a and 29 b fix the toner image onto the paper 21 while transporting the paper 21 onto which the toner image has been transferred by the secondary transfer roller 24 to the downstream side in the transport direction.

  The multifunction machine 11 also includes a pair of transport rollers 32a and 32b, a cooling fan 33 as a cooling mechanism, and an actuator 36 as a paper detection unit. The pair of transport rollers 32 a and 32 b are provided on the downstream side in the transport direction of the fixing rollers 29 a and 29 b and on the upstream side in the transport direction of the discharge tray 19. The paper 21 is finally discharged to the discharge tray 19 by the transport rollers 32a and 32b.

The cooling fan 33 is provided above the fixing rollers 29a and 29b and the transport rollers 32a and 32b in terms of the device configuration. The cooling fan 33 can be activated to cause wind. The induced wind is sent in the direction of arrow D ₂ using the cooling air passage 34. In this way, the cooling fan 33 can be blown onto the discharge tray 19 by operation. The sheet 21 discharged onto the discharge tray 19 can be cooled from above by the wind caused by the cooling fan 33.

The actuator 36 contacts the paper 21 when the paper 21 is discharged to the discharge tray 19 and detects that the paper 21 has been discharged to the discharge tray 19. The actuator 36 has a rod shape. One end portion 38 a of the actuator 36 is attached to the attachment portion 37 located on the upper side of the discharge tray 19. The actuator 36 is supported so as to be rotatable at a predetermined angle with the end 38a as a fulcrum. Direction of rotation of the actuator 36 is the direction of the arrow R ₁ in FIG. Of the actuator 36, an end 38b opposite to the end 38a attached to the attachment 37 is bent in the rotational direction. In other words, the actuator 36 has a bent portion 39 between the end portions 38a and 38b. The actuator 36 is provided outside the multifunction machine 11 except for one end 38 a attached to the attachment part 37.

The sheet 21 conveyed from the conveyance rollers 32 a and 32 b comes into contact with the actuator 36 at the upstream end in the conveyance direction. As actuator 36 by the sheet 21 is pushed in the conveying direction of the sheet 21 rotates in the direction of arrow R _1. If it is detected that the actuator 36 has rotated to a predetermined angle, it is detected that the paper 21 has passed the position where the actuator 36 is provided. The discharged paper 21 is discharged so as to be placed on the discharge tray 19 by its own weight. After the paper 21 is discharged, the actuator 36 is released from the state of being pushed by the paper 21, and thus returns to the state before the rotation due to the weight of the actuator 36. At this time, the bent portion 39 is brought into contact with the paper 21, specifically, at a position close to the rear end side in the conveyance direction of the paper 21. 2 and 3, the angle of the actuator 36 about the fulcrum is different, but the bent portion 39 of the actuator 36 comes into contact with the upper surface of the sheet 21 discharged to the top.

  Here, a thermistor 41 serving as a temperature detection unit that detects the temperature of the paper 21 is provided in the bent portion 39 of the actuator 36 that comes into contact with the uppermost discharged paper. Specifically, the thermistor 41 is provided at a position below the bent portion 39 that contacts the paper 21. In this case, since the bent portion 39 of the actuator 36 is provided outside the multi-function device 11, the thermistor 41 is provided outside the multi-function device 11. The thermistor 41 detects the temperature of the abutting sheet 21, specifically, the sheet 21 discharged to the top of the sheets 21 discharged onto the discharge tray 19.

  According to the MFP 11 having such a configuration, since the thermistor 41 is provided outside the MFP 11, there is no need to unnecessarily increase the size of the MFP 11, and the MFP 11 has a compact configuration. can do. In this case, since the actuator 36 is a member originally provided in the multifunction machine 11, it is not necessary to newly provide a member for attaching the thermistor 41 to the multifunction machine 11. Further, since the thermistor 41 is provided at a position where the thermistor 41 abuts the paper 21 and is provided outside the multi-function device 11, the temperature of the paper 21 can be accurately detected. Therefore, the multi-function device 11 having such a configuration can accurately detect the temperature of the discharged paper 21 with a compact configuration.

  In this case, the thermistor 41 is configured to come into contact with the uppermost sheet 21 on the discharge tray 19, so that the temperature of the uppermost sheet 21 can be accurately detected.

  The management after detecting the temperature of the discharged paper 21 is as follows. FIG. 4 is a flowchart showing the flow of processing when managing the temperature of the discharged paper 21.

  Referring to FIG. 4, when image formation using a plurality of sheets 21 is started, sheets 21 on which images are formed one after another are discharged onto discharge tray 19. Then, the temperature of the uppermost sheet 21 on the discharge tray 19 is detected by the thermistor 41 provided in the actuator 36 (in FIG. 4, step S11, hereinafter “step” is omitted).

  Thereafter, it is determined whether or not the temperature of the uppermost sheet 21 is equal to or lower than a predetermined temperature (S12). The predetermined temperature is determined depending on the type of toner used. If it is determined that the temperature is not lower than the predetermined temperature, that is, higher than the predetermined temperature (NO in S12), control unit 12 controls cooling fan 33 to operate (S13). Then, the cooling fan 33 blows air onto the discharge tray 19 to cool the paper 21. If the temperature is equal to or lower than the predetermined temperature (YES in S12), the cooling fan 33 is not operated, and image formation is continued until image formation is completed (YES in S14). In this way, the sheet 21 on the discharge tray 19 is prevented from becoming hot.

  In the above-described embodiment, the thermistor 41 is provided in the actuator 36. However, the present invention is not limited to this, and the thermistor may be provided in the discharge tray 19. In this case, the discharge tray 19 is provided on the rear end side of the discharged paper 21.

  FIG. 5 is a diagram showing a configuration in the vicinity of the discharge tray 19 included in the multi-function device 43 according to another embodiment of the present invention. FIG. 5 corresponds to FIG. 5, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIGS. 1 to 5, the discharge tray 19 is provided with a thermistor 42. The thermistor 42 is provided so as to be positioned on the rear end side of the discharged paper 21 in the discharge tray 19.

  With this configuration, the thermistor 42 is provided at the position where the sheet 21 discharged to the discharge tray 19, specifically, the sheet 21 that is discharged first, is in contact with the sheet 21. Temperature can be detected. The sheet 21 discharged first means the lowermost sheet 21 on the discharge tray 19. In this case, based on the temperature of the sheet 21 discharged first, the temperature of the sheet 21 discharged at the top can be derived.

  FIG. 6 is a block diagram showing the configuration of the multifunction machine 43 in the case shown in FIG. Referring to FIG. 6, the multi-function device 43 includes a control unit 12, an operation unit 13, an image reading unit 14, an image forming unit 15, and a hard disk 44. The control unit 12 includes a temperature deriving unit 45. The basic configuration of the multi-function device 43 shown in FIG. 6 is the same as that of the multi-function device 11 shown in FIG. That is, the attachment position of the thermistor 42 is different, and the hard disk 44 and the temperature deriving unit 45 are newly added.

  Here, an example of temperature derivation by the temperature derivation unit 45 will be described. FIG. 7 is a graph showing the relationship between the paper temperature and the continuous printing time. In FIG. 7, a line 46a indicates the temperature of the paper 21 discharged at the end of continuous printing, a line 46b indicates the temperature of the paper 21 discharged at the first continuous printing, and a line 46c indicates 10 sheets. The temperature of the tenth sheet 21 when continuously printed is shown. Continuous printing is a case where printing is continued for 20 minutes. For example, in the case of the multifunction machine 43 that prints 20 sheets 21 per minute, 400 sheets can be printed continuously for 20 minutes.

  Referring to FIG. 7, according to line 46c, when ten sheets are printed continuously, the temperature of the tenth sheet 21 tends to continue to decrease. That is, it is not necessary to consider the operation of the cooling fan 33 in particular.

  On the other hand, according to the line 46a, the temperature of the paper 21 discharged at the end of continuous printing continues to rise. Specifically, in the printing for 20 minutes, the temperature continues to rise until 20 minutes have passed. According to the line 46b, the temperature of the sheet 21 discharged to the first sheet of continuous printing also continues to rise until 20 minutes have elapsed in printing for 20 minutes. This is considered to be because heat tends to be accumulated when the next sheet 21 is stacked without the temperature being lowered in the stacked sheets 21. For each of the lines 46a and 46b, the temperature gradually decreases after 20 minutes.

  In line 46a and line 46b, the rate at which the temperature rises is almost the same from 20 minutes after the lapse of 2-3 minutes from the start of printing. Therefore, as an example, based on this correlation, the temperature deriving unit 45 derives the temperature of the sheet 21 discharged to the top from the temperature detected by the thermistor 42 provided on the discharge tray 19. Then, the operating state of the cooling fan 33 is controlled based on the derived temperature. The correlation data is stored in the hard disk 44. The temperature deriving unit 45 uses the correlation data stored in the hard disk 44 as necessary to derive the temperature of the sheet 21 discharged to the top.

  In the above-described embodiment, the thermistor 42 is provided so as to be positioned on the rear end side of the discharged paper 21 in the discharge tray 19. However, the present invention is not limited thereto, and the thermistor 42 is not limited to the discharge tray 19. 19 may be provided so as to be positioned on the front end side or the center side of the discharged paper 21.

  Further, the temperature deriving unit 45 derives the temperature of the uppermost sheet 21 discharged based on the correlation shown in FIG. 7, but is not limited to this, and the temperature of the uppermost sheet 21 discharged. And the temperature of the sheet 21 discharged at the bottom are stored in the hard disk 44 as table format data, and the temperature of the sheet 21 discharged at the top is derived using this table format data. May be.

  It should be understood that the embodiments disclosed herein are illustrative in all respects and are not restrictive in any aspect. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

  The image forming apparatus according to the present invention is particularly effectively used when a compact configuration and accurate detection of the temperature of discharged paper are required.

  11, 43 MFP, 12 control unit, 13 operation unit, 14 image reading unit, 15 image forming unit, 16 ADF, 17 manual feed tray, 18a, 18b, 18c paper feed cassette, 19 discharge tray, 21 paper, 22 LSU, 23 Transfer belt, 24 Secondary transfer roller, 26a, 26b, 26c, 26d Photoconductor unit, 27a, 27b, 27c, 27d Photoconductor, 28a, 28b, 28c, 28d Development unit, 29a, 29b Fixing roller, 32a, 32b Conveying roller, 33 Cooling fan, 34 Cooling air path, 36 Actuator, 37 Mounting part, 38a, 38b End part, 39 Bending part, 41, 42 Thermistor, 44 Hard disk, 45 Temperature deriving part, 46a, 46b, 46c Line.

Claims (5)

An image forming apparatus for forming an image on paper,
A developer for forming a toner image that is a visible image with toner;
A transfer unit that transfers the toner image formed by the developing unit to a sheet;
The toner image is provided in the image forming apparatus on the downstream side of the transfer unit with respect to the conveyance direction of the sheet, and the toner image is transferred to the downstream side while conveying the sheet on which the toner image is transferred by the transfer unit A fixing roller for fixing to the paper;
The sheet is provided on the downstream side in the sheet conveyance direction with respect to the fixing roller and outside the image forming apparatus, and the sheets discharged to the outside of the image forming apparatus are stacked after the toner image is fixed on the sheet. A discharge tray,
A paper detection unit that contacts the paper when the paper is discharged to the discharge tray and detects that the paper is discharged to the discharge tray;
An image forming apparatus comprising: a temperature detection unit that is provided outside the image forming apparatus at a position in contact with the sheet discharged to the discharge tray and detects the temperature of the sheet. The image forming apparatus according to claim 1, wherein the temperature detection unit is a part of the paper detection unit and is provided at a position where the temperature detection unit contacts the paper discharged to the discharge tray. The image forming apparatus according to claim 1, wherein the temperature detection unit is provided in a part of the discharge tray on which the sheet discharged thereon is stacked. The image forming apparatus according to claim 3, wherein the temperature detection unit is provided on a rear end side of the sheet to be discharged in the discharge tray. A storage unit for storing data;
Based on the correlation data of the continuous printing time, the temperature of the first sheet of continuous printing and the temperature of the paper discharged at the end of continuous printing stored in the storage unit, The image forming apparatus according to claim 3, further comprising a temperature deriving unit that derives a temperature of the sheet to be printed.

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