Patent Grant
10942477
Embodiments described herein relate generally to an image forming apparatus and an image forming method.
An image forming apparatus including an on-demand heating device, such as a film fixing device, is known. For example, sheets of paper of the same size may continuously pass through such an on-demand heating device during image forming operations. In such a case, the temperature of a heater in the on-demand heating device may increase excessively in those portions/regions through which paper is not passing during the image forming operations, and thus there is a problem in that deterioration, breakdown, or burn out, or the like of a component of the on-demand heating device may occur.
Embodiments provide an image forming apparatus and an image forming method directed to suppressing unwanted temperature increases in a heater.
In general, according to an embodiment, an image forming apparatus includes a fixing unit, an image forming unit, and a controller. The image forming unit is configured to form an image on a sheet (for example, with toner). The fixing unit extends in a sheet width direction and is configured to fix images on sheets from the image forming unit. The controller is configured to receive image data corresponding to a target image to be formed on the sheet and convert the received image data to modified image data corresponding to a modified image that includes the target image and a margin added on at least one side of the target image in the sheet width direction. The controller controls the image forming unit to form the modified image based on a sheet, and cause the sheet to be conveyed to the image forming unit such that a positioning of the sheet in the sheet width direction that overlaps with the target image included in the modified image and a fixing portion (for example, a heated portion) of the fixing unit overlaps with the target image in the modified image formed on the sheet.
Hereinafter, an image forming apparatus and an image forming method according to certain example embodiments will be described with reference to the drawings.
The image forming apparatus 100 includes a housing 10, a display 1, a scanner unit 2, an image forming unit 3, a sheet supply unit 4, a conveying unit 5, a paper discharge tray 7, an inversion unit 9, a control panel 8, and a controller 6. The image forming unit 3 may be a device that fixes a toner image or an ink jet device.
The image forming apparatus 100 forms an image on a sheet S using a developer such as toner. The sheet S is, for example, paper or label paper. The sheet S may be any material as long as the image forming apparatus 100 can form an image on a surface of the sheet.
The housing 10 forms an external shape of the image forming apparatus 100.
The display 1 is an image display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display 1 displays various information relating to the image forming apparatus 100.
The scanner unit 2 acquires image information from a reading target based on brightness and darkness of reflected light from the reading target and generates image data accordingly. The scanner unit 2 records the generated image data. The scanner unit 2 outputs the generated image data to the image forming unit 3. The recorded image data may be transmitted to another information processing apparatus through a network.
The image forming unit 3 forms an output image (hereinafter, referred to as “toner image”) using a recording agent such as toner based on the image data received from the scanner unit 2 or image data received from an external apparatus. The image forming unit 3 transfers the toner image to a surface of the sheet S. The sheet S may be a sheet supplied by the sheet supply unit 4 or a sheet that is manually fed. The image forming unit 3 applies heat and pressure to the toner image on the surface of the sheet S such that the toner image is fixed to the sheet S.
The sheet supply unit 4 supplies sheets S to the conveying unit 5 one by one so the image forming unit 3 can form the toner image on the conveyed sheet S. The sheet supply unit 4 includes a sheet accommodation unit 20 and a pickup roller 21.
The sheet accommodation unit 20 accommodates a sheet S of a predetermined size and a predetermined type. The image forming apparatus 100 includes a plurality of sheet accommodation units 20. Each of the sheet accommodation units 20 may be referred to as a sheet storage. A sheet S is accommodated at different positions along a direction (an axial direction of a fixing belt 57 described below or a sheet width direction) perpendicular to a conveyance direction of the sheet S depending on the sheet accommodation units 20. Hereinafter, the conveyance direction of the sheet S will be referred to as “sheet conveyance direction”, and the direction perpendicular to the conveyance direction of the sheet S in plane with the sheet S will be referred to as “sheet width direction”.
The pickup roller 21 picks up each sheet S from the sheet accommodation unit 20 one by one. The pickup roller 21 supplies the just picked sheet S to the conveying unit 5.
The conveying unit 5 conveys the sheet S supplied from the sheet supply unit 4 to the image forming unit 3. The conveying unit 5 includes a conveying roller 23 and a registration roller 24.
The conveying roller 23 conveys the sheet S from the pickup roller 21 to the registration roller 24. The conveying roller 23 allows a tip (edge) of the sheet S in the sheet conveyance direction to abut against a nip N of the registration roller 24.
The registration roller 24 aligns a position of the tip of the sheet S in the sheet conveyance direction by bending the sheet S in the nip N. The registration roller 24 conveys the sheet S to image forming unit 3 at which time the image forming unit 3 transfers the toner image to the sheet S.
Hereinafter, the image forming unit 3 will be described.
The image forming unit 3 includes a plurality of image forming units 25 (25Y, 25M, 25C, and 25K), a laser scanning unit 26, an intermediate transfer belt 27, a transfer unit 28, and a fixing device 30.
Each image forming unit 25 includes a photoconductive drum 25d. Each image forming unit 25 forms the toner image on the photoconductive drum 25d based on the image data received from the scanner unit 2 or an external apparatus. The image forming units 25Y, 25M, 25C, and 25K form toner images using yellow, magenta, cyan, and black toners, respectively.
A charging unit, a developing unit, and the like are arranged around a periphery of the photoconductive drum 25d. The charging unit charges a surface of the photoconductive drum 25d. The developing unit stores a developer including the yellow, magenta, cyan, or black toners. The developing unit develops an electrostatic latent image on the photoconductive drum 25d with toner. As a result, the toner image is formed on a photoconductive drum 25d by each of the respective color toners.
The laser scanning unit 26 scans the charged photoconductive drums 25d with laser light L such that each photoconductive drum 25d is appropriately exposed. The same laser scanning unit 26 exposes the photoconductive drums 25d of each the image forming units 25Y, 25M, 25C, and 25K with the laser light components LY, LM, LC, and LK, respectively. As a result, the laser scanning unit 26 forms the electrostatic latent image on the photoconductive drums 25d.
The toner image on the surface of a photoconductive drum 25d is transferred (referred to as a primary transfer) to the intermediate transfer belt 27.
The transfer unit 28 then transfers (referred to as a secondary transfer) the toner image(s) from the intermediate transfer belt 27 to the surface of the sheet S at a secondary transfer position.
The fixing device 30 applies heat and pressure to the toner image on the sheet S such that the toner image is fixed to the sheet S.
The inversion unit 9 inverts, e.g., flips, the sheet S so an image can be formed on a back surface (other side) of the sheet S. The inversion unit 9 “switches back” the sheet S previously discharged from the fixing device 30 so as to invert the front and back surfaces of the sheet S. The inversion unit 9 then conveys the inverted sheet S to the registration roller 24.
A discharged sheet S on which the intended image has already been formed (e.g., printed) can be placed on the paper discharge tray 7.
The control panel 8 includes a plurality of buttons, for example. The control panel 8 receives an operation from a user. The control panel 8 then outputs a signal corresponding to the operation input by the user to the controller 6 of the image forming apparatus 100. The display 1 and the control panel 8 may be integrated as a touch panel or the like such that user inputs may be received as touch selections of items graphically displayed on display 1.
The controller 6 controls the respective units of the image forming apparatus 100.
The CPU 91 functions as the controller 6 by executing a program stored in the memory 92 and/or the auxiliary storage device 93. The controller 6 controls operations of the respective functional units of the image forming apparatus 100.
The auxiliary storage device 93 may comprise a storage device such as a magnetic hard disk device or a semiconductor memory device. The auxiliary storage device 93 stores various information relating to operations and controls of the image forming apparatus 100.
The communication unit 90 comprises a communication interface for connecting the image forming apparatus 100 to an external apparatus. The communication unit 90 communicates with the external apparatus through the communication interface.
The fixing device 30 according to the embodiment illustrated in
The fixing belt 57 is a thin, flexible material formed into a cylindrical shape. The fixing belt 57 can be referred to as an endless belt-shaped member or a film-shaped member in some contexts. Although not specifically illustrated in
Opposite end of the fixing belt 57 in the axial direction can be fit to a support member (not separately illustrated). The support member supports the axial ends of the fixing belt 57 during fixing operations. The support member helps hold the desired shape of the ends of the fixing belt 57 in the axial direction. On the other hand, an intermediate portion of the fixing belt 57 between the axial ends is likely to be deformed because the support member is not fitted thereto. The fixing belt 57 is rotatable around the axis of the fixing belt 57 when supported by the support member.
For example, the fixing belt 57 and the pressing roller 58 are arranged along a horizontal plane. The pressing roller 58 is pressed toward the fixing belt 57 by a pressing unit so as to come into contact with an outer circumferential surface of the fixing belt 57. At the portion where the pressing roller 58 and the fixing belt 57 are pressed against each other, a surface layer of the pressing roller 58 and the fixing belt 57 are compressed by each other and form a nip N. In the nip N, the sheet S passes between the pressing roller 58 and the fixing belt 57.
The pressing roller 58 is rotated by a drive source such as a motor provided in the housing 10. When the pressing roller 58 is rotated, the driving force of the pressing roller 58 is transmitted to the fixing belt 57 in the nip N such that the fixing belt 57 is rotated. Due to the rotation of the pressing roller 58 and the fixing belt 57, the sheet S inserted into the nip N is conveyed to the downstream side in the conveyance direction. At this time, the toner image transferred to the sheet S is fixed to the sheet S due to heat of the fixing belt 57.
The heater 59 is arranged on an inner peripheral side of the fixing belt 57 and extends toward the longitudinal direction (in parallel) in the sheet width direction. The heater 59 has a length exceeding the full width of the sheet S having a maximum width in which the sheet S can pass through the fixing device 30. The fixing belt 57 has a width exceeding the length of the heater 59. The fixing belt 57 is heated in a range facing the heater 59.
The heater 59 is formed in a band plate shape extending in the longitudinal direction, which may be along the axial direction of the fixing belt 57 and/or the sheet width direction. The heater 59 is arranged in a state where one surface (upper surface in
The fixing device 30 according to the embodiment illustrated in
The fixing device 30 can align the sheet S in the sheet width direction such that a center portion of the sheet S in the width direction overlaps a center portion (indicated by CL in the drawing) of the heater 59 in the longitudinal direction. That is, the fixing device 30 can convey the sheet S in a state where the center portion of the sheet S in the width direction matches the center portion CL of the heater 59 in the longitudinal direction. Alternatively, the fixing device 30 can also align (side alignment) the sheet S in the sheet width direction based on one side in the sheet width direction. Alternatively, the fixing device 30 can also align the sheet S at any position in the sheet width direction.
For the heat generation resistor layers 69a to 69g, an input-side electrode 66 (also referred to as a common electrode in some contexts) and output-side electrodes 67a to 67g (also referred to as individual electrodes in some contexts) that apply an alternating current from an alternating current power supply 65 are provided. A switching element of a drive IC 68 is connected to each of the output-side electrodes 67a to 67g. Energization of each of the heat generation resistor layers 69a to 69g can be individually controlled by the drive IC 68. In this example, the input-side electrode is arranged upstream of the heater in the sheet conveyance direction. The output-side electrodes 67a to 67g are arranged downstream of the heater 59 in the sheet conveyance direction.
In
As illustrated in
The heater front surface 59a is a heating surface on which the heat generation resistor layers 69a to 69g are arranged below a protective layer (not specifically illustrated). The heater back surface 59b is a heat transfer surface to which heat from the heat generation resistor layers 69a to 69g is transferred through the thickness of the heater 59. When the entire heater back surface 59b is in contact with the holder 61, the heat from the heater 59 will be transferred to the holder 61. In this case, the performance of the heater 59 may deteriorate, and the holder 61, which is formed of a resin, is likely to be thermally affected.
The heater 59 is also in contact with and supported by the holder 61 on both the nip upstream side surface and the nip downstream side surface. However, the heater 59 (heater front surface 59a) is not in contact with the holder 61 between the nip upstream side and the nip downstream side thus heat transfer to the holder 61 is suppressed.
The holder 61 includes, in this example, a bottom wall portion 71 that is supported by the frame 62; an upstream wall portion 72 that rises from the nip upstream side of the bottom wall portion 71; and a downstream wall portion 73 that rises from the nip downstream side of the bottom wall portion 71. In the cross-sectional view of
The holder 61 includes a first rib 74 (also referred to as a projection or a protrusion) that supports the upstream side of the heater 59 on the nip upstream side, and includes a second rib 75 (also referred to as a projection or protrusion) that supports the downstream side of the heater 59 on the nip downstream side. The first rib 74 and the second rib 75 rise from the bottom wall portion of the holder 61 to the heater 59 so as to be perpendicular to the front and back surfaces of the heater 59. The rising heights of the first rib 74 and the second rib 75 are lower than the rising heights of the upstream wall portion 72 and the downstream wall portion 73. In the embodiment, the first rib 74 is integrated with the upstream wall portion 72 of the holder 61, and the second rib 75 is integrated with the downstream wall portion 73 of the holder 61.
The first rib 74 and the second rib 75 extend along the longitudinal direction (direction corresponding to the sheet width direction) of the heater 59. The first rib 74 and the second rib 75 extend over the full length of the heater 59. The first rib 74 and the second rib 75 are in contact with and support both the nip upstream side and the nip downstream side of the heater back surface 59b from below. A side edge 59c of the heater 59 in the sheet conveyance direction is near or in contact with the inner wall surface of the upstream wall portion 72 and another side edge 59c of the heater 59 in the sheet conveyance direction is near or in contact with the inner wall surface of the downstream wall portion 73. The heater 59 is fixed to the first rib 74, the second rib 75, the upstream wall portion 72, and the downstream wall portion 73 of the holder 61. For example, the heater 59 is bonded to the holder 61 with a silicon-based adhesive.
The holder 61 is separated from the heater back surface 59b between the first rib 74 and the second rib 75. A rib or the like that partially supports the heater back surface 59b may be provided between the first rib 74 and the second rib 75 of the holder 61. The specific design of holder 61 is not particularly limited so long as some portion is provided that avoids the heater back surface 59b between the nip upstream side and the nip downstream side.
The first rib 74 and the second rib 75 come into contact with the heater back surface 59b to form a support portion 61a that supports the heater 59. The first rib 74 and the second rib 75 are partially notched in the longitudinal direction of the heater 59. That is, a notch portion that is not in contact with the heater back surface 59b is partially formed in the first rib 74 and the second rib 75. A retreated (recessed) portion that is not in contact with the heater back surface 59b is not limited to a notch portion formed in the rib(s) and may, in other examples, be a hole or other recessed portion that avoids contact with the heater back surface 59b. If the retreated portion is only partially formed, the support stiffness of the heater 59 can be improved.
Next, different positions of sheets S accommodated in the sheet accommodation unit 20 will be described.
In this way, sheets S are accommodated to be at positions that are different from each other along a direction perpendicular to the sheet conveyance direction in each of the different sheet accommodation units 20.
Next, a paper-passing position of a sheet S fed from each of the sheet accommodation units 20a to 20c in the fixing device 30 will be described.
In this case, as illustrated in
However, for example, as illustrated in
In this case, as illustrated in
However, as illustrated in
In this case, as illustrated in
However, as illustrated in
When temperature information regarding an unwanted temperature increase in a particular heat generation resistor layer is acquired, the controller 6 of the image forming apparatus 100 according to the embodiment feeds the sheet S from the sheet accommodation unit 20 such that the entire position of the particular heat generation resistor layer indicated by the temperature information becomes a paper-passing position for the sheet S.
As a method in which the controller 6 acquires the temperature information regarding the unwanted temperature increase in a particular heat generation resistor layer, any suitable method may be adopted. For example, the controller 6 may generate the temperature information for specific heat generation resistor layers based on an operation history of the fixing unit, such as the paper-passing position of the sheet S that has been most recently fed or fixed. Specifically, for example, when a predetermined number of sheets S have been continuously fed from the sheet accommodation unit 20a, the controller 6 may estimate that the temperature of the heat generation resistor layer 69c (that is, the heat generation resistor layer including an oblique line portion illustrated in
In other examples, or in combination with the above example, the image forming apparatus 100 may include a detection unit (e.g., thermistor, thermocouple, etc.) that can detect a temperature increase in each of the heat generation resistor layers 69a to 69g. In this case, the controller 6 can detect the temperature increase(s) in specific heat generation resistor layers based on the detection result from the detection unit. Specifically, the fixing device 30 may include a member (for example, a thermistor) that can measure the temperatures of each of the heat generation resistor layers 69a to 69g. In this case, the controller 6 may generate the temperature information regarding the temperature increase in a specific heat generation resistor layer, for example, based on the fact that the measured temperature is higher than or equal to a predetermined temperature.
As a method of determining or selecting the sheet accommodation unit 20 that should feed the next sheet S when the controller 6 acquires the temperature information regarding a temperature increase in a specific heat generation resistor layer, in general, any method may be adopted. For example, the controller 6 may select a sheet accommodation unit 20 to feed the sheet S by referring to correspondence information stored in the auxiliary storage device 93. The correspondence information refers, in this context, to information by which each of the heat generation resistor layers 69a to 69f is associated with a sheet accommodation unit 20 to be used when temperature information indicates a temperature increase the particular heat generation resistor layers 69a to 69f.
The controller 6 also converts or adjust the image data based on the sheet accommodation unit 20 that is being used to feed the sheet S the image formed on the sheet is appropriately formed at a position corresponding to the paper-passing position of the sheet S as be fed.
The controller 6 adds a margin to the periphery of the image p1, for example, such that the image p2 has a maximum width for which the image p1 is fixable by the fixing device 30 or a maximum width of an image formable by an image forming unit, such as the image forming unit 3 described above.
Next, operations of the image forming apparatus 100 will be described. The operations of the image forming apparatus 100 described below are exemplary, and the present disclosure is not limited thereto as various operational modifications are possible.
The controller 6 acquires the temperature information (ACT 001). Next, the controller 6 causes functional units of the image forming apparatus 100 to start an image forming process (ACT 002).
When the temperature indicated by the temperature information is lower than a predetermined temperature (NO in ACT 003), the controller 6 feeds the sheet S from a predetermined one of the sheet accommodation units (for example, the sheet accommodation unit 20a) (ACT 004).
When the temperature indicated by the temperature information is higher than or equal to a predetermined temperature (YES in ACT 003), the controller 6 changes the sheet accommodation unit 20 used to feed the sheet S based on the position of the particular heat generation resistor that has been indicated by the temperature information as too high (ACT 005).
The controller 6 executes image conversion on image data such that a margin is added to a periphery of an image as a target image to be formed based on the determination of the sheet accommodation unit 20 that feeds the sheet S (ACT 006). For example, when the controller 6 determines that a sheet is to be fed from the sheet accommodation unit 20a (
The controller 6 feeds the sheet S from the selected sheet accommodation unit 20 (ACT 007).
The controller 6 control the image forming unit to perform image formation based on image data or modified image data on the fed sheet S, and the fixing device 30 fixes the toner image formed on the fed sheet S (ACT 008). For example, when the controller 6 determines that a sheet is to be fed from the sheet accommodation unit 20a, the controller 6 causes the sheet to pass through a position as illustrated in
The operations of the image forming apparatus 100 illustrated in the flowchart of
As described above, the image forming apparatus 100 according to the embodiment includes the fixing device 30 and the controller 6. The controller 6 acquires image data for the image p1 (first image) as a target image to be formed. The controller 6 then converts the image p1 as necessary to an image p2 (second image) for which a margin is (or margins are) added to a periphery of the image p1. The controller 6 causes a sheet accommodation unit 20 to feed the sheet S at a position where the image p1 in the image p2 will be appropriately fixed by the fixing device 30.
With the above-described configuration, in the image forming apparatus 100 according to an embodiment, when the temperature of a specific heat generation resistor unwantedly or unnecessarily increases, a desired image can still be formed while causing a sheet S to pass through the position of the specific heat generation resistor experiencing the temperature increase. In this way, by causing a sheet S to pass through a position corresponding to specific heat generation resistor, heat from the specific heat generation resistor will be absorbed by the passing sheet S. As a result, in the image forming apparatus 100 according to the embodiment, the temperature increase in the heat generation resistor layers 69a to 69f (heaters) can be suppressed or mitigated.
In the image forming apparatus 100 according to an embodiment, when the paper-passing position is changed, for example, it is not necessary to align the position of the sheet S to be fed and a print position of an image as a target image to be formed relative to each other. As a result, the image forming apparatus 100 according to the embodiment can execute the image forming process with high speed.
In the above description, the image forming apparatus 100 includes three sheet accommodation units 20a to 20c as an example, and the sheets S are accommodated at different positions from each other in the direction perpendicular to the paper feed direction in each respective sheet accommodation units 20. However, the present disclosure is not limited to this configuration. For example, a single sheet accommodation unit 20 may include a guide member connected to a drive source, and the guide member can be movable in a direction perpendicular to the paper feed direction to vary a paper feeding position of each sheet S fed from the sheet accommodation unit 20.
Some portions of the image forming apparatus 100 may be implemented by a computer. In this case, the described function(s) may be performed by executing a program (e.g., software) on a processor of the computer. Such a program may be stored in a non-transitory computer-readable medium provided to the computer or otherwise provided over a network connection or the like.
“Computer system” as described herein may refer to a computer system built into the image forming apparatus 100 and includes software, such as an operating system (OS), and hardware including peripheral devices and the like. In this context, “computer-readable recording medium” refers to a storage medium such as a flexible disk, an magneto-optic disk, a flash memory, an electric erasable programmable read-only memory (EEPROM), a read only memory (ROM), a random access read/write memory (RAM), a compact disc-read only memory (CD-ROM), a storage device such as a hard disk drive, and/or a solid-state drive. Such a storage medium may be built into a computer system or portable and/or separately provided from the computer system.
Furthermore, a “computer-readable recording medium” may be a server or other networked terminal and may be accessed, or otherwise provided, via a network connection or the like, such as the Internet or a telephone line. Such a computer-readable medium may be a portion of a distributed and/or “cloud-based” system and the computer system implementing the program may similarly be a distributed or cloud-based system. The program may serve alone to implement some or all of the above-described functions or some or all of the above-described functions may implemented in combination with a program (or programs) recorded in the computer system in advance.
In some examples, aspects of image forming apparatus 100 according to the embodiment may be implemented by an integrated circuit such as a large scale integration (LSI) or the like. The respective functional blocks of the image forming apparatus 100 may be individually configured with dedicated processors and/or hardware circuits, or some or all of the functional blocks may be integrated into a single processor. The method for circuit integration is not limited to LSI, and an integrated circuit may be implemented by a variety of dedicated circuits and/or a general-purpose processor. In general, any circuit integration technique, whether a LSI technique or otherwise, may be adopted in this context.
While certain embodiments have been described these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6643475 | Hoberock et al. | Nov 2003 | B2 |
| 6842592 | Kinoshita | Jan 2005 | B2 |
| 7035578 | Young | Apr 2006 | B1 |
| 10108119 | Yahata | Oct 2018 | B1 |
