Patent Application
20200101766
This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2018-183348, filed on Sep. 28, 2018, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
Aspects of the present disclosure relate to an image forming apparatus, a method, and a recording medium.
With diversification of business forms in the printing industry, various techniques for controlling an image forming apparatus have been required.
A technique for heating a paper sheet used as a recording medium in order to improve image quality of an image to be printed has been known. For example, some inkjet type image forming apparatuses include a heating mechanism for drying ink droplets discharged on a surface of the recording medium. A laser type image forming apparatus generally heats the recording medium to fix a toner. In particular, there is a case where an industrial image forming apparatus uses a large paper sheet as a recording medium, and appropriate temperature control of the recording medium is required.
In a case where the temperature of the recording medium is not appropriate and temperature distribution is not uniform, thermal expansion of the recording medium locally occurs, and cockling occurs. As a result, the image quality is deteriorated. Furthermore, in a case where heating for drying the ink droplets is not sufficiently performed in the inkjet type image forming apparatus, there is a case where other recording medium laminated on the upper side may be blocked. In addition, in a case where the heating is excessively performed, there is a case where expansion (blister) of air in the recording medium occurs. These symptoms cause the deterioration in the image quality and an abnormality in conveyance of the recording medium.
In an aspect of the present disclosure, there is provided an image forming apparatus that includes a plurality of heaters, a plurality of temperature sensors, an object sensor, and control circuitry. The temperature sensors are formed at positions corresponding to the heaters. The object sensor is configured to detect an overlap region of a medium and the heaters. The control circuitry is configured to correct temperature information acquired by the temperature sensors, according to the overlap region detected by the object sensor and the positions of the temperature sensors, and control the heaters based on the corrected temperature information.
In another aspect of the present disclosure, there is provided a method for controlling a plurality of heaters formed in an image forming apparatus. The method includes acquiring, detecting, correcting, and controlling. The acquiring acquires temperature information at positions of the heaters with a plurality of temperature sensors. The detecting detects an overlap region of the medium and the heaters. The correcting corrects the temperature information acquired by the temperature sensors, according to the detected overlap region and positions of the temperature sensors. The controlling controls the heaters based on the corrected temperature information.
A more complete appreciation of the disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein:
The accompanying drawings are intended to depict embodiments of the present invention and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result. In the drawings to be referred below, common components are denoted with the same reference numeral, and description of the common component will be appropriately omitted. Furthermore, hereinafter, an inkjet type image forming apparatus using a paper sheet 50 as a recording medium will be described as an example. However, the embodiment is not limited to this.
A carriage 12 is held by the guide rod 15, the secondary guide rod 11, and the timing belt 13. With this structure, the carriage 12 can reciprocate in an arrow A direction in
Furthermore, the image forming apparatus 10 includes a cartridge 20 which supplies ink to the recording heads 23 (see
The recording heads 23 discharge different colors of inks, which are supplied from the cartridge 20 illustrated in
A platen 21 is arranged to face the carriage 12 and supports the paper sheet 50 conveyed in the sub-scanning direction from a lower side. The object detection sensor 25 mounted on the carriage 12 detects an object below the carriage 12. With this detection, it is possible to identify whether the position of the carriage 12 is in an area outside the platen 21, in an area on the platen 21, or in an area on the paper sheet 50. In addition, by combining detection information by the object detection sensor 25 and an encoder value of the main scanning encoder sensor 24, a dimension of the paper sheet 50 in the main scanning direction can be calculated.
A carriage home position indicated by an alternate long and short dash line in
The preheater 31 is a unit which heats the paper sheet 50 before the image forming process. By preheating the preheater 31, moisture of the ink is easily evaporated when an ink droplet lands on the paper sheet 50. As a result, since the ink can be quickly dried, image quality can be improved.
The platen heater 33 is a unit which heats the platen 21 arranged below a flow line of the carriage 12 and is intended to heat the paper sheet 50 together with the landed ink droplet and form a film on the surface of the ink droplet. By forming the film on the ink surface by heating the ink droplet, a size of the ink droplet can be adjusted to an appropriate size, and deterioration in the image quality can be prevented.
The post heater 35 is a unit which further heats the paper sheet 50 on which the ink droplet is landed and which is conveyed. By continuing to heat the ink by the post heater 35 after the ink has been landed, the moisture and the solvent of the ink are evaporated, and drying of the ink is accelerated.
The cure heater 37 is a unit which heats the ink surface from an inside of the ink by far infrared rays. By heating the ink from inside by the cure heater 37, a polymerization reaction of ink resin is caused so as to cure the ink and fix the ink on the paper sheet 50.
In addition, temperature sensors 32, 34, 36, and 38 which measure the temperatures of the conveyance surface and the paper sheet 50 are provided in the vicinity of the respective heaters 31, 33, 35, and 37. Each heater is controlled to have a predetermined temperature based on temperature data measured by each temperature sensor. In the example illustrated in
Next, a hardware configuration of the image forming apparatus 10 will be described.
The controller 400 is a unit which controls an operation of the image forming apparatus 10, receives signals from various hardware, and outputs control signals. The controller 400 includes a central processing unit (CPU) 401, a field programmable gate array (FPGA) 402, a random access memory (RAM) 403, a read only memory (ROM) 404, and a motor driver 405.
The CPU 401 is a device which executes a program for controlling the operation of the image forming apparatus 10 and executes predetermined processing. The FPGA 402 is an integrated circuit provided for image processing and has a configuration specific for a specific application. Therefore, the FPGA 402 can execute processing at a faster speed than the CPU 401.
The RAM 403 is a volatile storage device which provides a space for executing the programs executed by the CPU 401 and the FPGA 402 and used to store and develop programs and data. The ROM 404 is a non-volatile storage device which stores programs, firmware, and the like executed by the CPU 401 and the FPGA 402.
The motor driver 405 is a unit which controls various motors included in the image forming apparatus 10 and outputs drive signals calculated by the CPU 401 and the FPGA 402 to various motors.
The carriage 12 reciprocates in the main scanning direction by the main scanning motor 18 which has received a drive control signal from the controller 400. According to the movement of the carriage 12, the main scanning encoder sensor 24 reads the encoder sheet 22 and outputs the encoder value to the controller 400. The object detection sensor 25 mounted on the carriage 12 detects whether or not the platen 21 and the paper sheet 50 are provided at a position facing the carriage 12 and outputs the detection result to the controller 400. The controller 400 controls the image forming processing based on the encoder value and a sensor detection value.
A sub-scanning motor 411 which has received the control signal from the controller 400 controls an operation of a conveyance roller 412 so that the conveyer 410 conveys the paper sheet 50 on the conveyance surface in the sub-scanning direction. The conveyer 410 includes a sub-scanning encoder sensor 413, acquires a movement amount of the paper sheet 50 in the sub-scanning direction, and outputs the acquired movement amount to the controller 400 as an encoder value.
After drying the paper sheet 50, the winder 420 can arbitrarily change a print start position, for example, by winding the paper sheet 50 to adjust the print start position to a rear end position of the image which has been already formed. In the winder 420, a winding motor 421 which has received the control signal from the controller 400 controls an operation of a winding roller 422. The winder 420 includes a winding encoder sensor 423 and outputs a value to the controller 400 as an encoder value.
A paper feeding motor 431 which has received the control signal from the controller 400 controls an operation of a paper feeding roller 432 so that the paper feeder 430 moves the paper sheet 50 from a paper feeding tray to the conveyance surface. Furthermore, the paper feeder 430 includes a paper feeding encoder sensor 433 and outputs the movement amount of the paper sheet 50 to the controller 400 as an encoder value.
As illustrated in
The hardware configuration included in the image forming apparatus 10 according to the present embodiment has been described above. Next, functional units executed by each hardware according to the present embodiment will be described with reference to
The image forming apparatus 10 includes modules such as an image forming unit 501, an object detection unit 502, a distance calculation unit 503, a temperature acquisition unit 504, a temperature correction value calculation unit 505, and a heater control unit 506. Details of each functional unit will be described below.
The image forming unit 501 is a unit which controls the operations of the carriage 12, the conveyer 410, and the like based on a print job input from a personal computer terminal and the like and forms an image on the surface of the paper sheet 50.
The object detection unit 502 is a unit which controls the object detection sensor 25 mounted on the carriage 12 and detects whether or not an object exists below the carriage 12 which moves in the main scanning direction. For example, in a case where the object detection sensor 25 includes a light-emitting diode (LED) and a reflected light sensor, the object detection unit 502 can detect whether or not the object exists according to reflected light of light irradiated to the object. Furthermore, the object detection unit 502 can have a configuration which can identify whether the object existing below the carriage 12 is the platen 21 or the paper sheet 50 based on a light reflectance, a distance to the object, and the like.
The distance calculation unit 503 is a unit which calculates a width of the paper sheet on which an image is formed. For example, the distance calculation unit 503 can calculate the dimension of the paper sheet 50 existing below the carriage 12 in the main scanning direction based on the detection result regarding whether or not the object exists by the object detection unit 502 and the encoder value of the main scanning encoder sensor 24.
The temperature acquisition unit 504 is a unit which controls various temperature sensors 32, 34, 36, and 38 and acquires the temperature values of the conveyance surface and the paper sheet 50. In a case where the configuration includes the heaters divided in the main scanning direction, the temperature acquisition unit 504 can have a configuration which can acquire the temperature value for each of the divided heaters.
The temperature correction value calculation unit 505 is a unit which calculates a correction value for controlling the temperature of each heater based on the width of the paper sheet calculated by the distance calculation unit 503 and the temperature value acquired by the temperature acquisition unit 504. The temperature correction value calculation unit 505 refers to a predetermined function and table and calculates the correction value for controlling the temperature of the heater to be a predetermined temperature.
The heater control unit 506 is a unit which outputs signals used to control various heaters 31, 33, 35, and 37 so as to control the temperature of the heater. To control the temperature of the heater to the predetermined temperature, the heater control unit 506 can output a predetermined temperature control signal and a control signal based on the correction value calculated by the temperature correction value calculation unit 505.
The software block described above corresponds to a functional unit implemented by functioning each of the hardware by executing the program of the present embodiment by the CPU 401 and the FPGA 402. All the functional units indicated in each embodiment may be implemented as software, and a part or all of the functional units can be implemented as hardware providing equivalent functions.
First,
On the other hand, in the configuration illustrated in
As illustrated in
As described with reference to
Furthermore, references Lsa, Lsb, and Lsc in
First,
That is, as in the temperature distribution in
Therefore, in the present embodiment, as illustrated in
By controlling the temperature as described above, as illustrated in the temperature distribution in the lower diagram in
A parameter used to correct the measured temperature value can be defined by a function, a table, and the like, and an arbitrary parameter can be adopted. An example of the parameter is illustrated in
Note that the parameter for correcting the detected temperature value can be set by experiments and simulations performed in advance. Furthermore, a calculation method of the correction parameter is not limited to the method described above, and various calculation methods can be adopted. Moreover, since a heat quantity conducted to the paper sheet 50 differs according to the type and the conveyance speed of the paper sheet 50, a correction parameter can be set for each case.
The example for correcting the temperature value in the present embodiment has been described above. Hereinafter, processing executed by the image forming apparatus 10 according to the present embodiment will be described.
The image forming apparatus 10 starts processing from step S1000 and starts to move the carriage 12 in step S1001. The carriage 12 moves from the carriage home position in the main scanning direction and continues to move from step S1001.
Thereafter, in step S1002, it is determined whether or not the object detection unit 502 detects the end of the platen 21 according to the movement of the carriage 12. In a case where the end of the platen 21 is not detected (NO), the processing in step S1002 is repeated while the carriage 12 continues to move. In a case where the end of the platen 21 is detected (YES), the procedure proceeds to step S1003. In step S1003, the distance calculation unit 503 sets the number of counts of the distance to zero. The distance can be counted by reading the encoder sheet 22 by the main scanning encoder sensor 24.
In step S1004, it is determined whether or not the object detection unit 502 detects the right end of the paper sheet 50 according to the movement of the carriage 12. In a case where the right end of the paper sheet 50 is not detected in step S1004 (NO), the procedure proceeds to step S1005. In step S1005, a distance counter value is incremented, and then, the procedure returns to step S1004 while the carriage 12 continues to move. In a case where the right end of the paper sheet 50 is detected in step S1004 (YES), the procedure proceeds to step S1006. In step S1006, the distance calculation unit 503 defines a distance counter value which is counted before the time of step S1004 as Lr.
Thereafter, in step S1007, as in step S1004, it is determined whether or not the object detection unit 502 detects the left end of the paper sheet 50 according to the movement of the carriage 12. In a case where the left end of the paper sheet 50 is not detected in step S1007 (NO), the procedure proceeds to step S1008. In step S1008, as in step S1005, the distance counter value is incremented, and then, the procedure proceeds to step S1007 while the carriage 12 continues to move. In a case where the left end of the paper sheet 50 is detected in step S1007 (YES), the procedure proceeds to step S1009. In step S1009, the distance calculation unit 503 defines a distance counter value which is counted before the time of step S1007 as Ll.
After step S1009, the distance calculation unit 503 calculates a difference between the values of the lengths Ll and Lr and calculates the width of the paper sheet 50 in step S1010. Thereafter, in step S1011, the image forming apparatus 10 terminates the processing.
The image forming apparatus 10 determines the overlap between the platen heater 33 and the paper sheet 50 based on the lengths Lr and Ll and the width of the paper sheet calculated as in
The image forming apparatus 10 starts the processing from step S2000. Thereafter, based on the values of the lengths Lr and Ll calculated by the distance calculation unit 503 described with reference to
In step S2001, it is determined whether or not the paper sheet 50 exists on the temperature sensor 34a on the right side, and the procedure branches. Whether or not the paper sheet 50 overlaps with the temperature sensor 34 can be determined according to the following formula (1).
[Expression 1]
LrLsa
Ll (1)
In a case where the distance Lsa from the end of the platen to the temperature sensor 34a on the right side and the right end and the left end of the paper sheet 50 satisfy the above formula (1), it can be determined that the paper sheet 50 overlaps with the temperature sensor. Therefore, in a case where the above formula (1) is satisfied in step S2001, it is determined that the paper sheet 50 overlaps with the temperature sensor 34a on the right side (YES), and the procedure proceeds to step S2002. In a case where the paper sheet 50 overlaps with the temperature sensor 34, the temperature value detected by the temperature sensor is a value corresponding to the temperature value of the paper sheet 50. Therefore, in step S2002, the measured sensor temperature value is applied as it is.
On the other hand, in a case where the above formula (1) is not satisfied in step S2001, it is determined that the paper sheet 50 does not overlap with the temperature sensor 34a on the right side (NO), and the procedure proceeds to step S2003. In a case where the paper sheet 50 does not overlap with the temperature sensor 34, in order to control the temperature in consideration of the heat radiation by the paper sheet 50, the sensor temperature value is corrected in step S2003. The sensor temperature value can be corrected as follows as an example. First, a distance x from the end of the paper sheet 50 to the temperature sensor is calculated, and a correction value y is calculated based on the function (y=f(x)) illustrated in
Thereafter, regarding the temperature sensor 34b at the center and the temperature sensor 34c on the left side, the processing in steps S2004 to S2008 is executed similarly to the temperature sensor 34a on the right side.
Thereafter, in step S2010, the heater control unit 506 controls the temperatures of the respective platen heaters 33a to 33c based on the sensor temperature value. In a case where the sensor temperature value is corrected in steps S2003, S2006, and S2009, the temperature of each platen heater is controlled according to the corrected sensor temperature value in step S2010.
According to various processing described above, the temperature can be controlled based on the sensor temperature value in which the temperature decrease caused by the transfer of the heat to the paper sheet 50 is corrected. With this operation, since the paper sheet 50 can be uniformly heated to a predetermined temperature, occurrence of cockling and the like can be prevented, and the printed image quality can be improved.
In the embodiment described above, an example has been described in which the platen heater 33 is divided in the main scanning direction and the divided heaters are separately controlled. However, the embodiment is not limited to this. Therefore, the configuration may be used in which other heaters including the preheater 31, the post heater 35, the cure heater 37, and the like are divided in the main scanning direction and controlled.
According to the embodiment of the present invention described above, an image forming apparatus, method, and program for making a temperature of a recording medium uniform and controlling the temperature to be an appropriate temperature can be provided.
Each function of the embodiment of the present invention described above can be implemented by a program which can be executed by a device and is written in C, C++, C#, Java (registered trademark), and the like. The program according to the present embodiment can be stored in a device-readable recording medium such as a hard disk device, a compact disc read only memory (CD-ROM), a magneto optical disc (MO), a digital versatile disc (DVD), a flexible disk, an electronically erasable and programmable read only memory (EEPROM), and an erasable programmable read-only memory (EPROM) and distributed, and can be transmitted via a network in a format which can be read by other devices.
The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention.
Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
Each of the functions of the described embodiments may be implemented by one or more processing circuits or circuitry. Processing circuitry includes a programmed processor, as a processor includes circuitry. A processing circuit also includes devices such as an application specific integrated circuit (ASIC), digital signal processor (DSP), field programmable gate array (FPGA), and conventional circuit components arranged to perform the recited functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-183348 | Sep 2018 | JP | national |
