The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein:
Referring to the drawings, a printer and a method of controlling the printer of an embodiment of the present invention will be explained below.
The printer 1 of this embodiment is an ink jet printer to conduct printing on printing paper P, which is a printing medium, by jetting out ink drops to printing paper P. As shown in
The carriage 3 is connected to a carriage motor (CR motor) not shown through a belt and pulley not shown. This carriage 3 is driven by CR motor and moved at the same time in the horizontal scanning direction (the direction perpendicular to the surface of
A surface of PF drive roller 4 is coated with high friction material, the friction coefficient of which is high. As shown in
As shown in
As shown in
The paper detection device 9 is an optical type detection device in which a light emitting element and a light receiving element are arranged being opposed to each other in the vertical direction. This paper detection device 9 detects an end portion in the width direction of printing paper P passing through between the light emitting element and the light receiving element. The paper detection device 9 is arranged between PF drive roller 4, which is arranged on the rear side of the carriage 3, and the rear paper feeding mechanism 11. By this paper detection device 9, at the time of continuous printing of printing paper P, a trailing end of the preceding printing paper P and a leading end of the succeeding printing paper P can be detected.
The front paper feeding mechanism 10 includes: a front paper feeding cassette 20 in which printing paper P before printing fed from the front side is set; a front paper feeding roller 21 for feeding printing paper P, which is set in the front paper feeding cassette 20, into the printer 1, that is, toward a printing region in which printing is conducted with the printing head 2; an arm 22 for pivotally holding the front paper feeding roller 21; and a transporting passage 23 in which printing paper P, which has been taken in by the front paper feeding roller 21, passes through. In the present embodiment, as shown in
A friction member 24, which is made of material such as cork, the friction coefficient of which is relatively high, is attached onto a bottom face of the front paper feeding cassette 20. This friction member 24 fulfills a function of preventing the occurrence of double feeding of printing paper P. The front paper feeding roller 21 is attached to a leading end portion of the arm 22 capable of being oscillated around the rotary shaft 22a. In a case where paper feeding is conducted from the front side, this front paper feeding roller 21 comes into pressure contact with an upper face of printing paper P as shown by the solid line in
The rear paper feeding mechanism 11 includes: a rear paper feeding hopper 26 which is a medium setting portion in which printing paper P before printing fed from the rear side is set; a rear paper feeding roller 27 for feeding printing paper P, which is set in the rear paper feeding hopper 26, into the printer 1, that is, toward a printing region in which printing is conducted with the printing head 2; and a retard roller 28 for preventing the occurrence of double feeding of printing paper P.
As shown in
In this embodiment, ASF motor 31 is a DC motor. In the present embodiment, in the same manner as that of PF motor 14, concerning the method of controlling ASF motor 31, PWM control, which is one of the methods of controlling voltage, is employed. At the same time, PID control is employed which is a method of control for converging the present rotating speed of the ASF motor 31 to a target rotating speed by combining proportional control, integral control and derivative control with each other.
As shown in
The retard roller 28 is arranged at a position opposed to an oblique lower side of the rear paper feeding roller 27. An outer circumference of this retard roller 28 is formed out of a member made of material, the friction coefficient of which is high. As shown in
As schematically shown in
To be specific, as shown in
As shown in
PF encoder 40 includes: a rotary scale 43 fixed to a rotary shaft of PF drive roller 4; and a photo sensor 44 having a light emitting element and a light receiving element not shown arranged so that an outer circumferential portion of the rotary scale 43 can be interposed between them. An output signal outputted from this PF encoder 40 is inputted into the control portion 50 for conducting various control of the printer 1. The rotary scale 43 is formed out of a disk-shaped thin plate made of transparent plastics. At the circumferential edge of this rotary scale 43, a plurality of marks (not shown) are arranged at regular angular intervals in the circumferential direction. To be specific, along the outer circumference of one face of the rotary scale 43, black marks are printed at regular angular intervals in the circumferential direction. These printed black marks are used as marks. It is possible that the rotary scale 43 is formed out of a thin stainless steel plate and that slits penetrating the rotary scale 43 are formed in the rotary scale 43 instead of the marks described above.
ASF encoder 41 includes: a rotary scale 45 fixed to an output shaft of ASF motor 31; and a photo sensor 46 having a light emitting element and a light receiving element not shown arranged so that an outer circumferential portion of the rotary scale 45 can be interposed between them. An output signal of this ASF encoder 41 is inputted into the control portion 50. In the same manner as that of the rotary scale 43, the rotary scale 45 is formed out of a transparent plastic thin plate or a stainless steel thin plate. Marks or slits are formed in the rotary scale 45.
The position detection device 42 includes: a detection plate 47 fixed to a rotary shaft of the cam 34; and a photo sensor 48 having a light emitting element and a light receiving element not shown arranged so that an outer circumferential portion of this detection plate 47 can be interposed between them. An output signal outputted from the position detection device 42 is also inputted into the control portion 50.
As shown in
CPU 52 conducts arithmetic processing for executing a control program of the printer 1 stored in ROM 53 and the non-volatile memory 55. Further, CPU 52 conducts other arithmetic processing. ROM 53 stores a control program for controlling the printer 1 and also stores data necessary for processing. For example, ROM 53 stores: a target speed table on which a target rotating speed with respect to a rotating time or a rotating speed of PF motor 14 used for PID control is set; and a target speed table on which a target rotating speed with respect to a rotating time or a rotating distance of ASF motor 31 is set. In RAM 54, a program which is being executed by CPU 52 and data which is in the middle of arithmetic operation are temporarily accommodated. The non-volatile memory 55 stores various data which must be stored even after an electric power supply to the printer 1 is turned off.
As shown in
Speed control of PF motor 14 and ASF motor 31 is conducted when CPU 52 and ASIC 56 cooperate with each other. That is, DC unit 60, which is a control circuit for conducting speed control of PF motor 14 and ASF motor 31 which are DC motors, is composed by a portion of CPU 52 and a portion of ASIC 56. Specifically, in DC unit 60, a portion of CPU 52 conducts various arithmetic operation for conducting speed control of PF motor 14 and ASF motor 31 according to various signals inputted from PF encoder 40 or ASF encoder 41 through ASIC 56. In DC unit 60, a portion of ASIC 56 receives a signal from PF encoder 40 or ASF encoder 41. Alternatively, in DC unit 60, a portion of ASIC 56 outputs a signal to PF motor drive circuit 57 and ASF motor drive circuit 58 according to a result of arithmetic operation conducted in CPU 52.
As described above, PF motor 14 and ASF motor 31 of the present embodiment are controlled by PID control. Therefore, as schematically shown in
The speed operation portion 61 calculates the present rotating speed of PF motor 14 according to a signal inputted from PF encoder 40 and outputs a signal corresponding to this rotating speed to PID control portion 63. The speed operation portion 61 calculates the present rotating speed of ASF motor 31 according to a signal inputted from ASF encoder 41 and outputs a signal corresponding to this rotating speed to PID control portion 63.
The position operation portion 62 calculates the present rotating distance of PF motor 14 according to a signal inputted from PF encoder 40 and outputs a signal corresponding to this rotating distance to PID control portion 63. The position operation portion 62 calculates the present rotating distance of ASF motor 31 according to a signal inputted from ASF encoder 41 and outputs a signal corresponding to this rotating distance to PID control portion 63.
First, PID control portion 63 calculates a positional deviation, which is a distance between the target stop position and the present rotating distance, from a signal of the target stop position corresponding to the next stop position of printing paper P, which has been read out from ROM 53, and from a signal of the present rotating distance inputted from the position operation portion 62. After that, PID control portion 63 reads out a target rotating speed corresponding to the present rotating distance of PF motor 14 or ASF motor 31 from the target speed table, which is stored in ROM 53, according to this positional deviation. After that, PID control portion 63 calculates a speed deviation, which is a difference between the target rotating speed and the present rotating speed, from the present rotating speed signal and the target rotating speed signal inputted from the speed operation portion 61. After that, PID control portion 63 calculates a proportional control value, an integral control value and a derivative control value according to the speed deviation and adds these control values and outputs PID control signal. In the present embodiment, since PF motor 14 and ASF motor 31 are subjected to PWM control as described before, PID control signal is a pulse-like signal which is repeatedly turned on and off by a predetermined switching period.
PF motor drive circuit 57 controls to drive PF motor 14 by a signal (specifically, a signal sent from ASIC 56) sent from DC unit 60. In the present embodiment, since PF motor 14 is subjected to PWM control, PF motor drive circuit 57 outputs PWM drive signal. In the same manner, since ASF motor drive circuit 58 controls to drive ASF motor 31 by a signal sent from DC unit 60, ASF motor drive circuit 58 outputs PWM drive signal.
A bus 51 is a signal line connecting each component of the control portion 50 described above. This bus 51 connects CPU 52, ROM 53, RAM 54, non-volatile memory 55 and ASIC 56 with each other so that data can be given and received by the components.
In the printer 1 described above, printing paper P, which has been fed by the front paper feeding roller 21 from the front paper feeding cassette 20 into the printer 1, or printing paper P, which has been fed by the rear paper feeding roller 27 from the rear paper feeding hopper 26 into the printer 1, is intermittently transported by PF drive roller 4 in the vertical scanning direction SS. At the time of stop of this intermittent transporting, the carriage 3 is reciprocated in the horizontal scanning direction. When the carriage 3 is reciprocated, the printing head 2 jets out ink drops so as to conduct printing on printing paper P. After printing on printing paper P has been finished, printing paper P is transported outside the printer 1 by the ejecting drive roller 6.
When PF drive roller 4 is rotated, that is, when PF motor 14 is rotated, a signal is outputted from PF encoder 40. This signal is inputted into the control portion 50. From the thus inputted signal, the control portion 50 detects a rotating distance and a rotating speed of PF drive roller 4, that is, a rotating distance and a rotating speed of PF motor 14. According to the thus detected rotating distance (rotating position) and rotating speed of PF motor 14, the control portion 50 variously controls the printer 1. In the same manner, when the rear paper feeding roller 27 is rotated, that is, when ASF motor 31 is rotated, a signal sent from ASF encoder 41 is inputted into the control section 50. From the thus inputted signal, the control portion 50 detects a rotating distance and a rotating speed of the rear paper feeding roller 27, that is, a rotating distance and a rotating speed of ASF motor 31. According to the thus detected rotating distance (rotating position) and the rotating speed of ASF motor 31, the control portion 50 variously controls the printer 1.
In the present embodiment, at the time of continuous printing in which a plurality of sheets of printing paper P are continuously printed, a method of controlling PF motor 14 and ASF motor 31 at the time of a draft printing mode (an economy printing mode), in which high speed printing is conducted while a consumption of ink is being saved although resolution is made to deteriorate, is different from a method of controlling PF motor 14 and ASF motor 31 at the time of a printing mode (a normal printing mode) in which printing is conducted at a predetermined resolution or at a higher resolution than the predetermined resolution except for the draft printing mode. That is, at the time of continuous printing, the control portion 50 conducts different transporting control of printing paper P between the draft printing mode and the normal printing mode. A case in which printing paper P is fed inside the printer 1 from the rear side is taken up as an example, and a method of controlling transporting of printing paper P in the printer 1 will be explained below, that is, a method of controlling PF motor 14 and ASF motor 31 will be explained below. In this connection, in the present embodiment, the draft printing mode is the first printing mode in which at least synchronous transporting control described later is conducted. The normal printing mode is the second printing mode in which separate transporting control described later is conducted.
In the normal printing mode of the present embodiment, in the same manner as that of the conventional case, printing paper P, which is set in the rear paper feeding hopper 26, is transported and fed to PF drive roller 4 by the rear paper feeding roller 27. After that, printing paper P is transported by PF drive roller 4 and the ejecting drive roller 6. That is, in the normal printing mode, PF motor 14 and ASF motor 31 are individually controlled so that printing paper P can be transported. This transporting control of printing paper P is defined as separate transporting control, hereinafter.
Specifically, operation is performed as follows. First, as shown in
When the leading end portion of printing paper P is transported to the position where PF drive roller 4 and PF driven roller 5 are arranged, as shown in
After printing conducted on printing paper P has been finished, as shown in
In the normal printing mode, PF motor 14 and ASF motor 31 are subjected to PID control according to the respective target speed tables which are individually set and stored in ROM 53. At the time of printing of only one sheet of printing paper, irrespective of whether it is a draft printing mode or it is a normal printing mode, printing paper P, which is set in the rear paper feeding hopper 26, is first transported to PF drive roller 4 by the rear paper feeding roller 27 so that printing paper P can be fed inside the printer. After that, printing paper P is transported by PF drive roller 4 and so forth. That is, at the time of printing one sheet of printing paper, separate transporting control is performed.
In this connection,
In the draft printing mode of the present embodiment, for the transporting of printing paper P after printing paper P has been transported by the rear paper feeding roller 27 from the rear paper feeding hopper 26 to PF drive roller 4, in addition to PF drive roller 4 and the ejecting drive roller 6, the rear paper feeding roller 27 is used. That is, in the draft printing mode, PF drive roller 4 and the ejecting drive roller 6, which are driven by PF motor 14, and the rear paper feeding roller 27 driven by ASF motor 31 cooperate with each other. Due to this cooperation of the rollers, printing paper P can be transported at the time of printing action. Therefore, in the draft printing mode, PF drive roller 4 and the ejecting drive roller 6 must be rotated synchronously with the rear paper feeding roller 27, that is, at the same circumferential speed. Therefore, in the draft printing mode of the present embodiment, by synchronous control in which PF drive roller 4 and the ejecting drive roller 6 are rotated synchronously with the rear paper feeding roller 27, PF motor 14 and ASF motor 31 are controlled, so that printing paper P can be transported. This transporting control of transporting printing paper P is defined as synchronous transporting control, hereinafter.
In the draft printing mode of the present embodiment, in a case where synchronous transporting control is conducted, start correcting control is conducted in such a manner that when one sheet of printing paper P is transported by both PF drive roller 4 and the rear paper feeding roller 27, the start time of PF motor 14 is delayed from the start time of ASF motor 31. Further, in the draft printing mode of the present embodiment, the last sheet of printing paper P at the time of continuous printing is transported and fed to PF roller 4 by the rear paper feeding roller 27 and then transported by PF drive roller 4 and the ejecting drive roller 6. That is, the last sheet of printing paper P at the time of continuous printing is transported by separate transporting control.
A method of controlling the transporting of printing paper P in the draft printing mode will be explained in detail as follows.
As described before, PF motor 14 and ASF motor 31 are controlled by PID control. Therefore, as a first target speed table in which a target rotating speed corresponding to the rotating time or the rotating distance of PF motor 14 for conducting synchronous control is set, for example, PF target speed table T1 is stored in ROM 53. As a second target speed table in which a target rotating speed corresponding to the rotating time or the rotating distance of ASF motor 31 for conducting synchronous control is set, for example, ASF target speed table T2 is stored in ROM 53. Concerning this matter, refer to
In the present embodiment, the first and the second target speed table are set so that the first speed profile and the second speed profile can be substantially the same. In this case, the first speed profile is made according to the first target speed table, for example, according to PF target speed table T and shows a relation between the rotating time or the rotating distance and the target circumferential speed (the target transporting speed of printing paper P by PF drive roller 4). For example, the first speed profile is PF speed profile F1 made according to PF target speed table T1. The second speed profile is made according to the second target speed table, for example, according to ASF target speed table T2 and shows a relation between the rotating time or the rotating distance and the circumferential speed (the target transporting speed of printing paper P by the rear paper feeding roller 27). For example, the second speed profile is paper feeding speed profile F2 made according to ASF target speed table T2.
In the present embodiment, for example, ASF target speed table T2 is set on the basis of PF target speed table T1. Specifically, ASF target speed table T2 is set according to ratio α of resolving power of PF encoder 40 to resolving power of ASF encoder 41 and also according to the first target speed table T1.
In this case, α of resolving power of PF encoder 40 to resolving power of ASF encoder 41, that is, (resolving power of ASF encoder 41)/(resolving power of PF encoder 40) is calculated as follows. Resolving power of PF encoder 40 is πD1/(N1×i1) in a case where a rotating distance of PF drive roller 4 is used as reference, wherein diameters of PF drive roller 4 and the rear paper feeding roller 27 are respectively D1 and D2, numbers of marks formed on the rotary scales 43, 45 are respectively N1 and N2, a reduction ratio from PF motor 14 to PF drive roller 4 is i1 and a reduction ratio from ASF motor 31 to the rear paper feeding roller 27 is i2. In a case where a rotating distance of the rear paper feeding roller 27 is used as reference, resolving power of ASF encoder 41 is πD2/(N2×i2). Accordingly, ratio α is expressed by the following expression.
α=(D2×N1×i1)/(D1×N2×i2)
In this connection, in order to explain a method of setting ASF target speed table T2 of the present embodiment so as to facilitate the understanding, ratio α is set at 2, that is, α=2. A rotating distance (a transporting distance of printing paper P by PF transporting roller 4) of PF drive roller 4 corresponding to one pulse of the pulse signal (PF pulse signal), which is inputted from PF encoder 40 into ASIC 56 corresponding to the forming pitch of marks formed on the rotary scale 43 or which is generated by ASCI 56 according to the input signal sent from PF encoder 40, is one half of a rotating distance (a transporting distance of printing paper P by rear paper feeding roller 27) of the rear paper feeding roller 27 corresponding to one pulse of the pulse signal (ASF pulse signal), which is inputted from ASF encoder 41 into ASIC 56 corresponding to the forming pitch of marks formed on the rotary scale 45 or which is generated by ASCI 56 according to the input signal sent from ASF encoder 41. In other words, in a case where PF drive roller 4 and the rear paper feeding roller 27 are rotated by the same distance, that is, in a case where the rotating distance is the same, the number of pulses of PF pulse signal is twice as large as the number of pulses of ASF pulse signal.
According to the thus calculated ratio α and the first target speed table T1, ASF target speed table T2 is set as follows. First, in order to more quickly transport and accurately stop printing paper P, PF target speed table T1 is set. For example, as shown in
For example, as shown in table T3 used for calculation of
Since ratio α=2 as described above, a rotating distance corresponding to 20 pulses of PF pulse signal is the same as a rotating distance corresponding to 10 pulses of ASF pulse signal. That is, as shown in
PF speed profile F1, which is made according to PF target speed table T1 that has been set as described above, and paper feeding speed profile F2, which is made according to ASF target speed table T2, become substantially equal to each other as shown in
As described above, according to PF target speed table T1 corresponding to PF speed profile F1, PF motor 14 is subjected to PID control. According to ASF target speed table T2 corresponding to paper feeding speed profile F2 which is substantially the same as PF speed profile F1, ASF motor 31 is subjected to PID control.
Specific explanations will be made into synchronous control conducted according to PF target speed table T1 and ASF target speed table T2 stored in ROM 53. First, explanations will be made into synchronous transporting control conducted when the first sheet of printing paper P is transported at the time of continuous printing.
When the first sheet of printing paper P is fed inside the printer 1, as shown in
Simultaneously when AFS motor 31 is started, PF motor 14 is started. Therefore, PF drive roller 4 and the ejecting drive roller 6 are rotated. Therefore, a leading end of printing paper P appropriately enters between PF drive roller 4 and PF driven roller 5. At this time, PF drive roller 4 is subjected to rotation control according to PF speed profile F1. That is, PF motor 14 is subjected to PID control according to PF target speed table T1. In this way, in the draft printing mode, even when the first sheet of printing paper P is fed inside the printer 1, synchronous transporting control is conducted.
In this connection, in the draft printing mode, when the first sheet of printing paper P is fed inside the printer 1, synchronous transporting control may not be conducted. At the time of continuous printing conducted in the draft printing mode, until a leading end of the last sheet of printing paper P reaches the position where PF drive roller 4 and PF driven roller 5 are arranged, the lower end portion of the rear paper feeding hopper 26 and the retard roller 28 are raised up at all times as shown in
After that, printing paper P is subjected to transporting control by synchronous transporting control. Specifically, the first sheet of printing paper P is intermittently transported by PF drive roller 4, which is rotated being controlled by PF speed profile F1, and by the rear paper feeding roller 27 which is rotated being controlled by paper feeding speed profile F2. That is, PF drive roller 4, which is rotated being controlled by PF speed profile F1, and the rear paper feeding roller 27, which is rotated being controlled by paper feeding speed profile F2, cooperate with each other and one sheet of printing paper P is transported. In other words, PF motor 14, which is subjected to PID control according to PF target speed table T1, and ASF motor 31, which is subjected to PID control according to ASF target speed table T2, are intermittently driven. First, as shown in
As described above, in the draft printing mode of the present embodiment, when one sheet of printing paper P is transported by both PF drive roller 4 and the rear paper feeding roller 27, start correction control is conducted. That is, when one sheet of printing paper P is interposed between PF drive roller 4 and PF driven roller 5 and at the same time one sheet of printing paper P is interposed between the rear paper feeding roller 27 and the retard roller 28, the start time of PF motor 14 is delayed from the start time of ASF motor 31. Specifically, as schematically shown
Therefore, as shown in
After that, printing paper P is intermittently transported by PF drive roller 4 and the rear paper feeding roller 27. When the leading end of printing paper P reaches a position of the ejecting drive roller 6 and the ejecting driven roller 7 after that, as shown in
Next, explanations will be made into synchronous control conducted when two continuous sheets of printing paper P are transported at the time of continuous printing.
As shown in
In the present embodiment, when the trailing end portion of the preceding printing paper P has left the rear paper feeding roller 27 and a transporting of the following printing paper P by the rear paper feeding roller 27 has started, the rear paper feeding roller 27 and the retard roller 28 somewhat slip on the following printing paper P. Therefore, as shown in
After that, when the following printing paper P is transported by both PF drive roller 4 and the rear paper feeding roller 27 as shown in
After that, as shown in
As described above, at the time of continuous printing in the draft printing mode, first, PF drive roller 4 and the rear paper feeding roller 27, which are rotated at the substantially same circumferential speed, cooperate with each other so that printing paper P, which has been fed inside the printer 1, that is, printing paper P, the leading end portion of which has been transported to a position where PF drive roller 4 is arranged, can be transported. After that, when the leading end portion of printing paper P reaches a position where the ejecting drive roller 6 is arranged, in addition to PF drive roller 4 and the rear paper feeding roller 27, the ejecting drive roller cooperates so as to transport printing paper P inside the printer 1. After that, when the trailing end of printing paper P has left the rear paper feeding roller 27, PF drive roller 4 and the ejecting drive roller 6 cooperate with each other, so that printing paper P inside the printer 1 can be transported.
Successively, explanations will be made into control conducted when the last sheet of printing paper P is transported at the time of continuous printing.
As shown in
Specifically, only PF motor 14 is intermittently driven and printing paper P is intermittently transported by PF drive roller 4 and the ejecting drive roller 6. At the same time, ink drops are jetted out from the printing head 2, so that printing is conducted on printing paper P. After the completion of printing on printing paper P, PF motor 14 is continuously driven. Therefore, printing paper P is transported outside the printer 1.
Referring to the flow chart shown in
When a printing command is inputted from the control command portion 59 into the control portion 50, the control portion 50 starts printing control of printing paper P. That is, the control portion 50 starts transporting control of printing paper P. In the transporting control, first, it is judged whether or not printing conducted on printing paper P is continuous printing (step S1). In the case of continuous printing, it is judged whether or not the continuous printing is conducted in the draft printing mode (step S2).
In a case where it is judged in step S2 that the continuous printing is not in the draft printing mode but in the normal printing mode or in a case where it is judged in step S1 that printing is not continuous printing but one sheet printing, separate transporting control is conducted. Specifically, first, as shown in
After that, printing paper P is intermittently transported by PF drive roller 4 and the ejecting drive roller 6 (step S7). In step S7, the rear paper feeding roller 27 is stopped. At the time of stoppage of intermittent transporting, according to the necessity, printing is conducted on printing paper P with the printing head 2. After that, it is judged whether or not printing on the thus fed one sheet of printing paper P has been finished (step S8). In a case where printing on the thus fed one sheet of printing paper P has not been finished, the program is returned to step S7. In a case where printing on the thus fed one sheet of printing paper P has been finished, printing paper P is transported with the ejecting drive roller 6 (step S9). After the transporting of printing paper P or at the time of transporting printing paper P, it is judged whether or not printing on the designated number of sheets of printing paper P, which has been inputted from the control command portion 59, is finished (step 5b). In a case where printing on the designated number of sheets of printing paper P has been finished, transporting control conducted on printing paper P is finished, that is, printing control is finished. In a case where printing on the designated number of sheets of printing paper P has not been finished, the program is returned to step S3. In this connection, in the case of one sheet printing in step S1, step S10 is omitted.
In a case where it is judged in step S2 that it is a draft printing mode, as shown in
Then, it is judged whether or not the paper detection device 9 has detected a leading end of printing paper P (step S13). In a case where the paper detection device 9 has not detected the leading end of printing paper P, the program is returned to step S12. In a case where the paper detection device 9 has detected the leading end of printing paper P, printing paper P is intermittently transported by the PF drive roller 4 and/or the ejecting drive roller 6, which is subjected to rotation control according to PF speed profile F1, and by the rear paper feeding roller 27 which is subjected to rotation control according to the paper feeding speed profile F2 (step S14). That is, in step S14, synchronous transporting control is conducted. In step S14, start correcting control is also conducted. At the time of stoppage of the intermittent transporting action, according to the necessity, printing is conducted on printing paper P with the printing head 2.
After that, as shown in
It is judged whether or not the paper detection device 9 has detected a leading end of printing paper P (step S17). In a case where the paper detection device 9 has not detected the leading end of printing paper P, the program is returned to step S16. In a case where the paper detection device 9 has detected the leading end of printing paper P, it is judged whether or not the following printing paper P, which has been fed, is the last sheet of printing paper P in continuous printing (step S18). In a case where the following printing paper P is not the last sheet of printing paper P, the program is returned to step S14. In a case where the following printing paper P is the last sheet of printing paper P, the lower end portion of the rear paper feeding hopper 26 and the retard roller 28 are lowered in the same manner as that of step S6 (step S19).
After that, in the same manner as that of step S7, printing paper P is intermittently transported by PF drive roller 4 and the ejecting drive roller 6 (Step S20). In step S20, the rear paper feeding roller 27 is stopped. That is, the last sheet of printing paper P is transported by separate transporting control. At the time of stoppage of the intermittent transporting action, according to the necessity, printing is conducted on printing paper with the printing head 2. After that, it is judged whether or not printing conducted on the last sheet of printing paper P has been finished (step S21). In a case where printing on the last sheet of printing paper P has not been finished, the program is returned to step S20. In a case where printing on the last sheet of printing paper P has been finished, the printing paper P is transported by the ejecting drive roller 6 (step S22) and transporting control of printing paper P is finished.
In the present embodiment, step S2 is a judgment step for judging whether printing is conducted on printing paper P by the draft printing mode or printing is conducted on printing paper P by the normal printing mode. Steps S3 to S9 are the second transporting printing step for conducting transporting and printing on printing paper P when it is judged to be the normal printing mode in step S2 which is a judgment step. Steps S11 to S22 are the first transporting printing step for conducting transporting and printing on printing paper P when it is judged in step S2 that it is the draft printing mode.
As explained above, in the draft printing mode of the present embodiment, at the time of continuous printing, PF drive roller 4 and the rear paper feeding roller 27, which are rotated at the substantially same circumferential speed, cooperate with each other so as to conduct synchronous transporting control for transporting printing paper P. That is, in the draft printing mode, while PF drive roller 4 and the rear paper feeding roller 27 are being synchronized with each other, printing paper P, which has been fed from the rear paper feeding cassette 26 inside the printer 1, is transported. Therefore, printing paper P can be fed without causing any problem in the transporting action and the printing action of printing paper P. That is, in the present embodiment, the printing action, the transporting action and the feeding action can be conducted as a series of actions. As a result, at the time of continuous printing conducted in the draft printing mode, throughput can be more enhanced.
In the draft printing mode of this embodiment, while PF drive roller 4 and the rear paper feeding roller 27 are being synchronized with each other, printing paper P, which has been fed from the rear paper feeding cassette 26 inside the printer 1, is transported. Therefore, printing paper P can be transported in an appropriate state between PF drive roller 4 and the rear paper feeding roller 27. As a result, it is possible to suppress the generation of noise which is generated from printing paper P when tension given to printing paper P between the rollers is changed.
In the normal printing mode of the present embodiment, separate transporting control is conducted in such a manner that at the time of continuous printing, after printing paper P has been fed from the rear paper feeding cassette 26 to the inside of the printer 1, the rear paper feeding roller 27 is stopped and printing paper P, which has been fed from the rear paper feeding cassette 26 to the inside of the printer 1, is transported by PF drive roller 4. Therefore, in the normal printing mode, the transporting action of transporting printing paper P and the printing action can be separate from the feeding action of printing paper P. Accordingly, printing action can be performed without being affected by the feeding action. For example, in the normal printing mode, “cue of printing paper P” which is not conducted in synchronous transporting control, can be performed. In the normal printing mode, PF motor 14 and ASF motor 31 are subjected to PID control according to individual target speed tables which are independently set. Therefore, a transporting speed and an amount of transporting of printing paper P at the time of intermittent transporting conducted by PF drive roller 4 and the ejecting drive roller 6 can be set irrespective of the feeding action. As a result, the printing precision can be enhanced.
In the present embodiment, even in the draft printing mode, the last sheet of printing paper P at the time of continuous printing is subjected to separate transporting control. Therefore, even in a case where sheets of printing paper P, the number of which is not less than a designated number of continuous printing, are set in the rear paper feeding hopper 26, it is possible to prevent the following printing paper P from entering the inside of the printer 1.
The above embodiment is an example of the preferred embodiment of the present invention. However, it should be noted that the present invention is not limited to the above specific embodiment. Variations can be made without departing from the spirit and the scope of claim of the present invention.
In the embodiment described above, PF target speed table T1 and ASF target speed table T2 are set so that PF speed profile F1, which has been made according to PF target speed table T1, and paper feeding speed profile F2, which has been made according to ASF target speed table T2, can be substantially the same with each other, and start correcting control is conducted when one sheet of printing paper P is transported by both PF drive roller 4 and the rear paper feeding roller 27 in the draft printing mode. Therefore, at the time of transporting, printing paper P is loosened between PF drive roller 4 and the rear paper feeding roller 27. However, at the time of stoppage, printing paper P is stretched. Except for that, the following constitution may be employed. For example, when ASF target speed table T2 is a little corrected and start correcting control is conducted, printing paper P transported by PF drive roller 4 and the rear paper feeding roller 27 may be always loosened between PF drive roller 4 and the rear paper feeding roller 27.
For example, as shown in
The above embodiment is an example in which printing paper P is fed from the rear side to the inside of the printer 1. In this example, the method of transporting control of transporting printing paper P in the printer 1 is explained. That is, in the above embodiment, at the time of continuous printing in the draft printing mode, according to PF target speed table T1 corresponding to PF speed profile F1, PF motor 14 is controlled. According to ASF target speed table T2 corresponding to paper feeding speed profile F2, ASF motor 31 is controlled. Except for that, the following method may be employed. For example, according to PF target speed table T1 corresponding to PF speed profile F1, PF motor 14 is controlled. According to ASF target speed table corresponding to the substantially same speed profile as PF speed profile F1 in which a relation between the rotating time of the front paper feeding roller 21 and the target rotating speed or a relation between the rotating distance of the front paper feeding roller 21 and the target rotating speed is shown, ASF motor 31 may be controlled. That is, transporting control of transporting printing paper P of the present embodiment can be applied to a case in which printing paper P is fed inside the printer 1. In this case, it is preferable that a detection device having the same function as that of the paper detecting device 9 is arranged at a position close to the front paper feeding roller 21. In this case, the front paper feeding roller 21 is a feeding roller for feeding printing paper P into the inside of the printer 1. The front paper feeding cassette 20 is a medium setting portion in which printing paper P is set before printing.
Further, in the above embodiment, at the time of continuous printing conducted in the draft printing mode, when a leading end of the first sheet of printing paper P is transported to a position where PF drive roller 4 and PF driven roller 5 are arranged, synchronous transporting control is also conducted. Except for that, for example, when the leading end of the first sheet of printing paper P is transported to a position where PF drive roller 4 and PF driven roller 5 are arranged, in the same manner as that of the conventional example, only ASF motor 31 may be driven and only the rear paper feeding roller 27 may be rotated.
Further, in the above embodiment, PF motor 14 and ASF motor 31 are subjected to PID control. Except for that, for example, PF motor 14 and ASF motor 31 may be controlled by feedback control such as PI control or proportional control. The constitution of the present embodiment can be applied to ink jet printers and various devices having a paper feeding mechanism such as a laser beam printer.
Number | Date | Country | Kind |
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2006-201670 | Jul 2006 | JP | national |