JPH09314935A - Pulse motor control method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse motor control method and an image forming device for keeping the printing performance of high picture quality while controlling heat development of a motor. SOLUTION: Respective sections of a thermal color printer 1 are drive controlled by a control section formed on an electronic circuit base of an electrical equipment section 5. Printing indication is input from an operation panel 17. A paper feed lever 7 and a ribbon take-up roll 14 are driven by a ribbon motor through a one-direction clutch, and a platen roller 9 is driven in both of forward and reverse directions by a paper feed motor. When the paper is positioned and the operation is stopped before the start of printing, or when color ink is positioned and the operation is stopped until the start of printing, or else when the operation is stopped temporarily at the time of moving forward or reverse the paper P as represented by the both direction arrow marks C for the purpose of overlapping inks of three colors or four colors, the excitation to respective motors is continued. At the time of stopping other than the above- referred stops, the excitation to the motor is shut off. Also when the time more than the given time is passed during the excitation, the excitation is shut off similarly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse motor control method and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, there is an image forming apparatus such as a printer or a copying machine which uses a pulse motor as a drive source. In such an image forming apparatus, during a series of printing processes, the pulse motor is excited through a current even when the rotation of the pulse motor is stopped. For example, when printing continuously on multiple sheets of paper, the pulse motor frequently stops rotating (pauses) during the period from the start of printing the first sheet of paper to the end of printing of the last sheet of paper. Even in the case of printing only one sheet, in the case of color printing, the rotation stop of the pulse motor occurs at the process switching between the start of printing the first color and the end of printing the last color. In this way, even when the pass motor is not rotating, the energization is continued to excite the pulse motor.

[0003]

However, if the pulse motor is constantly excited in this way, the pulse motor overheats. If the pulse motor overheats, normal driving cannot be performed and a step out occurs. Further, if a fan for air cooling is provided inside for cooling in order to prevent this overheating, a relatively large space inside the device is occupied by the air cooling device. With this, there is a problem that it is not possible to meet the increasing demand for downsizing of OA equipment in recent years.
Further, even if this is the case, if the excitation is interrupted each time the pulse motor stops rotating, there is a problem in that a defect such as a print position shift due to backlash or the like occurs and the quality of the image deteriorates. .

[0004] The object of the present invention is to solve the above-mentioned conventional problems.
An object of the present invention is to provide a pulse motor control method and an image forming apparatus that maintain high-quality printing performance while suppressing heat generation of the motor.

[0005]

According to the first aspect of the present invention,
It is applied to a pulse motor control method for controlling the drive of a pulse motor that conveys paper or an ink ribbon.

According to the pulse motor control method of the present invention, the motor excitation is continued when the motor is stopped during printing, and the motor excitation is cut off when the motor is not directly related to printing.

The stop of the motor during the printing process is performed, for example, as described in claim 2, from the period after the paper alignment to the printing process start, the period from the ink ribbon alignment to the printing process start, or each color. This is a stop period when the paper is moved forward and backward for each color in order to print on top of each other.
Then, for example, as described in claim 3, the stop time during the printing process is timed, and the continuous excitation is cut off when the timed period exceeds a predetermined period.

A fourth aspect of the invention is premised on an image forming apparatus in which a sheet or an ink ribbon is conveyed by a pulse motor. The image forming apparatus of the present invention is configured to continue the excitation of the motor when the motor is stopped during the printing process and to shut off the excitation of the motor when the motor is not directly related to printing.

The stop of the motor during the printing process is performed, for example, as described in claim 5, from the period after the paper alignment to the printing process start, the period from the ink ribbon alignment to the printing process start, or each color. This is a stop period when the paper is moved forward and backward for each color in order to print on top of each other.
Further, for example, as described in claim 6, it is provided with a timing means for timing the stop time during the printing process, and the continuous excitation is cut off when the timing period measured by the timing means exceeds a predetermined period. Is composed of.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the overall configuration of a thermal color recording apparatus according to an embodiment. In FIG. 1, a thermal color recording device (hereinafter, referred to as a main body device or simply a printer) 1 includes a paper feed unit 3 below an inside of an outer casing 2, and a recording unit 4 above and behind (to the right of the drawing) An electric component section 5 is provided on the front part (on the left side of the drawing).

The above-mentioned paper feeding section 3 comprises a paper feeding cassette 6, a paper feeding roller 7, a guide plate 8 and the like. Paper cassette 6
Is loaded with a large number of sheets of paper P, and is detachably attached to the main body apparatus 1 from the lower front portion of the main body apparatus 1. Paper feeding roller 7
Separates the paper P in the paper feed cassette 6 one by one from the uppermost part, and feeds the separated paper P to the recording unit 4 via the guide plate 8.

The recording unit 4 is provided with a platen roller 9, a thermal print head 11, a feed-back guide plate 12, etc., and forms a printing unit for transferring an image onto a sheet by the facing portion of the platen roller 9 and the thermal print head 11. ing. An ink ribbon 13 is stretched between the platen roller 9 and the thermal print head 11 which form this print portion. The ink ribbon 13 has three primary colors of subtractive colors Y (yellow: yellow), M (magenta: red dye), and C (cyan: greenish) on the long base film (lower surface in the figure) in the longitudinal direction. Ink layers of three colors (a certain blue color) or four colors to which Bk (black: black) is further added are formed in an area unit corresponding to one sheet of paper, respectively. The ink ribbon 13 is pulled out from the supply reel 15 by rotating the take-up reel 14 in a clockwise direction indicated by an arrow in the drawing by a pulse motor (ribbon motor) described later, and an unused portion is printed. Supplied to the department. The thermal print head 11 is located at a position indicated by a solid line in the drawing at the time of printing, and presses the ink ribbon 13 and the paper P fed from the paper feed unit 3 against the platen roller 9 in the print unit. Further, at the time of non-printing, the above-mentioned pressing in the printing portion is released by rotating upward to the position shown by the broken line in the figure.

The platen roller 9 is driven to rotate in both forward and reverse directions by a paper motor, which will be described later, and rotates in the clockwise direction (forward rotation direction) during printing. Then, until the printing of all colors is completed, the paper P printed every time printing of one color is completed.
The leading end of the sheet P is sent to the outside of the main body apparatus 1 to release the rear end of the sheet P from the guide plate 8 and then rotated in the counterclockwise direction (reverse rotation direction). As shown by, the trailing edge of the paper P is fed back and guided toward the feed-back guide plate 12. After that, the process of rotating in the clockwise direction (forward rotation direction) again and starting printing of the next color is repeated. When printing of all colors is completed, the paper P is discharged from the discharge port 16 to the outside of the main body apparatus 1. By this. During multi-color printing with each color, the leading end of the paper sheet P forms the discharge port 16, as shown by the double-headed arrow C in the figure.
Moves in and out of the main unit 1.

The electrical equipment section 5 is provided with an electronic circuit board provided near the side surface of the inner wall of the main body device 1, and a drive system such as a motor and a gear controlled by the electronic circuit. An operation panel 17 is provided above the front part of the main body device 1, and an operator can perform a desired input operation with a user interface including simple message texts, numbers, graphics, and the like. It is like this.

FIG. 2 is a configuration block diagram of the main part of the printer 1 described above. As shown in FIG.
Is composed of an interface (I / F) controller 18, an image processing circuit 19, a thermal print head 11, an engine controller 20, a paper motor 21, a ribbon motor 22, a cam motor 23 and the like.

The I / F controller 18 includes a control unit, a reception buffer, an image data generation unit, a frame memory, a data transfer unit, etc., which are not shown in the drawing. The control unit uses the I / F controller 1 according to a predetermined program.
The above-mentioned respective parts in 8 are controlled. The receive buffer is a SCSI (small-com
puter-system-interface) Temporarily stores print information including commands, character codes, graphics data, etc., input via 24. Frame memory is paper 1
It has a storage capacity for expanding drawing data (bit image data) for one surface. When the image data generation unit recognizes that the frame memory is in a state where the drawing data can be expanded, the print information is sequentially read from the reception buffer to analyze the color components and other information, and based on the analysis result. Drawing data to be printed is individually generated for each name color of yellow (Y), magenta (M), and cyan (C), and the generated drawing data is sequentially written and developed in a predetermined address of the frame memory. That is, drawing data for one color at a time is expanded in the frame memory, and when printing of the drawing data for one color is completed, the frame memory is cleared and the drawing data for the next one color is expanded. repeat.

The data transfer unit confirms the completion of the expansion of the drawing data, transfers the drawing data line-sequentially to the image processing circuit 19 through the parallel interface 26, and notifies the engine controller 20 of it. The image processing circuit 19 outputs a parallel print drive signal Dd corresponding to the drawing data transferred from the I / F controller 18 to drive the thermal print head 11. The thermal print head 11 selectively causes a plurality of heating elements to generate heat on the basis of the input print drive signal Dd, transfers heat energy based on the heat generation to the ink ribbon 13, and transfers the ink of the ink ribbon 13 to the paper. Transfer (print) to P.

A paper motor 21, a ribbon motor 22 and a cam motor 23 are connected to the engine controller 20 via a motor driver (not shown). The paper motor 21 is a pulse motor, and drives the paper P transport mechanism. Further, the ribbon motor 22 is also a pulse motor, and is synchronized with the transport mechanism of the paper P, and the ink ribbon 1
The winding mechanism of No. 3 is driven. Engine controller 2
0 generates a motor feed signal (drive signal) corresponding to the drawing data for each block based on the notification from the data transfer unit, and transmits this drive signal to the paper motor 21 and the ribbon via the motor driver. It is configured to output to the motor 22 and the cam motor 23, and to control excitation and de-excitation during rotation stop described later.

FIGS. 3A, 3B and 3C are timing charts showing the sheet conveying operation under the control of the engine controller 20. FIG. 3A is a cam motor and FIG. 3B is a timing chart.
Shows the operation of the paper motor, and FIG. 6 (c) shows the operation of the ribbon motor. The figures (a), (b), and (c) show forward rotation in the vertical direction (CW rotation), reverse rotation in the vertical downward direction (CCW rotation), and time (operating period) in the horizontal right direction. Showing.

The cam motor 23 presses and releases the thermal print head 11 to the platen roller 9 and pushes up and releases the bottom plate of the paper feed cassette 6. Although not specifically shown, this cam mechanism is shown from the home position.
The bottom plate is pushed up by the rotation in the CW direction shown upward in (a),
The platen roller 9 of the thermal print head 11 is rotated from the home position in the CCW direction shown in FIG.
Perform crimping. Also, at the start of rotation, it slows up,
It slows down when rotation stops.

The paper motor 21 conveys the paper P fed from the paper feed cassette 6 to the recording unit 4 by the ribbon motor 22 which will be described later in detail, and further prints the paper P in the recording unit 4 and sends it back. The paper is discharged from the discharge port 16.
When the paper P is fed back, it rotates in the CCW direction, and in other cases, it rotates in the CW direction. When the paper P is fed back, slow-up, high-speed rotation, and slow-down are performed. This reduces the return time.

The ribbon motor 22 takes up the ink ribbon 13 by the take-up reel 14 and feeds the paper P from the paper feed cassette 6 by the paper feed roller 7. When the ribbon is wound, it rotates in the CW direction, and when the paper P is fed from the paper feed cassette 6, it rotates in the CCW direction. Although not specifically shown, two one-way clutches for CW and CCW are provided on the downstream side of the drive system of the ribbon motor 22, and two completely different operations of ribbon winding and paper feeding are possible. I am trying.

The timing of this sequence (repetitive control) will be described below. First, the I / F controller 18
In response to the paper feed start signal output from the engine controller 20, the engine controller 20 rotates the ribbon motor 22 in the CW direction,
The yellow (Y) color surface of the ink ribbon 13 is indexed (period C1 in FIG. 7C). Next, the cam motor 23 is rotated CW from the home position to push up the bottom plate of the paper feed cassette 6 (period A2 in FIG. 9A). Then, the ribbon motor 22 is rotated by CCW to feed paper from the paper feed cassette 6 (period C3 in FIG. 7C). Next, the paper motor 21 is rotated by CW to convey the paper P further to the front of the recording unit 4 (period B2 in FIG. 7B). Further, during this process, the cam motor 23 is rotated CCW to lower the bottom plate of the paper feed cassette 6 (period A4 in FIG. 9A). As a result, the cam (not shown) returns to the home position.

Following the above, the cam motor 23 is further CCW
The thermal print head 11 is rotated and pressed against the platen roller 9 (period A6 in FIG. 9A). Next, the paper motor 21 and the ribbon motor 22 are simultaneously rotated by CW,
The front end of the paper P is advanced to the paper reference position and the ink ribbon 13 is advanced (period B4 in FIG. 9B and period C5 in FIG. 7C). Whether or not the paper P has reached the paper reference position is detected by a photo sensor (not shown). After that, the engine controller 20 outputs an image data transfer request signal to the I / F controller 18. The I / F controller 18 sends the image data to the image processing circuit 19 via the parallel interface 26 in response to the image data transfer request signal.

Upon receiving this image data, the image processing circuit 19 sends a print feed start command to the engine controller 20. As a result, the re-engine controller 20 rotates the paper motor 21 and the ribbon motor 22 in the CW direction, and prints yellow (Y) on the paper P in synchronization with the control of the print head 11 (see (b) in the figure). Period B6 and period C7 of FIG.

When the printing of yellow (Y) is completed, the cam motor 23 is rotated by CW to release the pressure contact of the thermal print head 11 (period A8 in FIG. 9A). Then, the paper motor 21 is rotated by CCW to feed the paper P back along the feed-back guide plate 12 (B8 in FIG.
At the same time, the ribbon motor 22 rotates CW, and the next color of the ink ribbon 13, magenta (M), is cued (period C9 in FIG. 7C). Then, the cam motor 23 is rotated by CCW, and the print head 11 is pressed against the platen roller 9 again (period A10 in the same figure).

Thereafter, magenta (M) printing is performed in the same manner as in yellow (Y) printing. That is, the cam motor 23 is at the timing shown in the periods A11 to A14 in FIG. 11A, and the paper motor 21 is the period B10 to B15 in FIG.
At the timing shown by, and the ribbon motor 22
At the timings of the periods C11 to C16 in (c), the periods A7 to A10, the periods B4 to B9, and the period C5 described above, respectively.
The operation is similar to that shown at the timing of C10.

Thereafter, the cam motor 23 is further processed in the same manner as above.
In the period A15 to A16 in the same figure, the paper motor 21 operates in the periods B16 to B19 in the same figure (b), and the ribbon motor 22 operates at the timing C17 to C20 in the same figure (c). Then, cyan (C) is printed. When the printing of the cyan (C) is completed, the paper motor 21 is rotated by CW to eject the paper P out of the machine (period B2 in the same figure (b)).
0). In this way, each pulse motor rotates CW, stops,
Then, the CCW rotation operation is performed at a predetermined timing to complete the printing of one sheet of paper P.

Here, during printing of one sheet of paper P (when printing a plurality of sheets of paper continuously, during the series of printing),
Even if the motor (pulse motor) is rotating or stopped, if the motor is always excited, the motor will overheat and cause a malfunction. While each pulse motor is stopped (the period Al, A3 ..., Bl, B3 ..., C2, C4 ...
If the excitation of the pulse motor is cut off (the power supply to the motor is cut off), the temperature rise of the motor can be suppressed. However, if the excitation of the motor is always turned off while the motor is stopped, even in the portion related to the leading edge alignment of the printing position (the periods B5, B11, B17 in the paper motor 21 and the periods C6, C12, C18 in the ribbon motor). Excitation will be interrupted once. When the excitation is cut off, the motor is in a free rotation state, and the backlash of the gear and vibration from the outside generate a rotational force in an unnecessary direction of the drive system. Even if this rotational force is small, it causes a problem in the entire device. For example, there is a possibility that a misalignment of the tip position and the like, which is performed with great care, may occur and the control accuracy may be deteriorated.

In the present embodiment, the period relating to the leading edge position alignment of the printing (the above-mentioned periods B5, Bll, B
(17, C6, C12, C18), the excitation of the paper motor 21 and the ribbon motor 22 is kept held so that the accuracy of the tip position alignment is not impaired. Then, other stop periods of these motors (the above-mentioned periods B7, B9, B13, B15, B19 and B21, and C2, C4, C8, C10, C14, C16 and C2).
In 0), the excitation is cut off to suppress the temperature rise of the motor. Next, a specific method of realizing the above will be described below.

FIG. 4 is a general flow chart (main routine) for explaining the operation of the engine controller 20 for maintaining and interrupting the above-mentioned excitation, and FIGS. 5 (a) and 5 (b).
Is a flow chart which explains it supplementarily. 6 (a) is a flowchart of an interrupt routine for controlling the cam motor 23, and FIG. 5 (b) is a paper motor 2
5 is a flowchart of an interrupt routine for controlling the ribbon motor 22, and FIG. 5C is a flowchart of an interrupt routine for controlling the ribbon motor 22.

In the flowchart of FIG. 4, the engine controller 20 first determines whether or not the print start request signal "1"("H") is input from the I / F controller 18 (step S1). When the print start request signal "1" is not input (S1 is N), it is immediately determined whether or not the processing completion flag is "1" (step S4), and it is determined that the processing is not completed. After confirming (N in S4), other processing described later in detail is performed (step S8), and the above step S
The process of returning to 1 is repeated to wait for the input of the print start request signal “1” from the I / F controller 18.

When the print start request signal "1" is input in the step S1 (S1 is Y), the trigger for the period C1 for performing the cueing process of the yellow (Y) ribbon is output (step S1). In step S2, the flag indicating printing is set to "1" (step S2).
3) Wait for completion of processing of the interrupt routine (step S4).

This interrupt processing is permitted by the above-mentioned trigger, so that the interrupt routine INT for the control processing for the ribbon motor 22 shown in FIG. 6 (c).
RBM is called. This interrupt routine INTR
The BM determines whether or not the processing procedure is the period C1 (step SC1), and if the processing procedure is the period C1 (SC1 is Y), executes the motor drive processing of the period C1 (step SC2). . Then, it is judged whether or not the processing is completed, that is, whether or not the driving of the motor is continued for a predetermined period (step SC3), and if the processing is completed (SC3).
Is Y), and the process completion flag is set to "1" (step S
C4) and returns to the main routine.

In the main routine, after confirming that the processing completion flag is "1" (S4 is Y), the processing completion flag is initialized to "0"("L") (step S
5) Then, it is determined whether or not the processing procedure which has been completed is the processing procedure of the period C1 (step S6). And
Since the process just completed is the process procedure of the period C1 (S6 is Y), after the trigger of the period A2 which is the next process procedure is output (step S7), the above-mentioned step S8 is performed, and the step S1 has already been performed. Since the print start request signal is "0", the process of waiting for the completion of the next processing procedure in step S4 (N in S4) is repeated. In the processing of the period A2, the interrupt is permitted by the trigger, and as a result, FIG.
An interrupt routine INTCMM for controlling the cam motor 23 is called. In this interrupt routine INTCMM, it is determined whether or not the processing procedure is the period A2 (step SA1), and if the processing procedure is the period A2 (SA1 is Y), the motor drive processing of the period A2 is executed ( Step SA2). Then, it is determined whether or not the processing is completed, that is, whether or not the driving of the motor is continued for a predetermined period (step SA3). If the processing is completed (SA3 is Y), the processing completion flag is set to "1". Then (step SA4), the process returns to the main routine.

In the main routine, after confirming that the processing completion flag is "1" (Y in S4 again), steps S5 and S6 described above are performed. Since the process just completed is not the process procedure of the period C1 (N in S6), it is subsequently determined whether or not it is the process procedure of the period A2 (step S9). Since the process just completed is the process procedure of the period A2 (Y in S9), the trigger of the period C3, which is the next process procedure, is output (step S9).
10) In this case as well, the above-described step S8 is performed, the process proceeds from step S1 to step S4, and the process of waiting for the completion of the above-described processing procedure (S4 is N) is repeated.

By the above trigger, the ribbon motor 2 is again activated.
The interrupt for the control processing to No. 2 is enabled, as shown in FIG.
Interrupt routine INTRBM is called. In this case, in the interrupt routine INTRBM, step S
It is determined that the period is not C1 in C1 (SC1 is N),
Next, it is determined whether or not the processing procedure is for the period C3 (step SC5). Then, since it is the process of the period C3 (SC5 is Y), the motor drive process of the period C3 is executed (step SC6), and it is determined whether or not the motor drive is continued for a predetermined period (the process is completed). (Step SC
7) If the processing is completed (SC7 is Y), the processing completion flag is set to "1" (step SC4), and the process returns to the main routine.

In the main routine, steps S4 to S5 are executed again, and "S6 is N" and "S9".
Is N ”, and then it is determined whether or not the processing procedure which has just been executed is the period C3 (step S11). Then, it recognizes that the process procedure that has just been executed is the period C3 (Y in S11), and outputs a trigger corresponding to the process of the period B2 which is the next process procedure (step S12). Then, the above-described step S8 is performed, the process proceeds from step S1 to step S4 and waits for the completion of the above-described processing procedure (S4 is N).

By the above trigger, the interruption for controlling the paper motor 21 is permitted. That is, in this case, the interrupt routine INTPFM of FIG. 6B is called. In this case, the interrupt routine INTPFM
Then, the processes of steps SB1 to SB4 are executed. The processing of steps SB1 to SB4 is the same as that shown in FIG.
Step SC in the interrupt routine INTRBM of
1 to SC4 processing, or interrupt routine I of FIG. 6 (a)
A drive process for the paper motor 21 similar to the process of steps SA1 to SA4 in the NTCMM is performed.
Return to the main routine.

Then, in the main routine, steps S4 to S5 are executed again, and it is further determined that "S6 is N", "S9 is N", and "S11 is N", and then it is executed. The processing procedure that completed the
It is determined whether or not (step S11). Then, it recognizes that the process procedure that has just been executed is the period C3 (Y in S11), and outputs a trigger corresponding to the process of the period B2, which is the next process procedure (step S1).
2). Then, the above step S8 is performed, and step S1
Then, the process proceeds to step S4 and waits for the completion of the above processing procedure (S4 is N), which is repeated.

In this way, the same processing procedure (refer to the timing chart of FIG. 3) is sequentially repeated, and in the middle of FIG.
(b) and (c) interrupt routine INTCMM, INTPF
Execute M and INTRBM. The processing of steps SA5 to SA7 of the interrupt routine INTCMM of FIG. 6 (a) is performed by the interrupt routine INTRBM of FIG. 6 (c) described above.
6 is the same as the processing of steps SC5 to SC7 of FIG. 6B, and step SB of the interrupt routine INTPMF of FIG. 6B.
The processing of 5 to SB7 is similar to the processing of steps SC5 to SC7 of the interrupt routine INTRBM.

Also, these interrupt routines INTCM
Steps SA8, SB8, and SC8 indicated by broken lines in M, INTPFM, and INTRBM are shown by omitting the processing procedure that follows, and here, the period A6,
A8, A10, ..., Periods B6, B8, B10, ...
.., and the process of confirming and executing each of the processing procedures of the periods C5, C7, C9, ... Are sequentially performed in the same manner as, for example, the process of steps SA5 to SA7 of the interrupt routine INTCMM.

Further, when the above step S11 is N, and when the processing timing of the period B4 shown in FIG. 3 (b) is reached, the processing shown in FIG. 5 (a) is performed. That is, it is determined whether or not the sequence to be processed now is the processing procedure of the period B4 (step S11-1), and the period B4
(S11-1 is Y),
An image data transfer request is output to the host computer 25 (step S11-2), a timer is started to measure a predetermined time corresponding to the period B4 (step S11-3), and the process proceeds to step S8. To do. Similarly, the processing of steps S11-1 to S11-3 is performed at the processing timings of the period B10 and the period B16 shown in FIG. 3B while confirming that the processing procedure is the period B10 or the period B16. Be seen.

The "other processing" in step S8 will be described. In step S8, as shown in FIG.
Perform the process shown in (b). That is, the timer started in the process of FIG. 5 (a) described above measures the time for each processing cycle (step S8-1). Then, it is determined whether or not the time period measured by the timer exceeds a preset allowable period (step S8-2). Then, if it does not exceed (N in S8-2), the process exits as it is and returns to step S1. On the other hand, if the allowable period is exceeded (Y in S8-2), the paper motor 21 and the ribbon motor 2
After the excitation of No. 2 is turned off (step S8-3), the process is exited and the process returns to step S1.

As a result, for example, when a plurality of paper sheets are continuously printed and a long blank period (standby period) occurs due to an abnormal transmission of print information or the like, the paper motor 21 and the ribbon motor 22. Excitation is cut off to prevent heating of the motor.

In this way, the procedure returns to the main routine, steps S4 to S5 are executed, and "S
6 is N ”,“ S9 is N ”,“ S11 is N ”, and the like are sequentially repeated, and the sequence proceeds until it is determined whether or not the processing procedure that has been completed is the period B20. Yes (step S13). Then, when it is recognized that the processing procedure which has just been executed is the period B20 (Y in S13), the flag indicating that printing is in progress is set to "0", and the marker during printing is released (step In S14), the print processing is ended. That is, after performing other processing in step S8, step S1
Then, it waits for the next print instruction.

Next, in the processing of the interrupt routine INTPFM shown in FIG. 6B, the processing described in the three steps (SB1 to SB3 or SB5 to SB7) for each sequence will be described in more detail.

FIG. 7 shows the interrupt routine INTPF.
It is a flowchart which shows the process of M in more detail. still,
The same processing steps as those shown in FIG. 6B are designated by the same step numbers as those in FIG. 6B. In FIG. 7, it is determined whether or not the processing procedure is the period B2 (step SB1), and if the processing procedure is the period B2 (SB1 is Y), the value of the stepping counter for counting the motor driving steps is set to " 1 ”is incremented (step SB1-1), and it is determined whether or not the value is a prescribed value for driving the motor in this period B2 (step SB1-2), and it is still the prescribed value. If not (SB1-2 is N), the drive of the paper motor 21 is continued for one step (step SB1-4), and the process is ended. As a result, in the main routine, the period B2
It is determined again that the value of the stepping counter is equal to the value of the period B2 in step SB1-2.
Is repeated until the specified value for driving the motor is reached.

Then, when the value of the stepping counter reaches the specified value for driving the motor in the period B2 in step SB1-2, that is, the motor is driven for a predetermined period corresponding to the processing period B2, When the interrupt process is completed (SB1-2 is Y), the process completion flag is set to "1" (step SB4), and the process returns to the main routine.

In step SB1, it is determined that the period is not B2 (SB1 is N), and then it is determined whether or not the process procedure is in the period B4 (step SB5), and the process in the period B4. When it is confirmed (SB5 is Y), the output of the paper reference position sensor (not shown) is discriminated (step SB5-1). Then, when the output of the paper reference position sensor is off, that is, when the paper is not yet at the reference position (SB5-1 is N), the above-mentioned step SB1 is performed.
-4 processing is performed.

On the other hand, if the output of the paper reference position sensor is on, the paper has reached the reference position (SB5-1 is Y), and in this case, the paper motor 21 is stopped (step SB5-2). Further, in this case, since it is a case where the paper is re-conveyed from the reference position to the printing unit next, excitation of the paper motor 21 is continued and the paper motor 21 is fixed to the stop position (also step SB5-2). ). This suppresses backlash and prevents misalignment of the paper.

Subsequently, when it is not the period B5 in step SB5 (SB5 is N), it is then determined whether or not the processing procedure is in the period B6 (step SB8-1). This determination is a process of determining whether or not a trigger indicating the printing process, which is the process procedure of the period B6, is output, and this trigger is that the transfer of the image data of the color from the host computer 25 is completed, and the printer It is output according to the print timing when the drive preparation of the thermal print head 11 of No. 1 is completed.

FIG. 8 is a flowchart of the interrupt process INTDRAW that outputs a trigger for executing the print process procedure. As shown in the figure, a processing procedure B6 for driving the paper motor 21 to perform the printing processing (see FIG. 3).
(see (b)) is output (step ST1), and subsequently, the trigger of the processing procedure C7 (see FIG. 3 (c)) for driving the ribbon motor 22 during the printing process is output (step S).
In T2), the clock counter is further cleared to "0" to initialize the clock state (step ST3), and the process ends. This trigger is determined in step SB8-1 of FIG.

Then, in step SB8-1 of FIG. 7, it is confirmed that the processing procedure is for the period B6 (SB8-1).
Is Y), the value of the stepping counter for counting the motor driving steps is incremented by "1" (step SB
8-2), it is determined whether or not the value is a prescribed value for driving the motor in the print processing period B6 (step SB8-3), and if it is not yet the prescribed value (step SB8-3), SB8-3 is N), and the above-mentioned steps SB1-4 and subsequent steps are performed.

Accordingly, the period B6 is discriminated again in the main routine, and the interrupt routine INTPFM is again determined.
In step SB8-2, the increment of the stepping counter is repeated until it reaches the specified value corresponding to the period B6, and the printing process for one page is continued.

Then, in step SB8-3, when the value of the stepping counter reaches the specified value corresponding to the print processing period B6 (SB8-3 is Y), the above-mentioned steps SB1-3 and subsequent steps are performed. I do. As a result, the excitation of the paper motor is stopped and the unnecessary heat generation of the motor is suppressed until the next paper alignment or the start of conveyance of a new paper when there is no need for alignment.

Incidentally, step SB8-7 shown by the broken line in FIG.
In the following processing, the processing procedure C7 in which the trigger is output in FIG. 8 is determined, and the processing of this processing procedure C7 is performed. The ribbon motor drive processing in the processing procedure C7 is the same as the paper motor drive processing in the processing procedure B6 described above.

In the above embodiment, the example of the thermal transfer printer has been described, but the image forming apparatus to which the present invention is applied is not limited to this, and another image forming apparatus,
For example, electrophotographic image forming apparatuses, ink discharge type image forming apparatuses, and the like, which are configured to accurately convey a sheet and bring the sheet into an image forming processing position at a highly accurate timing, are not used for carrying-in drive control. Applicable.

[0059]

As described above, according to the present invention,
When the motor is stopped during the printing process, continue to excite the motor,
Since the excitation of the motor is cut off when the motor is stopped normally, it is possible to keep the heat generation of the motor low on the other hand while maintaining the accuracy related to the print alignment (leading edge alignment) for each color that is most important in color printing. ,
The motor can be downsized, that is, the color printer can be downsized while maintaining the reliability of the image quality of the color print.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the overall configuration of a thermal color recording apparatus (printer) according to an embodiment.

FIG. 2 is a configuration block diagram of a main part of the thermal color recording apparatus.

FIG. 3 is a timing chart showing a sheet conveying operation under the control of the engine controller.

FIG. 4 is a general flowchart for explaining the operation of the engine controller.

FIG. 5 is a flowchart for supplementarily explaining the general flowchart.

6A is a flowchart of an interrupt routine for controlling a cam motor, FIG. 6B is a flowchart of an interrupt routine for controlling a paper motor, and FIG. 6C is a flowchart of an interrupt routine for controlling a ribbon motor.

FIG. 7 is a flowchart showing in more detail the processing of an interrupt routine for controlling the paper motor.

FIG. 8 is a flowchart of an interrupt process for outputting a trigger for executing a print process procedure.

[Explanation of symbols]

 1 Thermal color recording device (main unit, printer) 2 Outer casing 3 Paper feed unit 4 Recording unit 5 Electrical equipment unit 6 Paper feed cassette 7 Paper feed roller 8 Guide plate 9 Platen 11 Thermal print head 12 Send back guide plate 13 Ink ribbon 14 Take-up reel 15 Supply reel 16 Ejection port 17 Operation panel 18 Interface (I / F) controller 19 Image processing circuit 20 Engine controller 21 Paper motor 22 Ribbon motor 23 Cam motor 24 SCSI (small-computer-system-interface) 25 Host computer 26 Parallel Interface P Paper

Claims (6)

[Claims] 1. A pulse motor control method for controlling driving of a pulse motor for carrying a sheet or an ink ribbon in an image forming apparatus, wherein the motor is continuously excited when the motor is stopped during printing processing,
A pulse motor control method characterized in that the motor excitation is controlled so as to be cut off when the motor is stopped, which is not directly related to printing. 2. The motor is stopped during the printing process in order to perform printing from the time after the paper is aligned to the start of the printing process, from the time after the alignment of the ink ribbon to the start of the printing process, or to print each color in an overlapping manner. 2. The pulse motor control method according to claim 1, wherein the pulse motor control method is a stop period when the paper is moved forward and backward for each color. 3. The pulse motor control method according to claim 1, wherein the stop time during the printing process is timed, and the continuous excitation is interrupted when the timed period exceeds a predetermined period. . 4. An image forming apparatus equipped with a pulse motor for carrying a sheet or an ink ribbon, wherein the motor is continuously excited when the motor is stopped during printing.
An image forming apparatus characterized in that the excitation of the motor is cut off when the motor is stopped, which is not directly related to printing. 5. The motor is stopped during the printing process in order to perform printing from the time after the paper is aligned to the start of the printing process, from the time after the alignment of the ink ribbon to the start of the printing process, or to print each color in a superimposed manner. The image forming apparatus according to claim 4, wherein the image forming apparatus is a stop period when the sheet is advanced and retracted for each color. 6. The apparatus according to claim 1, further comprising a time measuring unit for measuring a stop time during the printing process, and interrupting the continuous excitation when a time measuring period measured by the time measuring unit exceeds a predetermined period. 4. The image forming apparatus according to 4 or 5.