JP2594432B2 - Writing implement elevation control method in automatic drawing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for drivingly controlling a writing instrument of an automatic image forming apparatus (XY plotter) in a direction perpendicular to a screen.

[Conventional technology]

Japanese Patent Publication No. 53-34532 discloses an apparatus for driving and controlling a writing implement of a writing implement of an automatic image forming apparatus in a direction perpendicular to a sheet of paper or a drafting table, and a moving coil directly or indirectly connected to the writing implement. A high-speed writing implement vertical drive control system, comprising: a field component for driving a coil; and a drive circuit for accelerating and decelerating the writing implement and applying writing pressure to the writing implement after arriving at the drawing surface or a drafting table is disclosed. Have been. In the above method, when the writing implement is lowered, a positive current for rapidly lowering the writing implement is applied to the moving coil, and then a negative current is applied to the moving coil, so that the writing implement is decelerated and lands. In order to detect that the writing instrument has arrived on the paper surface or the drawing table, connect the output end of a position detector that detects the moving amount of the moving coil and outputs a voltage signal to one input end of the comparator, A predetermined reference voltage is applied to the other input terminal. When the output voltage of the position detector matches this reference voltage,
The coincidence is detected by the comparator, and the time when this coincides is defined as the time when the writing implement arrives on the paper surface or the drafting board.

When raising the writing implement, apply a negative current that rapidly raises the writing implement to the moving coil, and then apply a reverse positive current to slow down the writing implement and bring the writing implement holding member into contact with the upper limit stopper. ing. The contact position of the writing implement holding member with the upper limit stopper is detected by the configuration of the position detector and the comparator, and after this detection, a negative current is applied to the moving coil to press the writing implement holding member against the upper limit stopper with a predetermined pressure. ing.

Japanese Patent Application Laid-Open No. 58-86675 discloses a plotter that controls the elevation of a writing instrument with respect to a screen by energizing a moving coil. The position is set in two stages. When the moving distance along the platen in the rising state of the writing implement is long, raise the writing implement to a higher position,
When the moving distance is short, the writing implement is raised to a lower position to bring the pen up state, and in this state, the writing implement is controlled in the horizontal direction on the platen to shorten the drawing time.

[Problems to be solved by the invention]

As shown in FIG. 20, a positive acceleration current and a negative deceleration current are given to a moving coil that controls the writing instrument (pen) 2 to move up and down, thereby controlling the writing instrument 2 to accelerate and decelerate. When the descending speed is almost reduced to zero, the landing is soft-landed on the paper surface 6 (screen) on the drawing board, and then the pen pressure current 4c is supplied to the moving coil. It is possible to reduce the pen up-down sound and to speed up the pen up-down. To perform this control, the distance (stroke) from the pen tip of the writing implement 2 in the pen-up state to the paper surface 6
Must know. Above 53-34532
In the publication, the value of the reference voltage applied to the comparator is constant.

However, when the writing implement is replaced, the dimension S between the lower surface and the tip of the writing implement shown in FIG. 2 is different, which changes the stroke. Also,
As shown in Fig. 29, there is a plane error due to warpage in the drawing plate surface,
As a result, the stroke changes depending on the movement position of the writing instrument. This means that when the reference voltage is fixed, it is not possible to accurately detect when the writing instrument arrives at the screen image, and it is not possible to effectively prevent pen splashing. Also,
The device disclosed in Japanese Patent Application Laid-Open No. 58-86675 can read the stroke amount by lowering the writing implement based on the output of a sensor for detecting the position of the writing implement. However, the stroke cannot be determined unless the writing implement is lowered once. Absent. Therefore, when descending from the rising state of the writing implement, it is necessary to set an arbitrary value and descend. In drawing, the writing implement repeatedly goes up and down frequently. In the minute range of the drawing plate, there is almost no error in its flatness. Therefore, when the writing implement is raised and moves in a minute range in the horizontal direction with respect to the drawing board and moves down within that range, the previous stroke and the current actual stroke have almost no error, so the previous stroke is Even if the pen is set down and pen-down is performed, problems such as pen splashing do not occur. However, when the writing implement is raised and makes a large movement in the horizontal direction with respect to the drawing board, and then goes down, the actual stroke is largely changed by the warp of the drawing board compared to the previous stroke. Therefore, in this case, when the previous stroke is set and the writing implement is controlled to descend, the writing implement cannot be softly landed on the drawing screen, causing a problem of pen stroke. Further, when the writing implement is replaced, the stroke must be measured again because the size S of the writing implement is different. Therefore, pen landing occurs when the writing implement can be reliably soft-landed on the drawing screen only when the pen-up movement distance is short after pen-down once. In order to remove the disturbance of the line due to pen pen,
It is only necessary to take a long time to activate the motor that moves the drawing head in the XY direction after the pen is moved down, that is, a long waiting time, and move the pen in the drawing direction after the pen is stabilized on the drawing screen. Deteriorate. This waiting time will be described below with reference to FIGS. 21 to 23.

If any stroke is smaller than the actual stroke,
Writing implement 2 with pen-down signal corresponding to any stroke
As shown in FIG. 21b, the descending speed of the writing implement 2 becomes zero at the point P1, and the pen pressure current 4c (see FIG. 20) is supplied to the moving coil after this point P1. If the motor is started immediately after the writing pressure is applied to the writing implement 2, the head is driven with the tip of the writing implement 2 not landing on the drawing screen 6, as shown in FIG. The beginning cannot be written, and the line becomes dotted due to pen strokes. To prevent the drawing state of the writing implement 2 from being disturbed at the start of writing, the waiting time T (T1 +
T2) may be lengthened, but when an arbitrary stroke matches the actual stroke as shown in FIG. 21a, the waiting time is too long, and the drawing line is written as shown in FIG. 23a. The ink bleeds at the beginning. In addition, the waiting time needs to be set under the worst condition (the state with the most pen splashes) in order to eliminate the jump of the drawing line.
Therefore, the number of pen up / down operations per unit time is reduced, and the drawing efficiency is deteriorated.

In order to eliminate the above drawbacks, set the flatness of the drawing board to zero,
It is only necessary to accurately determine the parallelism between the drawing plate and the rail that guides the head, but the material and assembly labor become very expensive,
The board warps due to aging, causing problems in the market.

An object of the present invention is to solve the above problems.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, a moving coil is provided on a drawing head that can be controlled to move in the horizontal direction with respect to the drawing surface so as to be movable in a direction substantially perpendicular to the drawing surface, and the moving coil is controlled by a controller. A writing instrument connected to the moving coil by controlling the current to the lowering control from the ascending position in a direction substantially perpendicular to the drawing surface,
In an automatic image forming apparatus provided with a sensor for converting a position of the writing implement in a direction perpendicular to the drawing board surface into an electric signal, the moving range of the drawing head of the drawing board is divided into a plurality of areas. In the area, measure the distance between the screen and the tip of the reference tool in the up state in advance,
The stroke data is stored in the storage device for each area, and at the time of drawing, the distance from the set rising position of the selected writing tool tip to the drawing screen is measured, and the difference between the distance data and the stroke data of the area at the writing tool falling position is calculated. A correction value for correcting the dimensions of the writing implement and the paper thickness selected based on the writing implement is created for each writing implement, and the stroke data dedicated to the writing implement selected based on the correction value and the stroke data of each area is provided for each area. , A moving coil control signal optimal for the stroke is set based on the calculated stroke data, and the moving coil is controlled by the control signal.

[Action]

In the above configuration, at the time of drawing, the vertical stroke with respect to the drawing screen of the writing instrument is
It varies depending on the position of the writing implement on the drawing board due to the warpage or unevenness of the drawing board, and varies depending on the size of the selected writing implement and the thickness of the paper. If an accurate stroke can be known in advance, the writing implement can be lowered at a high speed and landed on the screen with the speed reduced to zero. Therefore, the drawing board is divided into a plurality of areas, and the stroke of the reference writing instrument in each area is measured in advance and stored for each area. As a result, almost accurate stroke data can be obtained without being affected by warpage or unevenness of the drawing board. Next, the stroke in an arbitrary area is measured using the writing implement actually used, and the difference between this stroke and the reference stroke stored in this area is measured, so that the dimensional accuracy of the writing implement to be used and the paper A correction value for correcting a stroke error due to thickness can be calculated. The above correction value is specific to the writing instrument used,
This correction value is registered in correspondence with the writing instrument, and when using the writing instrument, unless the paper is changed, the corresponding registered correction value is used, and the reference stroke of the area where the writing instrument is located by the correction value is used. By performing the correction, an almost accurate stroke can be obtained.

Of course, the correction value may be a value obtained by adding or subtracting another element. During drawing, when the writing implement moves to an arbitrary position on the drawing board in pen-up state due to the movement of the head, the controller is suitable for the stroke corresponding to the area of the drawing board where the corrected writing implement is located, based on the correction value specific to the writing implement. Set the moving coil control signal. When the moving coil is energized by the control signal, the writing implement softly lands on the screen with almost no pen splash.

〔Example〕

Hereinafter, the configuration of the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

First, an outline of an automatic drafting machine will be described with reference to FIGS. 9 to 10.

Reference numeral 10 denotes a Y supported on the drawing board 12 so as to be movable in the X coordinate axis direction.
A rail is movably connected to a Y cursor (not shown), and a drawing head 14 is connected to the Y cursor. A plurality of writing tools 2 are detachably held in each holding portion of a writing tool stocker 18 provided in the main body 16 of the automatic drawing apparatus. The substrate 20 of the head 14 includes an elevating member 22
Are supported along the guide shafts 24 and 26 so as to be able to move up and down.
The elevating member 22 is provided with a writing instrument holder 28. A shaft member 31 slidably fitted in the coil holder 30 is slidably fitted in the bearing member 23 fixed to the elevating member 22. The disc-shaped portion 31a of the shaft body 31 elastically contacts the lower surface of the horizontal wall of the holder 30 by the elastic force of the coil spring 33, and the holder 30 is in close contact with the lower surface of the member 23 by the elastic contact force. A moving coil 32 is fixed to the coil holder 30 attached to the elevating member 22, and the moving coil 32 faces a field constituting portion 34 provided on the substrate 20. When the moving coil 32 is in the non-excited state, the elevating member 22 is configured to rise by the elastic force of the return spring 36 until the upper end thereof is locked by the upper limit stopper 38 fixed to the substrate 20. .
Numeral 40 denotes a position sensor, which includes a light source 42 composed of an infrared LED, a light receiving element 44 composed of a phototransistor, and a shielding plate 46, and the shielding plate 46 is fixed to the elevating member 22. The light receiving element 44 constitutes a part of the position-voltage converter 48 built in the casing of the position sensor 40. When the X motor 50 is driven, the Y rail 10 translates in the X coordinate direction along the drawing board 12, and the drawing head 14
When the Y motor 52 is driven, it moves along the Y rail 10. The XY motors 50 and 52
As shown in the figure, it is connected to a central processing unit (CPU) 58 via XY motor drivers 54 and 56. The moving coil 32 is connected to the CPU 58 via a pen-up / down driver 58 and a digital / analog converter 60,
The output terminal of the position-voltage converter 48 is connected to a CPU 58 via an analog / digital converter 62. A normal drawing program is stored in a ROM (read only memory) 64, and a drawing data storage program is stored in the ROM 66. In FIG. 18, 68 is a RAM (random access memory) and 70 is an EEPROM (electrically readable / writable).
ROM), 72 is a panel operation unit, and 74 is an input / output device. The automatic drafting machine has a writing tool automatic exchange function. CP
The XY motors 50 and 52 are driven by the control of U58, and the head 14 is positioned in front of the writing implement 2 of the NO.1 holding unit in FIG. 9 among a plurality of writing implements of the writing implement stocker 18, for example, From this position, the head 14 is moved in a linear direction until the holder 28 is fitted to the writing implement of the NO. 1 holding part on the stocker 18 side. When the writing implement holder 28 of the head 14 reaches the writing implement 2 of the NO.1 holding part and is fitted with the writing implement, the writing implement 2 held by the NO.1 holding part of the writing implement stocker 18 becomes:
It is held by both the holder of the writing implement stocker 18 NO.1 holding section and the writing implement holder 28 of the head 14.

Next, when the head 14 is moved linearly in a direction away from the stocker 18 to a predetermined position, the writing implement 2 of the NO.1 holding portion of the stocker 18 is detached from the holder of the NO.1 holding portion of the stocker 18, The writing implement 2 is held only by the writing implement holder 28 of the head 14, as shown in FIG. In this state, the flange 2a of the writing instrument 2 is fitted into the groove 28a of the holder 28, and the vertical movement of the writing instrument 2 with respect to the holder 28 is prevented. The movement in the direction perpendicular to the direction is prevented by the holding force of the moving arm 76 that forms a part of the holder 28.

 Next, the raising and lowering operation of the writing implement will be described.

10 and 18, when the pen-up / down driver 58 outputs a positive current to the moving coil 32 according to a command from the CPU 58, a downward force acts on the moving coil 32, and the lifting member 22 resists the elasticity of the spring 36. And descend.
When a negative current is supplied to the moving coil 32 from the pen up / down driver 58, the moving coil 32
, An electromagnetic force acts in the ascending direction.

In FIG. 11, when the elevating member 22 is moved up and down with respect to the surface of the drawing plate 12 by the actuator 78 composed of the moving coil 32 and the field constituting portion 34, the shielding plate 46 is moved up and down,
The amount of light applied to 44 changes. The amount of light applied to the light receiving element 44 is output as a voltage signal from an output line 80 of the position-voltage converter 48 shown in FIG. This voltage signal is
The signal is converted into a digital signal by the converter 62 shown in FIG. The CPU 58 recognizes the vertical position of the elevating member 22, that is, the writing implement 2 with respect to the drawing board 12 based on the digital signal from the converter 62. The above position-
The voltage characteristics of the voltage converter 48 with respect to the amount of light and the position of the writing implement are shown in FIG.

The position of the writing implement 2 held by the writing implement holder 28 can also be detected using a magnetic sensor. FIG. 15 shows the principle diagram. An actuator 78 composed of a moving coil and a field component is connected to an elevating member 22 supported on the head substrate so as to be able to move up and down.
The writing tool 2 is held on the writing tool holder 22 via a writing tool holder (not shown), and a magnet 82 is fixed to the other end of the elevating member 22. Below the magnet 82, a magnetic sensor 84 arranged on the head substrate is arranged. The magnetic sensor 84 is constituted by a Hall element, and the Hall element 84 is used as a constituent element to constitute a position-voltage converter 86 as shown in FIG. The change in the strength of the magnetic field on the magnetic sensor 84 due to the vertical movement of the elevating member 22 is output from the output terminal 88 as a change in the voltage signal as shown in FIG. This output voltage is converted into a digital amount by an A / D converter and supplied to a CPU 58 shown in FIG. 18, and the CPU 58 recognizes the position of the writing implement 2 held by the writing implement holder 28 based on the digital signal. Can be.

 Next, the drawing data storage program will be described.

First, an outline of the program will be described. As shown in FIG. 19, the drawing range of the drawing board 12 is divided into n equal parts, and each area is defined as a ₁ to an.

As another type of automatic drafting machine, there is known an automatic drafting machine in which a Y rail is fixed and a sheet is fed on a platen in the X coordinate direction by a pinch roller mechanism. In this apparatus, the drawing head linearly moves on the platen (drawing board) only in the Y coordinate axis direction along the Y rail. Therefore, in this type of automatic drafting machine, the drawing plate may be divided into n equal parts only in the Y direction.

Prior to the drafting operation in drawing head 14, at the time of shipment of the automatic drafting machine, writing instruments stroke of each position of the area a ₁ .about.An i.e.,
The tip of the writing implement 2 descends from the set ascending position, and a ₁
The distance from the an to the reference paper surface on the drawing board 12 is measured by pen-down to the center of each area in the order of each area a ₁ , a ₂ , a _3. Then, the writing instrument stroke data is stored in the RAM 68 shown in FIG.
To memorize.

Next, the data is written to the EEPROM 70. CPU 58, drawing board 1
By being able to recognize the flatness of 2, the stroke data of the writing implement at the position where the writing implement is lowered can be recognized by recognizing the coordinate position of the writing implement. The CPU 58 supports the recognized stroke data.
A writing implement lowering control signal is selected or created, and this signal is output to the D / A converter 60 in FIG.
2 is controlled to lower the writing implement 2.

Since the stroke data is created using a reference pen and a standard type of paper, in actual drawing, there are cases where the dimensions of the writing implement used and the thickness of the paper are different from those of the reference pen and the standard type of paper. . In this case, the stroke data created using the reference pen and the standard type paper is corrected. The greater the number n of equal divisions, the more accurately the flatness of the drawing board can be known. However, since the processing time of the CPU 58 increases, n is increased to such an extent that the drawing speed is not affected. From a different point of view, even a drawing plate having a rough flatness can be regarded as having a good flatness when viewed in each unit by dividing the drawing into a plurality of areas, which leads to cost reduction. For example, as shown in FIG.
Even for a 0.5 mm drawing board, the X direction is divided into ten equal parts, resulting in a flatness of about 0.1 mm per unit.

Next, the above operation will be described in detail with reference to the flowchart shown in FIG.

When the power switch or the reset switch of the operation panel is turned on (block 90), the controller 92 shown in FIG. 18 is initialized (block 94).

Next, the CPU 58 determines whether or not the drawing data is stored in the EEPROM 70 in a determination block 96. If NO, the drawing data storage program is executed in the following manner.

First, the CPU 58 drives the Y motor 52 to move the Y rail 10
The head 14 is moved in the X coordinate axis direction until it comes into contact with the X origin limit switch, and the X motor 50 is driven to move the Y cursor along the Y rail 10 in the + Y coordinate axis direction until it comes into contact with the Y origin limit switch. XY on Diagram 12
Move to origin. Pulse encoders 98 and 100 are connected to the rotation axes of the XY motors 50 and 52, and when the drawing head 14 is moved by driving the XY motors 50 and 52, the pulse encoders 98 and 100 are moved.
Outputs a pulse, and the pulse is supplied to the CPU 58, and the CPU 58
Counts these XY pulses, and recognizes the position of the head 14 on the drawing board 12 based on the count value.
When the Y rail 10 and the Y cursor have been moved to the XY origin, the CPU 58 in FIG. 5 resets the value of the counter to zero, and matches the position of the head 14 with the count value of the counter (block 102). . Next, CPU58
Determines whether the writing implement is placed in the No. 1 holding unit of the writing implement stocker 18 (decision block 104). This determination is made by determining whether or not the writing tool detection switch of the NO. 1 holding unit among the writing tool detection switches provided for each holding unit of the stocker 18 is ON.

Next, the CPU 58 drives the drawing head 14 to get the writing implement of the NO.1 holding unit, and the NO.1
The writing implement 2 of the holding unit is held (block 106).

Next, the CPU 58 sets a variable n of the drawing area number counter to 1 (block 108). The variable n is a number indicating the order of each area a of the drawing board subdivided into 30. Then CPU58
Drives the XY motor 50 and 52, among the subdivided areas in FIG plate 12, to move the drawing head 14 to the center position of an namely a ₁ (block 110).

Next, the CPU 58 supplies a writing implement lowering control current to the moving coil 32, lowers the writing implement 2, and lands its tip on the paper forming screen on the drawing board 12 (block 112).
When the writing implement 2 lands on the drawing screen and a predetermined minute time elapses (block 114), and when the writing implement 2 stops on the drawing screen, the writing implement 2 is moved from a previously set ascending position to reach the drawing screen. Is read by the output of the position sensor 40 (block 116), and this stroke data is written to the EEPROM 70 (block 11).
8). Next, in FIG. 6, the CPU 58 is
Ascend to the preset ascent position (block 12
0). Next, the CPU 58 determines whether n = 30 (block 12).
2) If NO, add 1 to the value of n, and n = n + 1
(Block 124), and then returns to block 110 in FIG. 5 to repeat the above-described operation. When n = 30, the CPU 58 writes the writing implement 2 held by the drawing head 14.
Is returned to the No. 1 holding unit of the writing instrument stocker 18 (block 126). Next, the process proceeds to the decision block 128 in FIG. The above operation is a method of moving the writing implement up and down for each area of the drawing board 12 and storing the drawing board data in the EEPROM each time, but moving the writing implement with the writing implement lowered on the drawing board, and moving the drawing board data to the EEPROM. You may write it. The method will be described below. In FIG. 7, first, the drawing head 14
Is moved to the XY origin, and the CPU 58 recognizes that the drawing head 14 has moved to the XY origin (block 130). Next, it is determined whether or not there is a writing implement in the NO.1 holding section of the writing implement stocker 18 (decision block 132). If YES, the drawing head 14 takes out the writing implement of the NO.1 holding section under the control of the CPU 58. The holder 28 of the drawing head 14 holds the writing implement (block 134).

Next, the CPU 58 places the drawing head 14 in the subdivision area of the drawing board 12, a
The area is moved to the center position of the area ₁ (block 136). Next, the writing implement holder 28 is lowered, and the writing implement is moved to the area of the drawing board.
to land on the center point of a ₁ (block 138). When a predetermined minute waiting time has elapsed (block 140), the variable n
Is set to 2 (block 142), and the CPU 58 sets a ₁
Reads writing instrument strokes at (block 144) E
Write to EPROM 70 (block 146). Next, the CPU58 the Figure 8, n = 30 + 1 if it is determined whether (decision block 148), if NO, the drawing in a state in which lowering the writing instrument to the center point of the center point or a ₂ area an The head 14 is moved (block 150), and then n = n + 1 is set (block 152). Next, returning to block 144 in FIG. 7, the above operation is repeated. When n = 30 + 1 (block 148), the writing implement is raised (block 1).
54) Then, the drawing head 14 is moved to the No. 1 holding section of the writing implement stocker 18, and the writing implement of the drawing head 14 is returned to the No. 1 holding section (block 156). By the above operation, EEP
The ROM 70 stores, at the midpoint of each area an of the subdivided drawing board 12, the movement amount required until the writing tool 2 of No. 1 held by the drawing head 14 lands from the rising position to the drawing screen ( Stroke data) is written in order for each area. This writing operation is performed at the factory when the automatic drafting machine is shipped.

However, after storing the drawing data, the drawing may be warped or twisted due to a change in climatic conditions or a change in temperature during transportation, etc., during transportation of the automatic drafting machine and at a storage location. In that case, the drawing board is different from the drawing board shape at the time of shipment, so that the data written in the EEPROM 70 becomes inaccurate. Therefore, when drawing at the user's site, pen splash may occur. In the event that a pen stroke occurs, the pen stroke data can be easily re-input on site by the following method. When re-inputting at the site, the operator turns on the power switch while pressing the designation key on the operation panel 72 in FIG. 7 (block 90 '). When the power is turned on, the controller is initialized. Then, it is determined whether or not the designation key is pressed, that is, whether or not the drawing data is stored (decision blocks 158 and 15).
8 '), if YES, proceed to the block 102 or 130 in the flowchart shown in FIG. 5 or 7 above, where new drawing data considering the thickness of the paper actually used is stored in the EEPROM.
Written to 70. After the new drawing data is written into the EEPROM 70, or when the CPU 58 determines in the decision block 158 of FIG. 1 that there is no need to re-input the drawing data, the CPU 58 moves the drawing head 14 to the XY origin. (Block 160). Next, the CPU 58 determines whether or not the drawing data has been input from the host computer to the RAM 68 of the controller via the input / output device 74 (block 12).
8) If YES, then it is determined at decision block 162 whether the paper has been replaced, and if NO, the drawing head 14 is the writing implement stocker 18 designated by the host computer.
Go to get one of the writing implements 2 and hold it. If YES is determined in the decision block 162, the correction values F1 to F8 of the writing implement are set to zero (block 164). That is, the writing instrument 2 corresponding to the writing instrument holder NO.1~NO.8 of the writing instrument stocker 18, P ₁ writing instrument numbers in numerical order of the writing instrument holding portion as shown in FIG. 32, P _2, P ₃ , P ₄ ... Px, a table is set in the RAM 68, and the writing implement numbers P ₁ , P
₂ , P ₃ , P ₄ ... Px include correction values R ₁ , R ₂ , R ₃ , R ₄ described below.
... Rx correspond to the flags F ₁ , F ₂ , F ₃ , F ₄ ... Fx.
The flag Fx is set to “1” when the writing of the correction value of the corresponding writing implement Px has been completed, and is set to “0” when the correction value has not been written yet. Following block 164, the process returns to decision block 128. If the decision block 162 determines NO, the drawing head 14 goes to pick up the designated writing implement (block 166). Next, based on the drawing data, the CPU 58 calculates to which area (an) on the drawing board 12 the position where the writing implement is lowered (block 168). Next, the CPU 58 moves the drawing head 14 to the drawing position, and lowers the writing implement at that position (block 170). At this stage, the stroke of the writing implement is set to an arbitrary length based on the stroke data of the drawing board area an to which the writing implement belongs, because the precise stroke of the writing implement is not yet known in consideration of the dimensions of the writing implement and the thickness of the paper. Then, the CPU 58 lowers the writing implement 2 of the drawing head 14 (block 170). When a predetermined waiting time T has elapsed since the start of the descent (block 172), the CPU 58
Reads the actual lowering stroke la'n of the writing implement 2 (block 174). Here, the waiting time T will be described.

When the writing implement is lowered for the first time, the accuracy of the writing implement being held, that is, the accurate distance S between the lower surface of the flange 2a of the writing implement 2 and its tip, as shown in FIG. Since it is not known, the distance (stroke data) between the lower end of the writing implement 2 and the paper surface when the writing implement 2 is lifted is not known. Therefore, the CPU 58 sets the writing implement descending stroke arbitrarily and causes the pen to go down, so that a pen splash occurs, and it takes time from when the writing implement lands on the paper to when the writing implement is stabilized. The time from when the writing implement 2 starts pen-down until the writing implement 2 stabilizes on the paper is referred to as a waiting time T.

If la is a descending stroke of the writing instrument and l is an actual descending stroke, if la <l, the writing instrument
As shown in FIG. 21, the downward movement is performed, and the pen pressure is applied at the point P1.

In the case of la> l, as shown in FIG. 21C, the writing implement 2 collides with the sheet surface at the point P2 while the deceleration current signal is supplied to the moving coil, so that the pen splash becomes large.

In FIG. 1, after the CPU 58 has read the stroke la'n (block 174), the CPU 58 reads the writing implement 2 of the EEPROM 70.
The reference stroke data lan at the midpoint of the area an of the drawing plate 12 where is located is read (block 176).

Next, the CPU 58 calculates a correction value Rx of the writing implement Px (block 1).
78). The Rx is a correction value in consideration of the thickness of the precision and the sheet of the writing instrument Px, can be determined by _{Rx = la'n-lan- (l 1} + l 2). Wherein l ₁ is as shown in FIG. 25, 'a step distance between the highest point of the region an, l ₂ is the midpoint an' midpoint an area an in FIG plate 12 most and This is the step distance from the lower point. In each of the equally divided regions an of the drawing plate 12, there is a height difference as shown in FIG. However, the stroke data written in each area an is the distance lan between the lower end of the pen-up reference pen at the midpoint an 'and the reference paper surface on the drawing board 12. Therefore, even when the accuracy of the writing implement and the thickness of the paper are the same, when the writing implement is pen-downed to a position lower than the middle point, the actual stroke d'la'1 of the writing implement is lowered.
Becomes la′1 = lan + l ₂ . In this case, FIG. 21 (b)
As shown in (1), in the downward movement of the writing implement, writing pressure is applied before the lower end of the writing implement reaches the paper surface, and the pen pressure is relatively small by this writing pressure. If the writing implement is controlled to descend based on the accurate descending stroke data, the writing implement can be landed on the sheet surface when the descending speed of the writing implement becomes exactly zero by the deceleration signal as shown in FIG. 21 (a). However, the actual stroke, at the lowest point in FIG plate region, the l ₂ longer than the write stroke data, correspondingly, an error occurs in the actual stroke data, controls the descent of the writing instrument by written stroke data lan If it does, some pen splashes will occur. Conversely, if the pen is lowered to the highest point,
2 = lan−l ₁ , which is shorter than the stroke data lan based on the midpoint an ′. This is shown in FIG.
As shown in (2), when a reverse voltage is applied to the moving coil 32, that is, an upward force acts on the writing implement, the lower end of the writing implement collides with the paper surface during deceleration, and pen repelling is promoted by the reverse voltage. The pen stroke becomes quite large, and it takes a considerable time for the writing implement 2 to stabilize on the paper surface. For this reason, when the writing implement descends, it is desirable that the correction stroke data of the corresponding drawing board area is always shorter than the actual stroke of the writing implement.

In FIG. 25, the stroke data 1 when the writing implement is lowered in the actual drawing is 1 = lan + correction value Rx '. In actual drawing, l
Since the writing instrument and the paper are different from those when an is measured, it is necessary to consider the accuracy of the writing instrument and the error data Rx 'of the thickness of the paper. The error data Rx 'is related to the accuracy of the writing implement and the thickness of the paper, and its correct value is Rx' = la when the actual stroke amount at the middle point an 'of the drawing area an is la'3. '3-lan.

The initial pen-down position for obtaining the correction value Rx is not necessarily the midpoint of the selected drawing area. Usually, the starting point of the drawing for determining the first pen down is a case other than the middle point of the selected drawing area.

Now, illustrated in FIG. 25, when the lowest place of H ₂ FIG plate area an a drawing starting point, CPU 58 has determined that recognizes the actual stroke la'1 of the writing instrument in block 174 of FIG. 1 . As apparent from FIG. 25, a la'1 = lan + Rx '+ l 2 now la'1-lan = Rx' + l 2.

If it is assumed that all write stroke data lan is corrected by using la′1-lan as a correction value Rx, the area an
Is the same length as lan + Rx, that is, la'1.

Now, the writing implement is positioned on the area an, and the writing implement control pattern 4 (see FIG. 20) is selected based on the corrected stroke data. With this pattern, the writing implement is lowered at the highest position of the drawing board area an. When, because the control pattern 4 is writing instrument 2 in FIG. 25, the lowering speed is set to be zero at the level H _3, writing instrument 2, moving coil
When the deceleration signal 4b is supplied to the sheet 32, the sheet lands on the drawing board. Level in Fig. 25
In order to select the control pattern 4 at which the descending speed of the writing implement 2 becomes zero at H1, it is necessary to select a writing implement control pattern corresponding to the descending stroke la'2 at the highest part of the area an as a reference. . This descending stroke
la′2 is obtained by subtracting the value of (l ₁ + l ₂ ) from this value without setting the correction value Rx to la′1-lan. In other words, the correction value _{Rx = la'n-lan- (l 1} +
l ₂ ), by correcting the stroke data of each area with the correction value Rx, it is possible to cover the change in the stroke of the writing implement in the actual drawing due to the accuracy of the writing implement and the thickness of the drawing, and to reduce the writing implement in the deceleration area. Can be prevented from landing on the screen and largely bouncing. The stroke error between high and low in each area is (l ₁ +
l ₂ ) However, since the length is very small, the pen stroke caused by this is extremely small, and the time required for the writing implement to stabilize on the drawing screen is extremely short. If the distance traveled after pen-up is short, the next pen-down is performed based on the stroke data at pen-up. In this case, the value of (l ₁ + l ₂ ) is subtracted from the stroke 1 at pen-up. Acceleration / deceleration control is performed with the writing tool control pattern corresponding to the value. It should be noted that l ₁ and l ₂ are determined by experiments and measured values from the size of the equally divided area and the finish of the drawing board. l ₁ and l ₂ may be common to all regions or may be set for each region.

The above description is summarized as follows.

In the case of controlling the writing implement, it is necessary to land on the drawing board during deceleration, so that control must be performed based on stroke data at a high place in a subdivided area of the drawing board. Assuming that the equally divided area is as shown in Fig. 25, the creation of correction values for writing instrument accuracy and paper thickness is performed with the first pen down, but the place where the pen is down is the lower part of the area. If you reference pen stroke data by, since with respect to the midpoint of the region, the correction value calculated by the stroke amount of the first pen-down error of l ₂ occurs. Further, when the pen-down at high area error of l ₁ occurs in the correction value based on the stroke amount. For writing instrument is prevented from landing on the paper on FIG plate during deceleration of the pen-down, the correction value (Rx) = la'n- (lan + l 1 + l 2) la'n: Actual writing instrument downward stroke data lan: It must be the writing implement descent stroke data using the reference pen.

Explaining with the example of FIG. 26, the stroke with the reference pen is 1.
Assuming that 0 mm, l ₁ and l ₂ are each 0.05 mm, the writing implement used for drawing is 0.2 mm shorter than the reference pen, and the thickness of the paper on the drawing board is the same as when measuring the stroke with the reference pen, The writing implement lowering stroke 1 at each point is as follows: middle point l = 1.2 mm Q point l = 1.25 mm P point l = 1.15 mm

When performing the correction, if the pen is down at Q point, to prevent the writing implement from landing on the paper on the drawing board 12 while the pen down is decelerating at the Q point, the middle point, and the P point, set the descending stroke data of the writing implement to 1.15 mm. Must be set. Therefore, the correction value Rx is 1.15 mm. That, Rx = la'n- (lan + l 1 + l 2) = 1.25- (1 + 0.05 + 0.05) = 0.15 (mm) If you pen-down point P, but it is sufficient to recognize the writing instrument downward stroke at the point P Since it is not possible to recognize whether the pen-down position is high or low in the area, the correction value Rx is determined by the above equation, and Rx = 1.15− (1 + 1.05 + 0.05) = 0.05 [mm] .

Pen down at point P to correct the writing instrument dimensions,
When the pen is lowered at point Q based on the correction value, the result is as shown in FIG. Since the writing implement descending stroke at the point Q is 1.25 mm, the maximum error L is (l ₁ + l ₂ ) × 2, which is 0.2 mm.

FIG. 28 shows a case where the pen is lowered at the point Q to perform dimensional correction of the writing implement, and the pen is lowered at the points Q and P based on the correction value.

At point Q, the maximum error L is 0.1 mm, and at point P, the maximum error L is zero.

Next, the description returns to the flowchart of FIG. In block 180, the CPU 58 stores the correction value Rx in the RAM 68. A table shown in FIG. 32 is set in the RAM 68, the correction value Rx is set in the correction value area corresponding to the number Px of the writing implement 2, and the flag Fx corresponding to the number Px of the writing implement 2 is set to "1". Set to. Thus, with respect to the writing instrument 2 numbers Px example P _1, indicating that the size correction (including the correction of the thickness of the paper used) has been completed. Next, CPU58
Starts the XY motors 50 and 52, draws a line on the paper on the drawing board 12 (block 182), and stops the XY motors 50 and 52 when one-step drawing is completed (block 184). Here, the CPU 58 reads the distance (stroke 1) from the rising position of the tip of the writing implement 2 to the screen based on the output of the position sensor 40 (block 186). Next, the writing implement 2 is raised by the stroke 1 (block 188). Next, the CPU 58 determines whether or not to print (decision block 190). If NO, the CPU 58 returns to the decision block 128, and if YES, decides whether or not to replace the pen (decision block 192). If YES, the CPU 58 sets the drawing head 1
The writing implement 2 of No. 4 is returned to the holding unit of the predetermined number of the writing implement stocker 18 (block 194).
Goes to the designated number of holding units of the writing implement stocker 18 (block 196). Then CPU58
It is determined whether the writing implement held by the drawing head 14 has been corrected, that is, whether the flag Fx corresponding to the writing implement in the RAM 68 is "1" or "0" (decision block 198), and NO, that is, " If "0", the process returns to block 168. If YES, in a block 200 in FIG. 4, the CPU 58 calculates an area an for pen-down, and moves the drawing head 14 to the drawing position. Next, the CPU 58 reads the stroke data lan of the EEPROM 70 corresponding to the area an (block 202). Next, CPU58
Represents the correction value Rx of the writing implement 2 held by the drawing head 14 in the RAM 68.
(Block 204). Next, the CPU 58 calculates the downward stroke 1 of the writing instrument (l = lan + Rx) (block 206). Next, the CPU 58. Performs descent of the writing instrument 2 stroke l (block 208), counts the time from the falling start point, the waiting time T ₃ after (Block 21
0), start the XY motors 50 and 52 and perform drawing (block
212). Waiting time T ₃ is set in consideration of the slight Penhane when writing instrument has landed on the drawing surface, the time to wait for writing instrument to stabilize at drawing surface. The waiting time T ₃ is the waiting time T downward stroke data in unknown state
It is set shorter than The T ₃ are those obtained from similar experiments and the T. Next, the CPU 58 stops the XY motors 50 and 52 (block 214), and reads the descending amount, that is, the stroke 1 from the set up position of the writing implement (block 21).
6). Next, the CPU 58 makes the pen rise with the stroke 1 (block 218), and returns to the decision block 190 shown in FIG. If NO is determined in the determination block 192 of FIG.
Determines whether the moving distance of the writing implement 2 along the drawing board 12 in the XY coordinate axis direction is equal to or less than m in the next drawing (decision block 220). As shown in FIG. 19, m is the length of the short side of the area an equally dividing the image forming range. Decision block 220
If NO is determined, the flow shifts to block 200 in FIG.
When the decision block 220 decides YES, the CPU 58 activates the XY motors 50 and 52 as shown in FIG. 3 (block 222).
The drawing head 14 is moved to the drawing position and stopped there (block 224). Next, the CPU 58 proceeds to the block 186
The stroke data l 'is calculated based on the stroke l read in step (1). l 'is, l' = determined with _{l- (l 1 + l 2)} , CPU58 causes the pen-down in the stroke data l '(block 226). The stroke data l ′ is changed to l− (l
_The reason why ₁ + l ₂ ) is that the writing implement does not land on the screen while the pen down is decelerating even if the stroke changes due to the warpage of the drawing board 12. From pen-down starting point where the waiting time T ₃ has elapsed (block 22
8) The XY motors 50 and 52 are started (block 230), and after the predetermined drawing is performed, the XY motors 50 and 52 are stopped (block 232). Next, the CPU 58 reads the stroke 1 (block 232), and performs a pen-up operation at the stroke 1 (block 236). Next, the process returns to the decision block 190 in FIG.

Next, a description will be given of an embodiment for further reducing pen strokes during pen down.

As shown in FIG. 30, in the present embodiment, the coil control current 4
The writing implement 2 lands on the screen 6 when the writing pressure current 4c is supplied to the moving coil. Therefore, when the writing implement 2 lands a little on the screen, it flies slightly. In order to reduce the splash, as shown in FIG.
Then, a portion 4d where the pen pressure current 4c gradually increases is formed. When the coil control current is configured in this manner, the writing implement 2 lands at the point A of the pen pressure current portion 4d when the pen is down. The bounce at this time is that the writing implement 2 has a repulsive force against the screen 6.
Assuming that Fa and pen pressure are Fb, the smaller the value of Fa−Fb, the smaller the value. Therefore, at the point A, the writing pressure Fa is applied to the writing implement 2, but immediately thereafter the writing pressure larger than the force is gradually applied, whereby Fa-Fb becomes smaller than when a constant writing pressure is applied, The bounce of the writing implement 2, that is, pen stroke, is reduced. Further, in FIG. 10, when the writing implement 2 is processed and its pen tip collides with the screen, the writing implement 2 attempts to bounce upward due to the impact.
Is still driven in the descending direction by the voltage current flowing through the moving coil 32, the shaft body 31 descends relatively to the tubular portion of the bearing member 23, and the adhesion between the holder 30 and the horizontal surface of the bearing member 23 Depart from each other. The spring 33 is compressed by the lowering of the shaft body 31, and this compressive force acts on the elevating member 22 as a descending force. This descending force exactly coincides with the ascending force of the writing instrument 2 that is about to bounce with respect to the screen, and the ascent force of the bounce of the writing instrument 2 is almost offset by the descending force of the deflection of the spring 33. Is blocked.

〔effect〕

As described above, the present invention measures the stroke of the writing implement at that position for each subdivided area on the drawing board,
Because the moving coil control signal suitable for this stroke is set, the drawing is not affected by the unevenness of the drawing board, the pen stroke of the writing implement can be reduced, the protection of the pen tip, the reduction of the sound of the writing implement up and down, It is possible to increase the speed of writing implement up / down and shorten the drawing time. Further, since high precision is not required for the flatness of the drawing board, there is an effect that the drawing board can be manufactured at low cost.

[Brief description of the drawings]

1 is a flowchart, FIG. 2 is a flowchart, FIG. 3 is a flowchart, FIG. 4 is a flowchart, FIG.
The figure is a flowchart, FIG. 6 is a flowchart, FIG. 7 is a flowchart, FIG. 8 is a flowchart, FIG. 9 is an overall plan view of an automatic image forming apparatus, FIG. 10 is a sectional view of a drawing head, and FIG. , FIG. 12 is an explanatory diagram, FIG. 13 is a circuit diagram, FIG. 14 is an explanatory diagram, FIG. 15 is an explanatory diagram, FIG. 16 is a circuit diagram, FIG. 17 is an explanatory diagram, FIG. 18 is a block circuit diagram , FIG. 19 is an explanatory diagram, FIG. 20 is an explanatory diagram, FIG. 21 is an explanatory diagram, FIG. 22 is an explanatory diagram, FIG. 23 is an explanatory diagram, FIG. 24 is an explanatory diagram, FIG. 26 is an explanatory diagram, FIG. 27 is an explanatory diagram, FIG. 28 is an explanatory diagram, FIG. 29 is an explanatory diagram, FIG. 30 is an explanatory diagram, FIG. 31 is an explanatory diagram, and FIG. 32 is an explanatory diagram. . 2 Writing instrument, 6 Drawing screen, 10 Y-rail, 12 Drawing board, 14 Drawing head, 16 Automatic picture device body, 18
Writing instrument stocker, 20 ... board, 22 ... elevating member, 23 ...
Bearing member, 24, 26 …… Guide shaft, 28 …… Writing tool holder, 30
... Coil holder, 31 ... Shaft, 32 ... Moving coil, 33 ... Coil spring, 34 ... Field constituent part, 36 ... Return spring, 38 ... Stopper, 40 ... Position sensor, 42 ... … Light source, 44
…… Light receiving element, 46 …… Shield plate

Claims (2)

(57) [Claims] A moving coil is provided on a drawing head which can be controlled to move in the horizontal direction with respect to the drawing surface so as to be movable in a direction substantially perpendicular to the drawing surface, and a controller controls a current to the moving coil. Then, the writing implement connected to the moving coil is controlled to descend from a rising position in a direction substantially perpendicular to the drawing surface, and the drawing head converts the position of the writing implement in the direction perpendicular to the drawing surface to an electric signal. In an automatic image forming apparatus provided with a sensor for performing the drawing, the distance between the screen and the tip of the reference tool in the ascending state is measured in advance at an appropriate position within the moving range of the drawing head of the drawing board, and the stroke data is stored in the storage device. When drawing, the distance from the set ascending position of the selected writing implement tip to the drawing screen is measured, and based on the difference between the distance data and the stroke data. A correction value for correcting the dimension of the selected writing implement and paper thickness is created, and the correction value is stored in a storage device of a controller in association with the selected writing implement, and based on the correction value and the stroke data. Calculating the stroke data dedicated to the selected writing implement, setting a moving coil control signal optimal for the stroke based on the stroke data, and controlling the moving coil by the control signal; Control method. 2. A moving coil is provided on a drawing head which can be controlled to move in the horizontal direction with respect to the drawing surface so as to be movable in a direction substantially perpendicular to the drawing surface, and a controller controls a current to the moving coil. Then, the writing implement connected to the moving coil is controlled to descend from a rising position in a direction substantially perpendicular to the drawing surface, and the drawing head converts the position of the writing implement in the direction perpendicular to the drawing surface to an electric signal. In the automatic image forming apparatus provided with a sensor, the moving range of the drawing head of the drawing board is divided into a plurality of areas, and in each area, the distance between the screen and the tip of the reference tool in the ascending state is measured in advance. Then, the stroke data is stored in the storage device for each area, and at the time of drawing, the distance from the set rising position of the tip of the selected writing implement to the drawing screen is measured. A correction value for correcting the size of the writing implement and the sheet thickness selected based on the difference between the stroke data of the area at the writing implement lowering position is created for each writing implement, and the correction value and the stroke data of each area are created. The stroke data dedicated to the writing implement selected based on the calculated stroke data is calculated for each area, a moving coil control signal optimal for the stroke is set based on the calculated stroke data, and the moving coil is controlled by the control signal. A writing implement elevating control method, comprising: