JP2005059540A - Recorder and its controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder capable of detecting a recording head touching the surface of a platen or a recording sheet accurately. <P>SOLUTION: The recorder comprises a mechanism for adjusting the platen gap based on the distance from a recording head 36 to the surface of a platen or a recording sheet detected by moving a carriage shaft 32 for holding a carriage 31 carrying the recording head 36 slidably in the direction of the platen 20 and touching the carriage shaft 32 to the surface of the platen or recording sheet. The carriage shaft 32 is arranged to move in the direction receding from the platen 20 depending on the impact when the recording head 36 touches the surface of the platen or recording sheet, to detect movement of the carriage shaft 32 due to impact, and to calculate the distance from the recording head 36 to the surface of the platen or recording sheet based on the detection results. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recording apparatus having a platen gap adjustment mechanism and a control method therefor.

  In general, a recording apparatus including a platen gap adjusting mechanism that adjusts a platen gap between a recording head and a platen is known (for example, see Patent Document 1). In this platen gap adjustment mechanism, the position of the platen surface is detected by lowering the recording head held slidably on the carriage shaft together with the carriage shaft in a direction substantially perpendicular to the platen via a stepping motor and a gear train. Then, the recording head is raised together with the carriage shaft and then lowered again to detect the position of the recording paper surface, and the paper thickness of the recording paper is calculated based on the difference between them to obtain the optimum platen gap for this paper thickness. adjust.

  In this type, a rotary encoder for detecting the moving speed of the carriage shaft is used to detect the contact position of the recording head on the platen surface or the paper surface. More specifically, when the carriage shaft is moved to the platen side together with the recording head, if the recording head actually contacts the platen surface or the medium surface, the moving speed of the carriage shaft is reduced. Accordingly, when the carriage shaft detects deceleration by the rotary encoder, the position of the platen surface or paper surface can be detected.

By the way, in the recording apparatus provided with the platen gap adjusting mechanism, the carriage is made of resin, and a resin holder is integrally formed on the carriage, and a sintered plastic bush is fitted into the holder, A mechanism (parallelism adjusting mechanism) is known in which a carriage shaft is inserted into the bush and the carriage is reciprocated while being guided by the carriage shaft. In this case, since the carriage is guided by the carriage shaft and moves at a high speed, the above-described bush is firmly fixed by press-fitting, for example, so as not to be easily removed once attached to the holder.
JP-A-5-32003

  However, in the above-described conventional configuration, the recording head on the platen surface or the paper surface is caused by the backlash between the carriage shaft and the bush, or the backlash of the train wheel that transmits the driving force from the stepping motor to the carriage shaft. The abutment cannot be accurately detected, and the detection result varies.

  Specifically, even if the recording head abuts against the platen surface or the paper surface, the carriage shaft continues to move by the amount of play such as a bush, so the timing at which the recording head abuts against the platen surface and the deceleration timing of the carriage shaft The position where the recording head abuts against the platen surface cannot be accurately detected.

  SUMMARY An advantage of some aspects of the invention is that it provides a recording apparatus and a recording apparatus control method capable of accurately detecting contact of a recording head with a platen surface or a recording paper surface. .

  In order to achieve the above object, according to the present invention, a carriage shaft that slidably holds a carriage holding a recording head is moved in the platen direction so that the recording head comes into contact with a platen surface or a recording paper surface. In the recording apparatus including a platen gap adjusting mechanism that detects a distance from the recording head to the platen surface or the recording paper surface and adjusts the platen gap based on the detection result, the carriage shaft includes the recording head. It is configured to be movable in a direction away from the platen in accordance with an impact force when abutting against a platen surface or a recording paper surface, and the impact force causes the carriage shaft to move in a direction away from the platen. By detecting this, contact between the recording head and the platen surface or the recording paper surface is detected, and the detection is performed. And calculates the distance from the recording head to the platen surface or the recording paper based on the results.

  According to the present invention, the carriage shaft that slidably holds the carriage holding the recording head is moved in the platen direction to bring the recording head into contact with the platen surface or the recording paper surface, thereby In a recording apparatus including a platen gap adjusting mechanism that detects a distance to a platen surface or a recording paper surface and adjusts a platen gap based on the detection result, the carriage shaft is supported so as to be able to contact and separate from the platen. A pair of side frames provided with a slide for sliding and the carriage shaft with a force that is weaker than the impact force that is received when the recording head comes into contact with the platen surface or the recording paper surface, and more than the impact during printing A biasing means that constantly biases in the platen direction with a strong force, and the carriage shaft includes the recording head A detection means for detecting movement in a direction away from the platen along the slide against an urging force by the urging means due to an impact at the time of contact; On the basis of this, it is also possible to calculate the distance from the recording head to the platen surface or the recording paper surface.

  According to the present invention, the carriage shaft that slidably holds the carriage holding the recording head is moved in the platen direction to bring the recording head into contact with the platen surface or the recording paper surface, thereby In a recording apparatus including a platen gap adjusting mechanism that detects a distance to a platen surface or a recording paper surface and adjusts a platen gap based on the detection result, at least one end of the carriage shaft is in contact with the platen. A mechanism for adjusting the parallelism between the carriage shaft and the platen by driving in a separating direction, provided at both ends of the carriage shaft, and supporting the carriage shaft so as to be in contact with and separated from the platen. The parallelism adjustment mechanism and the carriage shaft are brought into contact with the platen surface or recording paper surface by the recording head. When the recording head comes into contact with the urging means that constantly urges in the platen direction with a force that is weaker than the impact force received at the time of printing, and with a force stronger than the impact during printing, Detecting means for detecting movement in a direction away from the platen against the urging force of the urging means due to the impact of the urging means, and from the recording head to the platen surface based on the detection result by the detecting means Or the structure characterized by calculating the distance to a recording paper surface may be sufficient.

  The parallelism adjusting mechanism includes a bearing that pivotally supports the carriage shaft on a main body frame, and the bearing is mounted in a bearing mounting portion that is mounted on the main body frame, and the bearing mounting portion. It is desirable that the carriage shaft has a bearing bush that supports the end of the carriage shaft so as to be rotatable and movable in a direction in which the carriage shaft moves toward and away from the platen.

  The carriage shaft is moved in accordance with the rotation of the eccentric shaft provided at the end of the carriage shaft, and the detection means is provided in the eccentric shaft, and the amount of rotation of the eccentric shaft and the A configuration including a rotary encoder that detects movement of the carriage shaft in a direction away from the platen is also desirable.

  Furthermore, it is preferable that the detection unit includes a linear encoder that detects the movement of the carriage as the movement of the carriage shaft.

  The carriage shaft moves with the rotation of the eccentric shaft provided at the end of the carriage shaft, and the detection means moves the carriage shaft and the eccentric shaft away from the platen. A configuration including an on / off switch that is turned on or off when moved is also desirable.

  According to the present invention, the carriage shaft that slidably holds the carriage holding the recording head is moved in the platen direction to bring the recording head into contact with the platen surface or the recording paper surface, thereby In a control method of a recording apparatus including a platen gap adjusting mechanism that detects a distance to a platen surface or a recording paper surface and adjusts a platen gap based on the detection result, the carriage head is connected to the platen surface or the carriage shaft. It is configured to be movable in a direction away from the platen according to an impact force when contacting the recording paper surface, and detecting that the carriage shaft has moved in a direction away from the platen by the impact force. And detecting contact between the recording head and the platen surface or recording paper surface, and based on the detection result, And calculates the distance from the recording head to the platen surface or the recording paper.

  The carriage shaft moves with the rotation of an eccentric shaft provided at the end of the carriage shaft, and the idle section before the recording head contacts the platen surface or the recording paper surface. And detecting that the carriage shaft or the carriage has moved away from the platen based on a change in the rotational speed of the eccentric shaft with respect to the reference rotational speed. desirable.

  According to the present invention, since the recording head is brought into contact with the platen, it is configured to detect that the carriage shaft or the carriage moves away from the platen due to an impact when the recording head comes into contact with the platen. The contact can be accurately detected without being affected by the backlash of the driving wheel train or the backlash of the bush for driving the carriage shaft.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a dot impact printer to which an embodiment of a recording apparatus according to the present invention is applied. The dot impact printer 10 prints an image including characters by hitting a large number of recording wires onto a recording sheet via an ink ribbon (both not shown) to record dots.

  As shown in FIG. 1, a dot impact printer 10 includes a printer main body 11 as a recording apparatus main body, a sheet supply guide 14 that is installed on the front side of the printer main body 11 and that can cut paper K manually. The sheet feeding device CSF is provided on the rear side of the printer main body 11 and automatically feeds the cut sheet K to the recording unit.

  FIG. 2 is an external perspective view of the printer main body 11 with the paper feeding device CSF removed. A push tractor unit 12 that supplies continuous sheets to the recording unit is disposed almost directly below the sheet feeding device CSF. Here, as the cut sheet K, there is a cut film such as a cut sheet, a copy sheet, or an OHP (overhead projector) sheet. The continuous sheet includes continuous paper and continuous copy paper.

  FIG. 3 is a perspective view of the sheet conveyance mechanism unit of the printer main body 11. As shown in FIG. 3, the sheet conveyance mechanism unit 30 includes a paper feed roller 13 that is continuous with the push tractor unit 12, a platen 20, and a conveyance roller unit 21.

  FIG. 4 is an external perspective view showing the carriage together with its peripheral configuration. A carriage 31 is provided above the platen 20 as shown in FIG. A ribbon cartridge 35 and a recording head 36 are mounted on the carriage 31. The carriage 31 is supported by a carriage shaft 32 and moved by scanning above the platen 20 in the axial direction of the platen 20. The carriage shaft 32 is rotatably supported between the right side frame 33 and the left side frame 34. Each of the right side frame 33 and the left side frame 34 is formed with a slide (see FIG. 7) for supporting the carriage shaft 32 so as to be movable toward and away from the platen 20. Will be described in detail later.

  The printer body 11 rotates the carriage shaft 32 to detect that the recording head 36 has come into contact with the platen 20 or the recording paper surface by moving the carriage shaft 32 and detect the paper thickness of the recording paper. A platen gap adjusting mechanism (that is, an automatic paper thickness adjusting mechanism) for adjusting the platen gap between the recording head 36 and the platen 20 by rotating the carriage shaft 32 according to the paper thickness is provided.

  FIG. 5 is an external perspective view of the platen gap adjusting mechanism. As shown in FIG. 5, the carriage shaft 32 includes an eccentric shaft 32 </ b> A whose central axis is eccentric at its end. A gear 37 is fixed to the eccentric shaft 32A. The amount of eccentricity of the eccentric shaft 32A with respect to the carriage shaft 32 is, for example, about L = 1 mm. Reference numeral 40 denotes a lead wire. As shown in FIG. 6, the gear 37 is engaged with the gear 37, and the gear 39 is engaged with the gear 39 </ b> A of the stepping motor 39. A scale 41 is mounted on the same axis as the eccentric shaft 32A, and a detector 42 is mounted so as to sandwich the scale 41 in a rotatable manner. The scale 41 and the detector 42 constitute a rotary encoder. The detector 42 is attached to a flat plate 33a provided substantially perpendicularly on the surface of the right side frame 33. The detector 42 is attached to the right side frame 33 so as not to follow the movement of the carriage shaft 32 and the scale 41. It is fixedly arranged.

  The scale 41 has the same number of slits as the number of poles of the stepping motor 39 (for example, 96 poles), and the detector 42 is a light-emitting diode 43 and a phototransistor 44 (not shown) disposed opposite the scale 41. The projector / receiver 45 is provided. The detection light emitted from the light emitting diode 43 of the light projecting / receiving device 45 and passing through the slit of the scale 41 is received by the phototransistor 44 of the light projecting / receiving device 45 and converted into a detection signal having a pulse waveform. The rotation angle of the eccentric shaft 32A can be detected by counting the number of pulses of the detection signal. Further, the rotational speed of the eccentric shaft 32A (that is, the carriage shaft 32) can be detected based on the pulse period.

  When the stepping motor 39 is driven, the eccentric shaft 32A rotates via the gear 39A, the gear 38, and the gear 37, and the carriage shaft 32 also rotates together with the eccentric shaft 32A. As a result, the carriage shaft 32 moves up and down in the vertical direction by an eccentric amount (2 mm if L = 1 mm). As a result, the carriage 31 supported by the carriage shaft 32 and the recording head 36 integrated therewith move in a direction in which the platen 20 contacts and separates.

  By the way, the platen gap adjusting mechanism according to the present embodiment is configured to detect that the carriage shaft 32 moves due to the impact generated by the contact of the recording head 36 with the platen 20 as described above. It has become. This configuration will be described in detail with reference to FIG.

  FIG. 7 is a perspective view schematically showing the configuration of the printer body 11 as viewed from the right side. In this figure, a slide 70 indicated by a one-dot broken line is formed on the right side frame 33, and an eccentric shaft 32 </ b> A provided at the end of the carriage shaft 32 is pivotally supported on the slide 70. The slide 70 has an elongated rectangular shape extending upward from the platen side so that the carriage shaft 32 (eccentric shaft 32A) can move in the direction of contact with and away from the platen 20, and the carriage shaft 32 (eccentric shaft). 32A) is always biased to the platen 20 side by a spring force F1 by a spring 72 as biasing means. One end of the spring 72 is connected to the eccentric shaft 32 </ b> A, and the other end is connected to a fixing member such as a frame of the printer main body 11.

  Here, the spring force F1 is weaker than the impact force F2 when the recording head 36 abuts against the platen 20, and from the impact during printing (impact force when the recording wire is projected onto the recording paper) F3. Is strongly set. That is, the carriage shaft 32 (eccentric shaft 32A) is normally attracted to the lower end (platen side) of the slide 70 by the spring 72, but when the recording head 36 contacts the platen 20 during platen gap adjustment. The carriage shaft 32 temporarily moves in the direction away from the platen 20 along the slide 70 against the spring force F1 by the impact force F2, and again, the carriage shaft 32 (eccentric shaft) by the spring force F1. 32A) and pulled back to the lower end (platen side) of the slide 70. Further, during printing, even if an impact F3 during printing occurs, the carriage shaft 32 is fixed to the lower end of the slide 70 by the spring force F1, so that it is possible to maintain good printing quality and printing accuracy. It becomes.

  Further, in order to detect the movement of the carriage shaft 32 along the slide 70, the detection direction of the detector 42 is substantially perpendicular to the movement direction of the carriage shaft 32 (that is, the length direction of the slide 70). The detector 42 detects the movement of the carriage shaft 32. More specifically, when the recording head 36 is brought into contact with the platen 20, the gear 39A rotates clockwise (arrow A in the figure), and in conjunction with this, the gear 38 and the scale 41 rotate counterclockwise (in the figure). It is configured to rotate in the direction of arrows B and C). That is, as the recording head 36 comes into contact with the platen 20, when the carriage shaft 32 moves away from the platen 20, the scale 41 also moves together with the carriage shaft 32, and the detection is fixedly arranged with respect to the right side frame 33. In the instrument 42, since the detection direction is substantially perpendicular to the moving direction of the carriage shaft 32, in addition to the counterclockwise rotation of the scale 41, the scale 41 is moved upward (in the direction away from the platen 20). As a result of the movement, the rotational speed of the carriage shaft 32 (eccentric shaft 32A) as a detection value increases rapidly. Accordingly, the contact of the recording head 36 with the platen 20 is detected at the timing at which the rotational speed increases rapidly. In the present embodiment, a large circle is used as the scale 41, and the movement of the slit on the scale 41 in the detector 42 can be approximately linearly approximated, and the movement of the carriage shaft 32 is more accurate. It is possible to detect well. Moreover, by making the scale 41 into a large circle, it is prevented that the scale 41 deviates from the detectable area of the detector 42 when the scale 41 moves together with the carriage shaft 32.

  Next, as an operation of the present embodiment, the printing on the cut sheet K, the continuous sheet, and the automatic paper feeding printing operation using the paper feeding device CSF will be described, and then the platen gap adjustment operation will be described.

  First, when recording on the cut sheet K, the cut sheet K is manually fed from the front side of the printer main body 11 in FIG. 1, and then rotated by the transport roller unit 21, the platen 20, and the paper feed roller 13. The printer body 11 is conveyed from the front to the rear. Then, it is reversed by the rotation of the transport roller unit 21, the platen 20, and the paper feed roller 13, transported from the rear to the front of the printer body 11, and supplied to the recording unit including the recording head 36 facing the platen 20. Printing is executed.

  When recording on a continuous sheet such as continuous paper, the continuous sheet is supplied from the rear side of the printer body 11 by the push tractor unit 12 as shown in FIG. The paper is transported in the same direction by the unit 21 and supplied to a recording unit including the recording head 36 facing the platen 20 to execute printing.

  Furthermore, it is possible to record on a plurality of cut sheets K by automatic paper feeding using the paper feeding device CSF. As shown in FIGS. 8 to 10, the sheet feeding device CSF picks up and feeds a hopper 91 that holds a plurality of cut sheets K and the uppermost cut sheet K of the hopper 91 one by one. A sheet feeding roller 92 and a separation pad 93 for separating the cut sheet K that is double-fed together with the uppermost cut sheet K are provided. The paper feed roller 92 has a D-shaped cross section having an arc portion 92a that contacts the cut sheet K and a linear portion 92b that is separated from the cut sheet K, and at least the surface is made of a high wear material such as rubber. Yes.

  One cut sheet K is fed to the paper feed roller 13 through the paper guide 98 during one rotation while the arcuate portion 92 a of the paper feed roller 92 is in contact with the separation pad 93. The paper guide 98 is provided with a paper detector PE that detects the leading edge of the cut sheet K to be fed.

  During this automatic sheet feeding, so-called skew removal (medium alignment) of the cut sheet K is performed by the cooperative operation of the driving roller 13A and the driven roller 13B constituting the paper feeding roller 13. As shown in FIG. 9, the skew removal is performed by causing the leading end of the cut sheet K to bite between the driving roller 13A and the driven roller 13B by a certain length L1, and then stopping the feeding roller 13A with the paper feeding roller 92 stopped. This is performed by rotating (reversely rotating) the direction shown in the drawing, that is, the direction opposite to the paper feeding direction.

  After the skew removal is completed, as shown in FIG. 10, the driving roller 13A and the driven roller 13B are rotated forward to perform a cueing operation of a predetermined length L, and then the cut sheet K is moved to the recording head 36 in accordance with the recording timing. Send to the area and record. The recorded cut sheet K is discharged through the above-described transport roller unit 21 (FIG. 3).

  By the way, in the above configuration, the sheet thickness of the cut sheet K is detected at the following timing during the automatic sheet feeding. The platen gap is automatically adjusted according to the paper thickness. Then, next, the adjustment procedure of a platen gap is demonstrated.

  The platen gap is generally detected by the following procedure. First, by driving the stepping motor 39, the recording head 36 at the measurement reference position is lowered and brought into contact with the platen surface, and the distance from the measurement reference position to contact with the platen surface is calculated. Next, the recording head 36 is brought into contact with the paper surface of the recording paper, and the distance from the measurement reference position to the paper surface is calculated. Then, the sheet thickness is obtained by subtracting the distance until contact with the paper surface from the distance until contact with the platen surface. Then, a predetermined adjustment distance is added to the obtained sheet thickness to obtain a platen gap.

  FIG. 11 is a processing flowchart for calculating a distance while abutting against a platen surface or a paper surface in the platen gap detection operation. FIG. 12 is a timing chart of the platen gap detection operation.

  A controller (not shown) built in the printer main body 11 drives the stepping motor 39 to move the recording head 36 to the measurement reference position (step S1). Next, the controller discharges the recording paper from the platen surface to detect the platen surface (step S2). Subsequently, the controller drives the stepping motor 39, rotates the eccentric shaft 32A, and idles the carriage shaft 32 to the platen surface side (step S3). Then, the controller stores the period of the detection signal (FIG. 13) output from the detector 42 as a reference pulse period (step S4).

  FIG. 13 is a flowchart for storing the reference pulse period. In the storing process of the reference pulse period, the stepping motor 39 is rotated (step S21), and as shown in FIG. 14, the controller detects the pulse period Ti of the detection signal output from the detector 42 (step S22). ). Next, in order to reduce the fluctuation of the accumulated value Ub due to the influence of the characteristics of the stepping motor 39, the controller uses four consecutively obtained pulse periods Ti-3, Ti-2, Ti-1, Ti. Reference pulse cycle Sa = (Ti−3) + (Ti−2) + (Ti−1) + Ti is calculated and stored in a storage device such as a RAM (not shown) (step S23). Here, since a = i−3, i = 99 when a = 96 (the number of poles).

  After storing this reference pulse period Sa, the process shifts again to step S5 in FIG. 11, and detection of the position of the platen surface is started. When detection of the position of the platen surface is started, it is determined whether or not the recording head 36 has reached a position where it is considered to be in contact with the platen surface, that is, contact position determination is performed (step S6).

  FIG. 15 is a processing flowchart of contact position determination. A controller (not shown) rotates the stepping motor 39 (step S31), and detects the pulse period Ti of the detection signal output from the detector 42 (step S32). Then, b = i−3 is set, and the comparison pulse cycle Sb = (Ti−3) + (Ti−2) + (Ti−1) + Ti is calculated (step S33).

  Next, n satisfying the following equation (1) is obtained, and the value of a at that time is calculated (step S34). Here, n and a are integers, and since i ≧ 100, b ≧ 97.

1 ≦ a = {(b / 96) −n} × 96 ≦ 96 (1)
For example, when i = 100, since b = i−3 = 97, when these are substituted into the equation (1), n satisfying 1 ≦ a = {(97/96) −n} × 97 ≦ 97 The combination of a is n = 2 and a = 1.

  Next, a difference Δtb = Sb−Sa with respect to the reference pulse width Sa is calculated (step S35), and the difference Δtb is accumulated to calculate an accumulated value Ub = (Ub−1) + Δtb (step S36). For example, when i = 100, as described above, since b = 97 and a = 1, Δt97 = S97−S1 and U97 = U96 + Δt97.

  Then, the controller determines whether or not the cumulative value Ub is below a preset contact determination reference value UTh (step S37). That is, when the carriage shaft 32 moves in a direction away from the platen due to an impact caused by the contact of the recording head 36 with the platen surface, the pulse period Ti from the detector 42 is abruptly shortened. Will increase rapidly. Therefore, the contact of the recording head 36 is detected by detecting that the accumulated value Ub is lower than the contact determination reference value UTh.

  In the determination of step S37, when the controller determines that Ub> UTh (step S37; Yes), the process proceeds to step S31 again, and the above-described steps S31 to S37 are repeated. In step S37, if the controller determines that Ub ≦ UTh (step S37; No), the number of pulses of the detection signal from the detector 42 is stored as the platen surface position (step S38). Then, the process proceeds to step S7 in FIG. 11 to complete the platen surface detection (step S7). Subsequently, the controller drives the stepping motor 39 again to move the recording head 36 to the measurement reference position (step S8).

  Next, the controller feeds the recording paper onto the platen surface to detect the recording paper (medium) surface (step S9). Subsequently, the controller drives the stepping motor 39, rotates the eccentric shaft 32A, and idles the carriage shaft 32 to the platen surface side (step S10). Then, similarly to the above-described procedure, the controller stores the period of the detection signal output from the detector 42 as a reference pulse period (step S11), and starts detecting the position of the recording paper surface (step S12). . When the detection of the position of the recording sheet surface is started, it is determined whether or not the recording head 36 has reached a position where it is considered to be in contact with the platen surface, that is, a contact position determination is performed (step S13). In this contact position determination, similarly to the above-described procedure, when the controller determines that Ub ≦ UTh in the determination of step S37 (see FIG. 14), the number of pulses of the detection signal is stored as the recording sheet surface position. (Refer to FIG. 15, step S38) The recording paper (medium) surface detection is completed (step S14).

  Then, the controller obtains the paper thickness by subtracting the distance until contact with the paper surface as the medium surface from the distance until contact with the platen surface, and adds a predetermined adjustment distance to the obtained paper thickness. The platen gap PG is determined. Then, the controller functions as a platen gap adjusting device, drives the stepping motor 39 in accordance with the set platen gap PG, rotates the eccentric shaft 32A, and then moves the carriage shaft 32 up and down to actually move the platen gap. Adjust. When the adjustment of the platen gap is completed, the controller starts image recording (printing).

As described above, according to the present embodiment, the following effects can be obtained.
(1) In the platen gap adjustment, as the contact between the recording head 36 and the platen surface, the recording head 36 moves away from the platen 20 of the carriage shaft 32 due to an impact when contacting the platen surface or the recording paper surface. Therefore, the impression on the recording paper can be suppressed.

  More specifically, in the conventional platen gap adjustment, it is configured to detect that the recording head 36 is in contact with the platen surface or the recording paper surface by decelerating or stopping the carriage shaft 32 (so-called pre-step-out). detection). However, in this conventional configuration, since the stepping motor 39 is driven for a certain period after the recording head 36 contacts the platen surface or the recording paper surface, the recording paper surface is detected when the recording paper surface is detected. There has been a problem that indentation is generated by the pressing of the recording head 36 against the paper.

In contrast to this conventional configuration, according to the present embodiment, when the recording head 36 contacts the platen surface or the recording paper surface, the carriage shaft 32 instantaneously moves in the direction away from the platen 20 due to the impact. The recording head 36 is also separated from the platen surface or the recording paper surface, and no indentation is made on the recording paper.
(2) The carriage shaft 32 is constantly urged toward the platen 20 by the urging means (spring 72: see FIG. 7), and this urging force (spring force F1) is applied to the recording head 36 and the platen surface or Since the impact force F2 at the time of contact with the recording paper surface is smaller, the carriage shaft 32 is biased (spring force F1) when the recording head 36 contacts the platen surface or the recording paper surface. Therefore, this movement is remarkably reflected in the detection signal from the detector 42, and the movement of the carriage shaft 32, that is, the contact between the recording head 36 and the platen surface or recording sheet surface is accurately detected. It is possible to detect well.
(3) Furthermore, since the urging force (spring force F1) by the urging means (spring 72) is larger than the impact at the time of printing, even if this impact occurs at the time of printing, the carriage shaft 32. It becomes possible to fix without being loose, and it is possible to maintain good printing quality and printing accuracy.
(4) In the printer main body 11 according to the present embodiment, the carriage shaft 32 is not supported by the parallelism adjusting mechanism provided in the conventional recording apparatus. Alternatively, the position detection accuracy of the recording paper surface does not decrease. Furthermore, even if there is a backlash in the train wheel for driving the carriage shaft 32, such as the stepping motor 39 or the gear 38, the present embodiment makes the carriage contact with the platen surface or the recording paper surface of the recording head 36. The platen surface of the recording head 36 is accurately detected without being affected by the backlash because the movement of the carriage shaft 32 due to the impact at the time of contact is detected instead of detecting based on the deceleration of the shaft 32. Alternatively, contact with the recording paper surface can be detected, and variations in detection results can be suppressed.

  Next, another embodiment will be described. In the above-described embodiment, the slide 70 is provided on the right side frame 33 and the left side frame 34 that are the frames of the printer main body 11, and the carriage shaft 32 (more specifically, the eccentric shaft 32A) is pivotally supported on the slide 70. Thus, the carriage shaft 32 is configured to be movable along the slide 70 in a direction in which the carriage shaft 32 is in contact with or separated from the platen 20.

  On the other hand, in the present embodiment, the slide 70 is not provided on the right side frame 33 and the left side frame 34, but a mechanism for adjusting the parallelism of the carriage shaft 32 provided in a general recording apparatus (hereinafter, referred to as “the slide shaft 70”). A configuration in which the carriage shaft 32 can be moved in the direction of contacting and separating from the platen 20 when the recording head 36 abuts on the platen surface or the recording sheet surface will be described.

  16 is a perspective view showing a configuration of the printer main body 11 including the parallelism adjusting mechanism 80, and FIG. 17 is a side view schematically showing the configuration of the parallelism adjusting mechanism 80. As shown in FIG. The parallelism adjusting mechanism 80 includes a bearing bush 81 (see FIG. 17) and a bearing mounting member 82, and the bearing bush 81 and the bearing mounting member 82 constitute a bearing as a parallelism adjusting mechanism.

  The bearing mounting member 82 is rotatably disposed on each of the left side frame 34 and the right side frame 33 and is made of, for example, a flexible material such as resin. As shown in FIG. 17, the bearing bush 81 is rotatably fitted on the inner periphery of the bearing mounting member 82, and is made of an abrasion resistant material such as sintered metal.

  On the inner periphery of the bearing bush 81, the eccentric shaft 32A of the carriage shaft 32 is inserted integrally with the bearing bush 81. More specifically, a hole 73 into which the eccentric shaft 32 </ b> A is inserted is formed on the inner periphery of the bearing bush 81. The hole 73 is formed slightly larger than the diameter of the eccentric shaft 32 </ b> A, and is configured to be slightly movable by a gap with the hole 73 when the eccentric shaft 32 </ b> A is inserted into the hole 73. Further, the eccentric shaft 32A (carriage shaft 32) is always urged by the spring force F1 of the spring 72 as the urging means and is attracted to the side where the platen 20 is disposed, as in the above embodiment. The eccentric shaft 32A and the bearing mounting member 82 are configured to coincide with each other in a state where the eccentric shaft 32A is attracted to the platen 20 side.

  When the parallelism adjusting mechanism 80 adjusts the parallelism of the carriage shaft 32 with respect to the platen 20, the bearing attaching member 82 attached to each of the left side frame 34 and the right side frame 33 is rotated to thereby provide a bearing. The bush 81 and the eccentric shaft 32 </ b> A are rotated and adjusted so that the axis of the carriage shaft 32 is substantially parallel to the axis of the platen 20. Then, after adjusting the parallelism, the bearing mounting member 82 is fixed to the left and right side frames 33, 34 with screws or the like so that the parallelism is not displaced.

  In the above configuration, when adjusting the platen gap, the eccentric shaft 32A, that is, the carriage shaft 32 is rotated by the rotation of the stepping motor 39, and the recording head 36 approaches the platen 20 as in the above embodiment. When the recording head 36 contacts the platen surface or the recording paper surface, the impact force F2 causes the clearance between the carriage bushing 81 and the bearing bush 81 in a direction away from the platen 20 against the spring force F1. Will move in. By detecting this movement, it is possible to accurately detect the contact between the recording head 36 and the platen surface or recording paper surface.

<Modification>
The above-described embodiment is merely one aspect of the present invention, and can be arbitrarily modified within the scope of the present invention.
(Modification 1) In the above embodiment, the circular scale 41 (detector 42) is used to detect the rotational speed and movement of the eccentric shaft 32A attached to the carriage shaft 32. However, a linear scale is used as the scale. It is good also as a structure to use.

  FIG. 18 is a perspective view schematically showing the configuration of the printer main body 11 according to this modification as viewed from the right side. As shown in this figure, the printer main body 11 is fixed to the linear scale 41 ′ fixed to the right side frame 33 and the right side surface of the carriage 31 instead of the rotary encoder including the scale 41 and the detector 42. It differs from what was demonstrated in the said embodiment in the point which has a linear encoder provided with detector 42 '. When adjusting the platen gap, the carriage shaft 32 approaches the platen 20 so that the recording head 36 comes into contact with the platen surface, and the impact causes the carriage shaft 32 to move away from the platen 20. That is, as a detection result from the detector 42 ′, after a pulse period signal corresponding to the approach of the carriage shaft 32 to the platen 20 is obtained, the recording head 36 abuts on the carriage shaft 32 from the platen 20. A pulse period signal corresponding to the separation is obtained. Therefore, it is possible to detect the contact of the recording head 36 based on the point (inflection point) at which the pulse period signal has changed.

  By the way, the moving distance of the carriage 31 in the direction of moving toward and away from the platen 20 depends on the amount of eccentricity between the carriage shaft 32 and the eccentric shaft 32A, and is about several millimeters. Therefore, since the linear scale 41 ′ can be a small one of the order of several millimeters, according to this modification, in addition to the effects of the above embodiment, the apparatus can be reduced in size and space. In addition, the cost can be reduced.

  (Modification 2) In the said embodiment and modification, it was set as the structure which detects the rotational speed and movement of the carriage axis | shaft 32 using the scale 41 (linear scale 41 ') and the detector 42 (detector 42'). However, instead of this, a sensor that turns on and off according to the movement of the carriage 31 may be used.

  FIG. 19 is a perspective view schematically showing the configuration of the printer main body 11 according to this modification as viewed from the right side. As shown in this figure, the printer main body 11 includes an on / off switch 100. Specifically, the on / off switch 100 is fixed to the frame of the printer main body 11 and includes a sensor main body 101 and a detection lever 102 with which the eccentric shaft 32A comes into contact with the movement of the carriage shaft 32. . In this configuration, after the carriage shaft 32 approaches the platen 20, when the carriage shaft 32 moves away from the platen 20 due to an impact when the recording head 36 abuts, the eccentric shaft 32A is detected by this movement. Contact the lever 102. By this contact, the on / off switch 100 is turned on (or off), and the movement of the carriage shaft 32, that is, the contact of the recording head 36 is detected.

  Therefore, according to this modification, it is possible to accurately detect the contact of the recording head 36 with a simple configuration of the on / off switch 100 without using the scale 41, the detector 42, and the like. Cost can be reduced.

1 is a perspective view showing the front of a dot impact printer to which an embodiment of a recording apparatus according to the present invention is applied. 1 is a perspective view showing the rear of a dot impact printer to which an embodiment of a recording apparatus according to the invention is applied. It is a perspective view which shows the platen gap adjustment mechanism of FIG. 1 with a side frame. FIG. 4 is an enlarged perspective view illustrating a part of a right side frame and a platen gap adjustment mechanism in FIG. 3. FIG. 5 is a front view showing a part of the platen gap adjusting mechanism (a state in which the platen gap is intermediate) in FIG. 4 and the like. FIG. 6 is a front view showing a part of the platen gap adjusting mechanism (a state in which the platen gap is intermediate) in FIG. 5 excluding the eccentric cam. FIG. 2 is a perspective view schematically illustrating a configuration of the printer body as viewed from the right side. FIG. 4 is an enlarged perspective view showing the left side frame of FIG. 3 and the other part of the platen gap adjusting mechanism. It is a front view which shows the other part etc. of the platen gap adjustment mechanism (platen gap medium state) of FIG. FIG. 10 is a front view showing the other part of the platen gap adjusting mechanism of FIG. 9 excluding the eccentric cam and various gears. It is a processing flowchart of a platen surface and a medium surface (paper surface) detection. It is a timing chart of a platen surface and a medium surface (paper surface) detection. It is a flowchart of reference | standard pulse period storage. It is explanatory drawing at the time of reference pulse period storage. It is a processing flowchart of contact position determination. It is a perspective view which shows a part etc. of the right side frame and platen gap adjustment mechanism which concern on other embodiment of this invention. It is a side view which shows typically the structure of a parallelism adjustment mechanism. FIG. 6 is a perspective view schematically showing a configuration of a printer main body 11 according to a first modification of the present invention viewed from the right side. It is a perspective view which shows typically the structure which looked at the printer main body 11 which concerns on the 2nd modification of this invention from the right side surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Dot impact printer (printing apparatus), 11 ... Printer main body, 20 ... Platen, 31 ... Carriage, 32 ... Carriage shaft, 32A ... Eccentric shaft, 33 ... Right side frame, 34 ... Left side frame, 36 ... Recording head, DESCRIPTION OF SYMBOLS 39 ... Stepping motor, 41 ... Scale, 41 '... Linear scale, 42, 42' ... Detector, 45 ... Projector / receiver, 70 ... Slide, 72 ... Spring (biasing means), 73 ... Hole, 80 ... Parallel Degree adjustment mechanism, 81 ... bearing bush, 82 ... bearing mounting member, 100 ... on / off switch.

Claims (9)

A carriage shaft that slidably holds a carriage holding the recording head is moved in the platen direction so that the recording head comes into contact with the platen surface or the recording paper surface. In a recording apparatus equipped with a platen gap adjustment mechanism that detects the distance to and adjusts the platen gap based on the detection result,
The carriage shaft is configured to be movable in a direction away from the platen in accordance with an impact force when the recording head comes into contact with a platen surface or a recording paper surface.
By detecting that the carriage shaft has moved in a direction away from the platen by the impact force, contact between the recording head and the platen surface or the recording paper surface is detected, and based on the detection result. And calculating a distance from the recording head to the platen surface or the recording paper surface. A carriage shaft that slidably holds a carriage holding the recording head is moved in the platen direction so that the recording head comes into contact with the platen surface or the recording paper surface. In a recording apparatus equipped with a platen gap adjustment mechanism that detects the distance to and adjusts the platen gap based on the detection result,
A pair of side frames provided with slides for supporting the carriage shaft so as to be movable toward and away from the platen;
The carriage shaft is always urged in the platen direction with a force weaker than an impact force received when the recording head comes into contact with a platen surface or a recording paper surface and with a force stronger than an impact during printing. Biasing means;
Detecting means for detecting that the carriage shaft has moved in a direction away from the platen along the slide against an urging force of the urging means due to an impact at the time of contact of the recording head; A recording apparatus, comprising: calculating a distance from the recording head to a platen surface or a recording paper surface based on a detection result by the detecting means. A carriage shaft that slidably holds a carriage holding the recording head is moved in the platen direction so that the recording head comes into contact with the platen surface or the recording paper surface. In a recording apparatus equipped with a platen gap adjustment mechanism that detects the distance to and adjusts the platen gap based on the detection result,
A mechanism that adjusts the parallelism between the carriage shaft and the platen by driving at least one end of the carriage shaft in a direction toward and away from the platen; provided at both ends of the carriage shaft; A parallelism adjustment mechanism for supporting the carriage shaft so as to be able to contact and separate from the platen;
The carriage shaft is always urged in the platen direction with a force weaker than an impact force received when the recording head comes into contact with a platen surface or a recording paper surface and with a force stronger than an impact during printing. Biasing means;
Detecting means for detecting that the carriage shaft has moved in a direction away from the platen against an urging force of the urging means due to an impact at the time of contact of the recording head;
A recording apparatus, wherein a distance from the recording head to a platen surface or a recording paper surface is calculated based on a detection result by the detection means. The parallelism adjusting mechanism includes a bearing that pivotally supports the carriage shaft on a main body frame,
The bearing is attached to the main body frame and mounted in the bearing mounting portion so that the end portion of the carriage shaft can be rotated and moved in a direction in which the carriage is in contact with or separated from the platen. The recording apparatus according to claim 3, further comprising a bearing bush that supports the recording bush. The carriage shaft moves with the rotation of the eccentric shaft provided at the end of the carriage shaft,
5. The detection unit according to claim 1, further comprising a rotary encoder that is provided on the eccentric shaft and detects a rotation amount of the eccentric shaft and a movement of the carriage shaft in a direction away from the platen. The recording device according to any one of the above. The recording apparatus according to claim 1, wherein the detection unit includes a linear encoder that detects the movement of the carriage as the movement of the carriage shaft. The carriage shaft moves with the rotation of the eccentric shaft provided at the end of the carriage shaft,
5. The on / off switch according to claim 1, further comprising an on / off switch that is turned on or off when the carriage shaft and the eccentric shaft move in a direction away from the platen. 6. Recording device. A carriage shaft that slidably holds a carriage holding the recording head is moved in the platen direction so that the recording head comes into contact with the platen surface or the recording paper surface. In a control method of a recording apparatus provided with a platen gap adjustment mechanism that detects a distance to and adjusts a platen gap based on the detection result,
The carriage shaft is configured to be movable in a direction away from the platen according to an impact force when the recording head comes into contact with a platen surface or a recording paper surface,
By detecting that the carriage shaft has moved in a direction away from the platen by the impact force, contact between the recording head and the platen surface or recording paper surface is detected, and the detection result is based on the detection result. A method for controlling a recording apparatus, comprising: calculating a distance from a recording head to a platen surface or a recording paper surface. The carriage shaft moves with the rotation of the eccentric shaft provided at the end of the carriage shaft,
Based on the rotational speed of the eccentric shaft in the idle running section before the recording head comes into contact with the platen surface or the recording paper surface, the carriage is based on the rotational speed change of the eccentric shaft with respect to the reference rotational speed. The method for controlling a recording apparatus according to claim 8, wherein the movement of the shaft or the carriage in a direction away from the platen is detected.

Images