JP2019115944A - Medium cutting device and image formation apparatus having the same - Google Patents

Abstract

To provide means which performs cutting without curving a cutting surface by a medium cutting device such as a rotary cutter in order to solve such problems for the conventional medium cutting device which performs cutting by the rotary cutter while conveying a roll-shaped receipt sheet that the cutting surface by the rotary cutter might be curved when the thickness of the roll sheet is changed, and thus the conveyance failure and the appearance failure of a cutting end might occur.SOLUTION: In a medium cutting device which performs cutting by a cutter part while conveying a medium, at least one of the conveyance speed of the medium and the cutting speed by the cutter part is changed in accordance with the thickness of the medium.SELECTED DRAWING: Figure 14

Description

  The present invention relates to a medium cutting device for cutting a medium such as roll paper and an image forming apparatus provided with the same.

  A conventional medium cutting apparatus cuts a roll-shaped receipt sheet by a rotary cutter while conveying it (see, for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2004-106483 (Paragraphs 0009-0032, FIG. 1)

However, in the above-described conventional technique, when the thickness of the roll paper is changed, the cut surface by the rotary cutter may be curved, which may cause conveyance failure or appearance failure of the cut end. There is a problem of being there.
The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide means for cutting without curving a cut surface by a medium cutting device such as a rotary cutter.

  The present invention, in order to solve the above-mentioned problems, in a medium cutting device for cutting by a cutter unit while conveying the medium, the conveyance speed of the medium and the cutting speed by the cutter unit according to the thickness of the medium A medium cutting device characterized by changing at least one of them.

  Thereby, the present invention has an effect that the cut surface of the medium can be made parallel to the thickness direction.

Explanatory drawing which shows schematic structure of the printer of Example 1 Block diagram showing the printer of Example 1 The external view seen from the front side of the printer of Example 1 Appearance of the printer of Example 1 viewed from the back side Exterior view of the printer according to the first embodiment when the back cover is open An external view showing a cutter unit of Example 1 An external view showing a cutter unit of Example 1 An external view showing a swinging blade of Example 1 An external view showing a rotary blade of Example 1 Explanatory drawing which shows the waiting position of the rotary blade of Example 1 Explanatory drawing which shows the attachment angle of the rotary blade at the time of thick paper cutting of Example 1 Explanatory drawing which shows the attachment angle of the rotary blade at the time of thin paper cutting of Example 1 Explanatory drawing which shows the effect | action during cutting of the roll paper of Example 1 Explanatory drawing which shows the cutting state of the roll paper of Example 1. Explanatory drawing of the symbol which concerns on roll paper cutting of Example 1

  Hereinafter, embodiments of a medium cutting device and an image forming apparatus according to the present invention will be described with reference to the drawings.

The medium cutting device and the printer according to the present embodiment will be described below with reference to FIGS.
A printer 1 as an image forming apparatus according to the present embodiment is an electrophotographic printer, and includes an apparatus main body 1a and a medium feeding unit 2 disposed on the side of the apparatus main body 1a. It has the configuration shown in 2.

The medium supply unit 2 of the printer 1 is provided with a set shaft 2a for mounting the roll paper 3 as a medium, and the roll core of the roll paper 3 is detachably mounted on the set shaft 2a.
Each unit for printing on the roll paper 3 is disposed in the apparatus main body 1 a of the printer 1, and the operation display unit 4 is disposed in the upper part on the front side.

  As shown in FIG. 3, the operation display unit 4 includes a display screen 4a such as an LCD provided with a touch panel on its surface, and operation keys 4b for receiving key operations by the user. And displays various screens such as the status of the printer 1, predetermined information for the user, and an input screen, and has a function of receiving an instruction input from the user by the input unit including the touch panel and the operation key 4b. ing.

  Further, as shown in FIG. 1, an image forming section 5 for forming a toner image as a developer image to be printed is disposed in the upper part inside the apparatus main body 1a, and the roll paper 3 is conveyed below it. Along the direction (the direction from right to left in FIG. 1), the sheet feed sensor 6, the conveyance roller 7, the cutter sensor 8, the conveyance roller 9, the cutter unit 11, the conveyance roller 12, the writing sensor 13, the image forming unit A plurality of transfer rollers 14 for transferring the toner image formed in 5 onto the roll paper 3, a fixing unit 15 for fixing the toner image transferred onto the roll paper 3, a discharge detection sensor 16, a discharge roller 17 and the like are arranged. A conveying belt 18 is provided between the image forming unit 5 and the transfer roller 14.

  Three image development units 19 y, 19 m, and 19 n respectively containing toners as developers of a plurality of set colors, that is, yellow (Y), magenta (M), and cyan (C), in the image forming unit 5 of this embodiment. 19c are disposed along the transport direction, and transfer rollers 14 are disposed at positions facing the photosensitive drums of the respective developing units 19 with the transport belt 18 interposed therebetween.

The conveying belt 18 is an endless belt stretched between two pulleys, and conveys the roll paper 3 cut by the cutter unit 11 toward the fixing unit 15 in the image forming unit 5.
The paper feed sensor 6 is a mechanical or optical sensor that is disposed at the medium supply port 21 and detects the presence or absence of the roll paper 3 at the medium supply port 21.

The conveyance roller 7 is disposed at the most upstream portion in the conveyance direction of the apparatus main body 1a, and nips and conveys the roll paper 3 between the pair of opposed rollers.
The cutter sensor 8 is a mechanical or optical sensor that is disposed on the upstream side (hereinafter, also simply referred to as the upstream side) in the transport direction of the cutter unit 11 and detects the leading edge of the roll paper 3 transported in the transport direction. is there.

The conveyance roller 9 is disposed between the cutter sensor 8 and the cutter unit 11 and nips and conveys the roll paper 3 between the pair of opposed rollers.
The cutter unit 11 is a rotary cutter having a rotary blade 23 rotationally driven in a cutting direction (see FIG. 15) by the cutter motor of the cutter drive unit 22 and a swinging blade 24 pressing the rotary blade 23. The roll paper 3 is cut while being conveyed by the blade 23 and the swinging blade 24 (details will be described later).

Further, the cutting rotational speed N in the cutting direction as the cutting speed of the rotary blade 23 can be changed.
In the cutter driving unit 22, an electromagnetic clutch 22a is provided in the power transmission mechanism, and connection and disconnection of the driving force to the rotary blade 23 are possible.

The conveyance roller 12 is disposed between the cutter unit 11 and the image forming unit 5 and nips and conveys the roll paper 3 between the pair of opposed rollers.
The writing sensor 13 is disposed on the upstream side of the image forming unit 5 and whether the shielding unit 13b has entered between the light emitting unit provided in the optical detection unit 13a and the light receiving unit disposed opposite thereto. The leading end of the roll paper 3 conveyed to the image forming unit 5 is detected depending on whether or not it is.

The writing sensor 13 of this embodiment detects the arrival of the leading end of the roll paper 3 when the light blocked by the shielding unit 13 b changes to light transmission.
The fixing unit 15 fixes the toner image transferred onto the roll paper 3 after being cut by the transfer roller 14 in the image forming unit 5 on the paper by the heat of the heater or the like and the pressure of the two rollers disposed opposite to each other. Let

The discharge detection sensor 16 is disposed downstream of the fixing unit 15 and detects the roll paper 3 discharged from the fixing unit 15 and conveyed by the discharge roller 17.
The discharge roller 17 is disposed on the most downstream side in the transport direction, sandwiches the roll paper 3 between the pair of opposed rollers, and discharges the printed roll paper 3 to the outside of the apparatus main body 1a.

The above-described transport rollers 7, 9, 12 are rotationally driven by the same transport motor of the transport drive unit 25, and the transport speed of the roll paper 3 by rotation in the transport direction can be changed.
The medium cutting device according to this embodiment includes the cutter unit 11, the cutter drive unit 22, and the conveyance drive unit 25.

The cutter unit 11 of this embodiment is disposed under a back cover 1b provided on the back side of the apparatus main body 1a of the printer 1, as shown in FIGS.
The rotary blade 23 is rotationally driven in the cutting direction by the cutter drive gear 22b of the cutter drive unit 22 as shown in FIGS. 6 and 7, and a cylindrical sliding contact portion 23a is provided on the cutter drive gear 22b side. It is done.

The swinging blade 24 is swingably supported around the rotating shaft 24a, and as shown in FIGS. 7 and 8, in a direction in which the rotating blade 23 is pressed by the biasing member 24b such as a torsion spring, that is, The swinging blade 24 is urged in the direction of pushing it downstream in the transport direction, and its tip end is locked by the outer peripheral surface of the sliding contact portion 23a of the rotary blade 23 (see FIG. 10).
Further, the movement of the swinging blade 24 in the vertical direction is fixed by the rotating shaft 24 a.

The rotary blade 23 of the present embodiment has one cutting blade 27 as shown in FIG. 9, and the cutting ridge line 27a of the cutting blade 27 has the same rotation radius as the outer peripheral surface of the sliding contact portion 23a. Rotate in R
Further, the cutting ridge 27a of the cutting blade 27 is attached in a state of being twisted at a predetermined twist angle (120 degrees in this embodiment) with respect to the axial direction of the rotary blade 23, and meshing with the swinging blade 24 The portion is constituted by one point (referred to as contact point 28; see FIG. 13).

The contact point 28 moves in the width direction of the roll paper 3 which is orthogonal to the conveyance direction of the roll paper 3 as the rotary blade 23 rotates.
In the rotary blade 23 of this embodiment, as shown in FIG. 10A, a position where the flat portion of the rotary blade 23 faces the back surface of the roll paper 3 during conveyance of the roll paper 3 (referred to as a standby position). It has stopped at.

  At this time, the electromagnetic clutch 22a of the cutter drive unit 22 is in the state of disconnection of the driving force, and the rotary blade 23 is axially outside of the sliding contact portion 23a of the rotary blade 23, as shown in FIG. The notch portion 31 a formed in the shaft portion 31 is stopped in a state of being locked by the pressing plate 32.

The pressing plate 32 is biased by a spring member such as a compression coil spring in a direction (a direction shown by an arrow A in the figure) to press the flat portion of the notch 31a.
In order to cut the roll paper 3 straight in the direction orthogonal to the conveyance direction without stopping the conveyance operation while the roll paper 3 is conveyed, the rotary blade 23 and the swinging blade 24 of the present embodiment With respect to the width direction, it is attached in a state where it is inclined at the mounting angle α to the downstream side in the transport direction as seen from the sliding contact portion 23 a in the width direction.

The attachment angle α of the rotary blade 23 and the like is configured to be changeable, and is attached to the apparatus main body 1 a at an attachment angle α which is preset for each thickness P of the roll paper 3.
For example, in the case of thick paper having a large thickness P, as shown in FIG. 11, the paper is attached at a relatively small attachment angle αa, and in the case of thin paper having a small thickness P, as shown in FIG. Attached at an angle αb, αa <αb.

As described above, the mounting angle α decreases as the thickness P increases, and increases as the thickness P decreases. In other words, the mounting angle α is set to decrease as the thickness increases.
The control unit 35 of the printer 1 (see FIG. 2) has a function of controlling each unit in the printer 1 to execute print processing and the like.

  The storage unit 36 stores programs executed by the control unit 35, various data used therein, processing results by the control unit 35, and the like.

In order to cut in the direction parallel to the thickness direction, that is, in the direction perpendicular to the front surface of the roll paper 3 without curving the cut surface of the roll paper 3 in the thickness direction, cutting the rotary blade 23 Cutting time T1 (unit: s (seconds)) required to cut the roll paper 3 in the thickness direction at the contact point 28 between the rotary blade 23 and the swinging blade 24 by rotation in the direction; The transport time T2 (unit: s) during which the roll paper 3 is transported while being cut in the thickness direction is the same, that is, T1 = T2. ... (1)
Need to be

  This is because when the roll paper 3 is cut in the thickness direction, as shown in FIGS. 13 and 14, the moving speed of the cutting edge 27 at the contact point 28 in the transport direction of the cutting edge 27 a By making the conveyance speed V the same, it is possible to cut the roll paper 3 in the vertical direction of the front surface.

The control method at the time of cutting of the roll paper 3 of the present embodiment will be described below with reference to FIG.
In the present embodiment, the above equation (1) is obtained by changing the cutting rotational speed N (unit: rotation / second, described as rps) of the rotary blade 23 of the cutter unit 11 according to the thickness P of the roll paper 3. In order to meet the

  In the following description, the transport speed of the roll paper 3 is V (unit: mm / s), the cutting rotation speed is N (unit: rps), the thickness of the roll paper 3 is P (unit: mm), and the rotary blade 23 The rotation radius of R is R (unit: mm).

The cutting time T1 required to cut the roll paper 3 at the contact point 28 is
T1 = (θ2−θ1) / 360N ..... (2)
Calculated by

  Here, the movement of the swinging blade 24 in the vertical direction is fixed at the angle position θ2 (referred to as a cutting end angle θ2 unit. Degree) at the end of the cutting of the roll paper 3 by the cutting edge 27a of the cutting blade 27. Because it is immutable.

In addition, the angular position θ1 at the start of cutting (referred to as a cutting start angle θ1. Unit: degree) changes according to the thickness P,
R sin θ 1 = R sin θ 2 −P (3)
The cutting start angle θ1 is
θ ₁ = sin ⁻¹ (sin θ ₂ −P / R) (4)
Calculated by

On the other hand, the conveyance time T2 required for conveyance while cutting the roll paper 3 at the contact point 28 is
T2 = L / V ........... (5)
Calculated by

Here, the conveying distance L during cutting which is conveyed while the roll paper 3 is cut at the contact point 28 is
L = R (cos θ1−cos θ2) ············· (6)
Calculated by
The attachment angle α of the rotary blade 23 and the swing blade 24 is attached at the attachment angle α set in advance according to the thickness P when the roll paper 3 is attached.

  The processing operation of the cutting process of the roll paper 3 by the printer 1 of this embodiment will be described below.

  In the storage unit 36 of this embodiment, the conveyance speed Vn at printing, which is the conveyance speed at the time of printing, the rotation radius R of the rotary blade 23, and the cutting end angle θ2 are preset and stored as the conveyance speed V of the roll paper 3 It is done.

  In the following description, the user mounts the roll paper 3 made of continuous paper on the set shaft 2a of the medium supply unit 2, and swings the rotary blade 23 at the mounting angle α set according to the thickness P thereof. The blade 24 is attached, the leading end of the roll paper 3 is inserted from the medium insertion port 21 and the roll paper 3 is pinched by the transport rollers 7 and 9, and it is described that the leading end is stopped in front of the cutter unit 11 in that state. .

  At this time, the rotary blade 23 of the cutter unit 11 is stopped in a state of being locked to the pressing plate 32 at the standby position (see FIG. 10).

  The user inputs the thickness P and cut length of the loaded roll paper 3 from the display screen 4a of the operation display unit 4 before starting printing.

  The control unit 35 of the printer 1 having received the input of the thickness P and the cutting length of the roll paper 3 calculates the cutting start angle θ1 using the equations (3) and (4) based on the input thickness P The cutting conveyance distance L is calculated using the equation (6) from the rotation radius R, the cutting end angle θ2 stored in the storage unit 36, and the calculated cutting start angle θ1, and the printing time of the storage unit 36 is calculated. The conveyance time T2 is calculated using equation (5) using the conveyance speed Vn and the calculated conveyance distance L, the cutting rotation speed N is calculated using equations (1) and (2), and the calculated cutting rotation speed N is calculated. It is stored in the storage unit 36.

  For example, in the case where the storage unit 36 stores the printing conveyance speed Vn = 152.4 mm / s, the rotation radius R = 4 mm of the rotary blade 23, and the cutting end angle θ2 = 39.4 degrees, When the thickness P = 70 μm, the cutting rotational speed N is calculated as follows.

That is, the cutting start angle θ1 is given by
θ ¹ = sin ⁻¹ (sin 39.4−0.07 / 4) = 38.1 [degree]
The cutting conveyance distance L is given by the equation (6)
L = 4 × (cos 38.1−cos 39.4) = 0.057 [mm]
Therefore, the transport time T2 at the time of cutting is given by
T2 = 0.057 / 152.4 = 0.003742 [s]
Therefore, the cutting rotation speed N for satisfying the condition of the equation (1) is given by the equation (2):
N = {(39.4-38.1) / 360} / 0.000374 = 9.655 [rps]
Is calculated.

  The rotary blade 23 and the swinging blade 24 in this case are attached to the apparatus body 1a at the attachment angle αb (see FIG. 11).

In the case of the thickness P of the roll paper 3 = 250 μm,
θ1 = sin ⁻¹ (sin 39.4−0.25 / 4) = 34.9 [degree]
L = 4 × (cos 34.9-cos 39.4) = 0.190 [mm]
T2 = 0.19 / 152.4 = 0.001247 [s]
N = {(39.4-34.9) / 360} /0.001247=10.024 [rps]
Is calculated.

  The rotary blade 23 and the swinging blade 24 in this case are attached to the apparatus body 1a at the attachment angle αa (see FIG. 11).

  As described above, the cutting rotation speed N increases as the thickness P increases, and decreases as the thickness P decreases. That is, the cutting rotation speed N is calculated to increase as the thickness increases.

  In addition, the control unit 35 calculates the cutting position of the roll paper 3 from the input cutting length, and the cutting position corresponds to the rotary blade 23 of the cutter unit 11 when the writing sensor 13 detects the leading end of the roll paper 3. A predetermined cutting feed amount at a printing conveyance speed Vn is calculated before reaching the contact point 28 on the sliding portion 23 a side with the swinging blade 24, and the calculated cutting feed amount is stored in the storage unit 36. Save to

  When receiving the print instruction, the control unit 35 storing the calculated cutting rotational speed N and cutting feed amount starts conveyance of the roll paper 3 at the printing conveyance speed Vn, and the leading edge thereof is the rotary blade 23 of the cutter unit 11 and It passes between the swinging blades 24 and is transported to the transport roller 12, and is transported in the direction of the image forming unit 5 by the transport rollers 7, 9 and 12.

  When the leading edge of the roll paper 3 conveyed in the direction of the image forming unit 5 reaches the writing sensor 13 and the writing sensor 13 outputs a detection signal of the leading edge, the control unit 35 calculates the storage unit 36 Read out the cut rotation speed N and cut feed amount, connect the electromagnetic clutch 22a of the cutter drive unit 22 and connect the roll blade 3 to the contact point 28 on the sliding portion 23a side of the rotary blade 23 and the swing blade 24 In accordance with the timing when the cutting position arrives, driving of the rotary blade 23 in the cutting direction at the calculated cutting rotational speed N is started.

  Then, at the end of conveyance of the cutting feed amount, the control unit 35 causes the cutting edge 27 a of the cutting blade 27 to abut on the back surface of the side edge of the roll paper 3 on the sliding portion 23 a side by the rotary blade 23 and the swing blade 24. Cutting of the roll paper 3 by the cutting blade 27 of the rotary blade 23 rotating at the cutting rotation speed N calculated from time to time starts, the rotary blade 23 rotates by a predetermined twist angle, and the contact point 28 in the width direction When moving to reach the opposite side end, the cutting of the roll paper 3 is finished (see FIGS. 13 and 14).

The control unit 35, which has finished cutting the roll paper 3, returns the rotary blade 23 to the standby position, and causes the electromagnetic clutch 22a to be in the shut-off state and to be in the standby state in which the pressing plate 32 is locked.
Thus, the processing operation of the cutting process of the roll paper 3 made of continuous paper by the printer 1 of the present embodiment is performed.

  After being cut, the cut roll paper 3 is conveyed in the direction of the image forming unit 5 at the printing conveyance speed Vn, and the toner image is transferred by the image forming unit 5 and the transfer roller 14. After the toner image is fixed on the sheet, the sheet is discharged by the discharge roller 17 to the outside of the apparatus body 1a.

  As described above, in the present embodiment, the cutting time T1 when the roll paper 3 is cut by the rotary blade 23 and the conveyance time T2 during which the roll paper 3 is conveyed while cutting the roll paper 3 are made the same time. In order to change the cutting rotational speed N of the rotary blade 23 in accordance with the thickness P of the roll paper 3, the cut surface of the roll paper 3 can be made parallel to the thickness direction without being curved. As a result, it is possible to prevent a conveyance failure such as being caught by the conveyance roller 12 or the like, and to improve the appearance of the roll paper 3 after cutting.

The printer of this embodiment will be described below. The same parts as in the first embodiment are given the same reference numerals, and the description thereof is omitted.
The configuration of the printer 1 of this embodiment is the same as that of the first embodiment.

Below, the control method at the time of cutting of the roll paper 3 of a present Example is demonstrated.
In the present embodiment, the conveyance speed V at the time of cutting of the roll paper 3 is changed according to the thickness P of the roll paper 3 so as to satisfy the condition of the formula (1) of the above-mentioned first embodiment.

The cutting time T1 required to cut the roll paper 3 at the contact point 28 is calculated by the equation (2) of the first embodiment.
The cutting conveyance distance L which is conveyed while the roll paper 3 is cut at the contact point 28 is calculated by the equation (2) of the first embodiment.

Since the transport speed V for satisfying the equation (1) of the first embodiment, that is, T1 = T2 is T1 = T2 = L / V according to the equations (2) and (5) of the first embodiment,
V = L / T1 ........... (7)
Calculated by

  The attachment angle α of the rotary blade 23 and the swing blade 24 is attached at the attachment angle α set in advance according to the thickness P when the roll paper 3 is attached.

The processing operation of the cutting process of the roll paper 3 by the printer 1 of this embodiment will be described below.
The printing conveyance speed Vn of the roll paper 3, the cutting rotation speed N and the rotation radius R of the rotary blade 23, and the cutting end angle θ2 are preset and stored in the storage unit 36 of the present embodiment.

  In the following description, the user mounts the roll paper 3 made of continuous paper in the medium supply unit 2 in the same manner as in the first embodiment, and rotates at the mounting angle α set according to the thickness P The blade 23 and the swinging blade 24 are attached, and the roll paper 3 is pinched by the transport rollers 7 and 9, and it is assumed that the leading edge is stopped in front of the cutter unit 11 in that state.

At this time, the rotary blade 23 of the cutter unit 11 is stopped in a state of being locked to the pressing plate 32 at the standby position.
The user inputs the thickness P and cut length of the loaded roll paper 3 from the display screen 4a of the operation display unit 4 before starting printing.

  The control unit 35 of the printer 1 that has received the input of the thickness P and the cutting length of the roll paper 3 performs cutting using the equations (3) and (4) of the first embodiment based on the input thickness P. The start angle θ1 is calculated, and the conveyance distance L at the time of cutting is calculated using the equation (6) of the first embodiment from the rotation radius R, the cutting end angle θ2 stored in the storage unit 36 and the calculated cutting start angle θ1. The conveyance speed V is calculated using the equation (7) from the cutting rotational speed N of the storage unit 36 and the calculated conveyance distance L at the time of cutting, and the calculated conveyance speed V is stored in the storage unit 36.

  For example, in the case where the storage unit 36 stores the cutting rotational speed N = 10 [rps], the rotational radius R = 4 mm of the rotary blade 23, and the cutting end angle θ2 = 39.4 degrees, the thickness of the roll paper 3 When P = 70 μm, the transport speed V is calculated as follows.

That is, the cutting start angle θ1 can be calculated by the equation (4) of the first embodiment.
θ ¹ = sin ⁻¹ (sin 39.4−0.07 / 4) = 38.1 [degree]
The cutting conveyance distance L can be calculated by the equation (6) of the first embodiment.
L = 4 × (cos 38.1−cos 39.4) = 0.057 [mm]
The cutting time T1 required for cutting the roll paper 3 by the cutting blade 27 can be calculated according to the formula (2) of the first embodiment.
T1 = {(39.4-38.1) / 360} /10=0.00361 [s]
Therefore, the conveying speed V at the time of cutting is expressed by the equation (7)
V = 0.057 / 0.0000361 = 157.1 [mm / s]
Is calculated.

  The rotary blade 23 and the swinging blade 24 in this case are attached to the apparatus body 1a at the attachment angle αb (see FIG. 11).

In the case of the thickness P of the roll paper 3 = 250 μm,
θ1 = sin ⁻¹ (sin 39.4−0.25 / 4) = 34.9 [degree]
L = 4 × (cos 34.9-cos 39.4) = 0.190 [mm]
T1 = {(39.4-34.9) / 360} /10=0.00125 [s]
V = 0.190 / 0.00125 = 152.0 [mm / s]
Is calculated.

  The rotary blade 23 and the swinging blade 24 in this case are attached to the apparatus body 1a at the attachment angle αa (see FIG. 11).

  As described above, the transport speed V becomes slower as the thickness P becomes thicker, and becomes faster as the thickness P becomes thinner. That is, the transport speed V is calculated to become slower as the thickness becomes thicker.

  In addition, the control unit 35 calculates the cutting position of the roll paper 3 from the input cutting length, and the cutting position corresponds to the rotary blade 23 of the cutter unit 11 when the writing sensor 13 detects the leading end of the roll paper 3. A predetermined cutting feed amount at a printing conveyance speed Vn is calculated before reaching the contact point 28 on the sliding portion 23 a side with the swinging blade 24, and the calculated cutting feed amount is stored in the storage unit 36. Save to

  When receiving the print instruction, the control unit 35 storing the calculated transport speed V and cutting feed amount starts transporting the roll paper 3 at the printing transport speed Vn, and shakes the tip of the roll paper 3 with the rotary blade 23 of the cutter unit 11 The movable blade 24 is passed between the movable blades 24 and conveyed to the conveyance roller 12, and conveyed by the conveyance rollers 7, 9 and 12 in the direction of the image forming unit 5.

  When the leading edge of the roll paper 3 conveyed in the direction of the image forming unit 5 reaches the writing sensor 13 and the writing sensor 13 outputs a detection signal of the leading edge, the control unit 35 The set cutting rotational speed N and the calculated cutting feed amount are read out, the electromagnetic clutch 22a of the cutter drive unit 22 is connected, and the contact point 28 on the sliding portion 23a side between the rotary blade 23 and the swinging blade 24 is read. In accordance with the timing at which the cutting position of the roll paper 3 arrives, driving of the rotary blade 23 in the cutting direction at the cutting rotation speed N set in advance is started.

Then, at the end of conveyance of the cutting feed amount, the control unit 35 changes the conveyance speed of the roll paper 3 to the conveyance speed V calculated from the conveyance speed Vn at printing, and the sliding portion The roll paper 3 is rotated by the cutting blade 27 of the rotary blade 23 rotating at a preset cutting rotational speed N when the cutting edge 27a of the cutting blade 27 abuts on the back surface of the side edge of the roll paper 3 on the 23a side. Cutting is started, the rotary blade 23 is rotated by a predetermined twist angle, and cutting of the roll paper 3 is finished when the contact point 28 moves in the width direction and reaches the opposite side end. Cutting of the roll paper 3 The control unit 35, which has completed the process, changes the conveyance speed of the roll paper 3 from the calculated conveyance speed V to the conveyance speed Vn at printing, returns the rotary blade 23 to the standby position, and sets the electromagnetic clutch 22a in the disconnected state. Hold 32 and wait.

  Thus, the cut roll paper 3 is conveyed to the image forming unit 5 at the printing conveyance speed Vn after cutting, and the image forming unit 5 and the transfer roller are transferred to the roll paper 3 conveyed at the printing conveyance speed Vn. Since the toner image is transferred by the method 14, distortion or positional deviation of the toner image at the time of transfer is prevented.

  Thus, the processing operation of the cutting process of the roll paper 3 made of continuous paper by the printer 1 of the present embodiment is performed.

  As described above, in the present embodiment, the cutting time T1 when the roll paper 3 is cut by the rotary blade 23 and the conveyance time T2 during which the roll paper 3 is conveyed while cutting the roll paper 3 are made the same time. In order to change the transport speed V of the roll paper 3 in accordance with the thickness P of the roll paper 3, the same effect as that of the first embodiment can be obtained.

  In addition, when changing the transport speed of the roll paper 3, the transport speed is changed to the calculated transport speed V only when the roll paper 3 is cut, and after cutting, the transport speed is returned to the print transport speed Vn. At the time of transfer to the roll paper 3, distortion or positional deviation of the toner image can be prevented.

  In the above embodiment, when the roll paper 3 is cut, the cutting rotation speed N of the rotary blade 23 or the transport speed V of the roll paper 3 is changed according to the thickness P, but the cutting rotation speed N And the conveyance speed V may be changed together.

  In the above embodiments, the image forming apparatus has been described as a printer that uses the three developing units 19 to transfer a toner image by the developing unit 19 onto a medium such as roll paper 3 conveyed by the conveying belt 18. The image forming apparatus is not limited to the above, but may be a printer for transferring a toner image to a medium via an intermediate transfer belt, a monochrome printer using one developing unit 19, a printer using two or more developing units 19 or the like. May be

  In each of the above embodiments, the medium cutting device is applied to a printer. However, the present invention is also applicable to a copying machine, a multi-function machine, a medium cutting device provided in an automatic document reading device, etc. .

  Furthermore, in each of the above-described embodiments, the medium is described as the roll paper 3 made of continuous paper, but the medium is not limited to the above and may be cut paper such as A4.

  Furthermore, in each of the above embodiments, although the thickness P of the roll paper 3 is described as being input from the operation display unit 4 when the user mounts the roll paper 3, the thickness P of the roll paper 3 is detected A thickness detection mechanism may be provided to automatically detect when the roll paper 3 is attached.

DESCRIPTION OF SYMBOLS 1 printer 1 a main body 1 b back cover 2 medium supply unit 2 a set shaft 3 roll paper 4 operation display unit 4 a display screen 4 b operation key 5 image forming unit 6 sheet feeding sensor 7, 9, 12 conveyance roller 11 cutter unit 13 writing sensor 13a detection unit 13b shielding unit 14 transfer roller 15 fixing unit 16 discharge detection sensor 17 discharge roller 18 transport belt 19, 19y, 19m, 19c developing unit 21 medium supply port 22 cutter drive unit 22a, 25a electromagnetic clutch 22b cutter drive gear 23 rotation Blade 23a Sliding contact portion 24 Swinging blade 24a Rotary shaft 24b Biasing member 25 Transport drive portion 27 Cutting blade 27a Cutting ridge line 28 Current contact point 31 Shaft portion 31a Notch portion 32 Pressure plate 35 Control portion 36 Memory portion

Claims (9)

In a medium cutting device that cuts at a cutter unit while conveying a medium,
A medium cutting device characterized in that at least one of a conveyance speed of the medium and a cutting speed by the cutter unit is changed according to the thickness of the medium. In the medium cutting device according to claim 1,
Medium cutting characterized in that a cutting time required for cutting in the thickness direction of the medium by the cutting speed and a conveyance time during which the medium is conveyed while cutting in the thickness direction by the conveyance speed are the same. apparatus. In the medium cutting device according to claim 1 or 2,
A medium cutting apparatus characterized in that the cutting speed is increased when the thickness of the medium is large and decreased when the thickness is small. In the medium cutting device according to claim 1 or 2,
A medium cutting device characterized in that the transport speed is reduced when the thickness of the medium is large and is increased when the thickness is small. In the medium cutting device according to claim 4,
A medium cutting device characterized in that the transport speed is changed only when the medium is cut. The medium cutting device according to any one of claims 1 to 5.
A medium cutting device characterized in that the cutter unit has a rotary blade rotating in a cutting direction, and a swinging blade biased in a direction to press the rotary blade. In the medium cutting device according to claim 6,
A medium cutting device characterized in that a mounting angle with respect to a width direction which is a direction perpendicular to a conveyance direction of the medium is made variable.   An image forming apparatus comprising the medium cutting device according to any one of claims 1 to 7. In the image forming apparatus according to claim 8,
An image forming unit for forming a developer image on the medium;
An image forming apparatus characterized in that the medium cutting device is disposed upstream of the image forming unit in the medium conveyance direction.

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