CN102529417B - Thermal head system and electrifying control method for thermal head - Google Patents

Abstract

The utility model relates to a thermal head system and an electrifying control method for thermal head. Without carrying out resistance measurement and complicated electrifying control amid driving process and without increasing reconditioning amount, the thermal head system can inhibit the unevenness of the heating characterisitcs of the heating resistor element. For this purpose, the thermal head system does not carry out electrifying control which takes every heating resistor element as the unit and corresponds to the difference between the resistance value of multiple heating resistor elements and the mean resistor value. Instead, the thermal head system carries out the electrifying control which takes heating resistor element of the unit block as a unit and corresponds to the difference between the average resistor value of the heating resistor elements of the unit blocks and the target resistance. Therefore, the thermal head system can make the heating resistor elements to heat in a state that the amplitude of variation is smaller than that of the previous ones.

Description

Thermal head system and power supply control method of thermal head

technical field

The present invention relates to a system and method for controlling the energization amount of a heat-generating resistance element of a thermal head, such as a plate-making mechanism for a base paper for a heat-sensitive stencil in a stencil printing device, and a plurality of heat-generating elements are arranged. A voltage is applied to the heating resistors of the resistance elements to generate heat for each heating resistance element.

Background technique

Conventionally, among stencil printing devices, rotary stencil printing devices and simple press stencil printing devices have mainly been used as devices using base paper for heat-sensitive stencils. These printing apparatuses use base paper for thermal stencil printing (for thermal stencils) bonded with an adhesive to a thermoplastic resin film perforated by thermal fusion and a porous tissue paper or the like as a support for the film. The base paper is heated with a thermal head so that the non-blank portion corresponding to the printed image is perforated, thereby performing plate making. By aligning and pressing the pressed base paper and printing paper, the ink pressed from the support side of the base paper passes through the The holes in the film are transferred to the printing paper for printing.

In general, a thermal head has a heating resistor in which a plurality of heating resistors are arranged in a line, and is used to perforate a non-blank portion of a desired printed image on a base paper by selectively driving the heating resistors. However, the above-mentioned thermal head has a problem that since the resistance values of the heating resistor elements are not all equal, distribution of heat generation occurs in the head, resulting in uneven image density or missing dots (not perforated). In order to solve this problem, it has been conventionally proposed to drive each heating resistor by correcting it in accordance with a difference in resistance value.

For example, in the technology disclosed in Patent Document 1, there are: a measuring unit that respectively measures the resistance values of a plurality of heating resistance elements provided in the thermal head; , an adjustment unit that adjusts the energization time of each heating element respectively. Thereby, the heat generation amount of each heating element of the thermal head becomes equal, and high-precision printing can be performed.

In the technology disclosed in Patent Document 2, the energization pulse supplied to each heating resistor element is divided into a plurality of divided pulses respectively directed to each heating resistor element, and at the same time, each pulse supplied to each heating resistor element is individually controlled based on the resistance value of each heating element. The pulse width of the split pulse. In this way, the peak temperature and thermal response characteristics of the heat-generating resistor elements having different resistance values are made the same, and printing with uniform temperature and no recording unevenness can be performed.

In the technology disclosed in Patent Document 3, for the difference in the heat generation when the same amount of current is applied to each heating resistance element, an inverse heat generation distribution map is created as correction data to cancel out the difference, and the heat generation distribution based on the correction data is The figure pre-drives each heating resistor element in units of blocks, and then selectively formally drives the heating resistor element for recording. This makes it possible to make the amount of heat generated by the heat generating resistor element uniform, and to prevent recording unevenness.

However, the technologies disclosed in the above-mentioned Patent Documents 1 and 2 have the following problems: each time the thermal head is driven, the resistance value of each heat-generating resistor element is measured, and a device for adjusting the energization time of the heat-generating resistor element is required. Preprocessing such as measurement takes time, and a device for measurement is required, so that the structure and control of the system become complicated.

In addition, the technology disclosed in Patent Document 3 has the following problem: each time the thermal head is driven, it is necessary to pre-drive each heating resistance element on a block-by-block basis, and then perform main driving, which requires two-stage driving of pre-driving and main driving. control device, so the structure and control of the system become complicated.

Also, in the technologies disclosed in Patent Documents 1 to 3, the energization time of each heating resistor element or the energization pattern of the heating resistor element in a block unit is controlled based on the difference between the resistance values of all the heating resistor elements and their average value, so it is necessary to make the resistance The energization amount of the heating resistance element whose value is greatly different from the average resistance value is very different from the energization amount of other heating resistance elements. Therefore, there is a problem that aging of the heating resistance element varies greatly due to the difference in the total energization amount.

Citing documents:

Patent Document 1: Japanese Patent Laid-Open No. 2001-232840

Patent Document 2: Japanese Patent Laid-Open No. 2000-158691

Patent Document 3: Japanese Patent Application Laid-Open No. 8-300708

Contents of the invention

However, when the thermal head is shipped from the factory, each heating resistor element is subjected to trimming in order to make the resistance value of the thermal head uniform. This trimming process changes the resistance value of the heat-generating resistance element by applying pulse current to the heat-generating resistance element a plurality of times.

In general, in order to minimize structural deterioration due to pulsed energization of the heating resistor elements, trimming is usually performed only to the extent that the resistance values of the heating resistor elements are substantially uniform. Then, the uniformization of the remaining minute resistance value is usually carried out by the drive control of the above-mentioned thermal head.

Therefore, in order to avoid the above-mentioned drive control of the thermal head, it is necessary to increase the amount of trimming compared with the general amount to achieve uniformity of the resistance value of each heating resistor element. However, in this case, the heat-generating resistance element may be deteriorated structurally due to an increase in the amount of trimming, resulting in a shortened life.

The present invention is proposed in view of the above circumstances. The purpose of the present invention is to provide a thermal head system and a thermal head power supply control method. The thermal head system includes a device having a thermal head with a plurality of heat-generating resistance elements arranged in a straight line. When the thermal head is driven, the measurement of the resistance value of the heating resistor element or complicated energization control is not performed, the durability is not reduced due to the increase of the trimming amount, and the difference in the heating characteristics of each heating resistor element can be suppressed.

In order to achieve the above object, the first aspect of the present invention provides a thermal head system,

The thermal head system has a heating resistor body in which a plurality of heating resistor elements are arranged in a straight line, and is used to heat each heating resistor element by energizing the heating resistor body,

dividing the heating resistor body into a plurality of unit blocks along the extending direction of the straight line, each unit block is composed of a predetermined number of the heating resistor elements,

The thermal head system includes:

The energization amount storage unit stores, for each of the unit blocks, calculated based on the difference between the average resistance value of the predetermined number of heating resistance elements and the target resistance value in order to make the total heat generation amount coincide with a predetermined target heat generation amount, The energization amount related to the predetermined number of heat-generating resistive elements, wherein the total heat-generating amount is when the predetermined number of heat-generating resistive elements having the average resistance value of the predetermined number of heat-generating resistive elements as a resistance value are energized total calorific value;

An energization amount control unit for driving the thermal head, for each of the unit blocks, with the energization amount corresponding to the unit block and stored in the energization amount storage unit to drive the unit block. The predetermined number of heat-generating resistive elements of the block, so that the total heat generation of the unit block is the same as the total heat generation of other unit blocks.

In addition, in order to achieve the above object, the second aspect of the present invention provides a method for controlling power supply of a thermal head,

The thermal head has a heating resistor body in which a plurality of heating resistor elements are arranged in a straight line, and is used to heat each heating resistor element by energizing the heating resistor body,

dividing the heating resistor body into a plurality of unit blocks along the extending direction of the straight line, each unit block is composed of a predetermined number of the heating resistor elements,

The power control method includes:

In order to make the total calorific value coincide with the predetermined target calorific value, based on the difference between the average resistance value of the predetermined number of exothermic resistance elements and the target resistance value, the predetermined number of exothermic resistors are predetermined for each of the unit blocks. An element-related energization amount, wherein the total heat generation amount is a total heat generation amount when energizing the predetermined number of heat generation resistance elements having the average resistance value of the predetermined number of heat generation resistance elements as a resistance value;

When the thermal head is driven, the predetermined number of heat-generating resistive elements of each unit block are driven with predetermined energization amounts corresponding to each unit block, so that the total of the unit blocks The calorific value is the same as the total calorific value of other unit blocks.

According to the resistance value control system of the thermal head of the present invention described in the first aspect and the resistance value control method of the present invention of the thermal head described in the second aspect, a plurality of heating resistors are arranged in a straight line in the extending direction of the straight line. The heating resistor body of the element is divided into a plurality of unit blocks, and the average resistance value of a predetermined number of heating resistor elements in the unit block is measured during manufacture.

In addition, based on the difference between the measured average resistance value and the target resistance value, the amount of energization of a predetermined number of heat-generating resistance elements that causes heat generation to a predetermined number of resistance values of the average resistance value is predetermined for each unit block, respectively. The total calorific value when the resistance elements are energized matches the predetermined target calorific value.

Furthermore, when the thermal head is driven, the plurality of heat generating resistor elements of each unit block are driven with predetermined energization amounts for each unit block.

Therefore, in each unit block, assuming that the resistance values of a predetermined number of heat-generating resistive elements are all their average resistance values, the total heat generation of these predetermined number of heat-generating resistive elements is the same as the total heat generation of other unit blocks. , to drive a predetermined number of heating resistor elements. As a result, unit blocks with a low average resistance value have a shorter energization time than unit blocks with a high average resistance value.

The total calorific value of each unit block at this time is equal to the total calorific value when electricity is supplied to each unit block for the same period of time assuming that the average resistance value of each unit block is the target resistance value.

Therefore, when the thermal head is driven, the average resistance value of the predetermined number of heating resistance elements in each unit block appears to be uniformed to a target resistance value. In addition, the variation range of the resistance value of each heating resistor element of the heating resistor body based on the target resistance value is smaller than the variation range based on the average resistance value of all the heating resistor elements of the heating resistor body.

Therefore, compared with the case of driving each heating resistive element with a energization amount that matches the heat generation amount of all heating resistance elements with the target heat generation amount, the variation range of the energization amount of each heating resistance element can be reduced, and the total energization amount can be reduced. The aging non-uniformity of the heating resistance element caused by the difference becomes smaller.

In addition, since it is not necessary to measure the resistance value of the heat-generating resistive element or perform complicated energization control every time the thermal head is driven, the control method and control structure can be simplified.

Moreover, even without increasing the amount of trimming in the trimming process, the unevenness of the resistance value of each heating resistor element can be substantially reduced by the energization control, and therefore, the distortion of the heating resistor element due to the increase of the trimming amount can be prevented. Reduced durability.

Description of drawings

1 is a schematic cross-sectional view showing the internal structure of a stencil printing apparatus according to an embodiment of the present invention to which the thermal head system and the thermal head energization control method of the present invention are applied.

(a) in FIG. 2 is a plan view showing the thermal head unit of this embodiment, and (b) in the figure is a side view showing the thermal head unit in (a).

(a) in FIG. 3 is a plan view schematically showing a thermal head, (b) in the same figure is an X-X cross-sectional view of (a), and (c) is a diagram schematically showing the number of heating resistor elements.

FIG. 4 is a block diagram showing the energization amount control means of this embodiment.

FIG. 5 is a graph showing the difference in resistance value of each heating resistance element in the present embodiment.

FIG. 6 is a graph showing the amount of trimming when the resistance values of the heating resistor elements are equalized to a common target resistance value by trimming processing.

FIG. 7 is a process diagram showing a method of manufacturing the thermal head according to the present embodiment.

FIG. 8 is a cross-sectional view showing the progress of the manufacturing process of the thermal head according to the present embodiment step by step.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. In this embodiment, a case where the thermal head system and thermal head energization control method according to the present invention are applied to a plate making mechanism of thermal stencil base paper in a stencil printing apparatus will be described as an example. Note that in this embodiment, the case where the present invention is applied to a base paper plate making mechanism has been described, but the present invention is not limited thereto, and can also be used, for example, in a thermal recording device or a thermal transfer recording device. Such as all devices that apply a voltage to a heating resistor body in which a heating resistor element is arranged to generate heat for each heating resistor element.

(The overall structure of the stencil printing device)

FIG. 1 is a schematic cross-sectional view showing the internal structure of a stencil printing apparatus 1 according to this embodiment. In FIG. 1 , a stencil printing apparatus 1 is mainly composed of a document reading mechanism 2 , a plate making mechanism 3 , a printing mechanism 4 , a paper feeding mechanism 5 , a paper discharging mechanism 6 , a plate discharging mechanism 7 , and a control unit 8 for controlling the above mechanisms.

The printing mechanism 4 has a plate body 16 and a pressure roller 17 which are provided so that a part of the outer peripheral surfaces of the plate body 16 and the pressure roller 17 are slightly close to each other, and are each freely rotatable. A base paper clamping portion 18 is provided on the outer peripheral surface of the plate body 16 , and the front end of the stencil base paper is clamped by the base paper clamping portion 18 . In addition, a squeeze roller 47 as an outward pressing mechanism is provided at a position facing the pressure roller 17 on the inner peripheral surface of the plate body 16 . In addition, an open surface (effective printing surface) is formed on the outer peripheral surface of the plate body 16 , and a large number of holes are formed on the open surface, and ink is supplied from the inside of the plate body 16 to the outside through the open surface. In addition, the stencil base paper is wound on the outer peripheral surface, and the ink supplied between the opening portion of the outer peripheral surface and the stencil base paper is supplied to the outside only from the perforated surface of the stencil base paper.

The paper feeding mechanism 5 has: a paper feeding table 23, which stacks a plurality of printing paper 22 as a printing medium; a scraping part 24, which presses the printing paper 22 at the uppermost position of the paper feeding table 23; It is arranged downstream of the scraping part 24 and is located at a position slightly close to each other; the guide roller 27 and the timing roller 28 are arranged downstream of the pick-up roller 25 and is located at a position slightly close to each other. The printing paper supplied from the paper feed table 23 is pulled out by the scraper unit 24 and sent out to the pick-up roller 25 . The paper discharge mechanism 6 has: a paper stripping claw 32 that strips the printed printing paper 22 from the plate body 16; a paper transport mechanism 33 that transports the stripped printing paper 22; The printing paper 22 conveyed by the paper conveyance mechanism 33 is loaded in a stacked state.

The plate discharge mechanism 7 has: a plate discharge guide belt 35 that guides the front end of the stencil base paper 15 released from the base paper clamping portion 18 of the plate body 16; a plate discharge roller 36 that guides the plate discharge guide belt 35 The stencil base paper 15 is taken up and recovered while peeling off from the plate body 16; the pollution prevention guide 38 prevents the stencil base paper 15 from contacting the plate discharge roller 36 when the stencil base paper 15 is applied; the plate discharge box 37 accommodates the plate discharge roller 36 recycled stencil base paper 15.

The document reading mechanism 2 is a mechanism for optically reading a document by a scanner or the like through a lens, a CCD, or the like, and outputting it as an electrical signal. The read information is processed based on a predetermined command (enlargement, reduction, etc.), and sent to the plate making mechanism 3 . The plate-making mechanism 3 is a mechanism for making a plate on the strip-shaped base paper 10 based on the electrical signal read by the original document reading mechanism 2, and it has: a thermal head unit 12, which is arranged on the side of the strip-shaped base paper 10 wound on the roller. Downstream in the conveyance direction; platen roller 13 disposed facing the thermal head unit 12 ; and base paper cutter 14 disposed downstream in the conveyance direction of the elongated base paper 10 .

(Structure of thermal head)

(a) in FIG. 2 is a plan view showing the thermal head unit 12, and (b) in the figure is a side view showing the thermal head unit 12 of (a). As shown in FIGS. 2( a ) and ( b ), the thermal head unit 12 has a substrate 20 . On the lower surface side of the substrate 20, an aluminum heat radiation plate 121 and a connecting portion 122 are attached. An IC cover 123 is mounted on the upper surface side of the substrate 20 with nuts 124 . On the upper portion of the substrate 20, a thermal head 70 is formed.

(a) in FIG. 3 is a plan view schematically showing the thermal head 70, (b) in the same figure is an X-X cross-sectional view of (a), and (c) is a diagram schematically showing the number of heating resistor elements. As shown in FIGS. 3( a ) and ( b ), the thermal head 70 has an insulating substrate body 56 made of alumina ceramics as a base, and the upper surface of the substrate body is covered with a glass glaze layer 57 .

On the glaze layer 57, along the main scanning direction, a raised portion 57a having a linear shape in plan view is formed, and the raised portion 57a is formed so that its cross-sectional outer contour is slightly arc-shaped. A heating resistor 72 is provided on the top of the curved surface of the raised portion 57 a of the glaze layer 57 . The heat generating resistor 72 is configured by arranging a plurality of heat generating resistor elements 721 to 72n made of thin films in a line along the main scanning direction at predetermined intervals. In this embodiment, about 3600 heating resistor elements 721 to 72n are arranged as shown in FIG. 3( c ).

In addition, on both sides of the heating resistor 72 in the sub-scanning direction, conductive layers 64a and 64b made of aluminum or the like with a thickness of approximately 0.6 μm are electrically connected to the heating resistor elements 721 to 72n, and are formed on the glaze layer 57. . Moreover, in the thermal head 70, the protective layer 58 which covers the heating resistor 72 and each conductive layer 64a, 64b together is formed. In addition, common electrode portions 66 , 66 are arranged at both ends of the heating resistor 72 .

As shown in FIG. 3( a ), the heating resistor elements 721 to 72n are arranged at predetermined intervals in the longitudinal direction (main scanning direction) of the thermal head 70 , and a voltage is selectively applied thereto to control their heating respectively. The conductive layers 64a, 64b are made of metals such as silver (Ag), gold (Au), copper (Cu), nickel (Ni), tungsten (W), aluminum (Al), platinum (Pt), or metals containing them as main components. Alloys, or laminates of these metals and alloys. The uppermost protective layer 58 is formed to cover the common electrode portion 66 , the conductive layers 64 a , 64 b , and the heating resistor 72 .

(Electricity Control Mechanism)

The driving control of the thermal head of the present invention is performed by the control unit 8 described above. FIG. 4 is a block diagram showing mechanisms involved in drive control. Note that a "module" used in the description indicates a functional unit configured by hardware such as an apparatus or device, software having functions thereof, or a combination thereof, and realizing a predetermined operation.

As shown in FIG. 4 , the control unit 8 includes an energization amount control unit 81 and a correction data storage unit 84 as blocks related to drive control of the heating resistor elements 721 to 72n. The control unit 8 is connected to the external interface 83 and the user interface of the operation panel 80 , and inputs a signal from an external device connected to the external interface 83 or an operation signal based on a user operation from the operation panel 80 . In addition, the control unit 8 sends a control signal for controlling driving of plate making to the drive circuit 30 of the plate making mechanism 3 , the thermal head 70 , and the like.

The control unit 8 controls the heating resistor elements 721 to 72n of the heating resistor 72 for each unit block. Each unit block is formed by dividing the heat-generating resistive elements 721 to 72n into one of plural parts in the linear arrangement direction thereof, and each has a predetermined number of heat-generating resistive elements.

The energization amount control unit 81 is realized by, for example, an arithmetic processing device such as a CPU that performs various arithmetic processing. Here, it is a module having a function of reading from the correction data storage unit 84 when the thermal head 70 is driven during the plate making operation. The correction data is read out, and the respective heating resistor elements 721 to 72n are heated by the energization amount corresponding to the read correction data. In this embodiment, the amount of energization is adjusted by controlling the energization time to the heating resistance elements 721 to 72n, so that the energization amounts of the heating resistance elements 721 to 72n are different. Note that, as the adjustment of the energization amount, in addition to controlling the energization time, it is also possible to control the voltage or current so as to vary the energization amount.

The energization amount control unit 81 is connected to a correction data storage unit 84 , and the correction data storage unit 84 stores correction data for each of the above-mentioned unit blocks. The correction data for each of the unit blocks is created based on the flag value of each unit block input from the flag value storage unit 9 via the external I/F (interface) 83 . In the flag value storage unit 9 , the average resistance value of the heating resistance elements 721 to 72n belonging to each unit block is stored as the flag value of each unit block. The identification value of each unit block (the average resistance value of the heating resistor elements 721 to 72n belonging to each unit block) is based on each heating resistor element 721 measured by an external resistance value measuring device (not shown) when the thermal head 70 is manufactured. ~72n resistance value and made.

The correction data is based on the difference between the marker value of each of the unit blocks stored in the marker value storage unit 9 (the average resistance value of the heating resistance elements 721 to 72n belonging to each unit block) and a predetermined target resistance value. The data of each unit block calculated by the difference. In addition, the correction data of each unit block is data for correcting the energization amounts of the heating resistance elements 721 to 72n belonging to the unit block. The creation of the correction data may be performed by the flag value storage unit 9 , or may be performed using an arithmetic processing module of the device 1 .

(Creation of correction data)

Next, creation of correction data when manufacturing the above-mentioned thermal head will be described with reference to FIG. 5 . First, the heating resistance elements 721 to 72n of the present embodiment have a variation width W1 of resistance value shown in FIG. 5( a ).

Here, in order to control the energization amount of the heating resistor elements 721 to 72n, the resistance value of each heating resistor element 721 to 72n is substantially equal to the average resistance value of the average resistance values of all the heating resistor elements 721 to 72n, so that each When the heating values of the heating resistor elements 721 to 72n are the same, at least one heating resistor element needs to be corrected to correct the resistance value by W1/2 or more with respect to the normal energization amount.

In the energization control performed to make the heating values of the heating resistor elements 721 to 72n with different resistance values consistent within the variation width W1, there is a problem that a device for adjusting the energization time of the heating resistor elements 721 to 72n is required. , preprocessing such as measurement of the resistance value takes time, and a device for performing measurement is required, and the structure and control of the system become complicated. In addition, the heating resistor elements 721 to 72n that require energization control to increase the energization amount will deteriorate due to the difference in the total energization amount compared to the other heating resistor elements 721 to 72n that do not perform such energization control. difference is greater.

However, if the resistance values of all the heating resistor elements 721 to 72n are adjusted to a fixed target resistance value by increasing or decreasing the amount of trimming, as shown in FIG. Compared with the heating resistance elements 721 to 72n with a small amount of trimming, the degree of structural deterioration is greater and the lifetime is shorter.

On the other hand, for example, as shown in FIG. 5(b), if all the heating resistor elements 721-72n are divided into four unit blocks, and the average resistance values of the heating resistor elements 721-72n belonging to each unit block are respectively obtained, Then, the variation width W2 between the average resistance values of the unit blocks is smaller than the variation width W1 shown in FIG. 5( a ).

Therefore, in the present embodiment, assuming that an average resistance value is obtained from the actual resistance values of a predetermined number of heating resistor elements 721 to 72n belonging to each unit block, the following formula is determined for each unit block: The amount of electricity is a predetermined target heat generation amount which is the total heat generation amount of these predetermined number of heat generating resistance elements. Then, correction data for correcting the standard energization amount to the determined energization amount to drive a predetermined number of heating resistor elements corresponding to the unit block with the determined energization amount is stored in the correction data as correction data for each unit block. in the storage unit 84 .

By driving the predetermined number of heating resistor elements 721 to 72n corresponding to the unit block with the energization amount corrected by the correction data of each unit block determined in this way, as shown in FIG. The heating resistor elements 721 to 72n generate heat in the same state in which the average resistance value of the heating resistor elements 721 to 72n of each unit block is the same resistance value.

Note that the above target resistance value may be, for example, an intermediate value of the average resistance values of the four unit blocks, or a resistance value obtained by further averaging the four average resistance values. In addition, the target resistance value may be determined such that the maximum value of the difference from the average resistance value is minimized.

Next, refer to the process diagram of FIG. 7 and the cross-sectional view of FIG. Be explained.

As shown in the figure, first, in the manufacturing process of the glaze layer substrate in step S101, as shown in FIG. 8(b), on the substrate body 56 shown in FIG. Layer 57. At this time, on the upper surface of the glaze layer 57, a slightly arc-shaped raised portion 57a having a linear outer contour is formed. Next, as shown in FIG. 8( c ), in the heating resistor element film forming step S102 , the heating resistor 72 is formed on the glaze layer 57 . The heating resistor 72 is formed using, for example, a thin film forming technique such as vacuum deposition or sputtering. Then, in the photoprinting and etching process of step S103, the heat-generating resistor elements 721 to 72n formed into films are arranged at predetermined intervals in the longitudinal direction of the glaze layer 57 as shown in FIG. 3( a ) by photoprinting and etching.

Next, in the electrode layer film forming process of step S104, as shown in FIG. The conductive layer 64 can be formed by thin film forming techniques such as sputtering, or can be formed by a screen printing process. Next, in the photoprinting and etching process of step S105, patterning is performed by photoprinting and etching, and the conductive layer 64 in a desired region is removed. More specifically, as shown in FIG. 3( a ), the conductive layer 64 is removed by arranging at predetermined intervals in the longitudinal direction of the thermal head 70 and exposing the top regions of the heating resistors 72 . Through this step, the conductive layer 64 is electrically separated into the first conductive layer 64 a on the common electrode portion 66 side and the second conductive layer 64 b on the opposite side. Thereafter, in the protective film forming step of step S106, as shown in FIG. 8(e), a protective layer 58 is formed on the uppermost layer.

Then, the following heat treatment is performed. Specifically, in the annealing process of step S107, the entire heating resistor is heated. This annealing treatment eliminates local crystallization irregularities generated in the heating resistor 72 during the manufacturing process, and improves the crystallinity of all heating elements of the heating resistor 72, thereby stabilizing the film structure of the heating resistor elements 721 to 72n. After this annealing process, in the trimming process of step S108, trimming is performed to adjust the resistance value of each of the produced heating resistors 72 .

In this trimming process, the heating resistor elements 721 to 72n constituting each pixel are pulsed multiple times between the conductive layers 64a and 64b to change the resistance value of the heating resistor elements 721 to 72n, and the heating resistor elements 72. The resistance value at each point is adjusted to the desired resistance value. Note that in this embodiment, in this step S108, the degree of non-uniformity of the resistance value (the distribution width of the resistance value) can be greatly reduced to the degree shown in FIG. 5( a ).

Then, after the trimming process is completed in this way, the resistance value of the heating resistor 72 is measured (step S109 ), and the average resistance value per unit block is calculated ( S110 ). Note that, in this embodiment, as shown in FIG. 3( c ), there are 3,600 heating resistor elements 721 to 72n, which are divided into quarters to form a unit block. However, the equal numbers of the heating resistance elements 721 to 72n are not limited to quarters, but may be arbitrary. For example, the target change range of the resistance value of the heating resistance elements 721-72n in the unit block can be set first, and the range covered by the change range can be regarded as a unit block, thereby determining the heating resistance elements 721-72n in the unit block. quantity.

Next, based on the calculated average resistance value, the correction used for the energization control of each unit block to make the calculated average resistance value of each unit block substantially equal to a predetermined target resistance value during recording is prepared according to the method described above. data (S111). Note that, in this embodiment, the target resistance value is the lowest value among the average resistance values of the respective blocks, which is 2040Ω here.

Thereafter, the created correction data is sent from the flag value storage unit 9 to the stencil printing apparatus 1 through the external interface 83 of the control unit 8 and stored in the correction data storage unit 84 . Note that, although the creation of the correction data is performed by the flag value storage unit 9 here, it may also be performed using an arithmetic processing module of the stencil printing apparatus 1 .

(plate making action)

Next, the plate making operation of the stencil printing apparatus 1 having the above configuration will be described.

First, in the plate making mechanism 3 , the long base paper 10 is conveyed by the rotation of the platen roller 13 and the base paper feed roller, and sent out to the thermal head unit 12 . In the thermal head unit 12, based on the image information read by the document reading mechanism 2, the heating resistor elements 721 to 72n of the thermal head 70 selectively generate heat, thereby thermally perforating the strip-shaped base paper 10, thereby Stencil base paper 15 plates.

At this time, when the thermal head 70 is driven, the correction data is read from the correction data storage unit 84, and in the energization amount control unit 81, the energization time is adjusted to the energization amount corresponding to the read correction data, so that each heating resistor The elements 721 to 72n generate heat. Specifically, the correction data is created by calculating the average resistance value of each unit block based on the resistance value measured by the resistance value measuring device during the manufacturing process of the thermal head, so that the calculated average resistance value becomes a predetermined value. The target resistance value is created in units of unit blocks.

The energization amount control unit 81 analyzes the image data read by the document reading mechanism 2 to punch holes corresponding to non-blank portions of the printed image, and calculates the energization time of each pixel corresponding to the energization amount of each pixel. At this time, referring to the correction data, the energization time is stretched or contracted according to the resistance value of each heating resistance element 721 to 72n. Specifically, based on the resistance value ( FIG. 5( a )) measured during the manufacturing process by the resistance value measuring device, the average resistance value ( FIG. 5( b )) of each unit block is calculated, and when the thermal head 70 is driven, In order to make all the average resistance values of the unit blocks substantially coincide with the predetermined target resistance values, the energization amounts of the heat generating resistance elements 721 to 72n are corrected on a unit block basis. Note that this target resistance value is the lowest value among the average resistance values of the blocks, and in this embodiment, the target resistance value is 2040Ω.

Therefore, in controlling the energization of each of the heating resistor elements 721 to 72n based on the average resistance value of all the heating resistor elements 721 to 72n ( FIG. 5( a )), the resistance value variation width W1 of ±5% or more is corrected. The size of the energization produces unevenness in the correction range of the energization amount. On the other hand, according to the present embodiment, in order to make the average resistance value of each unit block coincide with the target resistance value, when energization control is collectively performed on the heating resistance elements belonging to the unit block, the unevenness of the energization amount correction width Since it is limited to correcting the magnitude of the average resistance value change width W2 of each unit block, it is small in this embodiment.

In addition, according to the corrected energization time, heating is performed by the thermal head, and punching is performed corresponding to the non-blank portion of the printed image, thereby performing plate making. Note that when printing is driven, the front end of the stencil base paper 15 after plate making is clamped by the base paper clamping part 18 of the plate body 16, and in this clamped state, the plate body 16 rotates to wind the stencil base paper 15 and install it on the plate. The outer peripheral surface of the body 16. Then, the printing paper 22 is pressed together with the plate body 16 and the stencil base paper 15 between the squeeze roller 47 and the pressure roller 17, and the ink from the perforated portion of the stencil base paper 15 is transferred on the printing paper 22 to print an image. .

(function and effect)

When manufacturing the thermal head 70, the average resistance value of the resistance values of the heating resistor elements 721 to 72n is calculated, and correction data for correcting the energization amounts of the heating resistor elements 721 to 72n for each unit block is prepared so that each unit block The heating resistor elements 721 to 72n of each unit block generate heat in a state where the average resistance value of the heating resistor elements 721 to 72n becomes a predetermined target resistance value. In addition, when the thermal head 70 is driven, the amount of energization (for example, energization time) to each of the heating resistance elements 721 to 72n is increased/decreased (expanded or contracted) according to the correction data. Therefore, there is no need to measure the resistance value of the heat-generating resistance elements 721 to 72n and control the energization time when the thermal head 70 is driven. Uneven or missing spots (not perforated).

In addition, according to this embodiment, when manufacturing the thermal head 70, the plurality of heating resistor elements 721 to 72n are divided into predetermined unit blocks, and the resistance value of each unit block is measured, and the average resistance value is calculated for each unit block. The amount of energization (for example, energization time) to each heating resistance element 721 to 72n is increased or decreased (expanded or contracted) so that the average resistance value of the block to which each element belongs becomes a predetermined target resistance value. Therefore, compared with the case where the average resistance value of all the heat generating resistance elements 721 to 72n is used as a reference, the variation range of the resistance value corrected by the energization amount control can be suppressed to a small range. Specifically, when the average resistance value of all the heating resistance elements 721 to 72n is used as a reference, as shown in FIG. However, in the present embodiment, as shown in FIG. 5( b ), it is only necessary to perform small energization amount control to correct the variation width W2 of the average resistance value of each unit block.

In addition, by correcting the energization amount in this way, the average resistance value of each unit block can be brought into the same state as the state where all the resistance values are substantially the same. The variation width of the resistance value of each unit block is kept below ±3%, which is the maximum value of the variation width W3 of the average resistance value of each unit block and the resistance value of the heating resistance elements 721 to 72n.

Thereby, without increasing the amount of trimming at the time of factory manufacture, it is possible to suppress a change in the amount of trimming at the time of driving while suppressing a change in the resistance value of each heating resistor element 721 to 72n.

Explanation of reference signs

1 Stencil printing device

2 Document reading mechanism

3 plate making institutions

4 printing mechanism

5 paper feeding mechanism

6 Exit Mechanism

7-version ejection mechanism

8 Control Department

9 Identification value storage unit

10 strips of base paper

12 thermal head unit

13 Platen Roller

14 base paper cutter

15 hole base paper

16 version

17 pressure roller

18 base paper clamping section

20 substrates

22 printing paper

23 paper table

24 Scraper

25 pick-up roller

27 guide roller

28 timing roller

30 drive circuit

32 Paper peeling claws

33 Paper conveying mechanism

34 Stacking section

35 layout leader

36 plate exit roller

37 edition output box

38 Pollution Prevention Guide

47 squeeze roller

56 Substrate body

57 glaze layers

57a Bump

58 protective layer

64 conductive layer

64a First conductive layer

64b Second conductive layer

66 Common electrode part

70 thermal head

72 Heating resistor

80 Operation panel

81 Electricity Control Unit

83 external interface

84 Correction data storage unit

121 aluminum exothermic plate

122 connection part

124 Nut

721～72n heating resistance element

Variation range of W1, W2, W3 resistance value

Claims (2)

1. a hot head system, has the linearly heating resistor that is arranged with multiple heating resistive elements, for by described heating resistor being switched on to make the heating of each heating resistive element,

Described heating resistor is divided into multiple units chunk by bearing of trend along described straight line, and constituent parts piece is made up of the described heating resistive element of predetermined quantity respectively,

Described hot head system comprises:

Energising amount storage part, its by described constituent parts piece store respectively that caloric value is consistent with predetermined target caloric value in order to make to add up to, the average electrical resistance of heating resistive element based on described predetermined quantity calculates with differing from of target resistance values, the energising amount relevant with the heating resistive element of described predetermined quantity, wherein, described total caloric value is the total caloric value to heating resistive element when energising using the average electrical resistance of the heating resistive element of described predetermined quantity as the described predetermined quantity of resistance value;

Energising amount control part, for in the time driving described heat, by each described constituent parts piece, drive respectively the heating resistive element of the described predetermined quantity of this units chunk with the energising amount of being stored in corresponding with described units chunk, described energising amount storage part, so that the total caloric value of this units chunk is identical with the total caloric value of other units chunk.

2. a conduction control method for heat head, this heat head has the linearly heating resistor that is arranged with multiple heating resistive elements, for by described heating resistor being switched on to make each heating resistive element heating,

Described heating resistor is divided into multiple units chunk by bearing of trend along described straight line, and constituent parts piece is made up of the described heating resistive element of predetermined quantity respectively,

Described conduction control method comprises:

In order to make to add up to caloric value consistent with predetermined target caloric value, the average electrical resistance of the heating resistive element based on described predetermined quantity and target resistance values poor, pre-determine respectively the energising amount relevant with the heating resistive element of described predetermined quantity by described constituent parts piece, wherein, described total caloric value is the total caloric value to heating resistive element when energising using the average electrical resistance of the heating resistive element of described predetermined quantity as the described predetermined quantity of resistance value;

In the time driving described heat, drive with heating resistive element corresponding with described constituent parts piece, the described predetermined quantity of predetermined energising amount to described constituent parts piece respectively, so that the total caloric value of this units chunk is identical with the total caloric value of other units chunk.